JP6018933B2 - Liquid supply apparatus, droplet discharge apparatus, and liquid filling method - Google Patents

Description

  The present invention relates to a liquid supply device, a droplet discharge device, and a liquid filling method, and more particularly to a liquid supply technique for filling a droplet discharge head such as an inkjet head with a liquid.

  An ink jet recording apparatus described in Patent Document 1 includes an ink supply channel that supplies ink to a common ink chamber of a recording head, and an ink discharge channel that discharges ink supplied to the common ink chamber. The ink discharged from the discharge channel is circulated through the ink supply channel. Further, in Patent Document 1, in the ink jet recording apparatus provided with the circulation supply system as described above, a pump (pressure variable means) is provided in the capping means for sealing the nozzles of the recording head. A method is described in which the recording head is filled with ink by reducing the pressure.

  On the other hand, an image forming apparatus described in Patent Document 2 includes a recording head that forms an image by ejecting ink onto a recording medium, a sealing member that contacts a nozzle of the recording head or close to the nozzle and seals the nozzle, and an ink flow. A suction pump that can make the passage a negative pressure higher than a predetermined value, a negative pressure tank that can maintain a negative pressure higher than a predetermined value, and air can be taken into the ink flow path after the negative pressure is higher than a predetermined value. Like the valve, it has a valve that can take in ink when the negative pressure is reached, and in order to remove bubbles in the ink flow path and the print head by a predetermined sequence, the ink flow path and the print head The ink is sucked in, and after a negative pressure of a predetermined level or more is reached, a predetermined air is taken into the ink channel from the valve to make the ink channel and the recording head have no ink. In addition, the recording head is sucked, ink is poured from a valve that can take in the ink after the negative pressure becomes equal to or higher than a predetermined level, and the ink is filled in the ink flow path and the recording head to recover the recording head. It has a recovery mechanism.

Japanese Patent Laid-Open No. 2006-256022 JP 2007-313817 A

  When the recording head is filled with ink, if the air bubbles are taken into the flow path in the head, the print quality is not stable, and much ink discharge and time are required to restore the drawing performance. Therefore, when the recording head is filled with ink by replacing the head or the like, it is desirable to fill the ink so that bubbles do not enter the head flow path.

  In the ink jet recording apparatus disclosed in Patent Document 1, a pump connected to the capping means is operated in the pressure reduction (suction) direction at the time of initial ink filling to reverse the normal ink discharge direction to the ink discharge channel of the ink circulation system. It is configured to flow ink in the direction.

  However, such a configuration requires a cap member and a suction pump separately for ink filling. For this reason, there is a problem that the cost is increased and the apparatus size is increased. In addition, there is a drawback that the ink discharge amount (waste liquid amount) at the time of filling is increased, and further, there is a possibility of entrainment of bubbles (air mixing) into the flow path in the head at the time of filling, and from the viewpoint of preventing bubble mixing However, no significant improvement can be expected.

  On the other hand, the image forming apparatus disclosed in Patent Document 2 also includes a separate suction pump, a negative pressure tank, an air flow path and a valve, and an ink flow path for ink filling in addition to the components of a normal ink supply system. It is necessary to provide a valve in the apparatus, which causes a problem that the cost is high and the apparatus size is increased.

  The above problem can be grasped as a common problem not only for ink jet devices used for printing but also for various droplet discharge devices using a droplet discharge head.

  The present invention has been made in view of such circumstances, and solves the above-described problems, suppresses increase in cost of the device, avoids enlargement of the device, and suppresses entrainment of bubbles in the flow path in the head. It is an object of the present invention to provide a liquid supply device, a droplet discharge device, and a liquid filling method that enable simple liquid filling that can ensure good discharge performance.

  In order to solve the above problems, the following aspects of the invention are provided.

  (First Aspect): A liquid supply apparatus according to a first aspect includes a tank for storing liquid, a supply-side flow path unit that supplies liquid from the tank to the droplet discharge head, and liquid from the droplet discharge head. A recovery-side flow path section to be recovered, a supply-side on-off valve capable of opening and closing the first flow path connected to the droplet discharge head of the supply-side flow path section, and a second flow connected to the droplet discharge head of the recovery-side flow path section A recovery-side on-off valve capable of opening and closing the path, a supply-side pressure adjusting unit for adjusting the pressure of the supply-side flow path unit, a recovery-side pressure adjusting unit for adjusting the pressure of the recovery-side flow path unit, a supply-side on-off valve, A recovery-side on-off valve, a supply-side pressure adjustment unit, and a control unit that controls the recovery-side pressure adjustment unit, and circulates and supplies liquid to the droplet discharge head when discharging droplets from the droplet discharge head A liquid supply device, wherein both the supply side on-off valve and the recovery side on-off valve are closed, and the supply side flow path section When performing initial filling of the liquid into the liquid droplet ejection head connected to the recovery side flow path section, the control unit is configured with the liquid droplet ejection port of the liquid droplet ejection head closed by the closing member. Open one of the supply-side on-off valve and the collection-side on-off valve, and reduce the pressure in the droplet discharge head using the open-side channel and pressure adjustment unit while the other on-off valve is closed. Then, the liquid supply device performs control to open the other on-off valve on the closed side and allow the liquid to flow into the droplet discharge head through the flow path interposed by the other on-off valve.

  According to the first aspect, the supply-side flow path portion, the recovery-side flow path portion, and the supply-side pressure used for circulating and supplying the liquid to the droplet discharge head when discharging the droplet from the droplet discharge head The adjustment unit and the recovery side pressure adjustment unit can be used to perform pressure reduction in the droplet discharge head and liquid filling after pressure reduction. Before the liquid is allowed to flow into the droplet discharge head, the air in the droplet discharge head can be discharged by reducing the pressure in the head using the flow path on either the supply side or the recovery side. Then, after the air in the head is discharged, the ink is introduced into the droplet discharge head through the other flow path, so that bubbles are prevented from being mixed into the head and satisfactory liquid filling is possible. According to this aspect, there is no need to separately provide a flow path or the like for pressure reduction in the head, and in addition to the structure of the flow path used for circulation supply, the additionally required closing member has a simple (inexpensive) structure. Therefore, an increase in cost can be suppressed and the size of the apparatus is not increased. Furthermore, since filling is performed using the circulation supply path during normal use, the amount of waste liquid waste during filling can be greatly reduced.

  (Second aspect): In the liquid supply apparatus according to the first aspect, when performing the initial filling, the control unit closes the supply-side on-off valve and the recovery-side on-off valve, and collects the supply-side pressure adjusting unit and the recovery side. The pressure of each of the supply side flow path section and the recovery side flow path section is set to a negative pressure using the side pressure adjustment section, and then either the supply side open / close valve or the recovery side open / close valve is set to It can be set as the structure which performs opening control.

  According to the second aspect, liquid does not flow into the droplet discharge head when one of the on-off valves is opened.

  (Third Aspect): In the liquid supply device according to the second aspect, when the controller performs pressure reduction, the pressure of the open-side channel portion of the supply-side channel portion and the recovery-side channel portion is reduced. However, the pressure can be controlled to be equal to the pressure of the channel portion on the closed side.

  Balance the pressure in the flow path used for pressure reduction in the head (path on the pressure reduction side) and the flow path used for filling liquid after pressure reduction in the head (path on the filling side). It is preferable to let it flow.

  The “equivalent” here is not limited to the case of being exactly equal, but includes a substantially equivalent range that can be regarded as substantially the same in terms of operational effects.

  (Fourth aspect): In the liquid supply device according to any one of the first to third aspects, the supply-side pressure adjusting unit can be driven in both directions of pressurization and depressurization of the supply-side flow path unit. A supply-side pump and a supply-side pressure detection unit for grasping the pressure in the supply-side flow channel unit are provided, and the recovery-side pressure adjustment unit can be driven in both directions of pressurization and depressurization of the recovery-side flow channel unit It can be set as the structure provided with the collection | recovery side pump and the collection | recovery side pressure detection part for grasping | ascertaining the pressure in the collection | recovery side flow-path part.

  By providing a pump and a pressure detector on each of the supply side and the recovery side, the pressure can be independently controlled on the supply side and the recovery side.

  (Fifth Aspect): In the liquid supply apparatus according to the fourth aspect, when performing the initial filling, the control unit opens the one on-off valve and performs pressure reduction, and then opens the other on-off valve on the closed side. When opening and letting liquid flow into the droplet discharge head, the supply-side pump and the recovery-side pump are controlled to drive the droplet discharge head in the opposite direction at the same speed. it can.

  It is also possible to fill the liquid droplet ejection head with a pressure difference between the flow path on the filling side that puts liquid into the liquid droplet ejection head and the flow path on the decompression side used for decompression in the head of the liquid droplet ejection head. However, highly accurate pressure control is required. The pressure reduction in the head and the pressure in the flow path on the filling side are controlled independently, and the filling side flow path and the internal flow path of the droplet discharge head are connected in a state where the pressure balance on both the pressure reduction side and the filling side is balanced. The liquid filling state quality is stabilized by opening (opening) and then filling the liquid into the droplet discharge head at a constant speed of the pump.

  The “same speed” here is not limited to the case of being exactly equal, but includes substantially the same range of ranges that can be regarded as substantially the same in terms of operational effects. There is a correlation between the pump speed (number of rotations) and the flow rate, and both pumps in the sense that the amount of liquid delivered by one pump of the supply side pump and the recovery side pump and the amount of fluid absorbed by the other pump are roughly balanced. Are driven in the reverse direction at the same speed. According to this aspect, the liquid can slowly flow into the droplet discharge head, and the effect of suppressing bubbles can be further enhanced.

  (Sixth aspect): In the liquid supply device according to the fourth aspect or the fifth aspect, each of the supply-side pump and the recovery-side pump has a multiple tube having a structure in which a plurality of tubes are arranged in different phases. It can be set as the structure which is a pump.

  According to the sixth aspect, the decompression capacity is high and the durability is excellent.

  (Seventh aspect): In the liquid supply device according to the fourth to sixth aspects, the supply-side pressure adjustment unit and the recovery-side pressure adjustment unit are respectively provided with a liquid chamber and a gas chamber with an elastic film inside the sealed container. It can be set as the structure provided with the pressure adjustment tank which has the structure divided into.

  According to the seventh aspect, pressure fluctuations due to fluctuations in the discharge amount of the liquid droplets from the liquid droplet discharge head and pulsations of the supply side and recovery side pumps can be suppressed by the action of the elastic film and the gas chamber, Stable pressure adjustment is possible.

  (Eighth aspect): In the liquid ejection device according to the seventh aspect, the pressure adjusting tank has a two-chamber configuration in which the gas chamber includes a first gas chamber and a second gas chamber, and the first gas chamber and the second gas chamber. A gas chamber split opening / closing mechanism that can open and close between the gas chambers is provided, and the control unit controls the gas chamber split opening / closing mechanism, and at least during the decompression operation during initial filling, the gas chamber split opening / closing mechanism is closed. It can be set as the structure.

  According to the eighth aspect, the pressure reduction in the head at the time of filling and the pressure control at the time of normal circulation supply can be achieved with a relatively small adjustment tank. At the time of pressure control during normal circulation supply, good damper performance is achieved by maintaining a state where the first gas chamber and the second gas chamber are open. On the other hand, when the liquid is initially filled in the droplet discharge head, the two chambers are closed.

  (Ninth aspect): In the liquid ejection apparatus according to the eighth aspect, the control unit pressurizes the liquid chamber once with the gas chamber dividing opening / closing mechanism opened before performing the pressure reducing operation, and the elastic film is deformed. A configuration in which the decompression operation is performed after the space between the first gas chamber and the second gas chamber is closed by closing the gas chamber dividing opening / closing mechanism after reducing the volume of the first gas chamber. it can.

  According to the eighth aspect, it is possible to prevent the elastic film from narrowing the liquid chamber during the pressure reducing operation, and the inside of the flow path can be set to a high negative pressure.

  (Tenth aspect): In the liquid supply apparatus according to any one of the first aspect to the ninth aspect, at least the droplet discharge head in each of the flow paths on the supply side and the recovery side with respect to the droplet discharge head The flow path on the pressure reduction side used for decompressing the inside may be configured to have a bubble discharge path for discharging bubbles in the flow path.

  According to the tenth aspect, by performing the bubble discharging operation using the bubble discharging path after filling, the bubbles in the flow path used for the pressure reduction in the head can be surely removed.

  (Eleventh aspect): In the liquid supply apparatus according to any one of the first aspect to the tenth aspect, the supply-side flow path section includes a supply-side manifold to which a plurality of droplet discharge heads are connected in parallel. The collection-side flow path section includes a collection-side manifold to which a plurality of droplet discharge heads are connected in parallel, and includes a supply-side opening / closing valve and a collection-side opening / closing valve for each of the plurality of droplet discharge heads. It can be configured.

  For example, in a wide line head bar in which a plurality of droplet discharge heads are arranged, only a part of the droplet discharge heads (head modules) that need to be replaced are replaced, and liquid can be easily applied to the replaced droplet discharge heads. Can be filled.

  (Twelfth aspect): A liquid droplet ejection apparatus according to a twelfth aspect includes the liquid supply apparatus according to any one of the first aspect to the eleventh aspect and a liquid droplet ejection head. It is.

  According to the twelfth aspect, high-quality liquid filling quality can be achieved at low cost.

  (Thirteenth aspect): The droplet discharge device according to the twelfth aspect includes a closing member that closes a droplet discharge port of the droplet discharge head, and the blocking member is a rubber sheet member. can do.

  (14th aspect): In the liquid droplet ejection apparatus according to the 12th aspect or the 13th aspect, a long line head bar is formed by connecting a plurality of liquid droplet ejection heads, and each of the plurality of liquid droplet ejection heads. Is an independently replaceable head module. When at least one of the plurality of droplet discharge heads is replaced, initial replacement of the new droplet discharge head after replacement is performed. It is possible to adopt a configuration in which control at the time is performed.

  (15th aspect): In the liquid droplet ejection apparatus according to the 14th aspect, the closing member is a member having a size that covers at least the liquid droplet ejection surface of the new liquid droplet ejection head after replacement. Can do.

  (Sixteenth aspect): A liquid filling method according to a sixteenth aspect includes a droplet discharge head, a tank for storing a liquid to be supplied to the droplet discharge head, and a supply for supplying the liquid from the tank to the droplet discharge head. Side flow path section, recovery side flow path section for recovering liquid from the liquid droplet ejection head, supply side on-off valve capable of opening and closing the first flow path connected to the liquid droplet ejection head of the supply side flow path section, and the recovery side A collection-side on-off valve that can open and close the second channel connected to the droplet discharge head of the channel unit, a supply-side pressure adjusting unit that adjusts the pressure of the supply-side channel unit, and the pressure of the recovery-side channel unit An initial liquid filling method for a droplet discharge head in a droplet discharge apparatus including a recovery-side pressure adjustment unit, the supply-side on-off valve and the recovery-side on-off valve being both closed with respect to the droplet discharge head A head connection step in which the supply-side flow path portion and the recovery-side flow path portion are connected to each other. Under the state where the droplet discharge port of the droplet discharge head is closed by the closing member, one of the supply-side on-off valve and the collection-side on-off valve is opened, and the other on-off valve is kept closed. After reducing the pressure inside the droplet discharge head using the flow path section and pressure adjusting section on the open side, and after the pressure reducing section in the head, the other on-off valve on the closed side is opened, And a filling step of flowing a liquid into the droplet discharge head through a flow path in which an on-off valve is interposed.

  (Seventeenth aspect): In the liquid filling method according to the sixteenth aspect, the supply side on-off valve and the recovery side on-off valve are both closed, and the supply side pressure adjusting part and the recovery side pressure adjusting part are used to supply It is possible to have a configuration in which an in-channel decompression step for setting each pressure of the channel portion and the recovery side passage portion to a negative pressure is performed, and the in-head decompression step is performed after the in-channel decompression step.

  (Eighteenth aspect): In the liquid filling method according to the seventeenth aspect, in the pressure reducing step in the head, the pressure of the open-side flow path part of the supply-side flow path part and the recovery-side flow path part is closed. It can be set as the structure which pressure-reduces so that it may become equivalent to the pressure of the flow-path part of an as-is side.

  (Nineteenth aspect): In the liquid filling method according to any one of the sixteenth aspect to the eighteenth aspect, the droplet discharge device includes a plurality of droplet discharge heads, and the plurality of droplet discharge heads are joined together. The long line head bar is configured, and each of the plurality of droplet discharge heads is an independently replaceable head module, and at least one of the plurality of droplet discharge heads is replaced. At this time, it is possible to perform the initial filling by performing the in-head decompression step and the filling step for the new droplet discharge head after the replacement.

  According to the present invention, an increase in the cost of the apparatus and an increase in the size of the apparatus are avoided, and bubbles are prevented from being entrained in the flow path in the head when the liquid is filled at the time of replacing the head, thereby realizing a good liquid filling. And stable discharge performance can be achieved. Moreover, the amount of liquid waste at the time of filling can be significantly suppressed.

Configuration diagram showing overall configuration of inkjet recording apparatus A perspective view showing a configuration example of an inkjet head Partial enlarged view of inkjet head viewed from nozzle side Plane perspective view of the head module An enlarged view of a part of FIG. 4A Longitudinal sectional view showing the internal structure of the head module Schematic configuration diagram of ink supply unit Flow chart showing the procedure at the time of initial filling with the head module replacement work Schematic diagram showing how the head module is replaced Schematic diagram showing the flow path decompression process Schematic diagram showing the state of the in-head decompression process Schematic showing the state of ink filling (filling process) Schematic diagram showing the configuration of the pressure adjustment tanks provided on the supply side and the recovery side, respectively. Explanatory drawing of the bubble discharge operation | movement in a flow path performed after ink filling (the 1) Explanatory drawing of the bubble discharge operation (the 2) in a flow path performed after ink filling The block diagram which shows schematic structure of the control system of the ink supply apparatus shown to this example Block diagram showing the configuration of the control system of the ink jet recording apparatus Schematic diagram showing another embodiment

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Overall configuration of inkjet recording apparatus]
First, the overall configuration of an ink jet recording apparatus to which the present invention is applied will be described. FIG. 1 is a configuration diagram showing the overall configuration of an ink jet recording apparatus according to an embodiment of the present invention. As shown in the figure, the ink jet recording apparatus 10 according to the present embodiment mainly includes a paper feeding unit 12, a processing liquid application unit 14, a drawing unit 16, a drying unit 18, a fixing unit 20, and a discharge unit 22. The

<Paper Feeder>
The paper supply unit 12 is a mechanism that supplies a sheet 24 as a recording medium to the processing liquid application unit 14. Sheets 24 that are sheets are stacked on the sheet feeding unit 12. The paper feed unit 12 is provided with a paper feed tray 50, and the paper 24 is fed from the paper feed tray 50 to the processing liquid application unit 14 one by one.

  As the paper 24 as a recording medium, general-purpose printing paper (paper mainly composed of cellulose) is used. Note that the type of the recording medium is not limited to this. In this example, a sheet (cut paper) is used, but a configuration in which a roll paper is cut to a required size and fed is also possible.

<Processing liquid application part>
The processing liquid application unit 14 is a mechanism that applies the processing liquid to the recording surface of the paper 24. The treatment liquid includes a color material aggregating agent that agglomerates the color material (pigment in this example) provided in the drawing unit 16. And the solvent are promoted.

  As shown in FIG. 1, the treatment liquid application unit 14 includes a paper supply drum 52, a treatment liquid drum 54, and a treatment liquid application device 56. The treatment liquid drum 54 is a drum that holds the sheet 24 and rotates and conveys the sheet 24. The treatment liquid drum 54 is provided with a claw-shaped holding means (gripper) 55 on its outer peripheral surface, and the paper 24 is sandwiched between the claw of the holding means 55 and the peripheral surface of the treatment liquid drum 54 so that the front end of the paper 24 is moved. It can be held. The treatment liquid drum 54 may be provided with suction holes on the outer peripheral surface thereof and connected to suction means for suction from the suction holes. As a result, the sheet 24 can be held in close contact with the peripheral surface of the treatment liquid drum 54.

  A processing liquid coating device 56 is provided outside the processing liquid drum 54 so as to face the peripheral surface thereof. The treatment liquid coating device 56 is disposed on the treatment liquid container in which the treatment liquid is stored, the anix roller partially immersed in the treatment liquid in the treatment liquid container, and the sheet 24 on the anix roller and the treatment liquid drum 54. It is composed of a rubber roller that is in pressure contact and transfers the measured processing liquid to the paper 24. According to the processing liquid application device 56, the processing liquid can be applied to the paper 24 while being measured.

  The sheet 24 to which the processing liquid is applied by the processing liquid applying unit 14 is transferred from the processing liquid drum 54 to the drawing drum 70 of the drawing unit 16 via the intermediate transport unit 26.

<Drawing part>
The drawing unit 16 includes a drawing drum 70, a paper holding roller 74, and ink jet heads 72M, 72K, 72C, 72Y. The drawing drum 70 includes a claw-shaped holding means (gripper) 71 on the outer peripheral surface thereof, like the processing liquid drum 54. The paper 24 fixed to the drawing drum 70 is conveyed with the recording surface facing outward, and ink is applied to the recording surface from the inkjet heads 72M, 72K, 72C, 72Y.

  The inkjet heads 72M, 72K, 72C, 72Y function as a droplet discharge head in the droplet discharge device. Each of the inkjet heads 72M, 72K, 72C, and 72Y is a line head having a length corresponding to the width of the paper 24. On the ink ejection surface, a nozzle row in which a plurality of nozzles for ink ejection are arranged over the entire width of the image forming area is formed. Each inkjet head 72M, 72K, 72C, 72Y is installed so as to extend in a direction orthogonal to the conveyance direction of the paper 24 (the rotation direction of the drawing drum 70).

  The droplets of the corresponding color ink are ejected from the respective ink jet heads 72M, 72K, 72C, 72Y toward the recording surface of the paper 24 held tightly on the drawing drum 70, so that the processing liquid application unit 14 in advance. The ink comes into contact with the treatment liquid applied to the recording surface, and the color material (pigment) dispersed in the ink is aggregated to form a color material aggregate. Thereby, the color material flow on the paper 24 is prevented, and an image is formed on the recording surface of the paper 24.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special colors are used as necessary. Ink may be added. For example, it is possible to add an inkjet head that ejects light-colored ink such as light cyan and light magenta, and the arrangement order of the inkjet heads for each color is not particularly limited.

  The sheet 24 on which an image is formed by the drawing unit 16 is transferred from the drawing drum 70 to the drying drum 76 of the drying unit 18 via the intermediate conveyance unit 28.

<Dry section>
The drying unit 18 is a mechanism for drying moisture contained in the solvent separated by the color material aggregating action, and includes a drying drum 76 and a solvent drying device 78 as shown in FIG.

  Similar to the treatment liquid drum 54, the drying drum 76 includes a claw-shaped holding unit (gripper) 77 on the outer peripheral surface thereof, and the holding unit 77 can hold the leading end of the paper 24.

The solvent drying device 78 is disposed at a position facing the outer peripheral surface of the drying drum 76, and hot air jets disposed between a plurality of IR heaters (Infrared Radiation heaters) 82 and each IR heater 82. And a nozzle 80.

  Various drying conditions can be realized by appropriately adjusting the temperature and air volume of the hot air blown toward the paper 24 from each hot air jet nozzle 80 and the temperature of each IR heater 82. Drying is promoted by heating from the back side of the paper 24, and image destruction during fixing can be prevented.

  Holding on the outer peripheral surface of the drying drum 76 so that the recording surface of the paper 24 faces outward (that is, in a state in which the recording surface of the paper 24 is curved so as to be convex), and drying while rotating and transporting. Accordingly, the occurrence of wrinkles and floating of the paper 24 can be prevented, and drying unevenness caused by these can be surely prevented.

  The paper 24 that has been dried by the drying unit 18 is transferred from the drying drum 76 to the fixing drum 84 of the fixing unit 20 via the intermediate conveyance unit 30.

<Fixing part>
The fixing unit 20 includes a fixing drum 84, a halogen heater 86, a fixing roller 88, and an inline sensor 90. Like the processing liquid drum 54, the fixing drum 84 includes a claw-shaped holding unit (gripper) 85 on its outer peripheral surface, and the holding unit 85 can hold the leading end of the sheet 24.

  By the rotation of the fixing drum 84, the paper 24 is conveyed with the recording surface facing outward. The recording surface is preheated by the halogen heater 86, fixing processing by the fixing roller 88, and inspection by the inline sensor 90. Is done.

  The fixing roller 88 is a roller member for heating and pressurizing the dried ink to weld the self-dispersing thermoplastic resin fine particles in the ink to form a film of the ink, and is configured to heat and press the paper 24. Is done. Specifically, the fixing roller 88 is disposed so as to be in pressure contact with the fixing drum 84, and constitutes a nip roller with the fixing drum 84. As a result, the sheet 24 is sandwiched between the fixing roller 88 and the fixing drum 84, nipped at a predetermined nip pressure, and a fixing process is performed. The unevenness of the image surface is leveled by the fixing process, and glossiness is obtained.

  In the embodiment of FIG. 1, only one fixing roller 88 is provided. However, a configuration in which a plurality of fixing rollers 88 are provided may be employed depending on the thickness of the image layer and the Tg characteristics of the thermoplastic resin fine particles.

  In addition, in the case of using ultraviolet (UV) curable ink, instead of or in combination with the fixing roller 88 for heat fixing, ultraviolet (active light) such as a UV lamp or an ultraviolet LD (laser diode) array is used. Means for irradiating are provided. After sufficiently evaporating moisture in the drying unit 18, the UV curable monomer in the ink is cured and polymerized by irradiating the image with ultraviolet rays in the fixing unit equipped with ultraviolet irradiation means, thereby improving the image strength. Can do.

  On the other hand, the in-line sensor 90 is a measuring means for measuring a check pattern, moisture content, surface temperature, glossiness, etc. for an image (including a test chart) recorded on the paper 24, and a CCD line sensor or the like is applied. Is done.

<Discharge unit>
As shown in FIG. 1, a discharge unit 22 is provided following the fixing unit 20. The discharge unit 22 includes a discharge tray 92, and a transfer drum 94, a conveyance belt 96, and a tension roller 98 are provided between the discharge tray 92 and the fixing drum 84 of the fixing unit 20 so as to be in contact therewith. It has been. The sheet 24 is sent to the conveying belt 96 by the transfer drum 94 and discharged to the discharge tray 92.

<Other configuration>
Although not shown in FIG. 1, the inkjet recording apparatus 10 of this example includes an ink supply unit that supplies ink to the inkjet heads 72M, 72K, 72C, and 72Y, and the inkjet heads 72M and 72K, in addition to the above configuration. , 72C, 72Y, etc. are provided.

<Configuration of inkjet head>
Next, the configuration of the inkjet heads 72M, 72K, 72C, 72Y will be described. The ink jet heads 72M, 72K, 72C, 72Y of the present embodiment are constituted by line heads having a length corresponding to the paper width. Since each inkjet head 72M, 72K, 72C, 72Y has the same configuration, the configuration of the inkjet head 72 will be described here. In addition, the ink jet heads 72M, 72K, 72C, and 72Y will be described as the ink jet head 72 unless otherwise specified.

  FIG. 2 is a perspective view of the inkjet head 72 used in this embodiment. FIG. 2 shows a state in which the nozzle surface (droplet discharge surface) is looked up from below the head (obliquely downward direction). FIG. 3 is a partially enlarged view of the inkjet head 72 as viewed from the nozzle surface side. As shown in the figure, the inkjet head 72 is formed by connecting a plurality of head modules 72-i (i = 1, 2,..., N) along the longitudinal direction (paper width direction orthogonal to the conveyance direction of the paper 24). It is configured as an elongated full line type line head bar (page wide head of a single pass printing method). “I” represents a module number corresponding to the arrangement order of the head modules. “N” is an integer of 2 or more and represents the number of head modules. Here, an example in which 17 (n = 17) head modules 72-i are connected is shown. However, the number and arrangement of the head modules constituting the line head bar, and the structure of each head module are illustrated. It is not limited to the example. Reference numeral 73 in FIG. 2 denotes a base frame (housing for constituting a bar-shaped line head) serving as a frame for fixing a plurality of head modules 72-i, and reference numeral 75 denotes each head module 72-i. It is the flexible substrate connected to.

  Each head module 72-i is attached to and integrated with the base frame 73 to constitute one inkjet head 72. Each head module 72-i is supported by the head module support member 72 </ b> B from both sides of the inkjet head 72 in the short direction, and is detachably attached to the base frame 73. Each head module 72-i can be replaced individually. Each head module 72-i (i = 1, 2,..., N) corresponds to a “droplet discharge head”.

  As shown in FIG. 3, a plurality of nozzles are arranged in a matrix on the nozzle surface 72A of each head module 72-i (n-th head module 72-n). In FIG. 3, an oblique solid line denoted by reference numeral 151A represents a nozzle row in which a plurality of nozzles are arranged in a row.

  FIG. 4A is a plan perspective view of the head module. FIG. 4B is an enlarged view of a part thereof. In order to increase the dot pitch formed on the paper 24, it is necessary to increase the nozzle pitch in the inkjet head 72. In the head module 72-i of this example, as shown in FIGS. 4A and 4B, nozzles 151 (corresponding to “droplet discharge ports”) as ink discharge ports are arranged in a matrix (two-dimensionally). This structure has a high density of substantial nozzle intervals (projection nozzle pitch) projected so as to be aligned along the longitudinal direction of the inkjet head (direction perpendicular to the conveyance direction of the paper 24; main scanning direction). Has been achieved.

  In the example of FIGS. 4A and 4B, the plurality of nozzles 151 are arranged at a constant pitch d along the direction of the angle θ with respect to the main scanning direction, and are projected so as to be aligned in the main scanning direction (orthographic projection). The nozzle pitch P is d × cos θ, and in the main scanning direction, each nozzle 151 can be handled equivalently as a linear array with a constant pitch P.

  The nozzle arrangement structure is not limited to the illustrated example, and various nozzle arrangement structures such as an arrangement structure having one nozzle row in the sub-scanning direction can be applied.

  By connecting a plurality of such head modules 72-i in the paper width direction (main scanning direction) (see FIG. 1), a nozzle row that covers the entire drawing range for the paper width is formed, and one drawing scan is performed. Thus, a full-line head capable of recording an image with a predetermined recording resolution (for example, 1200 dpi) is configured.

  FIG. 5 is a longitudinal sectional view showing the internal structure of the head module. As shown in the figure, the pressure chamber 152 is formed as a rectangular parallelepiped space, and a nozzle channel 154 communicates with one corner of the bottom surface. The nozzle channel 154 extends vertically downward from the pressure chamber 152 and communicates with the nozzle 151.

  The ceiling wall surface of the pressure chamber 152 is composed of a diaphragm 155 and is formed to be able to bend and deform in the vertical direction. A piezoelectric element (piezo element) 156 is attached on the diaphragm 155, and the diaphragm 155 is deformed in the vertical direction by the piezoelectric element 156. The diaphragm 155 is deformed in the vertical direction, so that the volume of the pressure chamber 152 expands and contracts (expands / contracts), and ink is ejected from the nozzle 151.

  The piezoelectric element 156 is driven by applying a predetermined drive voltage between an individual electrode (not shown) provided on the piezoelectric element 156 and a diaphragm 155 acting as a common electrode, whereby the diaphragm 155 is driven. Deforms vertically.

  An individual supply channel 157 </ b> A for supplying ink to the pressure chamber 152 is communicated with one corner of the ceiling wall of the pressure chamber 152. The individual supply channel 157A communicates with the common supply channel 158A.

  The common supply flow path 158A is provided in units of rows of nozzles 151 arranged with a predetermined inclination with respect to the transport direction of the paper 24. Ink is supplied to the pressure chambers 152 of the nozzles 151 belonging to each row from the common supply channel 158A via the individual supply channel 157A.

  The common supply flow path 158A of each column communicates with an ink supply flow path (not shown), and the ink supply flow path communicates with an ink supply port (not shown). Ink from the ink tank is supplied to the ink supply port. The ink supplied to the ink supply port is supplied to the common supply channel 158A of each column via the ink supply channel, and further supplied to each pressure chamber 152 via the individual supply channel 157A.

  One end of an individual recovery channel 157B communicates with the nozzle channel 154. The individual recovery channel 157B communicates with the nozzle channel 154 at a position near the nozzle 151. The other end of the individual recovery channel 157B communicates with the common recovery channel 158B.

  Similar to the common supply channel 158A, the common recovery channel 158B is provided in units of rows of nozzles 151 arranged with a predetermined inclination with respect to the transport direction of the paper 24. The common recovery flow path 158B of each row communicates with an ink recovery flow path (not shown). The ink recovery channel communicates with an ink recovery port (not shown).

  A part of the ink flowing through each nozzle channel 154 flows to the individual recovery channel 157B and is recovered to the common recovery channel 158B. Then, the ink is recovered from each common recovery channel 158B to the ink tank via the ink recovery channel and the ink recovery port. That is, in the ink jet head of the present embodiment, ink is circulated and supplied to each head module 72-i.

<Ink supply unit>
Next, the configuration of the ink supply unit will be described. The ink supply unit corresponds to a “liquid supply device”, and the inkjet recording device 10 corresponds to a “droplet discharge device”. The ink supply unit is configured by an ink supply device having an ink supply function for supplying ink to the inkjet head 72 and an ink recovery function for recovering ink from the inkjet head 72, and supplying liquid circulation in the inkjet recording apparatus 10. Functions as a means.

  FIG. 6 is a configuration diagram of a circulation supply type ink supply apparatus applied to the ink jet recording apparatus according to the present embodiment. The figure shows an ink supply system for one inkjet head (for one color). That is, the ink supply device 200 is provided for each color ink jet head, and ink is individually supplied for each ink jet head.

  As described above, the ink jet head 72 of the present embodiment is configured by connecting a plurality of head modules 72-i. Each head module 72-i is independent. For this reason, an ink circulation piping path for supplying ink equally (constant pressure, constant flow rate) to each head module 72-i is formed.

  As shown in FIG. 6, the head module 72-i is provided with an ink supply port 212A through which ink flows and an ink recovery port 212B through which ink is discharged.

  A tip of a supply side branch pipe 216 branched from the supply side manifold 214 is attached to the ink supply port 212A, and a tip of a recovery side branch pipe 220 branched from the recovery side manifold 218 is attached to the ink recovery port 212B. Yes. That is, the supply side manifold 214 and the recovery side manifold 218 are provided with as many branch pipes (supply side branch pipes 216 and recovery side branch pipes 220) as the number of head modules 72-i installed, and a plurality of head modules 72-i. Are connected in parallel between the supply side manifold 214 and the recovery side manifold 218 via corresponding branch pipes (216, 220).

  When drawing is performed by ejecting ink from the ink-jet head 72, the ink supplied to the supply-side manifold 214 is supplied to each head module 72-i at a predetermined pressure Pin and a predetermined flow rate. In addition, the ink supplied to the head module 72-i is recovered from the head module 72-i to the recovery side manifold 218 at a predetermined pressure Pout and a predetermined flow rate. .

  A pressure difference ΔP is generated in the head module 72-i by the pressure Pin of the supply side manifold 214 and the pressure Pout of the recovery side manifold 218. As a result, the ink supply port 212A and the ink recovery port 212B are generated in the head module 72-i. An ink flow is generated between the head module 72-i and the ink flow is always supplied to the head module 72-i. A back pressure Pnzl that depends on the pressure Pin 214 of the supply side manifold 214 and the pressure Pout of the recovery side manifold 218 is applied to the nozzle that is an ink ejection port (ejection port).

  Each supply side branch pipe 216 has a supply side valve 222 and a supply side sub-damper 224 interposed therebetween. Further, a recovery side valve 226 and a recovery side sub-damper 227 are interposed in the recovery side branch pipe 220, respectively. The supply side valve 222 and the recovery side valve 226 are opened and closed when the head module 72-i needs to be individually operated, and when starting circulation of ink to the head module 72-i or When it ends, it is opened and closed.

  The supply side branch pipe 216 corresponds to a “first flow path”, and the supply side valve 222 corresponds to a “supply side on-off valve”. The recovery side branch pipe 220 corresponds to a “second flow path”, and the recovery side valve 226 corresponds to a “recovery side on-off valve”.

  The supply-side sub-damper 224 has a role of relieving pressure fluctuations or the like when the ink supplied from the supply-side manifold 214 flows, and the recovery-side sub-damper 227 is used when the ink recovered to the recovery-side manifold 218 flows. It has a role to relieve pressure fluctuations.

  One end of the supply pipe 228 of the ink circulation piping system is attached to one end in the longitudinal direction (the right end in FIG. 6) of the supply side manifold 214. On the other hand, one end portion of the recovery pipe 230 of the ink circulation piping system is attached to one end portion in the longitudinal direction (right end portion in FIG. 6) of the recovery side manifold 218.

  In addition, a first bypass channel 232 and a second bypass channel 234 are provided between the other end portions (the left end portion in FIG. 6) of the supply side manifold 214 and the recovery side manifold 218. A first bypass valve 236 is interposed in the first bypass flow path 232. A second bypass valve 238 is interposed in the second bypass channel 234. The first bypass channel 232 and the second bypass channel 234 are used for adjusting the pressure and flow rate between the supply side manifold 214 and the recovery side manifold 218.

  Further, a supply-side pressure sensor 240 and a recovery-side pressure sensor 242 are attached to the other ends of the supply-side manifold 214 and the recovery-side manifold 218, respectively, and the ink pressure in the supply-side manifold 214 and the recovery-side manifold 218 is attached. Is monitoring. The supply side pressure sensor 240 corresponds to a “supply side pressure detection unit”, and the recovery side pressure sensor 242 corresponds to a “recovery side pressure detection unit”.

  The other end of the supply pipe 228 connected to the supply side manifold 214 is connected to a supply side pressure adjustment tank 244 that functions as a supply side main damper. The supply-side pressure adjustment tank 244 has a structure in which the sealed container is divided into an ink chamber 244B and a gas chamber 244C by an elastic film 244A. That is, the supply-side pressure adjustment tank 244 is divided into two chambers that are partitioned by an elastic film made of a thin film member having elasticity, one of which is an ink chamber 244B and the other is a gas chamber 244C (“first chamber”). Equivalent to “gas chamber”).

  One end of a supply-side main pipe 248 for drawing ink from the buffer tank 246 (and collecting it into the buffer tank 246) is connected to the ink chamber 244B. The opening at the other end of the supply side main pipe 248 is immersed in the ink stored in the buffer tank 246.

  In the supply side main pipe 248, a deaeration module 250, a one-way valve 252, a supply side filter 254, a supply side pump 256, and an ink temperature adjuster 258 are interposed in order from the buffer tank 246 to the supply side pressure adjustment tank 244. ing. The ink temperature adjuster 258 includes a heat exchanger and is connected to the chiller 259.

  The ink stored in the buffer tank 246 is supplied to the supply-side pressure adjustment tank 244 by the driving force of the supply-side pump 256, and air bubbles are removed from the ink along the way, dust is removed, and the ink temperature is controlled. ing.

  The inlet side of the supply side pump 256 is connected to one end of the branch pipe 253 separately from the supply side main pipe 248, and the other opening of the branch pipe 253 is ink stored in the buffer tank 246 via the one-way valve 255. Soaked in

  As the supply-side pump 256, a pump that can be driven and controlled in both a pressurizing direction for sending ink toward the supply-side manifold 214 and a decompression direction for drawing out ink from the supply-side manifold 214 is used. The structure of the pump is not particularly limited, but the supply-side pump 256 applied in the present embodiment is a tube pump using a stepping motor (the tube having elasticity is rotatively driven by the stepping motor and the ink in the tube is removed). Supply). The supply-side pump 256 is a multiple-type tube pump (multiple-tube) having a structure in which tubes having a small inner diameter (for example, an inner diameter of 3 mm or less) and a thick wall (for example, a tube thickness of 1 mm or more) are arranged in different phases. It is preferable to use a tube pump. By supplying or sucking the liquid by the supply side pump 256, the supply side flow path including the supply side manifold 214 is pressurized or depressurized.

  While monitoring the pressure in the supply side manifold 214 by the supply side pressure sensor 240, the drive direction and speed (rotation speed) of the supply side pump 256 are controlled. As described above, since it is required to accurately drive and control both the forward direction and the reverse direction, the above-described multiple-type tube pump is preferable.

  An open pipe 260 is attached to the gas chamber 244 </ b> C of the supply side pressure adjustment tank 244. In the open pipe 260, an air connect valve 262 (corresponding to a “gas chamber split opening / closing mechanism”), an air tank 264 (corresponding to a “second gas chamber”), and an air release valve 266 are interposed.

  The ink chamber 244B is connected to one end of the drain pipe 268. The opening at the other end of the drain pipe 268 is immersed in the ink stored in the buffer tank 246. A supply side drain valve 270 is interposed in the drain pipe 268.

  The supply-side pressure adjustment tank 244 has a function of adjusting and maintaining the pressure in the ink chamber 244B to a desired value by the action of the gas chamber 244C and the elastic film 244A.

  On the other hand, the other end of the recovery pipe 230 connected to the recovery side manifold 218 is connected to a recovery side pressure adjustment tank 272 that functions as a recovery side main damper. The structure of the recovery side pressure adjustment tank 272 is the same as the structure of the supply side pressure adjustment tank 244, and the sealed container is partitioned by an elastic film 272A, and is divided into an ink chamber 272B and a gas chamber 272C by the elastic film 272A. Have The ink chamber 272B corresponds to a “liquid chamber”, and the gas chamber 272C corresponds to a “first gas chamber”.

  One end of a recovery side main pipe 274 for drawing ink from the buffer tank 246 (and drawing from the buffer tank 246) is connected to the ink chamber 272B.

  The other end of the recovery-side main pipe 274 is connected to the branch pipe 275 and is connected to the buffer tank 246 through the branch pipe 275. A one-way valve 276 is interposed in the recovery side main pipe 274, and the ink in the recovery side pressure adjustment tank 272 is recovered to the buffer tank 246 by the driving force of the recovery side pump 280.

  Similar to the supply-side pump 256, the recovery-side pump 280 is a pump that can be driven and controlled in both the pressurizing direction for sending ink toward the collecting-side manifold 218 and the depressurizing direction for drawing ink from the collecting-side manifold 218. It has been. The recovery side pump 280 of this example is configured by a multiple tube pump similar to the supply side pump 256. By feeding or sucking the liquid by the collection side pump 280, the supply side flow path including the collection side manifold 218 is pressurized or depressurized.

  An open pipe 282 is attached to the gas chamber 272 </ b> C of the recovery side pressure adjustment tank 272. The open pipe 282 includes an air connect valve 284 (corresponding to a “gas chamber split opening / closing mechanism”), an air tank 286 (corresponding to a “second gas chamber”), and an air release valve 288.

  The ink chamber 272B is connected to one end of the recovery-side drain pipe 290. The other end of the recovery side drain pipe 290 is connected to the drain pipe 268 of the supply side pressure adjustment tank 244 via the recovery side drain valve 292.

  The collection-side pressure adjustment tank 272 has a function of adjusting and maintaining the pressure in the ink chamber 272B to a desired value by the action of the gas chamber 272C and the elastic film 272A.

  The pressure by the supply-side pump 256 and the recovery-side pump 280 during normal ink supply (circulation supply), such as when recording (printing) an image using the inkjet head 72, is the pressure Pin> of the supply-side manifold 214> Although it is the pressure Pout of the collection | recovery side manifold 218, each is made into negative pressure. That is, the supply pressure of the supply-side pump 256 is negative, but the recovery pressure of the recovery-side pump 280 is a lower negative pressure, so that the ink flows from the supply-side manifold 214 to the recovery-side manifold 218, and The back pressure Pnzl of the nozzle 151 of the head module 72-i is maintained at a negative pressure. Therefore, the ink is circulated to the nozzle 151 while the ink is held at the nozzle 151 of the head module 72-i.

  Note that the pressure range of the back pressure Pnzl that can hold the ink at the nozzle 151 differs depending on the specifications of the head module 72-i and the ink type. In the present embodiment, it is about −3000 Pa (G) (“(G)” means gauge pressure (atmospheric pressure reference pressure, relative pressure)).

  In the ink supply unit 202 of the present embodiment, a pressure purge pipe 294 is provided between the inlet side of the recovery side pump 280 and the outlet side of the degassing module 250 in the supply side main pipe 248 to connect the two. ing.

  A one-way valve 296 and a recovery-side filter 298 are interposed in order from the degassing module 250 to the recovery-side pump 280 in the pressure purge pipe 294. When air bubbles are eliminated by pressurizing the inside of the head module 72-i and discharging ink at once, in addition to driving the supply side pump 256, the driving direction of the recovery side pump 280 is reversed with respect to the normal time, and the buffer Ink is supplied from the tank 246 to the recovery side manifold 218. A drain tube 268 is used for discharging.

  The buffer tank 246 is connected to the main tank 300 via the refill pipe 302. The buffer tank 246 stores an amount of ink necessary for circulating the ink, and is configured to be replenished with ink from the main tank 300 according to ink consumption. The buffer tank 246 corresponds to a “tank”, or a combination of the buffer tank 246 and the main tank 300 corresponds to a “tank”.

  One end of the replenishment pipe 302 is immersed in the ink stored in the main tank 300, and the other end is connected to the recovery-side main pipe 274. A filter 304 is attached to one end opening of the replenishment pipe 302 immersed in the ink in the main tank 300. A refill pump 306 is interposed in the refill pipe 302. By driving the refill pump 306, the buffer tank 246 is refilled with ink.

  An overflow pipe 308 is provided between the buffer tank 246 and the main tank 300 so that ink is returned to the main tank 300 when it is excessively replenished.

  The overflow pipe 308 is connected to one end of the recovery side relief pipe 312. The other end of the collection side relief pipe 312 is connected to a collection side main pipe 274 between the collection side pump 280 and the collection side pressure adjustment tank 272.

  A recovery side relief valve 316 is interposed in the recovery side relief pipe 312. The recovery side relief valve 316 opens when the pressure of the ink flowing in the pipeline exceeds a preset pressure, and prevents high pressure from being applied to the inkjet head and the pipeline.

  A liquid level sensor 318 is provided in the buffer tank 246, and information on the amount of ink in the buffer tank 246 can be obtained by the liquid level sensor 318. Similarly, a liquid level sensor 320 is also provided in the main tank 300, and information on the amount of ink in the main tank 300 can be obtained by the liquid level sensor 320.

[Ink filling process associated with module replacement]
Next, an ink initial filling method associated with the replacement operation of the head module in the ink jet recording apparatus having the above configuration will be described. FIG. 7 is a flowchart showing a procedure at the time of initial filling accompanying the head module replacement work.

  (Procedure 1) First, the supply side valve 222 and the recovery side valve 226 corresponding to the head module to be replaced are both closed, the head module to be replaced is removed from the line bar, and replaced with a new head module (new head) ( Step S12, “head connection process”).

  FIG. 8 is a schematic view showing a state when the head module is replaced. In FIG. 8, three head modules 72-1, 72-2, 72-3 are shown. In the figure, the rightmost head module 72-3 is a new head module replaced.

  When replacing the head module, the supply side valve 222 and the recovery side valve 226 corresponding to the target head module are closed, the old head module is removed, and the head module is replaced with a new head module. FIG. 8 shows a state after replacement with a new head module. In the notation of the valve in the drawing, the white one represents the “open” state, and the black one represents the “closed” state. The same applies to the other drawings. The new head module 72 has air in the internal flow path.

  After completion of the head module replacement work, when an operator (operator) instructs the work end through the user interface, an initial filling process is performed. The initial filling process is performed by the following procedures 2 to 4.

  (Procedure 2) Next, all the valves (supply side valve 222 and recovery) of all the head modules connected to the same path in a state where at least the ejection port (nozzle hole) of the target head after replacement is closed by the closing member. Side valve 226) is closed, and the supply-side flow path and the recovery-side flow path are set to negative pressure (corresponding to step S14 of FIG. 7, “in-flow path decompression step”, see FIG. 9).

  FIG. 9 is a schematic view showing a state of the in-flow channel decompression step. In FIG. 9, the closing member 330 is attached to the nozzle surface of only the new head module (replacement target head) indicated by reference numeral 72-3. As the closing member 330, for example, a rubber sheet member (rubber sheet) is used. The rubber sheet is inexpensive and has excellent sealing performance on the nozzle surface.

  The blocking member 330 can be configured as a cap structure that can be attached to and detached from the head module, and can be attached to the nozzle surface of the target head by an operator. Alternatively, the closing member 330 can be a member that is also used as a protection member for the nozzle surface in the new head module. In this case, a protective member (protective cover) that functions as the closing member 330 is attached in advance to the new head module, and at the time of replacement of the head module (the head connection step described in step S12 in FIG. 7), A new head module is attached with the protective member attached.

  As shown in FIG. 9, all the supply side valves 222 and the recovery side valves 226 of all the head modules connected to the supply side manifold 214 and the recovery side manifold 218 to which the replaced head module 72-3 is connected are closed. In this state, the supply side pump 256 and the recovery side pump 280 (see FIG. 6) are driven to decompress the supply side flow path and the recovery side flow path. Since the internal pressures of the supply side manifold 214 and the recovery side manifold 218 become negative due to the pressure reducing step in the flow path, the supply side valve 222 or the recovery side valve 226 is used in the next pressure reducing step in the head (step S16 in FIG. 7). Ink does not flow into the head module when the is opened.

  (Procedure 3) In step S14, with the supply side flow path and the recovery side flow path reduced to a constant negative pressure, either the supply side or the recovery side valve corresponding to the replacement target head module is opened, The pressure on the open side is reduced so as to be substantially the same as the pressure on the closed side (step S16).

  FIG. 10 illustrates the case where the collection side valve 226 corresponding to the replacement head module 72-3 is opened. As shown in FIG. 10, when the recovery side valve 226 of the replaced head module 72-3 is opened, the air in the head module 72-3 is discharged to the recovery side flow path (recovery side manifold 218). By driving the collection side pump 280, the inside of the collection side manifold 218 is depressurized, and the inside of the head module 72-3 is depressurized so as to be a predetermined pressure (negative pressure) substantially equal to the pressure of the supply side manifold 214.

  (Procedure 4) Next, the valve on the closed side of the replacement target head module 72-3 (here, the supply side valve 222) is opened, and the pressure on the first opened side continues to be controlled to the initial negative pressure. Then, ink is gradually filled from the flow path on the side opened later (step S18).

  FIG. 11 shows an example in which the supply side valve 222 corresponding to the head module 72-3 to be replaced is opened and ink is filled into the head module 72-3 from the supply side branch pipe 216.

  In step S16 of FIG. 10, the supply side valve 222 of the head module 72-3 to be replaced is opened (see FIG. 11) in a state where the supply side and recovery side pressures are respectively set to predetermined negative pressures. In this example, since the pressure on the supply side and the recovery side are approximately the same negative pressure, the ink does not immediately enter the head module 72-3 even if the supply side valve 222 is opened. After the side valve 222 is opened, the supply side pump 256 and the recovery side pump 280 (see FIG. 6) are driven to cause ink to flow into the head module 72-3.

  For example, the supply-side pump 256 and the recovery-side pump 280 are set to the head module 72-3 in the pressurizing direction (ink feeding direction) and the recovery-side pump 280 is set in the depressurizing direction at substantially the same speed. (Ink suction direction) In this way, by controlling the supply-side pump 256 and the recovery-side pump 280 in the reverse direction at a constant speed, it is possible to slowly fill the ink into the head module 72-3.

  Before opening the supply-side valve 222, by providing a pressure difference between the pressure on the supply-side flow path and the pressure on the recovery-side flow path, it is only necessary to open the supply-side valve 222. It is also possible to flow into the head module 72-3.

  According to the steps 1 to 4 described above, after the air in the new head module 72-3 after replacement is removed, the ink can be put into the head module 72-3. Can be satisfied.

  After the ink filling of the replaced head module is completed, the closing member 330 is removed, and normal ink circulation is started.

  In the present embodiment, the supply-side flow path including the supply-side manifold 214 corresponds to a “supply-side flow path portion”, and the recovery-side flow path including the recovery-side manifold 218 corresponds to a “recovery-side flow path portion”. . The combination of the supply side pump 256, the supply side pressure adjustment tank 244 and the supply side pressure sensor 240 corresponds to a “supply side pressure adjustment unit”, and the recovery side pump 280, the recovery side pressure adjustment tank 272, and the recovery side pressure sensor 242. The combination corresponds to the “recovery side pressure adjustment unit”.

<Configuration of pressure adjustment tank>
FIG. 12 is a schematic diagram showing the configuration of the supply side pressure adjustment tank 244 and the recovery side pressure adjustment tank 272. Since the supply-side pressure adjustment tank 244 and the recovery-side pressure adjustment tank 272 have the same structure, the supply-side pressure adjustment tank 244 will be described here as an example.

  The supply-side pressure adjustment tank 244 has a structure in which the sealed container 340 is partitioned into an ink chamber 244B and a gas chamber 244C by an elastic film 244A. The gas chamber 244C is connected to the air tank 264 via the air connect valve 262. When the air connect valve 262 is closed, the gas chamber 244C (first gas chamber) and the air tank 264 (second gas chamber) are separated, and when the air connect valve 262 is opened, the gas chamber 244C and the air tank 264 are connected and integrated. Gas chamber. In this manner, the gas chamber 244C and the air tank 264 can be opened and closed by the air connect valve 262, and the air connect valve 262 functions as a gas chamber divided opening / closing mechanism.

  The supply-side pressure adjustment tank 244 is provided with a gas pressure sensor 342 that detects the gas pressure in the gas chamber 244C. While the pressure of the gas chamber 244C is monitored by the gas pressure sensor 342, the driving of the supply side pump 256 (not shown in FIG. 12, refer to FIG. 6) is controlled. A relief valve (safety valve) 344 is provided in a flow path connecting the supply side pump 256 and the ink chamber 244B.

  The elastic film 244A is deformed according to the volume of the ink that has flowed into the ink chamber 244B. The ink circulation method using the back pressure tanks (244, 272) having such a structure causes a sudden pressure fluctuation due to the ink discharge operation of the pumps (256, 280) and the ink jet head 72 to each of the back pressure tanks (244, 272). The elastic film (244A, 272A) having flexibility and the elastic force of the gas chamber (244C, 272C) can be attenuated by the action of an appropriate elastic force. For this reason, the internal pressure fluctuation | variation of an inkjet head can be restrained low and the discharge stability of an inkjet head can be improved.

  In the region where the elastic force of the elastic membrane 244A can be ignored as shown in (1) of FIG. 12 (for example, the region where the membrane is hardly applied with tension and the membrane is in a slack state), the gas is mainly used. The elastic force of the chamber 244C contributes. In this case, since it can be used in a place where the elastic force is small, the pulsation of the pump can be efficiently suppressed.

  On the contrary, in the region where the elastic force of the membrane as shown in FIG. 12 (2) is dominant (region where the membrane is tensioned and the membrane is stretched), the elastic membrane 244A. Is elastically deformed and the film elastic force is increased. When performing the decompression operation described in steps S14 and S16 of FIG. 7, as shown in (2) of FIG. 12, the elastic membrane 244A (272A) is elastically deformed, and the volume of the gas chamber 244C (272C) is increased. The pressure reducing operation is performed after the air connect valve 262 (284) is closed in the reduced state.

<Ingenuity during decompression operation>
At the time of pressure reduction in the flow path described in step S14 of FIG. 7 or pressure reduction in the head described in step S16, the elastic film (244A, 272A) of the pressure adjustment tank (244, 272) is attached to the inner wall of the sealed container 340. Depressurize after fixing.

  That is, before pulling the negative pressure in the flow path, first, the air connect valve 262 and the atmosphere release valve 266 are opened, the ink chamber 244B is pressurized to fill the ink chamber 244B with ink, and the gas chamber 244C (first gas) The elastic film 244A is attached to the wall surface of the chamber. Thereafter, the air connect valve 262 is closed, the gas chamber 244C and the air tank 264 are separated, and the ink chamber 244B is depressurized to a negative pressure. By doing so, the elastic film 244A is fixed to the inner wall of the gas chamber 244C, and the ink chamber 244B can be pulled to a high negative pressure.

  Similarly, when the pressure on the recovery-side flow path is reduced, the recovery side is pulled to a negative pressure after the elastic film 272A of the recovery-side pressure adjustment tank 272 is attached to the inner wall of the gas chamber 272C and fixed.

<About the pressure reduction level in the head when filling liquid>
During normal ink circulation such as printing, the supply-side flow path and the collection-side flow path are controlled with different pressures, and the liquid is constantly circulated by the differential pressure. Is discharged. As an example of pressure control during circulation, the supply side is set to 0 Pa (G), the recovery side is set to −5000 Pa (G), and the control is performed so that the head pressure is −2500 Pa at the nozzle surface of the head portion.

  On the other hand, the pressure reduction level in the head at the time of initial ink filling accompanying the replacement of the head module is preferably −50 kPa or less, more preferably −70 kPa or less with respect to the atmospheric pressure. In this embodiment, in step S16 of FIG. 7, the inside of the replacement target head module 72-3 is depressurized to −80 kPa with respect to the atmospheric pressure.

[Bubble discharge operation in the channel]
After the ink filling described with reference to FIGS. 7 to 11, all the valves (222, 226) on the head side are closed, the first bypass valve 236 is opened, the supply side and the recovery side flow paths are bypassed, and the flow path is closed. The step of discharging the bubbles is performed. The bubble discharge process in the flow channel after ink filling includes a first step (“bubble discharge operation in the flow channel (1)”) and a second step (“bubble discharge operation in the flow channel ( Part 2) ”) is performed in two stages. After performing the bubble discharge operation (No. 1 and No. 2) in such a flow path, normal ink circulation is started.

<Bubble discharge operation in channel (1)>
FIG. 13 is a diagram showing the ink flow during the bubble discharge operation in the flow path (part 1). As described with reference to FIGS. 7 to 11, the flow path when the collection side valve 226 is opened to decompress the head module 72-3 and then the supply side valve 222 is opened to fill the head module 72-3 with ink. The inner bubble discharge operation (part 1) is shown.

  As shown in FIG. 13, the first bypass valve 236 is opened, and the supply side valve 222 and the recovery side valve 226 connected to each head module 72-i are all closed. The drain valve 270 of the supply side pressure adjustment tank 244 is closed, and the drain valve 292 of the recovery side pressure adjustment tank 272 is opened. The air connect valve 262 connected to the gas chamber 244C of the supply side pressure adjustment tank 244 is opened, and the air release valve 266 of the air tank 264 is closed (normally closed).

  Similarly, the air connect valve 284 connected to the gas chamber 272C of the recovery side pressure adjustment tank 272 is opened, and the air release valve 288 of the air tank 286 is closed (normally closed).

  Under such a state, the supply-side pump 256 is driven in a pressurizing direction (a direction in which ink is sent to the supply-side manifold 214). Ink flows from the supply side manifold 214 to the recovery side manifold 218 via the first bypass flow path 232, and returns from the ink chamber 272 B of the recovery side pressure adjustment tank 272 to the buffer tank 246 via the drain valve 292. Thus, bubbles in the flow path are discharged to the buffer tank 246 by the ink flow indicated by the arrows in the figure.

[Bubble discharge operation in channel (part 2)]
Next, the second operation of the bubble discharging process (referred to as “bubble discharging operation (2)”) will be described. FIG. 14 is a diagram showing the ink flow during the bubble discharge operation in the flow path (part 2).

  In the case of the bubble discharge operation in the flow path described in FIG. 13 (part 1), air (bubbles) may be contained in the flow path from the recovery side pressure adjustment tank 272 to the recovery side pump 280. Therefore, in order to remove the air in the flow channel part, the bubble discharge operation (No. 2) in the flow channel shown in FIG. 14 is performed. As shown in FIG. 14, the first bypass valve 236 is closed, and the drain valve 292 of the recovery-side pressure adjustment tank 272 is opened as in FIG. In this state, the recovery side pump 280 is driven in a direction (pressure direction) to push out ink toward the recovery side pressure adjustment tank 272.

  The ink sent from the recovery side pump 280 to the ink chamber 272B of the recovery side pressure adjustment tank 272 returns from the ink chamber 272B to the buffer tank 246 through the drain valve 292 and the drain pipe 268. Thus, the air in the flow path section from the recovery side pump 280 to the recovery side pressure adjustment tank 272 is discharged to the buffer tank 246 by the ink flow indicated by the arrow in FIG.

  After performing the above-described bubble discharge operation (No. 1) and (No. 2) in the flow path, the drive control of the supply side pump 256 and the recovery side pump 280 for normal ink circulation is performed, and each head module 72-i. The supply side valve 222 and the recovery side valve 226 are all opened to start ink circulation. Thus, when normal ink circulation is started, drawing is possible.

  The supply-side drain valve 270, the recovery-side drain valve 292, and the drain pipe 268 correspond to the “bubble discharge path”.

<Ink supply unit control system>
FIG. 15 is a block diagram showing a schematic configuration of a control system of the ink supply apparatus 200 shown in this example. The ink supply device 200 includes an ink supply control unit 350 that performs overall control of the control system, a supply side pump control unit 352 that controls the supply side pump 256 based on a control signal sent from the ink supply control unit 350, and a supply side Based on a control signal sent from the ink supply control unit 350 and a supply side valve control unit 354 that controls the opening and closing of the valves (supply side valve 222, drain valve 270, air connect valve 262, atmosphere release valve 266, etc.). A collection-side pump control unit 362 that controls the collection-side pump 280 and a collection-side valve that controls the opening and closing of collection-side valves (such as the collection-side valve 226, the drain valve 292, the air connect valve 284, and the air release valve 288). A control unit 364 and a valve for controlling the first bypass valve 236 and the second bypass valve 238. And Pasubarubu control unit 366, a display device 375 as a means for presenting various kinds of information, such as notification to that effect when an abnormality occurs in the various units, the.

  The ink supply apparatus 200 includes a parameter storage unit 380, a program storage unit 382, a supply side pressure sensor 240, and a recovery side pressure sensor 242.

  The parameter storage unit 380 stores various parameters used for control of the ink supply apparatus 200 and a data table referred to at the time of control.

  The program storage unit 382 stores a program used for controlling the ink supply device 200. The ink supply control unit 350 reads out and executes various control programs stored in the program storage unit 382, and controls the ink supply apparatus 200 with reference to various parameters and data tables stored in the parameter storage unit 380. And control. The initial filling process and the bubble discharge operation in the flow path described with reference to FIGS. 7 to 14 are executed according to a program.

  The ink supply control unit 350 adjusts the insides of the supply side flow path and the recovery side flow path to predetermined pressures (set pressures) based on the detection results of the supply side pressure sensor 240 and the recovery side pressure sensor 242, respectively. The driving of the supply side pump 256 and the recovery side pump 280 is controlled.

  When supplying ink to the inkjet head 72 during printing, a predetermined pressure difference is set so that the internal pressure of the supply side manifold 214 is relatively higher than the internal pressure of the recovery side manifold 218, and The ink supply control unit 350 supplies the supply side pump 256 and the recovery side so that a predetermined back pressure (negative pressure) is applied to the ink inside the nozzles of the head modules 72-1, 12-2,. The drive of the pump 280 is controlled.

  FIG. 15 shows a configuration in which the valve control unit and the pump control unit are separately provided on the supply side and the collection side, but the control unit may be shared on the supply side and the collection side.

<Control system of inkjet recording apparatus>
FIG. 16 is a block diagram showing a schematic configuration of a control system of the ink jet recording apparatus. The inkjet recording apparatus 10 includes a communication interface 440, a system control unit 442, a conveyance control unit 444, an image processing unit 446, and an inkjet head drive unit 448, and an image memory 450 and a ROM (Read Only Memory) 452.

  The communication interface 440 is an interface unit that receives image data sent from the host computer 454. The communication interface 440 may be a serial interface such as USB (Universal Serial Bus) or a parallel interface such as Centronics. The communication interface 440 may be equipped with a buffer memory (not shown) in order to speed up communication.

The system control unit 442 includes a central processing unit (CPU (Central Processing Unit)) and its peripheral circuits. The system control unit 442 functions as a control unit that controls the entire inkjet recording apparatus 10 according to a predetermined program and performs various calculations. It functions as a computing device to perform. Also, it functions as a memory controller for the image memory 450 and the ROM 452. That is, the system control unit 442 controls each unit such as the communication interface 440 and the transport control unit 444, performs communication control with the host computer 454, read / write control of the image memory 450 and the ROM 452, and the like. A control signal to be controlled is generated.

  The image data sent from the host computer 454 is taken into the inkjet recording apparatus 10 via the communication interface 440 and subjected to predetermined image processing by the image processing unit 446.

  The image processing unit 446 has a signal (image) processing function for performing various processes and corrections for generating a print control signal from the image data, and supplies the generated print data to the inkjet head driving unit 448. To do. Necessary signal processing is performed in the image processing unit 446, and the ejection droplet amount (droplet ejection amount) of the inkjet head 72 and ejection timing are controlled via the inkjet head driving unit 448 based on the image data. . Thereby, a desired dot size and dot arrangement are realized.

  Note that the inkjet head drive unit 448 shown in FIG. 16 may include a feedback control system for keeping the drive conditions of the inkjet head 72 constant.

  The inkjet head drive unit 448 includes a drive waveform generation unit that generates a drive waveform, an amplification unit that amplifies the drive waveform to generate a drive voltage, and a drive voltage that supplies a drive voltage having a predetermined drive waveform to the inkjet head And a supply unit. A drive waveform is generated based on image data (digital data) sent from the system control unit (or a corresponding drive waveform is selected from the drive waveforms stored in advance), and the drive voltage having the drive waveform is Generated.

The conveyance control unit 444 controls the conveyance timing and conveyance speed of the paper 24 based on the print control signal generated by the image processing unit 446. The transport driving unit 456 includes a motor that rotates a transport drum of each unit, a motor that rotates an intermediate transport body, and the like, and the transport control unit 444 functions as a driver of the motor.

  The image memory 450 functions as a primary storage unit that temporarily stores image data input via the communication interface 440, a development area for various programs stored in the ROM 452, and a calculation work area for the CPU (for example, image processing). Function as a work area of the unit 446. As the image memory 450, a volatile memory (RAM) capable of sequential reading and writing is used.

  The ROM 452 stores programs executed by the CPU of the system control unit 442, various data necessary for control of each unit of the apparatus, control parameters, and the like, and data is read and written through the system control unit 442. The ROM 452 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used. Alternatively, a removable storage medium that includes an external interface may be used.

  Further, the inkjet recording apparatus 10 includes a processing liquid application control unit 460, a drying processing control unit 462, a fixing processing control unit 464, a maintenance control unit 486, an ink supply control unit 350, and the like. In accordance with the instructions, the operations of the processing liquid application unit 14, the drying unit 18, the fixing unit 20, the maintenance processing unit 170, and the ink supply unit 202 are controlled.

  Based on the print data obtained from the image processing unit 446, the processing liquid application control unit 460 controls the processing liquid application timing by the processing liquid application unit 14 and also controls the amount of processing liquid applied.

  The drying processing control unit 462 controls the solvent drying device 78 included in the drying unit 18 and controls the processing temperature, the air flow rate, and the like.

  The fixing process control unit 464 controls the temperature of the halogen heater 86 included in the fixing unit 20 and also controls the pressing of the fixing roller 88.

  The ink jet recording apparatus 10 shown in this example includes a user interface 470. The user interface 470 includes an input device 472 for an operator (user) to make various inputs and a display unit (display) 474. The input device 472 may employ various forms such as a keyboard, a mouse, a touch panel, and buttons. By operating the input device 472, the operator can perform input of printing conditions, selection of image quality mode, input / editing of attached information, search of information, etc. Various information such as input contents and search results can be obtained. This can be confirmed through display on the display unit 374. The display unit 474 also functions as a means for displaying a warning such as an error message.

  The parameter storage unit 480 stores various control parameters necessary for the operation of the inkjet recording apparatus 10. The system control unit 442 appropriately reads out parameters necessary for control and updates (rewrites) various parameters as necessary.

  The program storage unit 482 is a storage unit that stores a control program for operating the inkjet recording apparatus 10. The system control unit 442 (or each unit of the device) reads a necessary control program from the program storage unit 482 when executing control of each unit of the device, and appropriately executes the control program.

  The parameter storage unit 480 and the program storage unit 482 can also be used as the parameter storage unit 380 and the program storage unit 382 described with reference to FIG.

  A maintenance control unit 486 in FIG. 16 is a control block that controls the operation of the maintenance processing unit 170 based on a command signal sent from the system control unit 442. When the control of the ink jet recording apparatus 10 shifts to the maintenance mode, the ink jet head 72 is moved from the printing position directly above the drawing drum 70 to the maintenance position, and each part of the maintenance processing unit 170 corresponding to the movement of the ink jet head 72. To work.

  The ink supply control unit 350 controls the operation of the ink supply unit 202 based on the command signal sent from the system control unit 442. As described above, the ink jet recording apparatus 10 of the present embodiment circulates and supplies ink to the ink jet head 72. The ink supply control unit 350 operates each unit of the ink supply unit 202 so that ink is circulated and supplied to the inkjet head 72 during image recording.

  A combination of the ink supply control unit 350 and the ink supply unit 202 corresponds to the ink supply apparatus 200 described with reference to FIG. The function of the ink supply control unit 350 can be integrated into the system control unit 442. The ink supply control unit 350, the system control unit 442, or a combination thereof corresponds to the “control unit”.

<Modification 1 of Embodiment>
In the description of FIGS. 8 to 11, the example in which the closing member 330 is attached only to the head module to be replaced has been described. However, a configuration in which the nozzles are blocked for a plurality of head modules including the head module to be replaced is also possible. is there.

  FIG. 17 shows an example of a closing member that closes the nozzles of a plurality of head modules including the replaced head module. For example, in FIG. 17, among the three head modules 72-1, 72-2, 72-3, the replaced head module is only the central head module 72-2, and the other head modules 72-1, 72- It is assumed that 3 is not subject to exchange (non-exchange).

  In this case, after replacing the central head module 72-2, the nozzles of a plurality of head modules including the replacement target head module 72-2 and the non-replaceable head modules 72-1 and 72-3 adjacent thereto. A configuration in which the surface is integrally sealed with the closing member 390 is also possible. The configuration may be such that the nozzle surfaces of all the head modules constituting the head bar are closed by a common closing member 390, or the nozzles of some (a plurality of) head modules including the replacement target are closed. There may be. The closing member 390 only needs to have a size capable of closing at least the nozzle of the head module to be replaced.

  A plurality of head modules constituting the line head bar can be replaced at a time. When a plurality of head modules are replaced, the ink filling process after replacement can be performed one by one. It is also possible to perform a plurality of processes simultaneously. In addition, when ink filling is performed one by one for a plurality of replaced head modules, the bubble discharge process in the flow path can be performed collectively. That is, the filling step can be performed one by one in order, and finally the bubble removal step in the flow path can be performed collectively.

<Modification 2>
The in-channel pressure reducing step described in step S14 in FIG. 7 can be omitted. When omitting the pressure reducing step in the flow path, in the flow path on the open side so that ink does not flow into the head when either the supply side valve 222 or the recovery side valve 226 is opened in the pressure reducing process in the head. It is desirable to set to a negative pressure.

<Modification 3>
In the above-described embodiment, the recovery-side flow path is used as a pressure reducing path for performing pressure reduction in the head during the filling process, and the supply-side flow path is used as an ink filling path for performing ink filling after the pressure reduction in the head. However, on the contrary, it is possible to use a supply-side flow path as a pressure reducing path and a recovery-side flow path as an ink filling path.

  The configuration of the ink supply apparatus 200 described with reference to FIG. 6 is substantially the same (symmetric) configuration on the supply side and the collection side, and the same operation is performed even if the relationship between the supply side and the collection side is switched. Is possible.

<Modification 4>
In the above-described example, the pressure sensors (240, 242) for detecting the internal pressures of the supply side manifold 214 and the recovery side manifold 218 are used, but instead of or in combination with this, the gas chamber 244C, Using a sensor (gas pressure sensor) for monitoring the gas pressure of 272C, the pressure of the ink chambers 244B and 272B (that is, the pressure of the supply side flow path section and the recovery side flow path section from the information of the gas pressure of the gas chambers 244C and 272C) It is also possible to indirectly grasp the pressure.

<Modification 5>
The form of the line head bar composed of a plurality of head modules is not limited to the form illustrated in FIGS. For example, the present invention can be applied to a line head having a structure in which a plurality of head modules are arranged in a staggered manner.

<Modification 6>
In the above embodiment, an ink jet recording apparatus of a method (direct recording method) in which an ink droplet is directly formed on the recording medium 124 has been described. However, the scope of application of the present invention is not limited to this, and once, The present invention is also applied to an intermediate transfer type ink jet recording apparatus that forms an image (primary image) on an intermediate transfer member and transfers the image to a recording sheet in a transfer unit to form a final image. be able to.

<About other application examples>
In the above-described embodiment, the application to an inkjet recording apparatus for graphic printing is described as an example of one form of the droplet discharge apparatus, but the scope of application of the present invention is not limited to this example. For example, a wiring drawing apparatus for drawing a wiring pattern of an electronic circuit, a manufacturing apparatus for various devices, a resist printing apparatus that uses a resin liquid as a functional liquid for ejection, a color filter manufacturing apparatus, and a material deposition material. The present invention can be widely applied to a droplet discharge apparatus including a droplet discharge head that draws various shapes and patterns using a liquid functional material, such as a fine structure forming apparatus that forms a structure.

  In the embodiment of the present invention described above, the configuration requirements can be appropriately changed, added, and deleted without departing from the spirit of the present invention. The present invention is not limited to the embodiments described above, and many modifications are possible by those having ordinary knowledge in the field within the technical idea of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 24 ... Paper, 72 (72M, 72K, 72C, 72Y) ... Inkjet head, 72-i ... Head module, 151 ... Nozzle, 200 ... Ink supply device, 202 ... Ink supply unit, 212A ... Ink Supply port, 212B ... Ink recovery port, 214 ... Supply side manifold, 216 ... Supply side branch pipe, 218 ... Recovery side manifold, 220 ... Recovery side branch pipe, 222 ... Supply side valve, 226 ... Recovery side valve, 228 ... Supply 230, recovery pipe, 232 ... first bypass flow path, 234 ... second bypass flow path, 236 ... first bypass valve, 238 ... second bypass valve, 240 ... supply side pressure sensor, 242 ... recovery side pressure sensor 244 ... Supply side pressure adjusting tank, 244A ... elastic film, 244B ... ink chamber, 244C ... gas chamber, 2 6 ... Buffer tank, 248 ... Supply side main pipe, 254 ... Supply side pump, 262 ... Air connect valve, 264 ... Air tank, 266 ... Air release valve, 268 ... Drain pipe, 270 ... Supply side drain valve, 272 ... Recovery side pressure Adjustment tank, 272A ... elastic membrane, 272B ... ink chamber, 272C ... gas chamber, 274 ... collection side main pipe, 280 ... collection side pump, 282 ... open pipe, 284 ... air connect valve, 286 ... air tank, 288 ... atmospheric release valve 290: Recovery side drain pipe, 292 ... Recovery side drain valve, 300 ... Main tank, 330 ... Closure member, 340 ... Sealed container, 350 ... Ink supply control unit, 353 ... Supply side pump control unit, 354 ... Supply side valve Control unit, 362 ... recovery side pump control unit, 366 ... bypass valve control unit, 390 ... closed Member, 440 ... communication interface, 442 ... system control unit

Claims (17)

A tank for storing liquid,
A supply-side flow path section for supplying the liquid from the tank to a droplet discharge head;
A collection-side flow path section for collecting liquid from the droplet discharge head;
A supply-side on-off valve capable of opening and closing the first channel connected to the droplet discharge head of the supply-side channel unit;
A collection-side on-off valve capable of opening and closing a second channel connected to the droplet discharge head of the collection-side channel unit;
A supply-side pressure adjusting unit that adjusts the pressure of the supply-side channel unit;
A collection-side pressure adjusting unit that adjusts the pressure of the collection-side flow path unit;
The supply-side on-off valve, the collection-side on-off valve, the supply-side pressure adjustment unit, and a control unit that controls the collection-side pressure adjustment unit, and the liquid ejected from the droplet ejection head A liquid supply device that circulates and supplies liquid to a droplet discharge head,
When initial filling of the liquid into the droplet discharge head connected to the supply side flow path portion and the recovery side flow path portion with both the supply side open / close valve and the recovery side open / close valve closed. ,
Under the state where the droplet discharge port of the droplet discharge head is closed by a closing member, the control unit opens one of the supply-side open / close valve and the recovery-side open / close valve, and the other While the on-off valve is closed, the inside of the droplet discharge head is depressurized using the open-side flow path portion and the pressure adjusting portion,
Thereafter, the other on-off valve on the closed side is opened, and control is performed to allow the liquid to flow into the droplet discharge head through a flow path interposed by the other on-off valve .
When performing the initial filling, the control unit
With the supply side on-off valve and the recovery side on-off valve both closed, the supply side flow path unit and the recovery side flow path unit are respectively used by using the supply side pressure adjustment unit and the recovery side pressure adjustment unit. A liquid supply apparatus that controls the opening / closing valve of either the supply-side opening / closing valve or the recovery-side opening / closing valve to be set to a negative pressure . The control unit, when performing the pressure reduction, out of the supply-side channel unit and the recovery-side channel unit,
The liquid supply apparatus according to claim 1 , wherein control is performed to reduce the pressure so that the pressure of the channel portion on the open side is equal to the pressure of the channel portion on the closed side. The supply-side pressure adjustment unit includes a supply-side pump that can be driven in both directions of pressurization and decompression of the supply-side flow channel unit, and a supply-side pressure detection unit for grasping the pressure in the supply-side flow channel unit. With
The recovery-side pressure adjusting unit includes a recovery-side pump that can be driven in both directions of pressurization and decompression of the recovery-side flow channel unit, and a recovery-side pressure detection unit for grasping the pressure in the recovery-side flow channel unit. A liquid supply apparatus according to claim 1 or 2 . When performing the initial filling, the control unit
After opening the one on-off valve and performing the pressure reduction, when opening the other on-off valve on the closed side to allow liquid to flow into the droplet discharge head, the supply-side pump and the recovery pump The liquid supply apparatus according to claim 3 , wherein control is performed such that the side pumps are driven in the opposite direction with respect to the droplet discharge heads at the same speed. 5. The liquid supply apparatus according to claim 3 , wherein each of the supply-side pump and the recovery-side pump is a multiple tube pump having a structure in which a plurality of tubes are stacked and arranged with different phases. Wherein the collection-side pressure adjusting portion and the supply-side pressure adjustment unit, respectively, claims 3 and a pressure regulating tank having a separated structure in which the closed vessel into a liquid chamber and a gas chamber at the elastic membrane 5 The liquid supply apparatus according to any one of the above. In the pressure adjusting tank, the gas chamber has a two-chamber configuration of a first gas chamber and a second gas chamber, and a gas chamber divided opening / closing mechanism capable of opening and closing between the first gas chamber and the second gas chamber With
The liquid supply device according to claim 6 , wherein the control unit controls the gas chamber division opening / closing mechanism and closes the gas chamber division opening / closing mechanism at least during a decompression operation during the initial filling. Before performing the pressure reducing operation, the controller pressurizes the liquid chamber once with the gas chamber dividing opening / closing mechanism opened, and decreases the volume of the first gas chamber by deformation of the elastic film. The liquid supply apparatus according to claim 7 , wherein a control for performing a pressure reducing operation is performed after the gas chamber dividing opening / closing mechanism is closed to close the space between the first gas chamber and the second gas chamber. Of each flow channel of the supply side and the recovery side with respect to the liquid droplet ejection head, the reduced pressure side of the flow channel to be used for decompression at least the liquid droplet ejection in the head to discharge the bubble in the flow path The liquid supply apparatus according to any one of claims 1 to 8 , wherein a bubble discharge path is provided. The supply side flow path section includes a supply side manifold to which a plurality of the droplet discharge heads are connected in parallel,
The collection-side flow path section includes a collection-side manifold to which the plurality of droplet discharge heads are connected in parallel.
Wherein the plurality of liquid supply apparatus according to any one of the supply-side valve and the collection-side valve from which claim 1 comprising 9 to each of the droplet discharge head. A liquid supply device according to any one of claims 1 to 10 ,
A droplet discharge apparatus comprising the droplet discharge head. Comprising the closing member for closing the droplet discharge port of the droplet discharge head;
The droplet discharge device according to claim 11 , wherein the closing member is a rubber sheet member. A plurality of droplet discharge heads are connected to form a long line head bar,
Each of the plurality of droplet discharge heads is an independently replaceable head module,
When replacing the at least one droplet ejection heads in the plurality of droplet ejection heads, claim 11 or control during the initial filling for the new droplet discharge head after the exchange is performed 13. A droplet discharge device according to item 12 . 14. The droplet discharge device according to claim 13 , wherein the closing member is a member having a size covering at least a droplet discharge surface of the new droplet discharge head after the replacement. A droplet discharge head;
A tank for storing liquid to be supplied to the droplet discharge head;
A supply-side flow path section for supplying the liquid from the tank to a droplet discharge head;
A collection-side flow path section for collecting liquid from the droplet discharge head;
A supply-side on-off valve capable of opening and closing the first channel connected to the droplet discharge head of the supply-side channel unit;
A collection-side on-off valve capable of opening and closing a second channel connected to the droplet discharge head of the collection-side channel unit;
A supply-side pressure adjusting unit that adjusts the pressure of the supply-side channel unit;
An initial liquid filling method for the liquid droplet ejection head in a liquid droplet ejection apparatus comprising: a recovery side pressure adjustment unit that adjusts the pressure of the recovery side flow path unit;
A head connection step in which the supply-side flow path portion and the recovery-side flow path portion are connected to the droplet discharge head in a state where both the supply-side on-off valve and the recovery-side on-off valve are closed;
One of the supply side on-off valve and the recovery side on-off valve is opened while the other on-off valve is closed under the condition that the droplet discharge port of the droplet discharge head is closed by a closing member. In-head depressurization step of depressurizing the inside of the droplet discharge head using the open side flow path section and the pressure adjustment section,
After the in-head depressurization step, the filling step of opening the other on-off valve on the closed side and allowing the liquid to flow into the droplet discharge head through a flow path interposed by the other on-off valve;
Only including,
With the supply side on-off valve and the recovery side on-off valve both closed, the supply side flow path unit and the recovery side flow path unit are respectively used by using the supply side pressure adjustment unit and the recovery side pressure adjustment unit. A pressure reducing step in the flow channel for setting the pressure of
A liquid filling method for performing the in-head decompression step after the in-flow passage decompression step . In the in-head depressurization step, the pressure of the open-side flow channel portion of the supply-side flow channel portion and the recovery-side flow channel portion is equal to the pressure of the flow channel portion on the closed side. The liquid filling method according to claim 15 , wherein the pressure is reduced so that. The droplet discharge device includes a plurality of the droplet discharge heads,
A long line head bar is configured by connecting the plurality of droplet discharge heads,
Each of the plurality of droplet discharge heads is an independently replaceable head module,
When at least one droplet ejection head of the plurality of droplet ejection heads is replaced, the in-head pressure reducing step and the filling step are initially performed on the new droplet ejection head after the replacement. The liquid filling method according to claim 15 or 16 , wherein filling is performed.

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