JP6579018B2 - Inkjet head, inkjet recording apparatus, and bubble removal method for inkjet head - Google Patents

Description

  The present invention relates to an ink jet head, an ink jet recording apparatus, and a method for removing bubbles in an ink jet head, and more specifically, an ink jet head, an ink jet recording apparatus, and a method for removing air bubbles in an ink jet head that can efficiently remove residual bubbles in an ink storage chamber equipped with a filter. About.

  In an inkjet head, if bubbles in an ink storage chamber (also referred to as a common ink chamber) that stores ink to be supplied to a plurality of pressure chambers remain in the pressure chamber or in the vicinity of the pressure chamber, the ink from the nozzles Discharge may be affected.

  In particular, in an ink jet head equipped with a filter for preventing contaminants in the ink from entering the pressure chamber in the ink storage chamber, when air bubbles enter below the filter (on the pressure chamber side). However, it is difficult to remove the bubbles, and the bubbles may enter the pressure chamber.

  Conventionally, an ink storage chamber is divided into an upstream ink chamber (above the filter) and a downstream ink chamber (below the filter) by a filter, and an ink supply pipe (inlet) and an ink recovery pipe (circulation outlet) are connected to the upstream ink chamber. ) Is known to circulate ink in an upstream ink chamber to discharge bubbles (Patent Document 1). However, since the circulating flow only passes through the upstream ink chamber, the bubbles remaining in the downstream ink chamber cannot be discharged to the outside.

  In addition, an inkjet head having an ink storage chamber is also known which has a plurality of nozzle rows on one nozzle plate surface and can perform a suction operation for each nozzle row (Patent Document 2). However, in this ink jet head, it is necessary to perform a suction operation from the nozzle to prevent clogging of the nozzle, and waste ink is generated during this suction operation.

  Further, an upstream ink chamber (first ink chamber) to which ink is supplied from an ink supply source and a downstream ink chamber (second ink chamber) to which ink is supplied from the upstream ink chamber via a filter are provided. Ink jet heads have been proposed, in which nozzles for ejecting ink are provided in the downstream ink chambers, and gas-liquid separation means for restricting the discharge of liquid are provided at the first and second discharge ports for discharging the fluid from each ink chamber. (Patent Document 3). In this ink jet head, the flow path resistance to the first discharge port is made smaller than the flow path resistance to the second discharge port, so that the waste ink generated when discharging the bubbles remaining in each ink chamber is discharged. The amount is reduced, and bubbles moving from the upstream ink chamber to the downstream ink chamber can be reduced.

JP 2006-263996 A Japanese Patent Laid-Open No. 2001-80085 JP 2009-126044 A

  Incidentally, in Patent Document 3, since the flow path resistance to the first discharge port is smaller than the flow path resistance to the second discharge port, there are few bubbles moving from the upstream ink chamber to the downstream ink chamber. However, as in Patent Document 1, bubbles attached to the downstream ink chamber (below the filter) cannot be discharged to the outside.

  Therefore, an object of the present invention is to provide an ink jet head, an ink jet recording apparatus, and a method for removing air bubbles in an ink jet head that can efficiently remove residual bubbles in an ink storage chamber provided with a filter.

  The above problems are solved by the following inventions.

1.
An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe which communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Pressure loss adjusting means for adjusting the relative relationship with the road resistance,
By balancing the flow resistance of the main flow path and the flow resistance of the sub flow path by the pressure loss adjusting means, both the main flow path and the sub flow path are controlled by the ink pressure in the ink supply pipe. An ink jet head characterized by causing ink to flow.
2.
2. The inkjet head according to claim 1, wherein the check valve is disposed at a position higher than the junction.
3.
The upper end portion of the check valve is disposed at a position lower than the surface of the ink in the ink tank storing the ink supplied to the ink storage chamber via the ink supply pipe. The inkjet head according to 1 or 2 above.
4).
The inkjet according to any one of 1 to 3, wherein the check valve is disposed at a position where ink recovered from the ink storage chamber via the ink recovery pipe flows upward. head.
5).
5. The ink jet head according to any one of 1 to 4, wherein the pressure adjusting means imparts a pressure loss to the main flow path.
6).
6. The ink jet head as described in 5 above, wherein as the pressure adjusting means, the flow path cross-sectional area of the ink recovery pipe is narrower than the flow path cross-sectional area of the ink discharge pipe.
7).
6. The ink jet head according to 5, wherein the pressure adjusting means is a flow rate adjusting member that partially narrows a cross-sectional area of the main flow path.
8).
The inkjet head according to any one of 1 to 7, wherein a second check valve is provided on the upstream side of the confluence of the sub-flow path.
9.
9. The ink jet head according to claim 8, wherein the pressure adjusting unit sucks ink from the sub-flow path toward the junction point.
10.
10. The ink jet head according to 9, wherein the pressure adjusting means is a suction pump provided in the sub flow channel.
11.
The inkjet head according to any one of 1 to 10;
An ink tank for storing ink to be supplied to the inkjet head;
An ink jet recording apparatus comprising: ink transfer means for transferring ink in the ink tank to the ink jet head.
12
An ink transfer pipe, in which an ink supply pipe that forms a flow path for supplying ink into the ink storage chamber of an inkjet head that discharges ink supplied to the ink storage chamber through the pressure chamber and the nozzle is detachably mounted;
An ink return pipe that is detachably mounted on an ink collection pipe that forms a flow path for collecting ink from the ink storage chamber of the inkjet head; and
An ink tank for storing ink supplied to the ink storage chamber via the ink transfer pipe and the ink supply pipe;
An ink transfer means for transferring ink in the ink tank to the inkjet head via the ink transfer pipe;
An ink jet recording apparatus, wherein the ink return pipe is provided with a check valve.
13.
An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe which communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Using pressure loss adjusting means that adjusts the relative relationship with the road resistance,
By the action of the pressure loss adjusting means, the flow resistance of the main flow path and the flow resistance of the sub flow path are balanced, and both the main flow path and the sub flow path are adjusted by the ink pressure in the ink supply pipe. A method of removing bubbles in an ink jet head, wherein ink is allowed to flow through the ink jet head.
14
14. The method of removing bubbles in an ink jet head according to 13, wherein the check valve is arranged at a position higher than the junction.
15.
The said check valve is arrange | positioned in the position lower than the surface of the ink in the ink tank which stores the ink supplied to the said ink storage chamber through the said ink supply pipe | tube, The said 13 or 14 characterized by the above-mentioned. Method for removing bubbles in an inkjet head.
16.
The ink jet head according to any one of 13 to 15, wherein the check valve is disposed at a position where ink recovered from the ink storage chamber via the ink recovery pipe flows upward. Bubble removal method.
17.
17. The method for removing bubbles from an ink jet head according to any one of 13 to 16, wherein a pressure loss is applied to the main channel by the pressure adjusting means.
18.
18. The method of removing an air bubble in an ink jet head according to claim 17, wherein the pressure adjusting means is such that a cross-sectional area of the ink recovery pipe is narrower than a cross-sectional area of the ink discharge pipe.
19.
18. The method for removing bubbles in an ink jet head according to claim 17, wherein a flow rate adjusting member that partially narrows a cross-sectional area of the main flow path is used as the pressure adjusting means.
20.
20. The method for removing bubbles in an ink jet head according to any one of 13 to 19, wherein a second check valve is provided on the upstream side of the confluence of the sub flow path.
21.
21. The method for removing air bubbles from an ink jet head according to 20, wherein the pressure adjusting means sucks ink from the sub-flow path toward the confluence.
22.
22. The method for removing bubbles in an ink jet head according to item 21, wherein a suction pump is provided in the sub-channel as the pressure adjusting means.

  According to the present invention, it is possible to provide an ink jet head, an ink jet recording apparatus, and a method for removing air bubbles from an ink jet head that can efficiently remove residual bubbles in an ink storage chamber provided with a filter.

1 is a schematic configuration diagram of a main part showing an example of an ink jet recording apparatus according to the present invention. Partial enlarged sectional view of the inkjet head shown in FIG. The perspective view which shows an example of the flow volume adjustment member which shows the state which notched the ink collection pipe partially The figure explaining the bubble removal method of the inkjet head which concerns on this invention Schematic configuration diagram showing another example of the inkjet head according to the present invention in a partial cross section Schematic configuration diagram showing a partial cross-section of yet another example of an inkjet head according to the present invention 1 is a schematic configuration diagram showing a partial cross section of an example of an ink jet recording apparatus according to the present invention.

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

(Inkjet recording device)
FIG. 1 is a schematic configuration diagram of a main part showing an example of an ink jet recording apparatus according to the present invention, and shows an ink jet head partially in cross section.

  The ink jet recording apparatus 100 records an image by ejecting ink from the ink jet head 1 onto a recording medium transported in a certain direction (sub-scanning direction) by a transport unit (not shown). The inkjet head 1 is mounted on a carriage (not shown), and ejects ink from a nozzle toward a recording medium in a process in which the carriage moves along a main scanning direction orthogonal to the sub-scanning direction. In the ink jet recording apparatus 100 shown in the present embodiment, the ink jet head 1 is installed such that main scanning is performed in the horizontal direction, and the ink ejection direction from the nozzles is downward in the vertical direction. However, the inkjet head 1 may be installed in an inclined manner in the inkjet recording apparatus 100.

  In FIG. 1, only one ink jet head 1 is shown, but in general, an ink jet recording apparatus 100 is provided for each color ink such as yellow (Y), magenta (M), cyan (C), and K (black). A plurality of inkjet heads 1 are mounted. In the ink jet recording apparatus 100 shown in the present embodiment, an ink tank 101 that stores ink and an ink storage chamber 41 of the ink jet head 1 communicate with each other through an ink transfer pipe 102 and an ink return pipe 103.

  A circulation pump 105 that is driven and controlled by the control unit 104 of the inkjet recording apparatus 100 is provided in the middle of the ink transfer pipe 102. When the circulation pump 105 is driven, the ink in the ink tank 101 is supplied to the inkjet head 1 through the ink transfer pipe 102. In addition, when the circulation pump 105 is driven, the ink (ink including air bubbles) in the inkjet head 1 is returned to the ink tank 101 via the ink return pipe 103. In the ink jet recording apparatus 100, the ink transfer pipe 102, the control unit 104, and the circulation pump 105 constitute ink transfer means for transferring the ink in the ink tank 101 to the ink jet head 1.

  The ink tank 101 is not particularly limited, but is preferably partitioned into an ink transfer chamber 101b and an ink return chamber 101c by a partition plate 101a that does not reach the bottom of the tank. In this case, one end of the ink transfer tube 102 is arranged in the ink transfer chamber 101b, and one end of the ink return tube 103 is arranged in the ink return chamber 101c. The partition plate 101a is provided in order to sufficiently degas the ink so that bubbles in the ink returned to the ink return chamber 101c do not flow into the ink transfer tube 102 again. Since the bubbles themselves have high buoyancy, the bubbles are restricted from flowing under the partition plate 101a and flowing into the ink transfer chamber 101b. Such an embodiment is a preferred embodiment when the ink is circulated.

(Inkjet head)
Next, a specific configuration of the inkjet head 1 according to the present invention shown in FIG. 1 will be described. FIG. 2 is a partially enlarged cross-sectional view of the inkjet head 1.

  The ink jet head 1 shown in the present embodiment is installed and used such that the ink discharge surface 1S faces downward in the vertical direction. However, the inkjet head 1 may be installed and used while being inclined. In the present specification, “upper” and “lower” mean “upper side in the vertical direction” and “lower side in the vertical direction”, and correspond to the upper side and the lower side in the side view showing the use state of FIG.

  As shown in FIG. 1, the inkjet head 1 includes an ink manifold 4 constituting an ink storage chamber 41, a substrate 3 bonded to the ink manifold 4, and a surface (on the opposite side of the ink manifold 4 across the substrate 3) ( And the head chip 2 bonded to the lower surface.

  The ink manifold 4 is formed in a horizontally long box shape having an opening 4a on the lower surface, using synthetic resin or the like. A substrate 3 is bonded to the ink manifold 4 so as to close the opening 4a on the lower surface. The internal space of the ink manifold 4 becomes an ink storage chamber 41 in which ink transferred from the ink tank 101 is stored.

  The ink manifold 4 is provided with an ink supply pipe 5 a that forms a flow path for supplying ink into the ink storage chamber 41. The ink supply pipe 5 a communicates with the ink storage chamber 41 on the side (upper side) far from the pressure chamber 23. A connecting portion 7a is provided on the upper end side of the ink supply pipe 5a. The connecting portion 7a is detachably connected to the connecting portion 106a on the ink jet recording apparatus 100 side. The connecting portion 106 a on the ink jet recording apparatus 100 side communicates with the ink transfer tube 102. As a result, the ink jet head 1 can transfer ink from the ink jet recording apparatus 100.

  Further, the ink manifold 4 is provided with an ink collection pipe 5 b that forms a flow path for collecting ink from the ink storage chamber 41. The ink recovery pipe 5 b communicates with the ink storage chamber 41 on the side farther from the pressure chamber 23 (upper side). A connecting portion 7b is provided on the upper end side of the ink recovery tube 5b. The connecting portion 7b is detachably connected to the connecting portion 106b on the ink jet recording apparatus 100 side. The connection part 106 b on the ink jet recording apparatus 100 side communicates with the ink return pipe 103. As a result, the ink jet head 1 can return ink to the ink jet recording apparatus 100.

  In the inkjet head 1, a flow path from the ink supply pipe 5a to a later-described junction 46 of the recovery pipe 5b is a main flow path F1.

  The ink supply pipe 5a and the ink recovery pipe 5b are preferably arranged apart from both ends of the ink storage chamber 41 in the longitudinal direction. In the present embodiment, the ink supply pipe 5a is disposed at the left end in FIG. 1 on the top surface of the ink manifold 4, and the ink recovery pipe 5b is on the right end in FIG. Is arranged. Thereby, the ink supplied from the ink supply pipe 5a to the ink storage chamber 41 can be made to flow over the entire inside of the ink storage chamber 41 toward the ink recovery pipe 5b. Accordingly, it is difficult to form a portion where ink stays in the ink storage chamber 41, and bubbles in the ink can be more efficiently removed.

  In the ink storage chamber 41, a filter 42 formed of, for example, a mesh-like metal or resin porous body is disposed so as to divide the ink storage chamber 41 into two. With this filter 42, the ink storage chamber 41 is divided into an upstream ink chamber 411 far from the head chip 2 and a downstream ink chamber 412 near the head chip 2 with the filter 42 interposed therebetween.

  The filter 42 prevents bubbles and impurities contained in the ink supplied from the ink supply pipe 5 a into the ink storage chamber 41 from entering the downstream ink chamber 412.

  In the present invention, the filter 42 is one of the pressure loss elements when the ink supplied to the ink storage chamber 41 flows into the downstream ink chamber 412. As other pressure loss elements, the length of the pipe, the number of bent parts of the pipe, and the like can be considered. The circulation pump 105 generates a pressure P0 that exceeds the pressure loss ΔP due to pressure loss factors such as the length of the filter 42 and the pipe and the number of bent parts of the pipe.

  As shown in FIG. 2, the downstream ink chamber 412 communicates with all the pressure chambers 23 formed in the head chip 2 through the injection holes 31 formed in the substrate 3. A plurality of pressure chambers 23 are formed in the head chip 2. The injection hole 31 is formed corresponding to each pressure chamber 23. The ink in the downstream ink chamber 412 is injected into all the pressure chambers 23 through the injection holes 31 in common.

  The substrate 3 is, for example, a glass substrate, and has a wiring (not shown) for applying a voltage to the drive electrode formed on the drive wall 24 serving as a partition between the pressure chambers 23. Each pressure chamber 23 undergoes volume fluctuations when a voltage is applied to the drive electrode of the drive wall 24.

  In the head chip 2, a nozzle plate 21 having nozzles 22 corresponding to the pressure chambers 23 is bonded to the opposite surface (lower surface) of the substrate 3. The lower surface portion of the nozzle plate 21 becomes the ink ejection surface 1S. The nozzle 22 communicates with the lower end of the pressure chamber 23. The pressure chamber 23 applies a discharge pressure to the ink inside and discharges the ink from the nozzle 22.

  The number of the pressure chambers 23 formed in the head chip 2 is not particularly limited. In the head chip 2 shown in this embodiment, a plurality of pressure chambers 23 are arranged along the X direction in FIG. 2, which is the longitudinal direction of the head chip 2.

  Any specific means for applying discharge pressure to the ink in the pressure chamber 23 can be used, and any known means can be employed. In this embodiment, the adjacent pressure chambers 23 and 23 are separated by a drive wall 24 formed of a piezoelectric element. The driving wall 24 is applied to a driving electrode (not shown) formed on the surface facing the pressure chamber 23 by applying a driving voltage of a predetermined voltage from the control unit 104 via a wiring (not shown) formed on the substrate 3, for example. Shear deformation. When the drive walls 24, 24 on both sides of the pressure chamber 23 undergo shear deformation, the inside of the pressure chamber 23 expands or contracts. As a result, pressure is applied to the ink in the pressure chamber 23, and the ink is ejected from the nozzle 22.

  In the downstream ink chamber 412, a damper member 43 in which a gas is sealed is disposed. The damper member 43 is disposed at a predetermined distance from the substrate 3 with the damper surface 431 formed of a flexible film facing the substrate 3. The damper member 43 absorbs a pressure wave propagating from each pressure chamber 23 to the downstream ink chamber 412 when ink is ejected. Thereby, the influence of the pressure wave generated in the pressure chamber 23 on the other pressure chambers 23 via the downstream ink chamber 412 can be reduced.

  As shown in FIG. 1, the ink manifold 4 is provided with an ink discharge pipe 5 c that forms a flow path for discharging ink from the downstream ink chamber 412. The upper end side of the ink discharge pipe 5c joins the ink recovery pipe 5b. The ink recovery pipe 5 b and the ink discharge pipe 5 c are joined together by being connected to the junction box 6. The junction box 6 can be integrally formed of a synthetic resin material or a metal material, and a space serving as a junction point 46 is formed therein.

  First to third openings 6 a, 6 b, 6 c reaching the junction 46 are formed on the outer surface of the junction box 6. The flow path from the first opening 6a through the junction 46 to the third opening 6c is interposed in the middle of the ink recovery pipe 5b. As a mounting state, the ink recovery pipe 5b is divided into an upstream side and a downstream side in the middle part, the upstream side is connected to the first opening 6a, and the downstream side is connected to the third opening 6c. Then, the ink discharge pipe 5c is connected to the second opening 6b.

  In the inkjet head 1, a flow path that passes through the filter 42, passes through the downstream ink chamber 412 and the ink discharge pipe 5c, and reaches the junction 46 becomes a sub flow path F2.

  As described above, since the ink recovery pipe 5b and the ink discharge pipe 5c are joined together by the junction box 6 in the inkjet head 1 shown in the present embodiment, the connection portion with the piping on the inkjet recording apparatus 100 side has an ink supply. Only two places of the pipe 5a (connection portion 7a) and the ink recovery pipe 5b (connection portion 7b) are required. Therefore, the number of connection parts with piping or the like on the ink jet recording apparatus 100 side does not increase with respect to a general ink jet head, and the connection work does not become complicated.

  Further, the ink jet head 1 shown in the present embodiment is connected to the connection portions 106a and 106b on the ink jet recording apparatus 100 side only at two locations of the ink supply tube 5a (connection portion 7a) and the ink recovery tube 5b (connection portion 7b). Therefore, it is compatible with the ink jet head of an existing ink jet recording apparatus having a circulation mechanism. That is, in general, an ink jet recording apparatus having a circulation mechanism for circulating the ink in the ink manifold 4 has a structure in which each ink jet head is connected by piping at two places, an ink supply unit and a recovery unit. Therefore, according to the inkjet head 1 of the present embodiment, replacement and installation can be performed by connecting only the two connection portions 7a and 7b without changing the design of the existing apparatus.

  A check valve 8a is disposed on the downstream side of the junction 46 of the ink recovery pipe 5b. The check valve 8a functions to allow the ink to be collected from the ink storage chamber 41 and to block the flow of ink in the opposite direction. By providing the check valve 8a, it is possible to prevent bubbles and foreign substances from entering the upstream ink chamber 411 and the downstream ink chamber 412 due to the back flow of ink.

  The check valve 8a is preferably arranged at a position higher than the junction 46 of the main flow path F1 and the sub flow path F2. As long as this condition is satisfied, the ink jet head 1 may be disposed in an inclined manner in the ink jet recording apparatus. Since the check valve 8a is higher than the junction 46, the bubbles in the ink collected from the ink storage chamber 41 are collected in the vicinity of the check valve 8a, and the combined and enlarged bubbles pass through the check valve 8a. Thus, it is possible to reliably prevent the bubbles from returning to the ink storage chamber 41.

  Further, the check valve 8 a is preferably arranged at a position where the upper end portion thereof is lower than the ink surface 101 s in the ink tank 101. As long as this condition is satisfied, the ink jet head 1 may be disposed in an inclined manner in the ink jet recording apparatus. Since the check valve 8a is lower than the ink surface 101s, the ink can be circulated well in the inkjet head 1. Further, the check valve 8a functions to suppress an increase in internal pressure in the inkjet head 1 without hindering ink circulation and to prevent meniscus breaks in which ink overflows from the nozzles 22.

  The check valve 8a is preferably arranged at a position where the ink collected from the ink storage chamber 41 flows upward. As long as this condition is satisfied, the ink jet head 1 may be disposed in an inclined manner in the ink jet recording apparatus. When the ink does not flow due to the ink flowing upward in the check valve 8a, the check valve 8a is closed by gravity.

  By the way, in this ink jet head, the flow path resistance of the sub flow path F2 is increased by the filter 42 and the like. Therefore, even if the ink discharge pipe 5c is merged with the ink recovery pipe 5b, a lot of ink flows from the ink supply pipe 5a through the main flow path F1 through the ink recovery pipe 5b, and passes through the filter 42 and the ink discharge pipe 5c. The flow rate of the flow path F2 is small.

  Therefore, the ink jet head 1 includes a pressure loss adjusting unit that adjusts the relative relationship between the channel resistance of the main channel F1 and the channel resistance of the sub-channel F2. This pressure loss adjusting means applies a pressure loss ΔP corresponding to the flow path resistance of the sub flow path F2 to the main flow path F1. Alternatively, the pressure loss adjusting means reduces the flow resistance of the sub flow path F2 to correspond to the flow resistance of the main flow path F1. The channel resistance of the sub-channel F2 is mainly the channel resistance due to the filter 42.

  In the inkjet head 1, the main flow path is adjusted by the ink pressure P0 in the ink supply pipe 5a by balancing the flow resistance of the main flow path F1 and the flow resistance of the sub flow path F2 by the pressure loss adjusting means. Ink can flow evenly in both F1 and the subchannel F2.

  An example of the pressure adjusting means is shown in FIG. FIG. 3 is a perspective view showing a state in which the ink recovery pipe 5b provided with an example of the pressure adjusting means is partially broken.

  As the pressure loss adjusting means, for example, as shown in FIG. 3A, a flow rate adjusting member 9 that partially narrows the cross-sectional area of the ink recovery pipe 5b can be used. The flow rate adjusting member 9 is a member that is held in the ink recovery tube 5b and partially narrows the inner diameter of the ink recovery tube 5b.

  In the flow rate adjusting member 9 of this embodiment, large diameter portions 92 and 92 having a larger diameter than the small diameter portion 91 are integrally formed on both ends of the small diameter portion 91 in a coaxial manner. The material of the flow rate adjusting member 9 is not particularly limited, and examples thereof include metals such as stainless steel, ceramics, and synthetic resins that are excellent in ink impermeability, easy to insert into the ink recovery tube 5b, and excellent in corrosion resistance against ink.

  The outer diameters of the large diameter portions 92 and 92 are formed such that their outer peripheral surfaces can be in close contact with the inner peripheral surface of the ink recovery tube 5b. Therefore, after the flow rate adjusting member 9 is inserted into the ink recovery tube 5b, the large diameter portions 92 and 92 are held in a predetermined position in the ink recovery tube 5b by being in close contact with the inner peripheral surface of the ink recovery tube 5b. Is done.

  A groove portion 93 extending along the axial direction is formed in a part of the outer peripheral surface of the large diameter portion 92 on the ink inflow side. Due to the groove 93, air bubbles in the ink flow between the inner wall of the ink recovery tube 5b and the small diameter portion 91, and this air is trapped. Since this air is in contact with the ink in the ink recovery tube 5b, it plays the role of a damper. The role of the damper is to prevent the carriage vibration from propagating inside the head. When the ink is deaerated, the air between the inner wall of the ink recovery tube 5b and the small diameter portion 91 decreases, but this air is filled by the gas permeability of the tube.

  The flow rate adjusting member 9 is formed with a small-diameter portion 91 and a flow passage hole 94 extending vertically through the large-diameter portions 92 and 92. Since the large diameter portions 92 and 92 are in close contact with the inner peripheral surface of the ink recovery pipe 5b, the flow path of the ink recovery pipe 5b at the portion where the flow rate adjusting member 9 is disposed is only the flow path hole 94. Accordingly, the flow rate adjusting member 9 partially narrows the flow path cross-sectional area of the ink recovery pipe 5b by the flow path hole 94, and causes the pressure of the ink flowing in the ink recovery pipe 5b to be lost.

  The pressure loss ΔP applied by the flow rate adjusting member 9 is a pressure loss ΔP corresponding to the flow path resistance of the sub flow path F2, and is adjusted by the inner diameter of the flow path hole 94. The pressure loss ΔP balances the flow resistance of the main flow path F1 and the flow resistance of the sub flow path F2. That is, the ink pressure P0 in the ink supply pipe 5a is reduced to the pressure P1 immediately before the confluence 46 of the main flow path F1, and becomes substantially equal to the pressure P2 immediately before the confluence 46 of the sub flow path F2. Further, the ink pressure P0 in the ink supply pipe 5a is substantially equal to the pressure applied by the circulation pump 105. The pressure P2 of the sub flow path F2 is set to be smaller than the pressure Px at which the meniscus break occurs so that the meniscus break from the nozzle 22 does not occur. That is, when P0 = −XPa, the decompression after the merging is performed so that P2 = −YPa, and by giving a pressure loss ΔP = (Y−X) Pa such that P1 = −YPa. [P1 = (P0−ΔP) = P2 <Px]. As a result, the ink pressure P0 in the ink supply pipe 5a allows the ink to flow evenly in both the main flow path F1 and the sub flow path F2.

  Note that the pressure P2 may fluctuate when, for example, a nozzle discharge failure occurs. Therefore, the balance between the flow resistance of the main flow path F1 and the flow resistance of the sub flow path F2 indicates that the pressure P1 and the pressure P2 are substantially equal (± 10%) within a range where the effect of the present invention is achieved. .

  The ink pressure P0 can be measured with a manometer at the tip of the ink supply pipe 5a provided with a T-shaped branch. The pressure P1 can be measured with a manometer at the tip of the ink recovery pipe 5b (downstream from the flow rate adjusting member 9 and upstream from the junction 46) where a T-shaped branch is provided. The pressure P2 can be measured with a manometer at the tip of the ink discharge pipe 5c (upstream from the junction 46) provided with a T-shaped branch.

  The specific inner diameter of the flow path hole 94 of the flow rate adjusting member 9 is appropriately adjusted so that the pressure loss of the ink recovery pipe 5b becomes a desired pressure loss in consideration of the pressure loss due to the pressure loss element such as the filter 42. The For example, if the inner diameter of the flow path hole 94 of the flow rate adjusting member 9 is adjusted so that the ink flow rate recovered from the ink recovery pipe 5b and the ink flow rate discharged from the ink discharge pipe 5c are uniform, the main flow path Ink can flow evenly in both F1 and the subchannel F2. Accordingly, since ink can be quickly stored in the upstream ink chamber 411 (main flow path F1) and the downstream ink chamber 412 (sub flow path F2), particularly when the ink is initially introduced. This is a preferred embodiment.

  According to the ink jet head 1 and the ink jet recording apparatus 100 including the ink jet head 1, the residual bubbles in the upstream ink chamber 411 are discharged from the ink recovery pipe 5 b through the main flow path F 1 only by supplying ink from the ink supply pipe 5 a. In addition, the remaining bubbles in the downstream ink chamber 412 can be discharged from the ink discharge pipe 5c through the sub-flow path F2. Therefore, the entire remaining bubbles in the ink manifold 4 can be efficiently removed.

  Further, according to the ink jet head 1 and the ink jet recording apparatus 100 including the ink jet head 1, when the ink is circulated between the ink tank 101 during image recording, the ink in the downstream ink chamber 412 is also subsidized. It can be efficiently circulated through the flow path F2. For this reason, air bubbles drawn from the nozzles 22 during image recording can be quickly discharged. In addition, when ink containing particles or pigments that easily settle is used, the sedimentation of the particles or pigments in the downstream ink chamber 412 during image recording is effectively suppressed, and the ink density deviation is reduced. Can be suppressed.

  By adjusting the inner diameter of the flow path hole 94 of the flow rate adjusting member 9, the ink flow rate recovered from the ink recovery pipe 5b (main flow path F1) and the ink flow rate discharged from the ink discharge pipe 5c (sub flow path) F2) can be different. For example, the flow rate resistance of the flow rate adjusting member 9 is increased so that the ink flow rate (sub-flow channel F2) discharged from the ink discharge tube 5c is higher than the ink flow rate (main flow channel F1) recovered from the ink recovery tube 5b. By increasing the number (increasing the flow rate of the sub-channel F2), it is possible to more easily remove bubbles that are attached around the pressure chamber 23 and are difficult to remove. Conversely, the flow resistance of the flow rate adjusting member 9 can be lowered to increase the flow rate in the main flow path F1 (increase the flow rate of the main flow path F1) than in the sub flow path F2. In this case, it is possible to easily remove bubbles adhering to the ceiling surface and corners in the main channel F1. Further, in this case, bubbles that are likely to remain around the damper member 43 can be easily removed.

  The flow rate adjusting member 9 shown in FIG. 3A is merely an example, and the specific structure is not limited to that shown in FIG. For example, the large diameter portion 92 may be provided only on the ink outflow side. Further, when the flow rate adjusting member 9 does not need to have a damper function, the small diameter portion 91 may not be provided.

  When there is no need for the flow rate adjusting member 9 to function as a damper, or when a large amount of bubbles may flow through the main flow path F1, as shown in FIG. The length of the channel hole 94 is preferably shortened. The flow rate adjusting member 9 shown in FIG. 3B has a cylindrical portion 95 along the inner wall of the ink recovery tube 5b and a disk portion 96 that closes one end of the cylindrical portion 95, and is integrally configured. ing. A flow path hole 94 is formed in the center of the disk portion 96. By shortening the length of the flow path hole 94 of the flow rate adjusting member 9 in this way, fluctuations in flow path resistance when bubbles enter the flow path hole 94 can be suppressed, and variations in flow velocity can be suppressed. The length of the flow path hole 94 of the flow rate adjusting member 9 shown in FIG. 3A is about 14 mm, for example, but the length of the flow path hole 94 of the flow rate adjusting member 9 shown in FIG. For example, it is about 0.5 mm. By setting the length of the channel hole 94 to about 0.5 mm, it is possible to suppress variation in channel resistance due to bubbles.

  The flow rate adjusting member 9 can also be disposed in the junction box 6 between the first opening 6 a and the junction 46. In this case, a desired pressure loss can be imparted to the ink recovery pipe 5b simply by interposing the junction box 6 to the ink recovery pipe 5b. Further, when the flow rate adjusting member 9 is to be changed or exchanged, the junction box 6 can be exchanged, and the exchange can be performed quickly and easily. Furthermore, even when foreign matter adheres to the vicinity of the flow rate adjusting member 9 and is contaminated, the neat state can be quickly and easily obtained by replacing the junction box 6.

(Bubble removal method for inkjet head)
Next, in the ink jet head 1 configured as described above, a method of removing residual bubbles in the ink storage chamber 41 when ink is initially introduced will be described with reference to FIGS. 1 and 4.

  The bubble removing operation in the inkjet recording apparatus 100 is performed by controlling the driving of the circulation pump 105 according to a predetermined program stored in advance in the control unit 104, for example.

  First, the control unit 104 drives the circulation pump 105 to cause the ink in the ink tank 101 to flow into the upstream ink chamber 411 in the ink manifold 4 from the ink supply pipe 5a at a predetermined pressure. The ink flowing into the upstream ink chamber 411 flows through the main flow path F1 through the upstream ink chamber 411 toward the ink recovery pipe 5b (FIG. 4A).

  Here, since the flow rate adjusting member 9 in consideration of the pressure loss ΔP of the auxiliary flow path F2 is provided in the ink recovery tube 5b, the ink recovered from the ink recovery tube 5b is the flow rate adjusting member 9. Some are stopped and some ink pressure is lost. The pressure ΔP corresponding to the loss is a pressure at which ink can pass through the sub-channel F2 by appropriately adjusting the inner diameter of the channel hole 94. Accordingly, a part of the ink flowing through the main flow path F1 in the upstream ink chamber 411 flows through the filter 42 and also into the sub flow path F2 in the downstream ink chamber 412 (FIG. 4B).

  As a result, the ink storage chamber 41 has a flow of ink recovered from the ink recovery pipe 5b as it is through the main flow path F1 and a flow of ink discharged from the ink discharge pipe 5c through the sub flow path F2. Formed simultaneously.

  Accordingly, the ink supplied to the ink storage chamber 41 flows out from both the ink recovery pipe 5b and the ink discharge pipe 5c. At this time, the remaining bubbles in the upstream ink chamber 411 are collected together with the ink from the ink collection tube 5b, and the remaining bubbles in the downstream ink chamber 412 are discharged together with the ink from the ink discharge tube 5c (FIG. 4C). )).

  The control unit 104 stops the driving of the circulation pump 105 after continuing for a predetermined time set in advance. In addition, for example, a sensor for detecting bubbles in the ink is provided in the ink return pipe 103, and when this sensor no longer detects bubbles in the ink flowing in the pipe, the driving of the circulation pump 105 is stopped. Also good. Thereby, the bubble removing operation is completed, and the upstream ink chamber 411 and the downstream ink chamber 412 are filled with ink.

  As described above, the ink jet head 1 not only collects ink from the ink collection pipe 5b through the main flow path F1 but also discharges ink through the sub flow path F2 only by supplying ink to the ink storage chamber 41. Ink can also be discharged from the tube 5c. It is not necessary to operate the on-off valve or the like to remove the bubbles and individually flow the ink to the main flow path F1 and the sub flow path F2, so that the structure of the ink jet head 1 is not complicated and the ink storage chamber 41 and each Residual bubbles around the pressure chamber 23 can be efficiently removed.

  Further, since the ink containing bubbles can flow out from both the upstream ink chamber 411 and the downstream ink chamber 412, the bubble removal can be performed as compared with the case where the upstream ink chamber 411 and the downstream ink chamber 412 are individually used. Can be shortened, and the ink consumption for removing bubbles can be suppressed.

  The above bubble removal operation can be performed not only when ink is initially introduced but also when an image is recorded on a recording medium. That is, by driving the circulation pump 105 during image recording, not only the ink in the upstream ink chamber 411 but also the ink in the downstream ink chamber 412 can be circulated. Thereby, the ink circulation not only removes bubbles even during image recording, but also supplies homogeneous ink with no density deviation to each pressure chamber 23. For this reason, a higher quality image can be formed.

(Other embodiment of check valve)
The ink discharge pipe 5c may be provided with a second check valve 8b as shown in FIG. FIG. 5 is a schematic configuration diagram of a main part showing another example of the ink jet recording apparatus according to the present invention, in which the ink jet head is partially shown in cross section. Since the site | part of the same code | symbol as FIG. 1 is a site | part of the same structure, these description uses the said description and abbreviate | omits here.

  The second check valve 8b functions to allow the ink to flow from the downstream ink chamber 412 toward the confluence 46 and to block the ink flow in the opposite direction. For example, when the filter 42 is clogged by contaminants contained in the ink and the pressure P2 of the sub flow path F2 is reduced, a pressure difference is generated between the pressure P1 of the main flow path F1 in the upstream ink chamber 411. In this case, the ink recovered from the ink recovery tube 5b may flow back to the ink discharge tube 5c through the junction 46. By providing the second check valve 8b in the ink discharge pipe 5c, it is possible to prevent bubbles and foreign substances from entering the downstream ink chamber 412 due to the back flow of the ink.

  Further, as will be described later, when the ink in the downstream ink chamber 412 is sucked from the ink discharge pipe 5c, the second check valve 8b is necessary to prevent the backflow of the ink to the ink discharge pipe 5c. It is. The two check valves 8a and 8b can reliably prevent the backflow of ink from the outflow side. Since the second check valve 8b is also one of the pressure loss elements, the check valve cracking pressure (opening pressure) should be low, and the pressure Px (for example, 5 kPa) at which the meniscus break from the nozzle 22 occurs. Degree). In order to reliably prevent meniscus breakage from the nozzle 22, the ink return pipe 103 is not pressurized by the circulation pump 105 (downstream from the junction 46 between the ink recovery pipe 5b and the ink discharge pipe 5c). A suction pump may be provided on the side, and the ink may be circulated only by the negative pressure generated by the suction pump. Also in this case, it can be said that the ink circulates in both the main flow path F1 and the sub flow path F2 by the ink pressure in the ink supply pipe 100. .

(Other embodiments of pressure loss adjusting means)
In the present invention, the pressure loss adjusting means provided in the ink recovery pipe 5b is not limited to the flow rate adjusting member 9 described above. For example, although not shown, a flow rate adjustment valve may be provided in the ink recovery pipe 5b, and the pressure loss ΔP may be applied by partially narrowing the cross-sectional area of the ink recovery pipe 5b. Appropriate pressure loss ΔP can be applied to the ink recovery pipe 5b by appropriately adjusting the opening of the flow rate adjusting valve. Further, the pressure loss adjusting means provided in the ink recovery pipe 5b may be a check valve. Further, when the ink recovery tube 5b is formed of a flexible tube, the pressure loss ΔP is applied by partially narrowing the cross-sectional area of the flow path using a sandwiching member or the like from the outside of the ink recovery tube 5b. May be.

  Further, the pressure loss adjusting means is not limited to the one provided in the ink recovery pipe 5b (main flow path F1) like the flow rate adjusting member 9 shown in FIGS. 1 and 5, but the ink discharge as shown in FIG. It can also be provided in the pipe 5c (sub-flow path F2). FIG. 6 is a schematic configuration diagram of a main part showing another example of the ink jet recording apparatus according to the present invention, in which the ink jet head is partially shown in cross section. Since the site | part of the same code | symbol as FIG. 1 is a site | part of the same structure, these description uses the said description and abbreviate | omits here.

  The pressure loss adjusting means in FIG. 6 is constituted by a suction pump 10 provided in the ink discharge pipe 5c. The suction pump 10 is driven by the control of the control unit 104, and forcibly sucks the ink in the ink discharge pipe 5c toward the confluence 46 side. As a result, the pressure loss of the sub flow path F2 is reduced, and the pressure loss of the main flow path F1 is relatively increased with respect to the pressure loss of the sub flow path F2. As a result, the ink flow rate in the sub-flow path F2 where it is difficult for ink to flow due to pressure loss due to the filter 42 or the like is increased. The driving amount (suction amount) of the suction pump 10 at this time is appropriately adjusted by the control unit 104 so that a part of the ink supplied to the ink storage chamber 41 also flows into the sub flow path F2. When the suction pump 10 is provided in this way, it is preferable to provide a check valve 8 in the ink discharge pipe 5c.

  According to the ink jet head 1 provided with such a suction pump 10, not only the ink is recovered from the ink recovery pipe 5b through the main flow path F1, but also the sub flow path only by supplying the ink to the ink storage chamber 41. Since ink can also be discharged from the ink discharge pipe 5c through F2, as in the case where the flow rate adjusting member 9 is provided, there is an effect that the residual bubbles in the ink storage chamber 41 can be efficiently removed. can get.

  Further, the suction pump 10 can appropriately adjust the ink flow rate by controlling the drive amount. Therefore, by adjusting the driving amount of the suction pump 10, not only the ink flow rate recovered from the ink recovery tube 5b and the ink flow rate discharged from the ink discharge tube 5c are made uniform, but also the ink flow rate is higher than that of the ink recovery tube 5b. It is also possible to easily change the ink flow rates flowing out from the ink recovery tube 5b and the ink discharge tube 5c, such as increasing the ink flow rate discharged from the discharge tube 5c.

  Furthermore, since the negative pressure is generated in the downstream ink chamber 412 by driving the suction pump 10, it is possible to suppress the wasteful discharge of the ink from the nozzles 22 when the ink is initially introduced.

  In the case where the suction pump 10 is provided in this way, it is also preferable that the inner diameter of the ink discharge pipe 5c is made smaller than the inner diameter of the ink recovery pipe 5b. When the inner diameter of the ink discharge pipe 5c is reduced, the pressure fluctuation in the downstream ink chamber 412 can be suppressed when the suction pump 10 is driven, and the ink flow rate can be easily adjusted.

  Further, when the pressure of the flow path is adjusted by pressure reduction using a circulation pump downstream from the junction 46, even if the flow resistance of the sub flow path F2 is large, the pressure difference is larger than the circulation by pressurization. It can be circulated. For example, [(P1 + ΔP) = P0> Px, P1 = P2].

(Another embodiment of inkjet head and inkjet recording apparatus)
In the ink jet head 1 and the ink jet recording apparatus 100 shown in FIG. 6, in addition to providing the suction pump 10 in the ink discharge pipe 5c, for example, the flow rate adjusting member 9 is provided in the ink recovery pipe 5b, and these are used together when removing bubbles. It is also preferable. Since the pressure loss is applied by the flow rate adjusting member 9 provided in the ink recovery pipe 5b, the driving amount of the suction pump 10 can be reduced accordingly. Thereby, the suction pump 10 may be a low capacity pump, and the initial cost and running cost can be reduced.

  As described above, when the flow rate adjusting member 9 of the ink recovery pipe 5b and the suction pump 10 of the ink discharge pipe 5c are used in combination, the ink recovery pipe 5b is compared with the case where the flow rate adjusting member 9 is simply provided in the ink recovery pipe 5b. It is also possible to set the pressure loss ΔP to be applied to a small value. For example, the flow rate adjusting member 9 can increase the inner diameter of the flow path hole 94 as compared with the case where the flow rate adjusting member 9 is not used together with the suction pump 10. For this reason, it is possible to use high-viscosity ink that does not easily flow in the narrow flow passage hole 94, and the types of usable ink can be expanded.

  Further, the check valve 8a is not limited to being provided in the inkjet head 1 as in the above-described embodiment, and may be provided in the inkjet recording apparatus 100. That is, as shown in FIG. The ink return tube 5b may be provided in the ink return tube 103 that is detachably mounted. Also in this case, when the ink jet head 1 is mounted on the ink jet recording apparatus 100, the check valve 8a is provided on the downstream side of the junction 46 of the main flow path F1 and the sub flow path F2. As described above, the same operations and effects as those provided in the middle of the ink recovery tube 5b are exhibited.

  In each embodiment described above, the merging of the main flow path F1 and the sub flow path F2 may be performed in the ink manifold 4. By merging in the ink manifold 4, it is possible to configure an inkjet head having no difference in outer shape from the conventional inkjet head.

  In the ink jet recording apparatus 100 described above, ink is circulated between the ink jet head 1 and the ink tank 101. However, the present invention is not limited to this. For example, if it is only necessary to remove residual bubbles at the time of initial ink introduction, ink that has flowed out of the ink recovery pipe 5b and the ink discharge pipe 5c is returned to the waste ink tank without returning to the ink tank 101. You may comprise so that it may discharge | emit.

1: Inkjet head 1S: Ejection surface 2: Head chip 21: Nozzle plate 22: Nozzle 23: Pressure chamber 24: Drive wall 3: Substrate 31: Injection hole 4: Ink manifold 41: Ink storage chamber 411: Upstream ink chamber 412 : Downstream ink chamber 42: filter 46: confluence 5a: ink supply pipe 5b: ink recovery pipe 5c: ink discharge pipe 6: confluence box 6a: first opening 6b: second opening 6b: third Openings 7a, 7b: Connection portion 8a: Check valve 8b: Second check valve 9: Flow rate adjusting member (pressure adjusting means)
10: Suction pump (pressure adjusting means)
DESCRIPTION OF SYMBOLS 100: Inkjet recording device 101: Ink tank 102: Ink transfer pipe 103: Ink return pipe 104: Control part 105: Circulation pump 106a, 106b: Connection part

Claims (25)

An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe that communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber without passing through the filter to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Pressure loss adjusting means for adjusting the relative relationship with the road resistance,
By balancing the flow resistance of the main flow path and the flow resistance of the sub flow path by the pressure loss adjusting means, both the main flow path and the sub flow path are controlled by the ink pressure in the ink supply pipe. An ink jet head characterized by causing ink to flow. The check valve according to claim 1, characterized in that it is located lower than the surface of the ink in the ink tank in which ink to be supplied to said ink reservoir chamber through the ink supply tube is stored The inkjet head as described. An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe which communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Pressure loss adjusting means for adjusting the relative relationship with the road resistance,
By balancing the flow resistance of the main flow path and the flow resistance of the sub flow path by the pressure loss adjusting means, both the main flow path and the sub flow path are controlled by the ink pressure in the ink supply pipe. ink to flow to,
The inkjet head according to claim 1, wherein the check valve is disposed at a position lower than an ink surface in an ink tank in which ink supplied to the ink storage chamber is stored through the ink supply pipe . The inkjet head according to any one of claims 1 to 3 , wherein a second check valve is provided on the upstream side of the confluence of the sub flow path. An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe which communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Pressure loss adjusting means for adjusting the relative relationship with the road resistance,
By balancing the flow resistance of the main flow path and the flow resistance of the sub flow path by the pressure loss adjusting means, both the main flow path and the sub flow path are controlled by the ink pressure in the ink supply pipe. ink to flow to,
An inkjet head , wherein a second check valve is provided on the upstream side of the junction point of the sub-flow path . The ink jet head according to claim 4, wherein the pressure loss adjusting unit sucks ink from the sub-flow path toward the confluence. The inkjet head according to claim 6, wherein the pressure loss adjusting means is a suction pump provided in the sub-flow path. The inkjet head according to any one of claims 1 to 7 , wherein an upper end portion of the check valve is disposed at a position higher than the merging point. The check valve, as claimed in any of claims 1-8, characterized in that ink is recovered through the ink recovery tube from said ink storage chamber is disposed in a position that flows upward Inkjet head. The pressure loss adjusting means, the ink-jet head according to any one of claims 1 to 9, wherein applying the pressure loss in the primary flow passage. 11. The ink jet head according to claim 10, wherein the pressure loss adjusting means has a flow path cross-sectional area of the ink recovery pipe narrower than a flow path cross-sectional area of the ink discharge pipe. The inkjet head according to claim 10, wherein the pressure loss adjusting means is a flow rate adjusting member that partially narrows a cross-sectional area of the main flow path. The inkjet head according to any one of claims 1 to 12 ,
An ink tank for storing ink to be supplied to the inkjet head;
An ink jet recording apparatus comprising: ink transfer means for transferring ink in the ink tank to the ink jet head. An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe that communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber without passing through the filter to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Using pressure loss adjusting means that adjusts the relative relationship with the road resistance,
By the action of the pressure loss adjusting means, the flow resistance of the main flow path and the flow resistance of the sub flow path are balanced, and both the main flow path and the sub flow path are adjusted by the ink pressure in the ink supply pipe. A method of removing bubbles in an ink jet head, wherein ink is allowed to flow through the ink jet head. 15. The check valve according to claim 14 , wherein the check valve is disposed at a position lower than an ink surface in an ink tank storing ink supplied to the ink storage chamber via the ink supply pipe. A method for removing bubbles from an inkjet head. An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe which communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Using pressure loss adjusting means that adjusts the relative relationship with the road resistance,
By the action of the pressure loss adjusting means, the flow resistance of the main flow path and the flow resistance of the sub flow path are balanced, and both the main flow path and the sub flow path are adjusted by the ink pressure in the ink supply pipe. ink to flow to,
An air bubble removal for an inkjet head , wherein the check valve is disposed at a position lower than the surface of ink in an ink tank storing ink supplied to the ink storage chamber via the ink supply pipe. Method. The method of removing bubbles in an ink jet head according to any one of claims 14 to 16 , wherein a second check valve is provided on the upstream side of the confluence of the sub flow path. An ink storage chamber;
At least one pressure chamber communicating with the ink storage chamber via an injection hole and causing a volume variation by application of a voltage;
A nozzle that communicates with the pressure chamber and discharges ink in the pressure chamber to the outside;
A filter disposed in the ink storage chamber and dividing the ink storage chamber into an upstream ink chamber far from the pressure chamber and a downstream ink chamber close to the pressure chamber;
An ink supply pipe forming a flow path for supplying ink into the upstream ink chamber;
An ink collection tube forming a flow path for collecting ink from the upstream ink chamber;
An ink discharge pipe which communicates with the downstream ink chamber and forms a flow path for discharging the ink in the downstream ink chamber to join the ink recovery pipe at a merging point;
A check valve provided downstream of the junction;
The flow resistance of the main flow path from the ink supply pipe to the confluence point of the ink recovery pipe, and the flow of the sub flow path from the upstream ink chamber through the filter to the confluence point through the downstream ink chamber. Using pressure loss adjusting means that adjusts the relative relationship with the road resistance,
By the action of the pressure loss adjusting means, the flow resistance of the main flow path and the flow resistance of the sub flow path are balanced, and both the main flow path and the sub flow path are adjusted by the ink pressure in the ink supply pipe. ink to flow to,
A method of removing bubbles in an ink jet head, comprising: providing a second check valve upstream of the confluence of the sub-flow path . The method of removing bubbles from an ink jet head according to claim 17 or 18, wherein the pressure loss adjusting means sucks ink from the sub-flow path to the confluence point side. 20. The ink jet head air bubble removing method according to claim 19 , wherein a suction pump is provided in the sub-flow path as the pressure loss adjusting means. 21. The method of removing air bubbles from an ink jet head according to claim 14 , wherein the check valve is disposed at a position higher than the junction. The inkjet head according to any one of claims 14 to 21 , wherein the check valve is disposed at a position where ink collected from the ink storage chamber via the ink collection pipe flows upward. Bubbles removal method. The method of removing air bubbles from an ink jet head according to any one of claims 14 to 22 , wherein the pressure loss is imparted to the main flow path by the pressure loss adjusting means. 24. The method of removing air bubbles from an ink jet head according to claim 23, wherein the pressure loss adjusting means is configured such that a cross-sectional area of the ink recovery pipe is narrower than a cross-sectional area of the ink discharge pipe. 24. The method of removing bubbles from an ink jet head according to claim 23 , wherein a flow rate adjusting member that partially narrows a cross-sectional area of the main flow path is used as the pressure loss adjusting means.

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