JP6997286B2 - Ink supply device - Google Patents

Description

Embodiments of the present invention relate to an ink supply device.

The inkjet recording device includes an inkjet head that ejects ink onto a recording medium such as paper, and an ink supply device that supplies ink to the inkjet head. As an inkjet recording device, an ink supply device provided with an ink circulation mechanism is known.

The ink supply device of this inkjet recording device includes a diaphragm-type first pump that feeds ink introduced from an external ink storage unit to the inkjet head. The ink supply device has a discharge chamber facing the discharge portion of the first pump. Ink is supplied from the ejection portion of the first pump to the inkjet head via the ejection chamber. The inkjet head includes an introduction passage for introducing the ink supplied from the first pump into the nozzle portion and a return passage for returning the ink not ejected at the nozzle portion to the ink supply device. The ink supply device further includes a second pump that returns the ink returned from the return passage to the ejection chamber.

However, in the above-mentioned conventional inkjet recording device, a first pump and a second pump that alternately suck and discharge ink by operating a diaphragm communicate with a common discharge chamber. Therefore, the first pump and the second pump may weaken each other's discharge pressure due to the difference between the discharge timing of the first pump and the discharge timing of the second pump. In this case, the pump functions of the first pump and the second pump cannot be efficiently used.

Japanese Unexamined Patent Publication No. 2015-107569

An object to be solved by the present invention is to provide an ink supply device capable of efficiently utilizing the pump functions of the first pump and the second pump.

The ink supply device of the embodiment includes a diaphragm type first pump, a diaphragm type second pump, and a control device. The first pump feeds the ink introduced from the ink reservoir to the inkjet head. The second pump sucks the ink not ejected from the inkjet head and supplies the ink to the upstream portion of the ink supply path connected to the inkjet head. The control device drives the first pump and the second pump with drive voltage waveforms having the same phase so that the discharge timings match.

The front view schematically showing the inkjet recording apparatus of an embodiment. The plan view which shows schematic the inkjet recording apparatus of embodiment. The perspective view of the inkjet unit of an embodiment. An exploded perspective view of the inkjet unit of the embodiment. FIG. 6 is a cross-sectional view taken along the line 5-5 of FIG. 3 of the inkjet unit of the embodiment. The block diagram which shows the structure of the pump drive system of the inkjet recording apparatus of embodiment. The sectional view which shows the suction part of the pump of an embodiment. The cross-sectional view which shows the discharge part of the pump of an embodiment. The sectional view which shows the suction part of the pump of an embodiment. The cross-sectional view which shows the discharge part of the pump of an embodiment. The figure which shows the drive waveform of the 1st pump and the 2nd pump of an embodiment. The figure which shows the relationship between the phase shift of the ejection phase of the 1st pump and the 2nd pump, and the total ejection flow rate of ink.

Hereinafter, the ink supply device 12 of the embodiment will be described with reference to the drawings. In each figure, the same parts are designated by the same reference numerals.
FIG. 1 is a front view of the inkjet recording apparatus 1 according to the embodiment in which a part of the casing 2 is broken. FIG. 2 is a plan view of the inkjet recording apparatus 1 according to the embodiment in which a part of the casing 2 is broken.

In the inkjet recording device 1, a feed table 3, a carriage 4, and a maintenance unit 5 are installed in a casing 2. The feed table 3 is slidably held by a feed guide rail 6 installed in the casing 2. The feed guide rail 6 extends linearly in a substantially horizontal direction. The feed table 3 is moved in a direction along the feed guide rail 6 by a motor (not shown). Further, the feed table 3 is provided with a negative pressure generating device 7 for sucking and fixing a sheet-shaped recording medium S such as a sheet of paper on the feed table 3. The recording medium S is not limited to paper, but may be a resin or metal film, a wood board, or the like.

The carriage 4 is slidably held by a scanning guide rail 8 installed in the casing 2. The scanning guide rail 8 extends linearly in a substantially horizontal direction orthogonal to the feeding guide rail 6. The carriage 4 is moved in a direction along the scanning guide rail 8 by a transport belt 9 driven by a motor (not shown).

A plurality of inkjet units 10 arranged along the scanning direction of the carriage 4 are mounted on the carriage 4. The inkjet unit 10 includes an inkjet head 11 that ejects ink onto a recording medium, and an ink supply device 12 that is coupled to the inkjet head 11 on the upper side of the inkjet head 11. The carriage 4 is equipped with a number of inkjet units 10 according to the type of ink jetted on the recording medium S. As the ink ejected from each inkjet unit 10, in addition to inks having different colors such as cyan, magenta, yellow, black, and white, transparent glossy ink, special ink that develops color when irradiated with infrared rays or ultraviolet rays, and the like can be used. ..

A corresponding ink cartridge 13 (ink storage unit) installed in the casing 2 is connected to the ink supply device 12 of each inkjet unit 10. The ink supply device 12 of each inkjet unit 10 and the corresponding ink cartridge 13 are connected by a flexible connecting tube 14.

The plurality of inkjet units 10 are collectively arranged on the carriage 4 and move together with the carriage 4 along the scanning guide rail 8. When the ink jet head 11 ejects ink onto the recording medium S on the feed table 3, the carriage 4 moves in a range intersecting the moving trajectory of the feed table 3. When the ink jet head 11 does not eject ink, the carriage 4 stops at a standby position deviating from the moving trajectory of the feed table 3 as shown in FIGS. 1 and 2.

When the plurality of inkjet units 10 return to the standby position together with the carriage 4, the maintenance unit 5 covers the ink jetting portion of each inkjet head 11 to prevent the ink from evaporating. Further, the maintenance unit 5 appropriately cleans the contact portion of the inkjet head 11 with the recording medium S when the plurality of inkjet units 10 return to the standby position.

The inkjet head 11 of each inkjet unit 10 includes a plurality of nozzle portions (not shown) for injecting ink onto the recording medium S, and actuators (not shown) arranged facing each nozzle portion. The actuator is composed of, for example, a piezoelectric diaphragm using piezoelectric ceramics. The structure of the actuator is not limited to this structure, and may be any other structure as long as it can increase the pressure of the ink in response to the input signal.

In the inkjet recording apparatus 1 according to this embodiment, when printing according to an input signal on the recording medium S, the carriage 4 on which the inkjet unit 10 is mounted and the feed table 3 on which the recording medium S is mounted are appropriately linearly aligned. While moving, ink is ejected from a specific nozzle portion corresponding to the input signal of the inkjet head 11.

In this embodiment, the recording medium S is sucked and fixed to the feed table 3, the feed table 3 is moved in one direction, and the inkjet unit 10 is moved in a direction orthogonal to the moving direction of the feed table 3. , Printing is performed on the recording medium S according to the input signal. However, the feeding method of the recording medium S and the recording medium S is not limited to this. For example, a roll-type recording medium such as a roll may be used, and printing may be performed on the recording medium with an inkjet head while pulling out the recording medium from the roll. Further, printing may be performed on the recording medium with the inkjet head while feeding the sheet-shaped recording media one by one by the platen roll.

FIG. 3 is a perspective view of the inkjet unit 10. FIG. 4 is an exploded perspective view of the inkjet unit 10. FIG. 5 is a cross-sectional view of the inkjet unit 10 along line 5-5 of FIG.
In the inkjet unit 10, the ink supply device 12 is integrally coupled to the upper portion of the inkjet head 11 as described above. The ink supply device 12 according to this embodiment provides a supply path for supplying ink introduced from an external ink cartridge 13 (ink storage portion) to the inkjet head 11 and ink not ejected from the nozzle portion of the inkjet head 11. It has a return route and a return route. As shown in FIGS. 4 and 5, the ink supply device 12 has a casing 17 containing a first pump 15 and a second pump 16. As shown in FIGS. 3 and 4, the casing 17 has an ink supply tube 18 for supplying ink to the nozzle portion of the inkjet head 11 and ink not ejected by the nozzle portion of the inkjet head 11 from the inkjet head 11. An ink return tube 19 for returning is provided.

The first pump 15 is a supply pump for replenishing the amount of ink consumed in printing, maintenance, and the like from the ink cartridge 13 and supplying the ink to the inkjet head 11. As shown in FIG. 5, a discharge chamber 20 is formed in the casing 17. The ejection chamber 20 is arranged so as to face the ejection portion 15a of the first pump 15 in the upstream portion of the ink supply path toward the inkjet head 11.

Inside the casing 17, a supply-side ink chamber 21 and a recovery-side ink chamber 22 that can temporarily store ink are formed. The supply-side ink chamber 21 is provided adjacent to the downstream portion of the discharge chamber 20 in the casing 17. An ink supply pipe 18 is connected to the supply side ink chamber 21. The ink stored in the supply-side ink chamber 21 is supplied to the inkjet head 11.

An ink return tube 19 is connected to the collection side ink chamber 22. Ink that has not been ejected by the inkjet head 11 flows into the collection side ink chamber 22 through the return tube 19. The collection side ink chamber 22 is arranged in the return path in the casing 17. The suction chamber 23 is adjacent to the downstream side of the return path. In the suction chamber 23, the suction portion 16b of the second pump 16 is arranged so as to face the suction chamber 23.

The second pump 16 is a recirculation pump for returning the ink flowing into the suction chamber 23 from the collection side ink chamber 22 to the discharge chamber 20. The discharge portion 16a of the second pump 16 is arranged so as to face the discharge chamber 20. The discharge portions 15a and 16a of the first pump 15 and the second pump 16 face the discharge chamber 20 side by side in parallel. The ink supply device 12 according to this embodiment uses the second pump 16 as a drive source to circulate the ink with the inkjet head 11.

Further, the upper part of the ink liquid surface in the supply side ink chamber 21 and the collection side ink chamber 22 is an air chamber. The pressure in each air chamber is detected by a pressure sensor (not shown). As shown in FIGS. 3 and 4, a pressure adjusting unit 24 is provided on the upper portion of the casing 17. The pressure adjusting unit 24 adjusts the pressure of the ink supplied to the inkjet head 11 to an appropriate pressure according to the detection result of the pressure sensor.

The casing 17 of the ink supply device 12 is formed in a substantially rectangular parallelepiped shape as a whole. When the inkjet unit 10 is mounted on the carriage 4 (see FIGS. 1 and 2), the casing 17 has a depth in which the dimension W in the width direction that matches the scanning direction of the carriage 4 matches the feed direction of the feed table 3. It is shorter than the dimension in the direction D and the dimension in the height direction H. As shown in FIGS. 4 and 5, the casing 17 is coupled to the casing main body 17A in which the supply side ink chamber 21 and the recovery side ink chamber 22 are formed, and to one side of the casing main body 17A in the width direction W. It is equipped with a pump unit case 17B. The casing 17 further includes a unit cover 17C that is coupled to the pump unit case 17B in a state where the pump unit 25, which will be described later, is sandwiched between the casing 17 and the pump unit case 17B.

The supply-side ink chamber 21 and the collection-side ink chamber 22 are arranged side by side in parallel in the depth direction D in the casing main body 17A, and the ink supply pipe 18 and the ink return pipe 19 are connected to each lower end. When the inkjet unit 10 is mounted on the carriage 4, ink flows vertically downward from the supply-side ink chamber 21 to the ink supply tube 18.

The pump unit case 17B is formed in a substantially elliptical shape with a long front view in the depth direction D. The inside of the peripheral wall of the pump unit case 17B is divided into three regions by a first partition wall 26 and a second partition wall 27 extending in the height direction H. Three communication ports 28 are formed in the central region sandwiched between the first partition wall 26 and the second partition wall 27 of the pump unit case 17B. The three communication ports 28 are formed in a range biased downward in the height direction H of the pump unit case 17B.

The side surfaces of the pump unit 25 and the casing main body 17A are overlapped on the front and back of the pump unit case 17B in the width direction W. The central region of the pump unit case 17B forms the discharge chamber 20 together with the side surfaces of the pump unit 25 and the casing main body 17A. The discharge chamber 20 faces the discharge portions 15a and 16a of the first pump 15 and the second pump 16 on the pump unit 25. Further, filters 29 are attached to the three communication ports 28 of the pump unit case 17B. The filter 29 separates the inside of the discharge chamber 20 into the upstream chamber 30 and the downstream chamber 31, and traps air bubbles mixed in the ink passing through the communication port 28 on the upstream chamber 30 side. The downstream chamber 31 communicates with the supply side ink chamber 21 of the casing main body 17A through the opening 21a.

The area on one side partitioned by the first partition wall 26 of the pump unit case 17B constitutes a suction chamber 32 facing the suction portion 15b of the first pump 15 on the pump unit 25. The pump unit case 17B is formed with an ink introduction portion 33 communicating with the suction chamber 32. The other end of the connection tube 14 (see FIGS. 1 and 2), one end of which is connected to the corresponding ink cartridge 13, is connected to the ink introduction unit 33. Ink is introduced from the ink cartridge 13 into the suction chamber 32 through the ink introduction unit 33.

The other side region partitioned by the second partition wall 27 of the pump unit case 17B constitutes a suction chamber 23 facing the suction portion 16b of the second pump 16 on the pump unit 25. The suction chamber 23 communicates with the collection side ink chamber 22 on the casing main body 17A side.

In this embodiment, the first pump 15 and the second pump 16 constitute an ink feeding pump that feeds ink to the inkjet head 11. Both the first pump 15 and the second pump 16 are composed of a diaphragm type pump. The first pump 15 and the second pump 16 are arranged adjacent to each other on an integral block as a pump unit 25.

As shown in FIG. 4, the pump unit 25 includes a base plate 34 sandwiched and fixed by a casing main body 17A and a unit cover 17C, and a pair of piezoelectric vibrating membranes 35 attached to a surface of the base plate 34 on the unit cover 17C side. ing. On one side of the base plate 34 in the depth direction D, a suction hole 36 and a discharge hole 37 of the first pump 15 that penetrate the base plate 34 in the width direction W are formed. On the other side of the base plate 34 in the depth direction D, a suction hole 38 and a discharge hole 39 of the second pump 16 that penetrate the base plate 34 in the width direction W are formed. One of the piezoelectric vibrating membranes 35 is attached to the region of the base plate 34 that straddles the suction hole 36 and the discharge hole 37 so as to cover the periphery of the region. Similarly, in the region straddling the suction hole 38 and the discharge hole 39 on the base plate 34, the other piezoelectric vibrating membrane 35 is attached so as to cover the periphery of the region.

As shown in FIG. 5, the piezoelectric vibrating membrane 35 forms a pump chamber 40 of the first pump 15 with the base plate 34. Further, as shown in FIG. 5, the other piezoelectric vibrating membrane 35 forms a pump chamber 41 of the second pump 16 with the base plate 34. As shown in FIG. 4, the piezoelectric vibration film 35 is mainly configured by laminating a piezoelectric element 35a and a metal plate 35b. Reference numeral 42 in FIG. 4 is a protective sheet that covers the front and back surfaces of the piezoelectric vibration film 35. Further, reference numeral 43 in FIG. 4 is a retaining ring for holding the peripheral portions of the piezoelectric vibration film 35 and the protective sheet 42 and fixing them to the base plate 34.

In the suction portion 15b of the first pump 15, a sheet-shaped valve body 44i that opens and closes the suction hole 36 is attached to a suction hole 36 forming portion that communicates the suction chamber 32 and the pump chamber 40. The valve body 44i is arranged inside the pump chamber 40, and is in contact with and separated from the inside of the pump chamber 40 with respect to the valve seat 45i on the peripheral edge of the suction hole 36. In the discharge portion 15a of the first pump 15, a sheet-shaped valve body 44o that opens and closes the discharge hole 37 is attached to a discharge hole 37 forming portion that communicates the pump chamber 40 and the discharge chamber 20 (upstream chamber 30). ing. The valve body 44o is arranged on the discharge chamber 20 side (outside of the pump chamber 40), and is in contact with and separated from the discharge chamber 20 side with respect to the valve seat 45o on the peripheral edge of the discharge hole 37.

In the suction portion 16b of the second pump 16, a sheet-shaped valve body 44i that opens and closes the suction hole 38 is attached to a suction hole 38 forming portion that communicates the suction chamber 23 and the pump chamber 41. The valve body 44i is arranged inside the pump chamber 41, and is in contact with and separated from the inside of the pump chamber 41 with respect to the valve seat 45i on the peripheral edge of the suction hole 36. In the discharge portion 16a of the second pump 16, a sheet-shaped valve body 44o that opens and closes the discharge hole 39 is attached to a discharge hole 39 forming portion that communicates the pump chamber 41 and the discharge chamber 20 (upstream chamber 30). ing. The valve body 44o is arranged on the discharge chamber 20 side (outside of the pump chamber 41), and is in contact with and separated from the discharge chamber 20 side with respect to the valve seat 45o on the peripheral edge of the discharge hole 39.

FIG. 6 is a block diagram showing a configuration of a drive system of the first pump 15 and the second pump 16.
As shown in FIG. 6, each piezoelectric vibration film 35 of the first pump 15 and the second pump 16 is driven by receiving a drive voltage from the corresponding drive circuits 46 and 47. Each drive circuit 46, 47 outputs a drive voltage corresponding to the control signal of the control device 49 to the corresponding piezoelectric vibration film 35. By periodically applying a pulsed drive voltage from the drive circuits 46 and 47, the central region of each piezoelectric vibration film 35 fluctuates according to a change in the drive voltage. In the first pump 15 and the second pump 16, the volumes of the pump chambers 40 and 41 are increased or decreased by this, and the valve bodies 44i and 44o on the suction side and the discharge side are alternately opened and closed.

FIG. 7A is a cross-sectional view showing the behavior of the valve bodies 44i of the suction portions 15b and 16b when the volumes of the pump chambers 40 and 41 of the first pump 15 and the second pump 16 are increased. FIG. 7B is a cross-sectional view showing the behavior of the valve bodies 44o of the discharge portions 15a and 16a when the volumes of the pump chambers 40 and 41 of the first pump 15 and the second pump 16 are increased. Further, FIG. 8A is a cross-sectional view showing the behavior of the valve bodies 44i of the suction portions 15b and 16b when the volumes of the pump chambers 40 and 41 of the first pump 15 and the second pump 16 are reduced. FIG. 8B is a cross-sectional view showing the behavior of the valve bodies 44o of the discharge portions 15a and 16a when the volumes of the pump chambers 40 and 41 of the first pump 15 and the second pump 16 are reduced.

In the first pump 15 and the second pump 16, as shown in FIGS. 7A and 7B, when the piezoelectric vibration film 35 receives a driving voltage to increase the volume in the pump chambers 40 and 41, the suction unit 15b, The valve body 44i of 16b opens the suction holes 36 and 38, and the valve body 44o of the discharge portions 15a and 16a closes the discharge holes 37 and 39. As a result, ink is sucked from the intake chambers 32 and 23 into the pump chambers 40 and 41. Further, in the first pump 15 and the second pump 16, as shown in FIGS. 8A and 8B, when the piezoelectric vibrating membrane 35 reduces the volume in the pump chambers 40 and 41, the valves of the suction portions 15b and 16b The body 44i closes the suction holes 36 and 38, and the valve body 44o of the discharge portions 15a and 16a opens the discharge holes 37 and 39. As a result, the ink in the pump chambers 40 and 41 is ejected to the ejection chamber 20 (upstream chamber 30) through the ejection holes 37 and 39. By repeating the above operations, the first pump 15 and the second pump 16 continuously supply the ink in the suction chambers 32 and 23 to the discharge chamber 20.

In the ink supply device 12 according to this embodiment, when ink is ejected from the first pump 15 and the second pump 16 to the upstream chamber 30 of the ejection chamber 20, the ink passes through the filter 29 and the downstream chamber 31. Inflow to. At this time, the filter 29 traps the bubbles mixed in the ink and suppresses the bubbles from flowing into the downstream chamber 31. The ink from which bubbles have been removed and flowed into the downstream chamber 31 is temporarily stored in the supply-side ink chamber 21 and then supplied to the nozzle portion of the inkjet head 11 through the ink supply pipe 18. Further, the ink that has not been ejected by the nozzle portion of the inkjet head 11 flows into the collection side ink chamber 22 of the ink supply device 12 through the ink return tube 19. The ink that has flowed into the collection-side ink chamber 22 flows into the suction chamber 23. The ink that has flowed into the suction chamber 23 is ejected again to the upstream chamber 30 by the second pump 16.

As shown in FIG. 5, the ink flow path from the ejection portion 15a of the first pump 15 to the central portion C of the ejection chamber 20 in the ejection chamber 20 and the ejection chamber 20 from the ejection portion 16a of the second pump 16 The ink flow path leading to the central portion C is formed in a target shape. That is, the two ink flow paths are located at symmetrical positions sandwiching the central portion C of the ejection chamber 20, and the flow path length and the cross-sectional shape are set to be substantially the same.

Further, when the first pump 15 and the second pump 16 operate together, the control device 49 drives each piezoelectric drive so that the discharge timings of the first pump 15 and the second pump 16 always match. It controls the operation of the membrane 35. That is, the control device 49 controls the drive circuits 46 and 47 of the first pump 15 and the second pump 16 to output drive voltage waveforms having the same phase to the corresponding piezoelectric vibration membrane 35.

FIG. 9 is a diagram showing a drive voltage waveform output from the drive circuit 46 of the first pump 15 and a drive voltage waveform output from the drive circuit 47 of the second pump 16. V1 in FIG. 9 is a pulse voltage output from the drive circuit 46 of the first pump 15 to the piezoelectric element 35a of the piezoelectric vibration film 35, and V2 in FIG. 9 is the drive circuit 46 of the first pump 15. It is a pulse voltage output from the metal plate 35b of the piezoelectric vibration film 35. Further, V1'in FIG. 9 is a pulse voltage output from the drive circuit 47 of the second pump 16 to the piezoelectric element 35a of the piezoelectric vibration film 35, and V2'in FIG. 9 is the second pump 16 It is a pulse voltage output from the drive circuit 47 of the above to the metal plate 35b of the piezoelectric vibration film 35.

AB in the upper part of FIG. 9 shows a drive voltage waveform obtained by synthesizing the drive voltage output from the drive circuit 46 to the piezoelectric element 35a of the piezoelectric vibration film 35 and the metal plate 35b. Further, AB in the lower row in FIG. 9 shows a drive voltage waveform obtained by synthesizing the drive voltage output from the drive circuit 47 to the piezoelectric element 35a of the piezoelectric vibration film 35 and the metal plate 35b. The control device 49 controls the drive circuits 46 and 47 so that the drive voltage waveforms in the upper stage and the drive voltage waveforms in the lower stage match.

In the inkjet recording device 1 according to this embodiment, the control device 49 drives the first pump 15 and the second pump 16 with drive voltage waveforms having the same phase. Therefore, the discharge timing of the first pump 15 and the discharge timing of the second pump 16 match, and the phenomenon that the first pump 15 and the second pump 16 weaken each other's discharge pressure does not occur.

FIG. 10 shows the relationship between the phase shift of the ejection phases of the first pump 15 and the second pump 16 and the total ink ejection flow rate when both the first pump 15 and the second pump 16 are operating. It is a graph.

As shown in FIG. 10, the total ink discharge flow rate becomes almost the minimum when the discharge phases of the first pump 15 and the second pump 16 are 180 ° out of phase, and the first pump 15 and the second pump 16 have a second discharge phase. It becomes almost maximum when the discharge phase of the pump 16 is not deviated. In the inkjet recording device 1 according to this embodiment, since the discharge phases of the first pump 15 and the second pump 16 do not shift, the pump functions of the first pump 15 and the second pump 16 are efficiently used. Can be done.

Further, in the inkjet recording device 1 according to this embodiment, the ink flow path from the ejection portion 15a of the first pump 15 to the central portion C of the ejection chamber 20 and the ejection chamber 20 from the ejection portion 16a of the second pump 16 The ink flow path leading to the central portion C of the above is formed in a symmetrical shape. Therefore, the pressure of the ink ejected from the ejection portion 15a of the first pump 15 and the pressure of the ink ejected from the ejection portion 16a of the second pump 16 have the same phase in the vicinity of the central portion C of the ejection chamber 20. Is synthesized with. Therefore, in this inkjet recording device 1, the pump functions of the first pump 15 and the second pump 16 can be used more efficiently.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Inkjet recording device, 11 ... Inkjet head, 15 ... First pump, 16 ... Second pump, 20 ... Discharge chamber, 49 ... Control device.

Claims (3)

A first diaphragm-type pump that feeds the ink introduced from the ink reservoir to the inkjet head,
A second diaphragm-type pump that sucks ink that has not been ejected from the inkjet head and feeds the ink upstream of the ink supply path connected to the inkjet head.
A control device that drives the first pump and the second pump with drive voltage waveforms having the same phase so that the discharge timings match.
Ink supply device. The ink supply device according to claim 1 , wherein a drive voltage corresponding to a control signal of the control device is output to the piezoelectric vibration membrane of the first pump and the piezoelectric vibration membrane of the second pump. The piezoelectric vibrating membrane is composed of a piezoelectric element and a metal plate.
The control device has a drive voltage waveform obtained by synthesizing the piezoelectric element of the piezoelectric vibration film and the drive voltage output to the metal plate from the drive circuit of the first pump, and the drive circuit of the second pump. The ink supply device according to claim 2 , wherein the drive voltage waveform obtained by combining the piezoelectric vibration film and the drive voltage output to the metal plate is controlled to match.

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