JP2017154490A - Liquid discharge head, liquid discharge unit and device for discharging liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge unit having a liquid discharge flow passage for circulation that prevents a decline in discharge efficiency.SOLUTION: The liquid discharge head includes: a plurality of nozzles 4 for discharging liquid; a plurality of individual liquid chambers 6 communicated to the nozzles 4; nozzle communication passages 5 for communicating the nozzles 4 to the individual liquid chamber 6; a plurality of liquid discharge flow passages 41 communicated to the individual liquid chambers 6 via the nozzle communication passages 5. The liquid discharge flow passage 41 includes flow passage part disposed a partition wall part 60 between adjacent individual liquid chambers 6. The liquid discharge head includes a piezoelectric element 12B deforming at least part of the flow passage part of the liquid discharge flow passage 41.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid discharge head, a liquid discharge unit, and an apparatus for discharging liquid.

  As a liquid discharge head (droplet discharge head) that discharges liquid, the liquid that has not been discharged among the liquids supplied to the individual liquid chambers is returned to the circulation common liquid chamber from the liquid discharge flow path and circulated individually. A circulation type head is known which improves the discharge of bubbles mixed in a liquid chamber and suppresses changes in liquid characteristics.

  For example, an ink supply channel that supplies ink from an ink introduction port, an ink discharge channel that discharges ink to an ink discharge port, and a nozzle that discharges ink by connecting the ink supply channel and the ink discharge channel There is known an ink chamber having an ink chamber and a piezoelectric actuator that displaces a vibration plate of the ink chamber and applies pressure to the ink in the ink chamber (Patent Document 1).

Japanese Patent No. 5045824

  However, in the configuration disclosed in Patent Document 1, the ink discharge channel faces the ink chamber, and when pressure is applied to the ink in the ink chamber to discharge the ink, a part of the pressure is discharged from the ink discharge flow. There is a problem that the discharge efficiency decreases due to escape to the road.

  The present invention has been made in view of the above problems, and an object of the present invention is to allow liquid to circulate while preventing a decrease in discharge efficiency.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A plurality of nozzles for discharging liquid;
A plurality of individual liquid chambers leading to the nozzle;
A nozzle communication path through the nozzle and the individual liquid chamber;
A plurality of liquid discharge passages communicating with the individual liquid chambers via the nozzle communication path,
The liquid discharge flow path includes a flow path portion disposed in a partition between adjacent individual liquid chambers,
A configuration is provided that includes means for deforming at least a part of the flow path portion of the liquid discharge flow path.

  According to the present invention, the liquid can be circulated while preventing the discharge efficiency from being lowered.

FIG. 3 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the liquid ejection head according to the first embodiment of the present invention. FIG. 4 is a cross-sectional explanatory view in a direction along the nozzle arrangement direction corresponding to the BB cross section of FIG. 3 (liquid chamber short direction). FIG. 2 is an explanatory plan view of the flow path plate of FIG. 1 as viewed from the diaphragm side. FIG. 6 is a cross-sectional explanatory diagram along the nozzle arrangement direction for explaining the operation by controlling the flow rate of the liquid discharge channel in the same embodiment. It is explanatory drawing with which it demonstrates to an example of the relationship between the drive voltage of the drive waveform for liquid discharge, and the discharge speed when not performing the flow control of a liquid discharge flow path. FIG. 6 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to a nozzle arrangement direction of a liquid ejection head according to a second embodiment of the present invention. FIG. 9 is a cross-sectional explanatory view in a direction (liquid chamber short direction) along the nozzle arrangement direction corresponding to the CC cross section of FIG. 8. FIG. 7 is an explanatory plan view of the flow path plate of FIG. 6 as viewed from the diaphragm side. FIG. 6 is an explanatory cross-sectional view along the nozzle arrangement direction for explaining the operation of the flow rate control of the liquid discharge channel in the same embodiment. It is explanatory drawing with which it demonstrates to an example of the relationship between the drive voltage of the drive waveform for liquid discharge, and the discharge speed when not performing the flow control of a liquid discharge flow path. FIG. 10 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to a nozzle arrangement direction of a liquid ejection head according to a third embodiment of the present invention. FIG. 3 is a block diagram for explaining a first example of a head drive control device that drives and controls a liquid discharge head according to each embodiment. It is explanatory drawing explaining an example of the drive waveform and flow control waveform of the 1st example. FIG. 6 is an explanatory block diagram for explaining a second example of a head drive control device that drives and controls a liquid discharge head according to each embodiment. It is explanatory drawing explaining an example of the drive waveform and flow control waveform of the 2nd example. FIG. 10 is a block diagram for explaining a third example of a head drive control device that drives and controls a liquid discharge head according to each embodiment. It is sectional explanatory drawing of the direction (liquid chamber short direction) in alignment with the nozzle arrangement direction with which it uses for description of 4th Embodiment of this invention. It is sectional explanatory drawing of the direction in alignment with the nozzle arrangement direction with which it uses for description of 5th Embodiment of this invention. It is principal part plane explanatory drawing of an example of the apparatus which discharges the liquid which concerns on this invention. It is principal part side explanatory drawing of the apparatus. It is principal part plane explanatory drawing of the other example of the liquid discharge unit which concerns on this invention. It is front explanatory drawing of the further another example of the liquid discharge unit which concerns on this invention. 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. FIG. 2 is a block explanatory diagram for explaining an example of a liquid circulation system in the apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A liquid discharge head according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional explanatory diagram of a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the liquid discharge head, and FIG. 2 is a direction along the nozzle arrangement direction corresponding to the BB cross section of FIG. FIG. 3 is an explanatory plan view of the flow channel plate of FIG. 1 as viewed from the diaphragm side.

  In the liquid discharge head, a nozzle plate 1, a flow path plate 2, and a diaphragm 3 as a wall surface member are laminated and joined. And the piezoelectric actuator 11 which displaces the diaphragm 3 and the frame member 20 as a common liquid chamber member are provided.

  The nozzle plate 1 has a plurality of nozzles 4 that discharge liquid. Here, there are two nozzle rows in which a plurality of nozzles 4 are arranged, but only the nozzles 4 included in one nozzle row are illustrated.

  The flow path plate 2 has an individual liquid chamber 6 that communicates with the nozzle 4 via the nozzle communication passage 5, a fluid resistance portion 7 that communicates with the individual liquid chamber 6, and a through-hole and a groove that serve as a liquid introduction portion 8 that communicates with the fluid resistance portion 7. Forming. The nozzle communication path 5 is a flow path that communicates with the nozzle 4 and the individual liquid chamber 6. Further, the fluid resistance portion 7 and the liquid introduction portion 8 constitute a liquid supply channel.

  The vibration plate 3 has a deformable vibration region 30 that forms the wall surface of the individual liquid chamber 6 of the flow path plate 2.

  A piezoelectric actuator 11 including an electromechanical conversion element as a driving means (actuator means, pressure generating means) for deforming the diaphragm 3 is disposed on the opposite side of the diaphragm 3 from the individual liquid chamber 6.

  The piezoelectric actuator 11 includes piezoelectric elements (piezoelectric columns) 12A and 12B, which are a required number of columnar electromechanical transducers arranged at predetermined intervals along the nozzle arrangement direction. It is joined to.

  The frame member 20 is formed with a common liquid chamber 10 to which liquid is supplied from a head tank or a liquid cartridge.

  Further, the flow path plate 2 is provided with a liquid discharge flow path 41 constituting a circulation flow path leading to the nozzle communication path 5 on the nozzle plate 1 side opposite to the individual liquid chamber 6. Is communicated with the circulation common liquid chamber 45 formed in the frame member 20 through the passage 44 penetrating the flow path plate 2 and the opening 46 of the vibration plate 3.

  In the liquid ejection head configured as described above, for example, by lowering the voltage applied to the piezoelectric element 12A from the reference potential, the piezoelectric element 12A contracts, the vibration region 30 of the diaphragm 3 is drawn, and the volume of the individual liquid chamber 6 increases. By expanding, the liquid flows into the individual liquid chamber 6.

  Thereafter, the voltage applied to the piezoelectric element 12A is increased to extend the piezoelectric element 12A in the stacking direction, and the diaphragm 3 is deformed in the direction toward the nozzle 4 to contract the volume of the individual liquid chamber 6, thereby causing the individual liquid chamber to contract. The liquid in 6 is pressurized, and the liquid is discharged from the nozzle 4.

  Then, by returning the voltage applied to the piezoelectric element 12A to the reference potential, the vibration region 30 of the diaphragm 3 is restored to the initial position, and the individual liquid chamber 6 expands to generate negative pressure. At this time, the common liquid chamber The individual liquid chamber 6 is filled with liquid from 10. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation for the next discharge is started.

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

  When this head is used, the liquid is constantly circulated so that the liquid flows through the liquid discharge channel 41 regardless of whether or not the liquid is discharged from the nozzle 4.

  And in this embodiment, the liquid discharge flow path 41 provided in the nozzle plate 1 side of the flow-path plate 2 is the partition part 60 between the adjacent individual liquid chambers 6, as shown in FIG.2 and FIG.3. The flow path part 41a arrange | positioned in is included.

  On the other hand, the piezoelectric element 12 </ b> B of the piezoelectric actuator 11 is joined to the diaphragm 3 and connected to the partition wall 60 at a position corresponding to the partition wall 60 between the adjacent individual liquid chambers 6.

  Therefore, the partition wall 60 can be deformed by driving the piezoelectric element 12B. That is, the piezoelectric element 12 </ b> B that is an electromechanical conversion element constitutes a means for deforming the flow path portion 41 a of the liquid discharge flow path 41. The piezoelectric element 12B and the piezoelectric element 12A that is an electromechanical conversion element that pressurizes the individual liquid chamber 6 are arranged adjacent to each other.

  Next, the flow rate control action of the liquid discharge channel in the present embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional explanatory view along the nozzle arrangement direction for explaining the operation.

  In order to control the flow rate of the liquid discharge flow channel 41 by driving the piezoelectric element 12B, (1) the opening cross-sectional area of the flow channel portion 41a of the liquid discharge flow channel 41 (the cross-sectional area in the direction orthogonal to the liquid flow direction) ) Is reduced to increase (increase) the fluid resistance. Further, (2) there is a method of performing drive control in which the flow path portion 41a of the liquid discharge flow path 41 is deformed at least once to generate a pressure wave toward the inlet side.

Method (1) By extending and driving the piezoelectric element 12B, as shown in FIG. 4, the partition wall portion 60 is pushed and deformed toward the nozzle plate 1, and the flow path portion 41a of the liquid discharge flow path 41 is deformed. The opening cross-sectional area is reduced, and the fluid resistance of the flow path portion 41a is increased (increased).

  Therefore, when the piezoelectric element 12A is driven to discharge the liquid from the nozzle 4, the piezoelectric element 12B is extended and driven to increase the fluid resistance of the flow path portion 41a of the liquid discharge flow path 41. It becomes difficult for the liquid to escape into the liquid discharge channel 41.

  Thereby, the pressure by the piezoelectric element 12A is efficiently used for liquid discharge, and the discharge efficiency is suppressed from decreasing.

Regarding (2) The partition wall portion 60 is repeatedly deformed by extending and contracting the piezoelectric element 12B, and the wall surface of the flow channel portion 41a of the liquid discharge flow channel 41 vibrates, so that the liquid in the flow channel portion 41a is vibrated. A pressure wave is generated from the flow path portion 41a toward the inlet side of the liquid discharge flow path 41 (in this embodiment, the nozzle communication path). In order to generate the pressure wave toward the inlet side, the flow path portion 41a of the liquid discharge flow path 41 may be deformed one or more times.

  At this time, by controlling the driving timing of the piezoelectric element 12B, a pressure wave from the flow path portion 41a toward the inlet side of the liquid discharge flow path 41 can be generated when the liquid in the individual liquid chamber 6 is pressurized. it can. This pressure wave makes it difficult for the liquid to escape from the nozzle communication path 5 to the liquid discharge channel 41.

  Thereby, the pressure by the piezoelectric element 12A is efficiently used for liquid discharge, and the discharge efficiency is suppressed from decreasing.

  On the other hand, when the liquid is not discharged from the nozzle 4, the piezoelectric element 12B is not driven so that the fluid resistance of the flow channel portion 41a of the liquid discharge flow channel 41 is not increased, or the flow channel portion 41a of the liquid discharge flow channel 41 is set. Does not generate pressure waves.

  Thereby, the liquid can be smoothly discharged and circulated to the circulation common liquid chamber 45 through the liquid discharge channel 41, the change in the viscosity of the liquid such as thickening in the nozzle 4 is suppressed, and the bubbles are discharged. Can do.

  Here, an example of the relationship between the drive voltage of the liquid discharge drive waveform and the discharge speed when the flow control of the liquid discharge channel is performed and when it is not performed will be described with reference to FIG. FIG. 5 is an explanatory diagram for explaining the same.

  When a liquid is ejected by applying a discharge drive waveform to the piezoelectric element 12A, (a) the piezoelectric element 12B is not driven (non-driven), (b) the piezoelectric element 12B is extended and driven to increase fluid resistance (fluid) Resistance), (c) When the piezoelectric element 12B was expanded and contracted to generate a pressure wave (pressure wave), the liquid discharge speed was measured by changing the drive voltage of the discharge drive waveform. The result is shown in FIG.

  As can be seen from FIG. 5, when the piezoelectric element 12B is driven to increase the fluid resistance or when a pressure wave is generated, the piezoelectric element 12B is not driven, that is, the flow path portion of the liquid discharge flow path is Compared with the case where there is no means for deforming, the discharge speed is increased and the discharge efficiency is improved.

  In addition, when the piezoelectric element 12B is driven to increase the fluid resistance, the discharge speed is increased and the discharge efficiency is further improved when the pressure wave is generated.

  Next, a liquid ejection head according to a second embodiment of the present invention will be described with reference to FIGS. 6 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the liquid discharge head, and FIG. 7 is a direction along the nozzle arrangement direction corresponding to the CC cross section of FIG. 8 (liquid chamber short). FIG. 8 is an explanatory plan view of the flow path plate of FIG. 6 as viewed from the diaphragm side.

  In the present embodiment, the liquid discharge channel 41 that opens to the nozzle communication path 5 on the nozzle plate 1 side of the channel plate 2 reaches the diaphragm 3 side via the channel portion 41 b in the thickness direction of the channel plate 2. The passage 44 is communicated with a passage portion 41 a provided on the diaphragm 3 side of the partition wall 60.

  Here, the channel portion 41 a of the liquid discharge channel 41 is formed with a wall surface 33 that can be deformed by the diaphragm 3.

  And between the adjacent individual liquid chambers 6, the piezoelectric element 12B corresponding to the partition wall portion 60 is joined and connected to the deformable wall surface 33 of the flow path portion 41a.

  Therefore, the wall surface 33 of the channel portion 41a of the liquid discharge channel 41 can be deformed by driving the piezoelectric element 12B. That is, the piezoelectric element 12 </ b> B that is an electromechanical conversion element constitutes a means for deforming the flow path portion 41 a of the liquid discharge flow path 41.

  Next, the flow rate control action of the liquid discharge channel in the present embodiment will be described with reference to FIG. FIG. 9 is a cross-sectional explanatory view along the nozzle arrangement direction for explaining the operation.

  Also in the present embodiment, as in the first embodiment, in order to control the flow rate of the liquid discharge channel 41 by driving the piezoelectric element 12B, (1) the fluid in the channel portion 41a of the liquid discharge channel 41 There is a method of performing drive control to increase resistance. In addition, (2) there is a method of performing drive control in which the wall surface 33 of the channel portion 41a of the liquid discharge channel 41 is vibrated to generate a pressure wave toward the inlet side.

Method (1) By extending and driving the piezoelectric element 12B, as shown in FIG. 9, the wall surface 33 is deformed in a direction to be pushed into the flow channel portion 41a, and the flow channel portion 41a of the liquid discharge flow channel 41 is obtained. , And the fluid resistance of the flow path portion 41a increases (increases).

  Therefore, when the piezoelectric element 12A is driven to discharge the liquid from the nozzle 4, the piezoelectric element 12B is extended and driven to increase the fluid resistance of the flow path portion 41a of the liquid discharge flow path 41. It becomes difficult for the liquid to escape into the liquid discharge channel 41.

  Thereby, the pressure by the piezoelectric element 12A is efficiently used for liquid discharge, and the discharge efficiency is suppressed from decreasing.

(2) By expanding and contracting the piezoelectric element 12B, the wall surface 33 of the flow path portion 41a repeatedly deforms and vibrates, whereby vibration is applied to the liquid of the flow path portion 41a, and the flow path portion 41a A pressure wave is generated toward the inlet side of the liquid discharge channel 41 (in this embodiment, the nozzle communication path).

  At this time, by controlling the driving timing of the piezoelectric element 12B, a pressure wave from the flow path portion 41a toward the inlet side of the liquid discharge flow path 41 can be generated when the liquid in the individual liquid chamber 6 is pressurized. it can. This pressure wave makes it difficult for the liquid to escape from the nozzle communication path 5 to the liquid discharge channel 41.

  Thereby, the pressure by the piezoelectric element 12A is efficiently used for liquid discharge, and the discharge efficiency is suppressed from decreasing.

  On the other hand, when the liquid is not discharged from the nozzle 4, the piezoelectric element 12B is not driven so that the fluid resistance of the flow channel portion 41a of the liquid discharge flow channel 41 is not increased, or the flow channel portion 41a of the liquid discharge flow channel 41 is set. Does not generate pressure waves.

  Thereby, the liquid can be smoothly discharged and circulated to the circulation common liquid chamber 45 through the liquid discharge channel 41, the change in the viscosity of the liquid such as thickening in the nozzle 4 is suppressed, and the bubbles are discharged. Can do.

  Here, an example of the relationship between the drive voltage of the liquid discharge drive waveform and the discharge speed when the flow control of the liquid discharge channel is performed and when it is not performed will be described with reference to FIG. FIG. 10 is an explanatory diagram for explaining the same.

  When a liquid is ejected by applying a discharge drive waveform to the piezoelectric element 12A, (a) the piezoelectric element 12B is not driven (non-driven), (b) the piezoelectric element 12B is extended and driven to increase fluid resistance (fluid) Resistance), (c) When the piezoelectric element 12B was expanded and contracted to generate a pressure wave (pressure wave), the liquid discharge speed was measured by changing the drive voltage of the discharge drive waveform. The result is shown in FIG.

  As can be seen from FIG. 10, when the piezoelectric element 12B is driven to increase fluid resistance, or when a pressure wave is generated, the piezoelectric element 12B is not driven, that is, the flow path portion of the liquid discharge flow path is Compared with the case where there is no means for deforming, the discharge speed is increased and the discharge efficiency is improved.

  In addition, when the piezoelectric element 12B is driven to increase the fluid resistance, the discharge speed is increased and the discharge efficiency is further improved when the pressure wave is generated.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the liquid discharge head.

  In the present embodiment, the nozzle 4 is disposed at a position for discharging the liquid in the direction of the liquid flow in the individual liquid chamber 6.

  Then, a liquid discharge passage 41 is opened on the side wall surface of the individual liquid chamber 6 on the nozzle 4 side, and here, as in the first embodiment, the flow of the liquid discharge passage 41 on the nozzle plate 1 side of the partition wall portion. Road part is arranged. As in the second embodiment, the liquid discharge channel 41 may be disposed on the vibration plate 3 side to have a deformable wall surface.

  Even with such a head configuration, it is possible to obtain the same effects as those of the above embodiments.

  Next, a first example of a head drive control device that is drive control means for driving and controlling the liquid ejection heads of the above embodiments will be described with reference to FIGS. FIG. 12 is a block diagram for explaining the head drive control device, and FIG. 13 is an explanatory diagram for explaining an example of a drive waveform and a flow rate control waveform.

  The drive waveform generation unit 701 generates and outputs a drive waveform PV including one or a plurality of drive pulses for discharging the liquid applied to the piezoelectric element 12A of the liquid discharge head. For example, as shown in FIG. 13A, a drive waveform PV including a plurality of drive pulses within one drive cycle is generated and output.

  The drive waveform generation unit 701 includes, for example, a storage unit that stores and holds the data of the drive waveform PV, a D / A conversion unit that reads the data of the drive waveform PV and performs D / A conversion, current amplification of the signal of the converted drive waveform, Amplifying means for amplifying the voltage is included.

  The flow rate control waveform output unit 703 generates and outputs a flow rate control waveform PS that deforms the flow path portion 41a of the liquid discharge flow path 41 applied to the piezoelectric element 12B of the liquid discharge head.

  As shown in FIG. 13B, the flow rate control waveform output unit 703 generates and outputs a flow rate control waveform PS that is a voltage waveform that rises from the start of output of the drive waveform PV and falls at the end of output of the drive waveform PV.

  Similarly to the drive waveform generation unit 701, the flow rate control waveform output unit 703 also has a storage means for storing and holding data of the flow rate control waveform PS, a D / A conversion unit for reading out the waveform PS data, and performing D / A conversion. Amplifying means for amplifying the current of the drive waveform and amplifying the voltage are included. Note that it may be configured simply by switching means that turns on the input voltage at the start of one drive cycle and turns it off at the end.

  The data processing unit 702 receives print data, performs necessary data processing, and drives pulses that constitute 2-bit image data (gradation signals 0 and 1), a clock signal, a latch signal, and a drive waveform PV. A selection signal (droplet control signal) for selecting is output.

  Note that the selection signal is a signal for instructing opening and closing of the analog switch AS, which is a switch unit of the head driver 509, for each droplet. The state transitions to the H level (ON) by a drive pulse (or waveform element) to be selected in accordance with the printing cycle of the drive waveform PV, and the state transitions to the L level (OFF) when not selected.

  The head driver 509 includes a shift register 711, a latch circuit 712, a decoder 713, a level shifter 714, and analog switch arrays 715A and 715B.

  The shift register 711 inputs the transfer clock (shift clock) and serial image data (gradation data: 2 bits / 1 channel (1 nozzle)) from the data processing unit 702. The latch circuit 712 includes each register of the shift register 711. The value is latched by the latch signal.

  The decoder 713 decodes the gradation data and the selection signal and outputs the result. The level shifter 714 converts the logic level voltage signal of the decoder 713 to a level at which the analog switches AS of the analog switch arrays 715A and 715B can operate.

  The analog switches AS of the analog switch arrays 715A and 715B are turned on / off (opened / closed) by the output of the decoder 713 given through the level shifter 714.

  The analog switch AS of the analog switch array 715A is connected to the individual electrode of the piezoelectric element 12A, and the drive waveform PV from the drive waveform generation unit 701 is input.

  Therefore, the analog switch AS is turned on / off according to the result of decoding the serially transferred image data (gradation data) and the selection signal by the decoder 713. As a result, a required drive pulse (or waveform element) constituting the drive waveform PV passes (is selected), is given to the piezoelectric element 12A, and the liquid is ejected.

  The analog switch AS of the analog switch array 715B is connected to the individual electrode of the piezoelectric element 12B, and the flow control waveform PS from the flow control waveform output unit 703 is input.

  Also, the analog switch AS of the analog switch array 715B is turned on / off by latch data of the latch circuit 712 corresponding to the piezoelectric element 12A that pressurizes the individual liquid chamber 6 through which the liquid discharge channel 41 deformed by the piezoelectric element 12B communicates. The

  As a result, for the nozzle 4 that discharges the liquid, the flow rate control waveform PS is applied to the piezoelectric element 12B during one drive cycle, and the piezoelectric element 12B expands to increase the fluid resistance of the flow path portion 41a.

  Next, a second example of a head drive control device that drives and controls the liquid discharge heads of the above embodiments will be described with reference to FIGS. FIG. 14 is an explanatory block diagram for explaining the head drive control device, and FIG. 15 is an explanatory diagram for explaining an example of a drive waveform and a flow rate control waveform.

  In the present embodiment, the drive waveform generation unit 701 generates a drive waveform PV including a plurality of drive pulses within one drive cycle as shown in FIG. 15A, for example, as in the first example. Output.

  The flow rate control waveform output unit 703 is a drive waveform as a flow rate control waveform PS that deforms the flow path portion 41a of the liquid discharge flow path 41 applied to the piezoelectric element 12B of the liquid ejection head, as shown in FIG. A flow control waveform PS including a drive pulse synchronized with the PV drive pulse is generated and output. Here, the synchronization means that the piezoelectric element 12A is contracted by the drive pulse of the drive waveform PV in a direction in which the piezoelectric element 12B contracts the flow path portion 41a of the liquid discharge flow path 41 when the individual liquid chamber 6 contracts. It means to extend.

  Further, in the present embodiment, the analog switch AS of the analog switch array 715B is turned on / off by a decoding result given to the piezoelectric element 12A that pressurizes the individual liquid chamber 6 through which the liquid discharge channel 41 deformed by the piezoelectric element 12B communicates. The

  As a result, for the nozzle 4 that discharges the liquid, when the drive pulse of the drive waveform PV is given, the drive pulse of the flow rate control waveform PS is also selected and given to the piezoelectric element 12B, and the piezoelectric element 12B expands and flows. A pressure wave from the passage portion 41a toward the inlet of the liquid discharge passage 41 is generated.

  Next, a third example of the head drive control device that drives and controls the liquid discharge heads of the above embodiments will be described with reference to FIG. FIG. 16 is an explanatory block diagram for explaining the head drive control device.

  In the present embodiment, the liquid discharge drive waveform PV generated by the drive waveform generation unit 701 is used as it is as the flow path control waveform applied to the piezoelectric element 12B that deforms the flow path portion 41a of the liquid discharge flow path 41. .

  Similarly to the second example, the analog switch AS of the analog switch array 715B is turned on by the decoding result given to the piezoelectric element 12A that pressurizes the individual liquid chamber 6 through which the liquid discharge channel 41 deformed by the piezoelectric element 12B communicates. / Turned off.

  Thereby, when the drive waveform can be used as it is as the flow control waveform, it is not necessary to generate a separate flow control waveform for driving the piezoelectric element 12B, and the configuration is simplified.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 17 is a cross-sectional explanatory diagram in a direction along the nozzle arrangement direction (liquid chamber short direction) for explaining the embodiment.

  In the present embodiment, the deformation amount of the piezoelectric element 12B is varied for each nozzle 4 corresponding to the liquid discharge channel 41 so that the ejection characteristics of the nozzles 4 are aligned.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 18 is a cross-sectional explanatory diagram in a direction along the nozzle arrangement direction for explaining the embodiment.

  In the present embodiment, contrary to the above embodiments, when the piezoelectric element 12B is not driven, the flow channel portion 41a of the liquid discharge flow channel 41 has a required fluid resistance value as shown in FIG. It has a fluid resistance part.

  Then, by driving the piezoelectric element 12B, as shown in FIG. 18 (b), the piezoelectric element 12B contracts to increase the opening cross-sectional area of the flow path portion 41a, and the flow path portion 41a serving as the fluid resistance portion of the flow path portion 41a. Reduce fluid resistance.

  Therefore, in the present embodiment, when ejection is not performed from the nozzle 4, the piezoelectric element 12 </ b> B is driven to control to reduce the fluid resistance of the flow path portion 41 a that is the fluid resistance section of the liquid discharge flow path 41. Do.

  That is, in the case of a device that constantly discharges and occasionally discharges a liquid that performs maintenance, the timing for reducing the fluid resistance of the flow path portion 41a is reduced, so the time for which the piezoelectric element 12B is not driven is lengthened. As a result, drive control becomes easy.

  On the other hand, when the ejection time is short, driving control is easier if the fluid resistance of the flow path portion 41a is reduced when the piezoelectric element 12B is in the non-driven state.

  Next, an example of a device for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 19 is an explanatory plan view of an essential part of the apparatus, and FIG. 20 is an explanatory side view of an essential part of the apparatus.

  This apparatus is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction by the main scanning moving mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 spans the left and right side plates 491A and 491B and holds the carriage 403 so as to be movable. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 spanned between the driving pulley 406 and the driven pulley 407.

  A liquid discharge unit 440 in which the liquid discharge head 404 and the head tank 441 according to the present invention are integrated is mounted on the carriage 403. The liquid discharge head 404 of the liquid discharge unit 440 discharges, for example, yellow (Y), cyan (C), magenta (M), and black (K) liquids. The liquid ejection head 404 is mounted with a nozzle row composed of a plurality of nozzles arranged in the sub-scanning direction orthogonal to the main scanning direction, and the ejection direction facing downward.

  The liquid stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

  The supply mechanism 494 includes a cartridge holder 451 that is a filling unit for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is fed from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

  This apparatus includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412 serving as transport means, and a sub-scanning motor 416 for driving the transport belt 412.

  The conveyance belt 412 adsorbs the paper 410 and conveys it at a position facing the liquid ejection head 404. The transport belt 412 is an endless belt and is stretched between the transport roller 413 and the tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction.

  The transport belt 412 rotates in the sub-scanning direction when the transport roller 413 is rotationally driven by the sub-scanning motor 416 via the timing belt 417 and the timing pulley 418.

  Further, on one side of the carriage 403 in the main scanning direction, a maintenance / recovery mechanism 420 that performs maintenance / recovery of the liquid ejection head 404 is disposed on the side of the transport belt 412.

  The maintenance / recovery mechanism 420 includes, for example, a cap member 421 for capping the nozzle surface (surface on which the nozzle is formed) of the liquid ejection head 404, a wiper member 422 for wiping the nozzle surface, and the like.

  The main scanning movement mechanism 493, the supply mechanism 494, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

  In this apparatus configured as described above, the paper 410 is fed and sucked onto the transport belt 412, and the paper 410 is transported in the sub-scanning direction by the circular movement of the transport belt 412.

Therefore, the liquid ejection head 404 is driven in accordance with the image signal while moving the carriage 403 in the main scanning direction, thereby ejecting liquid onto the stopped paper 410 to form an image.

  Thus, since this apparatus includes the liquid ejection head according to the present invention, a high-quality image can be stably formed.

  Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 21 is an explanatory plan view of the main part of the unit.

  The liquid discharge unit includes a casing portion composed of side plates 491A and 491B and a back plate 491C, a main scanning moving mechanism 493, a carriage 403, and a liquid among the members constituting the liquid discharge device. The discharge head 404 is configured.

  Note that a liquid discharge unit in which at least one of the above-described maintenance and recovery mechanism 420 and the supply mechanism 494 is further attached to, for example, the side plate 491B of the liquid discharge unit may be configured.

  Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 22 is an explanatory front view of the unit.

  This liquid discharge unit includes a liquid discharge head 404 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

  The flow path component 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path component 444. In addition, a connector 443 that is electrically connected to the liquid ejection head 404 is provided above the flow path component 444.

  Next, another example of the apparatus for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 23 is a schematic explanatory view of the apparatus, and FIG. 24 is a plan explanatory view of the head unit of the apparatus.

  This apparatus includes a carry-in means 1501 for carrying a continuous body 1510 such as roll paper, a guide carrying means 1503 for guiding and carrying the continuous body 1510 carried from the carry-in means 1501 to the printing means 1505, and a liquid for the continuous body 1510. A printing unit 1505 that performs printing to form an image by ejecting the liquid, a drying unit 1507 that dries the continuous body 1510, a discharge unit 1509 that discharges the continuous body 1510, and the like.

  The continuous body 1510 is sent out from the original winding roller 1511 of the carry-in means 1501, guided and conveyed by the respective rollers of the carry-in means 1501, the guide conveyance means 1503, the drying means 1507, and the discharge means 1509, and the take-up roller 1591 of the discharge means 1509. It is wound up by.

  The continuum 1510 is conveyed on the conveyance guide member 1559 by the printing unit 1505 so as to face the head unit 1550 and the head unit 1555, and an image is formed by the liquid ejected from the head unit 1550. Post-processing is performed with the processing liquid.

  Here, the head unit 1550 includes, for example, four-line full-line type head arrays 1551K, 1551C, 1551M, and 1551Y (hereinafter referred to as “head array 1551” when colors are not distinguished) from the upstream side in the continuous conveyance direction. .) Is arranged.

  Each head array 1551 is a liquid ejection unit, and ejects black K, cyan C, magenta M, and yellow Y liquids to the continuum 1510 being conveyed. The type and number of colors are not limited to this.

  For example, as shown in FIG. 24, the head array 1551 is configured by arranging the circulation type liquid discharge heads 1000 according to the present invention side by side on a base member 1552. However, the present invention is not limited to this. In FIG. 24, the head unit is shown in a simplified manner.

  Next, an example of the liquid circulation system in this apparatus will be described with reference to FIG. FIG. 25 is a block diagram for explaining the system.

  The liquid circulation system 1630 includes a main tank 1602, a head 1000, a supply tank 1631, a circulation tank 1632, a compressor 1633, a vacuum pump 1634, a first liquid feed pump 1635, a second liquid feed pump 1636, a supply side pressure sensor 1637, and a circulation side. A pressure sensor 1638, regulators (R) 1639a and 1639b, and the like are included.

  The supply-side pressure sensor 1637 is connected between the supply tank 1631 and the head 1000 and on the supply flow path side connected to the supply port that communicates with the common liquid chamber 10 of the head 1000. The circulation-side pressure sensor 1638 is connected between the head 1000 and the circulation tank 1632 and on the discharge channel side connected to the discharge port leading to the circulation common liquid chamber 45 of the head 1000.

  One of the circulation tanks 1632 is connected to the supply tank 1631 via the first liquid feed pump 1635, and the other of the circulation tanks 1632 is connected to the main tank 1602 via the second liquid feed pump 1636.

  As a result, liquid flows from the supply tank 1631 through the supply port into the head 1000, discharged from the circulation port, and discharged to the circulation tank 1632. Further, the liquid is circulated by the liquid being sent from the circulation tank 1632 to the supply tank 1631 by the first liquid feed pump 1635.

  Further, a compressor 1633 is connected to the supply tank 1631 and is controlled so that a predetermined positive pressure is detected by the supply side pressure sensor 1637. On the other hand, a vacuum pump 1634 is connected to the circulation tank 1632, and the circulation side pressure sensor 1638 is controlled to detect a predetermined negative pressure.

  Thereby, the negative pressure of the meniscus can be kept constant while constantly circulating the liquid from the common liquid chamber in the head 1000 to the circulation common liquid chamber through the individual liquid chamber and the liquid discharge channel.

  Further, when liquid is ejected from the nozzle 4 of the head 1000, the amount of liquid in the supply tank 1631 and the circulation tank 1632 decreases. Therefore, liquid is replenished from the main tank 1602 to the circulation tank 1632 using the second liquid feed pump 1636 as appropriate. The liquid replenishment timing from the main tank 1602 to the circulation tank 1632 is the liquid level provided in the circulation tank 1632 such that liquid replenishment is performed when the liquid level in the circulation tank 1632 falls below a predetermined level. It can be controlled by the detection result of a sensor or the like.

  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 10 Common liquid chamber 11 Piezoelectric actuator 20 Frame member 41 Liquid discharge flow path 41a Flow path portion 45 Circulating common liquid chamber 60 Bulkhead section 403 Carriage 404 Liquid discharge head 440 Liquid discharge unit 1000 head

Claims (12)

A plurality of nozzles for discharging liquid;
A plurality of individual liquid chambers leading to the nozzle;
A plurality of liquid discharge passages communicating with the individual liquid chambers,
The liquid discharge flow path includes a flow path portion disposed in a partition between adjacent individual liquid chambers,
A liquid discharge head comprising means for deforming at least a part of a flow path portion of the liquid discharge flow path. A nozzle communication path through the nozzle and the individual liquid chamber;
The liquid discharge head according to claim 1, wherein the liquid discharge channel communicates with the individual liquid chamber via the nozzle communication path. The liquid ejection head according to claim 1, wherein the means for deforming is an electromechanical conversion element connected to the partition wall. The flow path portion of the liquid discharge flow path has a deformable wall surface,
The liquid discharge head according to claim 1, wherein the means for deforming is an electromechanical transducer element connected to the wall surface. An electromechanical transducer for pressurizing the individual liquid chamber;
The liquid discharge head according to claim 4, wherein the electromechanical conversion element connected to the wall surface and the electromechanical conversion element that pressurizes the individual liquid chamber are arranged adjacent to each other.   A liquid discharge unit comprising the liquid discharge head according to claim 1. A head tank for storing liquid to be supplied to the liquid discharge head, a carriage on which the liquid discharge head is mounted, a supply mechanism for supplying liquid to the liquid discharge head, a maintenance / recovery mechanism for maintaining and recovering the liquid discharge head, and the liquid The liquid discharge unit according to claim 6, wherein at least one of a main scanning movement mechanism for moving the discharge head in the main scanning direction and the liquid discharge head are integrated.   An apparatus for ejecting liquid, comprising the liquid ejection head according to claim 1 or the liquid ejection unit according to claim 6 or 7. Means for driving and controlling the means for deforming,
The means for controlling the drive increases the fluid resistance of the flow path portion of the liquid discharge flow path by deforming the flow path portion of the liquid discharge flow path by the deforming means when discharging the liquid from the nozzle. The apparatus for ejecting liquid according to claim 8. Means for driving and controlling the means for deforming,
The drive control means is configured to deform the flow path portion of the liquid discharge flow path one or more times by the deforming means when discharging the liquid from the nozzle, and pressure toward the inlet side of the liquid discharge flow path. The apparatus for discharging a liquid according to claim 9, wherein a wave is generated. 11. The apparatus for ejecting liquid according to claim 9, wherein a plurality of the means for deforming are individually driven. The apparatus for discharging a liquid according to claim 8, wherein the liquid flows through the liquid discharge channel regardless of whether or not a liquid is discharged from the nozzle.

Images