JP2019014066A - Liquid circulation device and liquid discharge device - Google Patents

Abstract

To reduce back flow to a discharge side passage in a circulation type head.SOLUTION: A liquid circulation device 200 forms a circulation path 290 including a head 100. The circulation path 290 includes: a supply side tank 210 which supplies a liquid to the head 100; and a discharge side tank 210 to which the liquid is discharged from the head 100. A difference between a pressure Vtin of the supply side tank 210 and a pressure tout of the discharge side tank 220 generated when the liquid is discharged from the head 100 is set so as to be larger than a difference between a pressure Vtin of the supply side tank 210 and a pressure Vtout of the discharge side tank 220 generated when the liquid is not discharged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid circulation device and a device for discharging liquid.

  As a liquid discharge head (hereinafter also simply referred to as “head”), the liquid supply head has a supply flow path to the individual liquid chamber that communicates with the nozzles and a discharge flow path that communicates with the individual liquid chamber. There is a flow-through type head (circulation type head) that includes a mouth and a liquid outlet that leads to a discharge channel.

  Conventionally, the supply side tank and the discharge side tank (recovery side tank) are used to pressurize the liquid from the supply port of the head, or pressurize the liquid from the recovery port of the head, thereby causing bubbles from the nozzle. Is known to be discharged (Patent Document 1).

Japanese Patent Laying-Open No. 2015-058581

  In the circulation type head, there is a problem that if the liquid supply from the supply side does not catch up when the liquid is discharged, a phenomenon occurs in which the liquid flows backward from the discharge side.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the backflow of liquid to the head.

In order to solve the above problems, a liquid circulation device according to the present invention is
A circulation path through which the liquid circulates through the liquid discharge head;
The circulation path includes
A supply-side tank leading to a supply port of the liquid discharge head;
A discharge side tank communicating with the discharge port of the liquid discharge head,
Causing the pressure of the supply-side tank to be higher than the pressure of the discharge-side tank and causing the liquid to circulate;
The difference between the pressure of the supply side tank when the liquid is discharged from the liquid discharge head and the pressure of the discharge side tank is the difference between the pressure of the supply side tank and the pressure of the discharge side tank when the liquid is not discharged. It was set as the structure made larger than the difference.

  According to the present invention, it is possible to reduce the backflow of liquid with respect to the head.

It is explanatory drawing of the liquid circulation apparatus which concerns on 1st Embodiment of this invention. It is explanatory drawing with which it uses for description of the relationship between Vin-Vout and the liquid flow volume in the liquid circulation apparatus. It is explanatory drawing of the liquid circulation apparatus which concerns on 2nd Embodiment of this invention. It is an external appearance perspective explanatory view of an example of an individual liquid room circulation type head. It is a cross-sectional explanatory drawing along the direction orthogonal to the nozzle arrangement direction. It is a schematic explanatory drawing of an example of the apparatus which discharges the liquid which concerns on this invention. It is a plane explanatory view of the head unit of the device.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram of a liquid circulation device including a liquid discharge head according to the embodiment.

  The head 100 includes a nozzle 104 that discharges liquid, an individual liquid chamber 106 that communicates with the nozzle 104, a supply channel 116 that communicates with the individual liquid chamber 106, and the individual liquid chamber 106 via each supply channel 116. A supply-side common liquid chamber 120 to be supplied, a discharge flow path 156 communicating with the individual liquid chamber 106, and a discharge-side common liquid chamber 150 through which the liquid is discharged through each discharge flow path 156 are provided.

  Liquid is supplied to the supply-side common liquid chamber 120 via the supply port 141, and liquid is discharged from the discharge-side common liquid chamber 150 via the discharge port 142.

  In the head 100, the liquid in the individual liquid chamber 106 is pressurized by pressure generating means such as a piezoelectric actuator or a thermal actuator, so that the liquid is discharged from the nozzle 104. At this time, the liquid that has not been discharged from the nozzle 104 is discharged from the discharge flow path 156 to the discharge side common liquid chamber 150, and is supplied again to the supply side common liquid chamber 120 via the circulation path outside the head.

  Even when the liquid is not discharged, the liquid flows from the supply-side common liquid chamber 120 to the discharge-side common liquid chamber 150 through the supply flow path 116, the individual liquid chamber 106, and the discharge flow path 156, and circulates outside the head. It is supplied again to the supply-side common liquid chamber 120 via the path.

  The liquid circulation device 200 that circulates liquid with respect to the head 100 includes a main tank 201 that is a liquid storage unit that stores the liquid 300 discharged from the head 100, a supply-side tank 210, and a discharge-side tank (recovery-side tank) 220. And a first liquid feed pump 202 and a second liquid feed pump 203.

  The supply-side tank 210 communicates with the discharge-side tank 220 via the liquid path 281 and communicates with the supply port 141 of the head 100 via the liquid path 282. The discharge side tank 220 communicates with the discharge port 142 of the head 100 via the liquid path 283 and communicates with the main tank 201 via the liquid path 284.

  That is, the supply side tank 210 communicates with the discharge side tank 220 through the liquid path 281, so that the liquid circulates through the liquid path 282, the internal flow path of the head 100, the liquid path 283, the discharge side tank 220, and the liquid path 281. A circulation path 290 is formed.

  Then, the liquid is supplied from the discharge side tank 220 to the supply side tank 210 via the liquid path 281 by the first liquid supply pump 202. Further, the liquid is fed from the main tank 201 to the discharge side tank 220 through the liquid path 284 by the second liquid feed pump 203.

  A compressor 211 as a compression unit is connected to the supply side tank 210 via a regulator 212. The compressor 211 is always driven during operation of the apparatus, and controls the pressure of the supply side tank 210 by the regulator 212.

  The supply-side tank 210 includes a supply-side float sensor 215 serving as a liquid remaining amount detection unit that detects the remaining amount of liquid as the liquid level, and a supply-side pressure sensor 216 that is a unit that detects the pressure in the supply-side tank 210. It has.

  A vacuum pump 221, which is a decompression unit, is connected to the discharge side tank 220 through a regulator 222. The vacuum pump 221 is always driven while the apparatus is operating, and controls the pressure of the discharge side tank 220 by the regulator 222.

  The discharge-side tank 220 includes a discharge-side float sensor 225 as a liquid remaining amount detection unit that detects the remaining amount of liquid as the liquid level, and a discharge-side pressure sensor 226 that is a unit that detects the pressure in the discharge side tank 220. It has.

  The circulation control unit 250 inputs a detection signal of the supply side float sensor 215 and drives the first liquid feeding pump 202 to control the supply of the liquid 300 from the discharge side tank 220 to the supply side tank 210. The circulation control unit 250 inputs a detection signal of the discharge side float sensor 225 and drives the second liquid feeding pump 203 to control supply of the liquid 300 from the main tank 201 to the discharge side tank 220.

  The circulation control unit 250 inputs the detection signal of the supply side pressure sensor 216, controls the opening and closing of the regulator 212, and controls the pressure of the supply side tank 210. The circulation control unit 250 inputs the detection signal of the discharge side pressure sensor 226, controls the opening and closing of the regulator 222, and controls the pressure of the discharge side tank 220.

  The circulation control unit 250 inputs a detection signal from the flow sensor 230 provided in the liquid path 283 on the discharge side.

  The liquid circulation device 200 configured as described above generates a differential pressure between the pressure of the supply-side tank 210 and the pressure of the discharge-side tank 220, thereby supplying the supply port (supply port) 141 of the head 100 from the supply-side tank 210. The liquid 300 is supplied, and the liquid 300 is discharged (collected) from the discharge port (discharge port) 142 of the head 100 to the discharge side tank 220.

  The liquid 300 supplied to the supply port 141 of the head 100 is supplied to each of the plurality of individual liquid chambers 106 via the supply-side common liquid chamber 120, and droplets of the liquid 300 are ejected from the nozzles 104 according to image data. Is done. The liquid 300 that has not been discharged from the nozzle 104 is discharged to the discharge side common liquid chamber 150 through the discharge flow path 156 and discharged from the discharge port 142 to the discharge side tank 220.

  Specifically, when the discharge side float sensor 225 detects that the liquid level in the discharge side tank 220 is lower than a predetermined height, the circulation control unit 250 discharges that the liquid level has reached a predetermined level. The second liquid feed pump 203 is driven until the side float sensor 225 detects it, and the liquid 300 is replenished and supplied from the main tank 201 to the discharge side tank 220.

  Further, when the supply-side float sensor 215 detects that the liquid level in the supply-side tank 210 is lower than a predetermined height, the supply-side float sensor 215 detects that the liquid level has reached a predetermined height. The liquid 300 is supplied from the discharge side tank 220 to the supply side tank 210 by driving the first liquid feeding pump 202.

  While the apparatus is turned on, the compressor 211 and the vacuum pump 221 are always driven. Then, the supply-side regulator 212 is opened and closed so that the pressure in the supply-side tank 210 detected by the supply-side pressure sensor 216 becomes a predetermined pressure. Further, the discharge regulator 222 is opened and closed so that the pressure in the discharge tank 220 detected by the discharge pressure sensor 226 becomes a predetermined pressure.

  As a result, a differential pressure is generated between the supply side tank 210 and the discharge side tank 220, and the liquid 300 circulates from the supply side tank 210 to the discharge side tank 220, and the liquid 300 in the supply side tank 210 is discharged from the discharge side tank 220. Is supplied.

  Next, setting (adjustment) of the pressure of the supply side tank and the pressure of the discharge side tank will be described.

The pressure applied to the liquid in the supply side common liquid chamber 120 of the head 100 (supply side pressure) is Vin [kPa],
The pressure (discharge side pressure) applied to the liquid in the discharge side common liquid chamber 150 of the head 100 is defined as Vout [kPa].

The pressure (supply side tank pressure) of the supply side tank 210 detected by the supply side pressure sensor 216 of the supply side tank 210 is Vtin [kPa],
The pressure (discharge side tank pressure) of the discharge side tank 220 detected by the discharge side pressure sensor 226 of the discharge side tank 220 is defined as Vtout [kPa].

The difference between the liquid level in the supply side tank 210 and the nozzle surface of the head 100 is expressed as Htin [m],
The difference between the liquid level in the discharge side tank 220 and the nozzle surface of the head 100 is Htout [m],
“+” Indicates that the liquid level in the tank is higher than the nozzle surface, and “−” indicates that the liquid level in the tank is lower than the nozzle surface.

The fluid resistance (supply-side fluid resistance) between the supply-side common liquid chamber 120 and the individual liquid chamber 106 of the head 100 is Rin [Pa · s / m ³ ],
Let Rout [Pa · s / m ³ ] be a fluid resistance (discharge side fluid resistance) between the discharge side common liquid chamber 150 and the individual liquid chamber 106 of the head 100.

The fluid resistance between the supply-side common liquid chamber 120 of the head 100 and the supply-side tank 210 is Rtin [Pa · s / m ³ ],
Let Rtout [Pa · s / m ³ ] be a fluid resistance between the discharge-side common liquid chamber 150 of the head 100 and the discharge-side tank 220.

  The pressure of the meniscus formed on the nozzle 104 of the head 100 (meniscus pressure) is Vm, and the meniscus pressure Vm can be calculated by the following equations (1) to (3).

  Further, the supply side pressure Vin can be calculated by the following equation (4).

  Further, the discharge side pressure Vout can be calculated by the following equation (5).

  When the liquid is discharged from the nozzle 104, the pressure Vtin of the supply side tank 210 and the pressure Vtout of the discharge side tank 220 are adjusted so that the nozzle meniscus pressure Vm is 0 to -3 [kPa].

  Next, the difference between the supply side pressure Vin and the discharge side pressure Vout will be described with reference to FIG. FIG. 2 is an explanatory diagram for explaining the relationship between Vin-Vout and the liquid flow rate.

  The difference (Vin−Vout) between the supply side pressure Vin and the discharge side pressure Vout is changed, and the supply side flow path (individual liquid chamber and supply) when the liquid is discharged and not discharged (non-discharge) The flow rate change in the flow path) and the discharge flow path is as shown in FIG. 2, for example. The supply side fluid resistance Rin / discharge side fluid resistance Rout = 0.8.

Here, as described above, the supply side pressure is Vin [Pa], the discharge side pressure is Vout [Pa], the supply side fluid resistance is Rin [Pa · sec / m ³ ], and the discharge side fluid resistance is Rout [Pa · sec / m ³ ].

Further, the flow rate flowing through the supply flow path 116, the individual liquid chamber 106, and the discharge flow path 156 when the liquid is not discharged from the nozzle 104 is Qo [m ³ / sec], and the supply flow path when the liquid is discharged. 116 and Qin [m ³ / sec] as the flow rate flowing through the individual liquid chamber 106, Qout [m ³ / sec] as the flow rate through the discharge flow path 156 when liquid is discharged, and the amount of liquid discharged from the nozzle 104 Is Qt [m ³ / sec].

  At this time, Qo, Qin, and Qout are obtained by the following equations (6) to (8).

  Here, in order to prevent the liquid from flowing backward in the discharge flow path 156, that is, (Qout> 0), the following relational expression (9) may be satisfied from the expression (8). Accordingly, if Qo is set so that the relational expression (9) is satisfied at the maximum value of Qt, the back flow of the liquid in the discharge flow path 156 can be reduced or prevented.

  Further, in order to prevent the liquid from flowing backward in the discharge flow path 156, that is, (Qout> 0), the following equation (10) is satisfied using the equation (6). Also good.

  That is, when the liquid is discharged, the supply side pressure is Vin, the discharge side pressure is Vout, the supply side fluid resistance is Rin, and the maximum discharge amount when discharging the liquid from the nozzle is Qt. By satisfying the following relational expression (11), the backflow in the discharge side individual flow path can be reduced or prevented.

  Therefore, the difference (Vin−Vout) between the supply side pressure Vin and the discharge side pressure Vout when the liquid is discharged is set within the range A in FIG. 2, and when the liquid is not discharged (liquid discharge operation is performed). The difference (Vin−Vout) between the supply side pressure Vin and the discharge side pressure Vout (when not) is set within the range B in FIG.

  Note that the time when the liquid is ejected is when the liquid ejecting operation is performed, for example, when the printing operation is performed if the liquid ejecting operation is printing. Further, when the liquid is not ejected, when the liquid ejecting operation is not performed, for example, if the liquid ejecting operation is printing, the printer is on standby for printing.

  That is, the difference between the supply side pressure Vin and the discharge side pressure Vout when the liquid is discharged is larger than the difference (Vin−Vout) between the supply side pressure Vin and the discharge side pressure Vout when the liquid is not discharged. doing.

  Here, the pressure (supply side pressure) Vin of the supply side common liquid chamber 120 is a pressure given by the supply side tank 210, and the pressure (supply side pressure) Vout of the discharge side common liquid chamber 150 is the discharge side tank 220. Is the pressure given by.

  Therefore, the difference between the pressure of the supply side tank 210 when the liquid is discharged from the liquid discharge head 100 and the pressure of the discharge side tank 220 is the difference between the pressure of the supply side tank 210 when the liquid is not discharged and the pressure of the discharge side tank 220. The difference from the pressure is larger.

  In this case, when the liquid is discharged from the liquid discharge head 100, the absolute value of at least one of the pressure of the supply-side tank 210 and the pressure of the discharge-side tank 220 is made larger than when the liquid is not discharged. Thus, the difference between the pressure of the supply-side tank 210 when the liquid is discharged from the liquid discharge head 100 and the pressure of the discharge-side tank 220 is the difference between the pressure of the supply-side tank 210 when the liquid is not discharged and the discharge-side tank 220. The difference from the pressure of

  In this case, when all of the liquid is circulated without discharging the liquid, the flow rate should not be lower than the flow rate (flow rate Qm in FIG. 2) at which the meniscus of the nozzle is dried and the pigment settles into the individual liquid chamber. It is preferable to set (Vin−Vout) so that the flow rate is as small as possible.

  As a result, while reducing the backflow, the quality is good and the driving time of the liquid feeding means for returning the liquid from the discharge side tank to the supply side tank can be shortened or the driving speed can be slowed down. Electricity can be reduced.

  In addition, when discharging the liquid, by setting (Vin−Vout) so that the liquid does not flow back into the discharge-side individual liquid chamber at the time of discharging, it is possible to reduce deterioration in quality due to the backflow.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is an explanatory diagram of a liquid circulation device including the liquid discharge head according to the embodiment.

  In the present embodiment, in the configuration of the first embodiment, the supply-side head pressure is a means for detecting the pressure of the liquid supplied to the head 100 in the supply-side liquid path 281 from the supply-side tank 210 to the head 100. A sensor 231 is arranged. A discharge-side head pressure sensor 232 that is a means for detecting the pressure of the liquid discharged from the head 100 is disposed in the discharge-side liquid path 282 from the head 100 to the discharge-side tank 220.

here,
The pressure (supply-side head pressure) detected by the supply-side head pressure sensor 231 is Vpin [kPa],
The pressure (discharge head pressure) detected by the discharge head pressure sensor 232 is Vpout [kPa],
And

The difference between the pressure detection position of the supply-side head sensor 231 and the height of the nozzle surface of the head 100 is expressed as Hpin [m],
The difference between the pressure detection position of the discharge-side head sensor 232 and the height of the nozzle surface of the head 100 is Hpout [m],
“+” Indicates that the pressure detection position is higher than the nozzle surface, and “−” indicates that the pressure detection position is lower than the nozzle surface.

The fluid resistance between the supply-side common liquid chamber 120 of the head 100 and the supply-side head pressure sensor 231 is Rpin [Pa · s / m ³ ],
Let the fluid resistance between the discharge side common liquid chamber 150 and the discharge side head pressure sensor 232 be Rpout [Pa · s / m ³ ].

  Other parameters are the same as those in the first embodiment.

  Here, the meniscus pressure Vm is calculated by the above-described equation (1).

  The supply side pressure Vin is calculated by the following equation (12).

  The discharge side pressure Vout is calculated by the following equation (13).

  When the liquid is discharged from the nozzle 104, the supply-side head pressure Vpin and the discharge-side head pressure Vpout are adjusted so that the nozzle meniscus pressure Vm is 0 to -3 [kPa].

  In this way, the pressure of the liquid supplied to the head 100 and the pressure of the liquid discharged from the head 100 are detected at locations close to the supply-side common liquid chamber 120 and the discharge-side common liquid chamber 150 of the head 100. The change in fluid resistance between the supply-side common liquid chamber 120 and the discharge-side common liquid chamber 150 is reduced.

  Thereby, even when the liquid viscosity changes due to a change in environmental temperature or a change in liquid characteristics over time, the pressure change applied to the liquid in the supply-side common liquid chamber 120 and the discharge-side common liquid chamber 150 of the head 100 is reduced. The meniscus pressure formed on the nozzle 104 is stabilized.

  Next, an example of the circulation type head will be described with reference to FIGS. 4 is an external perspective view illustrating the head, and FIG. 5 is a cross-sectional explanatory view along a direction orthogonal to the nozzle arrangement direction of the head.

  In this head, a nozzle plate 1, a flow path plate 2, and a diaphragm member 3 as a wall surface member are laminated and joined. The piezoelectric actuator 11 that displaces the vibration region (vibration plate) 30 of the vibration plate member 3, the common liquid chamber member 20 that also serves as a frame member of the head, and a cover 29 are provided.

  The nozzle plate 1 has a plurality of nozzles 4 that discharge liquid.

  The flow path plate 2 includes an individual liquid chamber 6 that communicates with the nozzle 4 via the nozzle communication path 5, a supply-side fluid resistance portion 7 that communicates with the individual liquid chamber 6, and a supply-side introduction portion 8 that communicates with each supply-side fluid resistance portion 7. Is forming. Here, the flow path plate 2 is configured by laminating plate-like members 2A to 2F. The supply side fluid resistance unit 7 and the supply side introduction unit 8 constitute a supply flow path. The supply side introduction unit 8 may have a configuration common to two or more or all the individual liquid chambers 6.

  The vibration plate member 3 has a deformable vibration region 30 that forms the wall surface of the individual liquid chamber 6 of the flow path plate 2. Here, the diaphragm member 3 has a two-layer structure (not limited), and is formed of a first layer that forms a thin portion and a second layer that forms a thick portion from the flow path plate 2 side. A deformable vibration region 30 is formed in a portion corresponding to the individual liquid chamber 6.

  Then, on the opposite side of the diaphragm member 3 from the individual liquid chamber 6, a piezoelectric actuator 11 including an electromechanical conversion element as drive means (actuator means, pressure generating means) for deforming the vibration region 30 of the diaphragm member 3 is provided. It is arranged.

  The piezoelectric actuator 11 has, for example, a required number of columnar piezoelectric elements 12 formed at a predetermined interval by grooving a piezoelectric member joined to a base member 13 by half-cut dicing. The piezoelectric element 12 is bonded to a vibration region (vibration plate) 30 of the vibration plate member 3. A flexible wiring member 15 is connected to the piezoelectric element 12.

  The common liquid chamber member 20 forms a supply side common liquid chamber 10 and a discharge side common liquid chamber 50. The supply-side common liquid chamber 10 communicates with a supply port 41 that is a supply port for supplying liquid from the outside, and the discharge-side common liquid chamber 50 communicates with a discharge port 42 that is a discharge port for discharging liquid to the outside.

  The supply-side common liquid chamber 10 communicates with the supply-side introduction unit 8 through the filter member 9. The filter member 9 is formed by the first layer of the diaphragm member 3.

  Further, the flow path plate 2 forms a discharge side fluid resistance portion 57, a discharge side individual flow path 56, and a discharge side lead-out portion 58 that communicate with each individual liquid chamber 6 via the nozzle communication path 5. The discharge side fluid resistance part 57, the discharge side individual flow path 56, and the discharge side derivation part 58 constitute a discharge flow path. The discharge side derivation unit 58 may have a configuration common to two or more discharge side individual flow paths 56.

  The discharge side lead-out part 58 communicates with the discharge side common liquid chamber 50 through the filter member 59. The filter member 59 is formed by the first layer of the diaphragm member 3.

  In the head configured in this way, for example, by lowering the voltage applied to the piezoelectric element 12 from the reference potential (intermediate potential), the piezoelectric element 12 contracts, and the vibration region 30 of the diaphragm member 3 is drawn, so that the individual liquid chamber 6 is pulled. As the volume of the liquid expands, the liquid flows into the individual liquid chamber 6.

  Thereafter, the voltage applied to the piezoelectric element 12 is increased to extend the piezoelectric element 12 in the stacking direction, and the vibration region 30 of the diaphragm member 3 is deformed in the direction toward the nozzle 4 to contract the volume of the individual liquid chamber 6. As a result, the liquid in the individual liquid chamber 6 is pressurized, and the liquid is discharged from the nozzle 4.

  The liquid not discharged from the nozzle 4 passes through the nozzle 4 and is discharged to the discharge side common liquid chamber 50 through the discharge side fluid resistance portion 57, the discharge side individual flow channel 56, the discharge side derivation portion 58 and the filter member 59. . Then, it is supplied again from the discharge side common liquid chamber 50 to the supply side common liquid chamber 10 through an external circulation path. Further, even when the liquid is not discharged, the liquid flows from the supply-side common liquid chamber 10 to the discharge-side common liquid chamber 50 and is supplied again to the supply-side common liquid chamber 10 through an external circulation path.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and it is also possible to perform striking or pushing depending on the direction to which the drive waveform is given.

  Next, an example of a device for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 6 is a schematic explanatory view of the apparatus, and FIG. 7 is a plan explanatory view of the head unit of the apparatus.

  This apparatus includes a carry-in means 501 for carrying in the continuous medium 510, a guide carrying means 503 for guiding and carrying the continuous medium 510 carried from the carry-in means 501 to the printing means 505, and discharging liquid to the continuous medium 510. A printing unit 505 that performs printing for forming an image, a drying unit 507 that dries the continuous medium 510, and a discharge unit 509 that discharges the continuous medium 510 are provided.

  The continuous medium 510 is fed out from the original winding roller 511 of the carry-in means 501, guided and conveyed by the respective rollers of the carry-in means 501, the guide conveyance means 503, the drying means 507 and the discharge means 509, and the take-up roller 591 of the discharge means 509. It is wound up by.

  The continuous medium 510 is conveyed by the printing unit 505 on the conveyance guide member 559 so as to face the head unit 550 and the head unit 555, and an image is formed by the liquid ejected from the head unit 550. Post-processing is performed with the processing liquid.

  Here, the head unit 550 includes, for example, full-line head arrays 551K, 551C, 551M, and 551Y for four colors from the upstream side in the medium conveying direction (hereinafter referred to as “head array 551” when colors are not distinguished). ) Is arranged.

  Each head array 551 is a liquid ejecting unit, and ejects black K, cyan C, magenta M, and yellow Y liquids to the transported continuous medium 510, respectively. The type and number of colors are not limited to this.

  The head array 551 has a plurality of circulation type heads 1000 arranged in a staggered manner on the base member 552, but is not limited thereto.

  Next, when a liquid circulation device is applied to this device, a first manifold is arranged between the supply side of the plurality of heads 1000 of each head array 551 and the supply side tank 210, and each head 1000 is connected from the first manifold. To supply liquid. Further, a second manifold is disposed between the discharge side of the head 1000 and the discharge side tank 220, and the liquid is discharged from each head 1000 to the second manifold.

  In the present application, the liquid to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, and the viscosity becomes 30 mPa · s or less at room temperature, normal pressure, or by heating and cooling. It is preferable. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, and biocompatible materials such as DNA, amino acids, proteins, and calcium. , Edible materials such as natural pigments, solutions, suspensions, emulsions, and the like. These include, for example, inkjet inks, surface treatment liquids, components of electronic devices and light emitting devices, and formation of electronic circuit resist patterns. It can be used in applications such as liquids for use, three-dimensional modeling material liquids, and the like.

  As energy generation sources for discharging liquid, piezoelectric actuators (laminated piezoelectric elements and thin film piezoelectric elements), thermal actuators using electrothermal transducers such as heating resistors, electrostatic actuators consisting of a diaphragm and counter electrode are used. To be included.

  The “liquid ejection unit” is a unit in which functional parts and mechanisms are integrated with a liquid ejection head, and includes an assembly of parts related to liquid ejection. For example, the “liquid discharge unit” includes a combination of at least one of a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, and a main scanning movement mechanism with a liquid discharge head.

  Here, the term “integrated” refers to, for example, a liquid discharge head, a functional component, and a mechanism that are fixed to each other by fastening, adhesion, engagement, etc., and one that is held movably with respect to the other. Including. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.

  For example, there is a liquid discharge unit in which a liquid discharge head and a head tank are integrated. Also, there are some in which the liquid discharge head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter may be added between the head tank and the liquid discharge head of these liquid discharge units.

  In addition, there is a liquid discharge unit in which a liquid discharge head and a carriage are integrated.

  In addition, there is a liquid discharge unit in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably on a guide member that constitutes a part of the scanning movement mechanism. In some cases, a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

  Also, there is a liquid discharge unit in which a cap member that is a part of the maintenance / recovery mechanism is fixed to a carriage to which the liquid discharge head is attached, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. .

  In addition, there is a liquid discharge unit in which a tube is connected to a liquid discharge head to which a head tank or a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated. The liquid from the liquid storage source is supplied to the liquid discharge head via this tube.

  The main scanning movement mechanism includes a guide member alone. The supply mechanism includes a single tube and a single loading unit.

The “apparatus for ejecting liquid” includes an apparatus that includes a liquid ejection head or a liquid ejection unit and that ejects liquid by driving the liquid ejection head. The apparatus for ejecting a liquid includes not only an apparatus capable of ejecting a liquid to an object to which the liquid can adhere, but also an apparatus for ejecting the liquid into the air or liquid.

  This “apparatus for discharging liquid” may include means for feeding, transporting, and discharging a liquid to which liquid can adhere, as well as a pre-processing apparatus and a post-processing apparatus.

  For example, as a “liquid ejecting device”, an image forming device that forms an image on paper by ejecting ink, a powder is formed in layers to form a three-dimensional model (three-dimensional model) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto the powder layer.

  Further, the “apparatus for ejecting liquid” is not limited to an apparatus in which significant images such as characters and figures are visualized by the ejected liquid. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  The above-mentioned “applicable liquid” means that the liquid can be attached at least temporarily and adheres and adheres, or adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic parts such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, unless specifically limited, includes everything that the liquid adheres to.

  The material of the above-mentioned “material to which liquid can adhere” is not limited as long as liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics can be adhered even temporarily.

  In addition, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can adhere move relatively, but is not limited thereto. Specific examples include a serial type apparatus that moves the liquid discharge head, a line type apparatus that does not move the liquid discharge head, and the like.

  In addition, as the “device for ejecting liquid”, other than the above, a treatment liquid coating apparatus that ejects a treatment liquid onto a sheet in order to apply the treatment liquid to the surface of the sheet for the purpose of modifying the surface of the sheet, There is an injection granulation apparatus that granulates raw material fine particles by spraying a composition liquid in which raw materials are dispersed in a solution through a nozzle.

  Note that the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling” and the like in the terms of the present application are all synonymous.

DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Flow path plate 3 Vibration plate 4 Nozzle 5 Nozzle communication path 6 Individual liquid chamber 7 Supply side fluid resistance part 8 Supply side introduction part 10 Supply side common liquid chamber 11 Piezoelectric actuator 20 Common liquid chamber member (frame member)
50 discharge side common liquid chamber 56 discharge side individual flow path 57 discharge side fluid resistance section 58 discharge side derivation section 100 liquid discharge head 104 nozzle 106 individual liquid chamber 116 supply side individual flow path 120 supply side common liquid chamber 150 discharge side common liquid Chamber 156 Discharge side individual flow path 200 Liquid circulation device 201 Main tank 202 First liquid feed pump 203 Second liquid feed pump 210 Supply side tank 220 Discharge side tank 250 Circulation controller 403 Carriage 404 Liquid discharge head 440 Liquid discharge unit 630 Liquid Circulation system 1000 Liquid discharge head

Claims (7)

A circulation path through which the liquid circulates through the liquid discharge head;
The circulation path includes
A supply-side tank leading to a supply port of the liquid discharge head;
A discharge side tank communicating with the discharge port of the liquid discharge head,
Causing the pressure of the supply-side tank to be higher than the pressure of the discharge-side tank and causing the liquid to circulate;
The difference between the pressure of the supply-side tank and the pressure of the discharge-side tank when the liquid is discharged from the liquid discharge head is the difference between the pressure of the supply-side tank and the pressure of the discharge-side tank when the liquid is not discharged. A liquid circulation device characterized by being larger than the difference between the two. When discharging the liquid from the liquid discharge head, the absolute value of at least one of the pressure of the supply-side tank and the pressure of the discharge-side tank is made larger than when not discharging the liquid. The liquid circulation device according to claim 1. 3. The liquid circulation device according to claim 1, wherein when the liquid is circulated, the pressure of the supply-side tank is set to a positive pressure and the pressure of the discharge-side tank is set to a negative pressure. Means for detecting a pressure of a path for supplying the liquid to the liquid discharge head;
Means for detecting the pressure of a path through which the liquid is discharged from the liquid discharge head,
4. The liquid according to claim 1, further comprising means for controlling the pressure of the supply-side tank and the pressure of the discharge-side tank according to the detection of each of the detection means. Circulation device. A liquid discharge head for discharging liquid;
An apparatus for ejecting liquid, comprising: the liquid circulation apparatus according to claim 1. The liquid discharge head is
A plurality of nozzles for discharging the liquid;
Individual liquid chambers respectively leading to the nozzles;
A supply-side common liquid chamber that leads to the individual liquid chamber via a supply flow path;
A discharge-side common liquid chamber communicating with the individual liquid chamber via a discharge flow path,
When the liquid is discharged, the pressure of the supply side common liquid chamber is Vin, the pressure of the discharge side common liquid chamber is Vout,
The fluid resistance of the supply channel is Rin,
When the maximum discharge amount when discharging liquid from the nozzle is Qt,
Vin-Vout> Qt × Rin
The apparatus for ejecting liquid according to claim 5, wherein the relational expression is satisfied. The liquid discharge head is
A plurality of nozzles for discharging the liquid;
An individual liquid chamber leading to the nozzle;
A supply-side common liquid chamber that leads to the individual liquid chamber via a supply flow path;
A discharge-side common liquid chamber communicating with the individual liquid chamber via a discharge flow path,
The pressure of the supply side common liquid chamber is Vin, the pressure of the discharge side common liquid chamber is Vout, the fluid resistance of the supply flow path is Rin, and the flow rate flowing through the discharge flow path when the liquid is not discharged is Qo, And when
Qo> Qt × Rin / (Rin + Rout)
The apparatus for ejecting liquid according to claim 5, wherein the relational expression is satisfied.

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