Patent Application
20220176697
The disclosed embodiments relate to a liquid discharge head and a recording apparatus.
Known printing apparatuses include inkjet printers and inkjet plotters that utilize an inkjet recording method. Such an inkjet printing apparatus has a liquid discharge head installed for discharging a liquid (see, for example, Patent Document 1).
However, when a large number of discharge holes are provided in a known liquid discharge head, the flow channel that supplies the liquid from the manifold to the plurality of discharge holes must be densely formed. This renders the downsizing of the head main body difficult.
An aspect of the embodiment has been made in view of the above, and an object is to provide a liquid discharge head and a recording apparatus with which a head main body can be downsized.
A liquid discharge head according to an aspect of an embodiment includes a flow channel member including a first surface and a second surface located opposite to the first surface, and a pressing unit located on the first surface. The flow channel member includes a first discharge hole and a second discharge hole located in the second surface, a first individual flow channel connected to the first discharge hole; a first pressurizing chamber located more on an upstream side than the first discharge hole in the first individual flow channel; a second individual flow channel connected to the second discharge hole; a second pressurizing chamber that is located more on an upstream side than the second discharge hole in the second individual flow channel; and a manifold commonly connected to an upstream side of first individual flow channel and an upstream side of the second individual flow channel. The first individual flow channel and the second individual flow channel have an overlapping portion in plan view.
A recording apparatus according to an aspect of an embodiment includes a liquid discharge head, a conveying unit configured to convey a recording medium to the liquid discharge head, and a control unit configured to control the liquid discharge head. The liquid discharge head includes a flow channel member including a first surface and a second surface located opposite to the first surface, and a pressing unit located on the first surface. The flow channel member includes a first discharge hole and a second discharge hole located in the second surface, a first individual flow channel connected to the first discharge hole; a first pressurizing chamber located more on an upstream side than the first discharge hole in the first individual flow channel; a second individual flow channel connected to the second discharge hole; a second pressurizing chamber that is located more on an upstream side than the second discharge hole in the second individual flow channel; and a manifold commonly connected to an upstream side of the first individual flow channel and an upstream side of the second individual flow channel. The first individual flow channel and the second individual flow channel have an overlapping portion in plan view.
According to an aspect of the embodiment, a liquid discharge head and a recording device with which a head main body can be downsized can be provided.
Embodiments of a liquid discharge head and a recording apparatus disclosed in the present application will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited by the embodiments described below.
Known printing apparatuses include inkjet printers and inkjet plotters that utilize an inkjet recording method. An inkjet printing apparatus is installed with a liquid discharge head for discharging a liquid.
A piezoelectric method is another method for discharging liquid from the liquid discharge head. A liquid discharge head for the piezoelectric method discharges ink in an ink flow channel by mechanically pressurizing the ink with a part of the wall of the ink flow channel bent and displaced by a displaced element.
However, when a large number of discharge holes are provided in a known liquid discharge head, the flow channel that supplies the liquid from the manifold to the plurality of discharge holes must be densely formed. This renders the downsizing of the head main body difficult.
On the other hand, reducing the number of discharge holes in order to downsize the head main body results in a problem in that the resolution of the printing apparatus is compromised.
Thus, there has been a demand for a liquid discharge head and a recording apparatus with which a head main body can be downsized even when a large number of discharge holes are provided.
First, a description will be given on an overview of a printer 1 that is one example of a recording apparatus according to an embodiment, with reference to
Specifically,
As illustrated in
The printer 1 includes a control unit 14 that controls the paper feed roller 2, the guide rollers 3, the applicator 4, the head case 5, the plurality of conveying rollers 6, the plurality of frames 7, the plurality of liquid discharge heads 8, the conveying rollers 9, the dryer 10, the conveying rollers 11, the sensor unit 12, and the collection roller 13.
The printer 1 records an image and characters on a printing sheet P by causing droplets to land on the printing sheet P. The printing sheet P is an example of a recording medium. The printing sheet P is rolled on the paper feed roller 2 prior to use. In this state, the printer 1 conveys the printing sheet P from the paper feed roller 2 to the inside of the head case 5 via the guide rollers 3 and the applicator 4.
The applicator 4 uniformly applies a coating agent over the printing sheet P. With surface treatment thus performed on the printing sheet P, the printing quality of the printer 1 can be improved.
The head case 5 houses the plurality of conveying rollers 6, the plurality of frames 7, and the plurality of liquid discharge heads 8. The inside of the head case 5 is formed with a space separated from the outside except for a part connected to the outside such as parts where the printing sheet P enters and exits.
If necessary, the control unit 14 controls at least one of controllable factors of the internal space of the head case 5, such as the temperature, the humidity, and barometric pressure. The conveying rollers 6 convey the printing sheet P to the vicinity of the liquid discharge heads 8, inside the head case 5.
The frame 7 is a rectangular flat plate, and is positioned above and close to the printing sheet P conveyed by the conveying rollers 6. As illustrated in
Liquid, which is ink for example, is supplied to the liquid discharge heads 8 from a liquid tank (not illustrated). Each liquid discharge head 8 discharges the liquid supplied from the liquid tank.
The control unit 14 controls the liquid discharge heads 8 based on data of an image, characters, and the like to discharge the liquid toward the printing sheet P. The distance between each liquid discharge head 8 and the printing sheet P is, for example, approximately 0.5 to 20 mm.
The liquid discharge heads 8 are fixed to the frame 7. The liquid discharge heads 8 are positioned such that the longitudinal direction of the liquid discharge heads 8 is orthogonal to the conveyance direction of the printing sheet P.
That is, the printer 1 according to the embodiment is what is known as a line printer with the liquid discharge heads 8 fixed inside the printer 1. Note that the printer 1 according to the embodiment is not limited to a line printer and may also be what is known as a serial printer.
The serial printer is a printer employing a method of alternately performing operations of recording while moving the liquid discharge heads 8 in a manner such as reciprocation in a direction intersecting (e.g., substantially orthogonal to) the conveyance direction of the printing sheet P, and conveying the printing sheet P.
As illustrated in
The plurality of liquid discharge heads 8 positioned in one frame 7 form a head group 8A. Four head groups 8A are positioned along the conveyance direction of the printing sheet P. The liquid discharge heads 8 belonging to the same head group 8A are supplied with ink of the same color. As a result, the printer 1 can perform printing with four colors of ink using the four head groups 8A.
The colors of the ink discharged from the respective head groups 8A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The control unit 14 can print a color image on the printing sheet P by controlling each of the head groups 8A to discharge the plurality of colors of ink onto the printing sheet P.
Note that a surface treatment may be performed on the printing sheet P, by discharging a coating agent from the liquid discharge head 8 onto the printing sheet P.
Furthermore, the number of the liquid discharge heads 8 included in one head group 8A and the number of the head groups 8A provided in the printer 1 can be changed as appropriate in accordance with printing targets and printing conditions. For example, if the color to be printed on the printing sheet P is a single color and the range of the printing can be covered by a single liquid discharge head 8, only a single liquid discharge head 8 may be provided in the printer 1.
The printing sheet P thus subjected to the printing process inside the head case 5 is conveyed by the conveying rollers 9 to the outside of the head case 5, and passes through the inside of the dryer 10. The dryer 10 dries the printing sheet P after the printing process. The printing sheet P thus dried by the dryer 10 is conveyed by the conveying rollers 11 and then collected by the collection roller 13.
In the printer 1, by drying the printing sheet P with the dryer 10, it is possible to suppress bonding between the printing sheets P rolled while being overlapped with each other, and rubbing between undried liquid at the collection roller 13.
The sensor unit 12 includes a position sensor, a speed sensor, a temperature sensor, and the like. Based on information from the sensor unit 12, the control unit 14 can determine the state of each part of the printer 1 and control each part of the printer 1.
In the printer 1 described above, the printing sheet P is the printing target (i.e., the recording medium), but the printing target in the printer 1 is not limited to the printing sheet P, and a roll type fabric or the like may be the printing target.
Furthermore, instead of directly conveying the printing sheet P, the printer 1 may be mounted on a conveyor belt and then conveyed. If a conveyor belt is used, the printing target of the printer 1 can be flat paper, cut cloth, wood, tile, or the like.
Furthermore, the printer 1 may discharge a liquid containing electrically conductive particles from the liquid discharge head 8, to print a wiring pattern or the like of an electronic device. Furthermore, the printer 1 may discharge liquid containing a predetermined amount of liquid chemical agent or liquid containing the chemical agent from the liquid discharge head 8 onto a reaction vessel or the like to produce chemicals.
The printer 1 may also include a cleaning unit for cleaning the liquid discharge heads 8. The cleaning unit cleans the liquid discharge heads 8 by, for example, a wiping process or a capping process.
The wiping process is, for example, a process of removing liquid attached to a second surface 24b (see
The capping process is performed as follows, for example. First of all, a cap is provided to cover the second surface 24b of the flow channel member 24 which is an example of the portion onto which the liquid is discharged (this action is referred to as capping). As a result, a substantially sealed space is formed between the second surface 24b and the cap.
The discharge of liquid is then repeated in such a sealed space. As a result, liquid with a viscosity higher than that in the normal state, foreign matter, or the like clogging a first discharge hole 45 (see
Next, the configuration of the liquid discharge head 8 according to the embodiment will be described with reference to
As illustrated in
The flow channel member 24 of the head main body 20 has a substantially flat plate shape and includes a first surface 24a, which is one main surface, and the second surface 24b located opposite to the first surface 24a. The first surface 24a has an opening 40a (see
A plurality of the first discharge holes 45 (see
The piezoelectric actuator substrate 25 is located on the first surface 24a of the flow channel member 24. The piezoelectric actuator substrate 25 includes a plurality of displaced elements 38 (see
Two signal transmission units 26 are electrically connected to the piezoelectric actuator substrate 25. Each signal transmission unit 26 includes a plurality of the drive integrated circuits (ICs) 27. Note that, in
The signal transmission unit 26 supplies a signal to each displaced element 38 of the piezoelectric actuator substrate 25. The signal transmission unit 26 is formed of, for example, a flexible printed circuit (FPC) or the like.
The drive IC 27 is provided in the signal transmission unit 26. The drive IC 27 controls the driving of each displaced element 38 in the piezoelectric actuator substrate 25.
Note that the head main body 20 has a discharge surface from which the liquid is discharged and an opposite surface located on a side opposite to the discharge surface. In the following description, the discharge surface is described as the second surface 24b of the flow channel member 24 and the opposite surface is described as the first surface 24a of the flow channel member 24.
The reservoir 21 is located on the opposite surface side of the head main body 20 and is in contact with the first surface 24a excluding the piezoelectric actuator substrate 25. The reservoir 21 has a flow channel therein, and is supplied with liquid from the outside through an opening 21a. The reservoir 21 has a function of supplying liquid to the flow channel member 24 and a function of storing the liquid to be supplied.
The electrical board 22 is provided in a standing manner on a surface on the side of the reservoir 21 opposite to the head main body 20. A plurality of connectors 28 are located on an end portion of the electrical board 22 on the reservoir 21 side. An end portion of the signal transmission unit 26 is housed in each connector 28.
Connectors 29 for power supply are located on an end portion of the electrical board 22 on the side opposite to the reservoir 21. The electrical board 22 distributes current, supplied from the outside via the connector 29, to the connectors 28 and supplies the current to the signal transmission unit 26.
The head cover 23 is located on the opposite surface side of the head main body 20 and covers the signal transmission unit 26 and the electrical board 22. Thus, the liquid discharge heads 8 can seal the signal transmission unit 26 and the electrical board 22.
The head cover 23 includes an opening 23a. The connector 29 of the electrical board 22 is inserted to be exposed to the outside, through the opening 23a.
The drive IC 27 is in contact with an interior side surface of the head cover 23. The drive IC 27 is pressed against the interior side surface of the head cover 23, for example. As a result, heat generated by the drive IC 27 can be dissipated (radiated) through a contact portion on the side surface of the head cover 23.
Note that the liquid discharge head 8 may further include a member other than the member illustrated in
Next, the configuration of the head main body 20 according to the embodiment will be described with reference to
As illustrated in
The plurality of first pressurizing chambers 43 and the plurality of second pressurizing chambers 53 are connected to the supply manifold 40. The plurality of first discharge holes 45 are connected to the plurality of respective first pressurizing chambers 43. The plurality of second discharge holes 55 are connected to the plurality of respective second pressurizing chambers 53.
The first pressurizing chambers 43 and the second pressurizing chambers 53 open to the first surface 24a (see
In the example illustrated in
The plurality of first pressurizing chambers 43 and the plurality of second pressurizing chambers 53 are formed in the flow channel member 24 in a two-dimensionally spreading manner. The first pressurizing chambers 43 and the second pressurizing chambers 53 are hollow regions having a substantially diamond-shaped planar shape with rounded corners. The first pressurizing chambers 43 and the second pressurizing chambers 53 open to the first surface 24a of the flow channel member 24, and are closed when the piezoelectric actuator substrate 25 is joined to the first surface 24a.
The first pressurizing chambers 43 form a first pressurizing chamber row arranged in the longitudinal direction, and the second pressurizing chambers 53 form a second pressurizing chamber row arranged in the longitudinal direction. The first pressurizing chambers 43 belonging to the first pressurizing chamber row and the second pressurizing chambers 53 belonging to the second pressurizing chamber row adjacent to the first pressurizing chamber row are alternately arranged.
One pressurizing chamber group includes two rows of first pressurizing chamber rows and two rows of second pressurizing chamber rows connected to one supply manifold 40. In the example illustrated in
Moreover, the relative arrangement of the first pressurizing chambers 43 and the second pressurizing chambers 53 is the same among the pressurizing chamber groups, with the pressurizing chamber groups arranged while being slightly shifted from each other in the longitudinal direction.
The first discharge holes 45 and the second discharge holes 55 are disposed at positions outside regions, of the flow channel member 24, facing the supply manifold 40. Thus, none of the first discharge holes 45 and the second discharge holes 55 overlap with the supply manifold 40 in a plane perspective of the flow channel member 24 as viewed from the first surface 24a side.
Furthermore, in plan view, the first discharge holes 45 and the second discharge holes 55 are disposed within a region in which the piezoelectric actuator substrate 25 is mounted. One group of the first discharge holes 45 and the second discharge holes 55 occupies a region of approximately the same size and shape as the piezoelectric actuator substrate 25.
Droplets are discharged through the first discharge holes 45 and the second discharge holes 55 by displacing the displaced elements 38 (see
As illustrated in
In other words, the flow channel member 24 includes a first individual flow channel C1 including the first aperture 41, the first connection flow channel 42, the first pressurizing chamber 43, and the first vertical flow channel 44. In the first individual flow channel C1, the first aperture 41 is located close to the supply manifold 40 and the first vertical flow channel 44 is located close to the first discharge holes 45, in the flow direction of the liquid.
Note that when a direction from the first surface 24a toward the second surface 24b is defined as a first direction D1, the first aperture 41 extends in a direction perpendicular to the first direction D1, the first connection flow channel 42 extends in the first direction D1, the first pressurizing chamber 43 extends in a direction perpendicular to the first direction D1, and the first vertical flow channel 44 extends in the first direction D1.
Similarly, the supply manifold 40 and the second discharge holes 55 are connected to each other via a second connection flow channel 51, a second aperture 52, the second pressurizing chamber 53, and a second vertical flow channel 54.
In other words, the flow channel member 24 includes a second individual flow channel C2 including the second connection flow channel 51, the second aperture 52, the second pressurizing chamber 53, and the second vertical flow channel 54. In the second individual flow channel C2, the second connection flow channel 51 is located close to the supply manifold 40 and the second vertical flow channel 54 is located close to the second discharge hole 55, in the flow direction of the liquid.
The second connection flow channel 51 extends in the first direction D1, the second aperture 52 extends in a direction perpendicular to the first direction D1, the second pressurizing chamber 53 extends in the direction perpendicular to the first direction D1, and the second vertical flow channel 54 extends in the first direction D1.
The first individual flow channel C1 has the first aperture 41 provided more on the upstream side than the first pressurizing chamber 43. In addition, the first aperture 41 includes a narrow portion 41a that is narrower than other portions of the first individual flow channel C1 and a wide portion 41b that is formed on the same plane as the narrow portion 41a and is wider than the narrow portion 41a.
With the narrow portion 41a that is narrower than the other portions of the first individual flow channel C1, the first aperture 41 has a high flow channel resistance.
As a result, in the embodiment, the pressure generated in the first pressurizing chamber 43 can be prevented from escaping to the supply manifold 40, instead of being directed to the first discharge holes 45. Therefore, according to the embodiment, the liquid can be efficiently discharged from the first discharge holes 45.
The second individual flow channel C2 has the second aperture 52 provided more on the upstream side than the second pressurizing chamber 53. In addition, the second aperture 52 includes a narrow portion 52a that is narrower than other portions of the second individual flow channel C2 and a wide portion 52b that is formed on the same plane as the narrow portion 52a and is wider than the narrow portion 52a.
With the narrow portion 52a that is narrower than the other portions of the second individual flow channel C2, the second aperture 52 has a high flow channel resistance.
As a result, in the embodiment, the pressure generated in the second pressurizing chamber 53 can be prevented from escaping to the supply manifold 40, instead of being directed to the second discharge holes 55. Therefore, according to the embodiment, the liquid can be efficiently discharged from the second discharge holes 55.
As illustrated in
In the embodiment, by setting the thickness of these plates to about 10 to 300 μm, the holes can be formed with increased accuracy.
Furthermore, in the embodiment, the first aperture 41 is connected to the first connection flow channel 42 at the wide portion 41b. With this configuration, when the plurality of plates are stacked and the first aperture 41 and the first connection flow channel 42 are connected to each other, variations in the flow path resistance caused by misalignment can be reduced.
Furthermore, in the embodiment, the second aperture 52 is connected to the second pressurizing chamber 53 at the wide portion 52b. With this configuration, when the plurality of plates are stacked and the second aperture 52 and the second pressurizing chamber 53 are connected to each other, variations in the flow path resistance caused by misalignment can be reduced.
In the embodiment, as illustrated in
In other words, in the embodiment, the first individual flow channel C1 and the second individual flow channel C2 have an overlapping portion in plan view that are disposed at different heights. As a result, the first individual flow channel C1 and the second individual flow channel C2 can be formed in the flow channel member 24 with high space efficiency.
Thus, according to the embodiment, even when a large number of the first discharge holes 45 and the second discharge holes 55 are provided, the flow channel member 24 can be downsized, whereby the head main body 20 can be downsized.
In particular, when the first aperture 41 and the second aperture 52 are formed in the same plane in a direction intersecting the first direction D1, the flow channel member 24 increases in size. On the other hand, as in the embodiment, when the first aperture 41 and the second aperture 52 are located vertically while having an overlapping portion in plan view, the first aperture 41 and the second aperture 52 are formed with high space efficiency, whereby the head main body 20 can be downsized.
In the embodiment, in plan view, preferably, the first pressurizing chamber 43 is located farther from the supply manifold 40 than the second pressurizing chamber 53, and the second aperture 52 is located closer to the first surface 24a than the first aperture 41.
With this configuration, the first aperture 41 can be disposed in the flow channel member 24 without interfering with the second pressurizing chamber 53. Thus, according to the embodiment, the first individual flow channel C1 can be formed in the flow channel member 24 with even higher space efficiency.
Additionally, in the embodiment, the volume of the second pressurizing chamber 53 is preferably larger than the volume of the first pressurizing chamber 43. As illustrated in
Thus, in the embodiment, because the volume of the second pressurizing chamber 53 is set to be larger than the volume of the first pressurizing chamber 43, it is possible to equalize the substantial volume of the second pressurizing chamber 53 with the substantial volume of the first pressurizing chamber 43, which are the volumes of the first pressurizing chamber 43 and the first connection flow channel 42.
With the substantial volume of the first pressurizing chamber 43 equalized with the substantial volume of the second pressurizing chamber 53, the characteristics of discharging as a result of application of pressure from the displaced elements 38 to the first pressurizing chamber 43 can be equalized with the characteristics of discharging as a result of application of pressure to the second pressurizing chamber 53 from the displaced elements 38.
Thus, with the embodiment, the printing quality of the printer 1 can be improved.
A description will be further given on other portions of the head main body 20. As illustrated in
The piezoelectric actuator substrate 25 includes the piezoceramic layer 31, the common electrode 33, the piezoceramic layer 32, and the individual electrode 34 stacked in this order.
Each of the piezoceramic layers 31 and 32 extends across the plurality of first pressurizing chambers 43 and second pressurizing chambers 53. The piezoceramic layers 31 and 32 each have a thickness of approximately 20 μm. The piezoceramic layers 31 and 32 may be made of a ferroelectric lead zirconate titanate (PZT)-based ceramic material.
The common electrode 33 is formed substantially over the entire surface in the region between the piezoceramic layer 31 and the piezoceramic layer 32 in a surface direction. Thus, the common electrode 33 overlaps all of the first pressurizing chambers 43 and the second pressurizing chambers 53 in the region facing the piezoelectric actuator substrate 25.
The thickness of the common electrode 33 is approximately 2 μm. A metal material such as a Ag—Pd based material can be used for the common electrode 33.
The individual electrode 34 includes a main body electrode 34a and an extraction electrode 34b. The main body electrode 34a is located in a region, on the piezoceramic layer 32, facing the first pressurizing chambers 43 and the second pressurizing chambers 53. The main body electrode 34a is one size smaller than each first pressurizing chamber 43 and each second pressurizing chamber 53, and has a shape substantially similar to that of the first pressurizing chamber 43 and the second pressurizing chamber 53.
The extraction electrode 34b is extracted from the main body electrode 34a to be outside the region facing the first pressurizing chambers 43 and the second pressurizing chambers 53. A metal material such as a Au based material can be used for the individual electrode 34.
The connection electrode 35 is located on the extraction electrode 34b, and is formed to have a protruding shape with a thickness of approximately 15 μm. The connection electrode 35 is electrically connected to an electrode provided to the signal transmission unit 26 (see
The dummy electrode 36 is located on the piezoceramic layer 32 and is located so as not to overlap various electrodes such as the individual electrode 34. The dummy electrode 36 connects the piezoelectric actuator substrate 25 and the signal transmission unit 26 to each other, and increases the connection strength.
Furthermore, the dummy electrode 36 uniformizes the distribution of the contact positions between the piezoelectric actuator substrate 25 and the signal transmission unit 26, and stabilizes the electrical connection. The dummy electrode 36 is preferably made of a material equivalent to that of the connection electrode 35, and is preferably formed in a process equivalent to that of the connection electrode 35.
The surface electrode 37 illustrated in
Thus, the surface electrode 37 is grounded and maintained at the ground potential. The surface electrode 37 is preferably made of a material equivalent to that of the individual electrode 34, and is preferably formed in a process equivalent to that of the individual electrode 34.
A plurality of the individual electrodes 34 are individually electrically connected to the control unit 14 (see
In other words, in the piezoelectric actuator substrate 25, portions of the individual electrode 34, the piezoceramic layer 32, and the common electrode 33 facing the first pressurizing chambers 43 and the second pressurizing chambers 53 function as the displaced elements 38.
Then, unimorph deformation of such displaced elements 38 results in the first pressurizing chambers 43 and the second pressurizing chambers 53 being pressed. Then, the liquid is discharged from the first discharge holes 45 and the second discharge holes 55.
Next, a drive procedure of the liquid discharge head 8 according to the embodiment will be described. The individual electrodes 34 are set to a higher potential (hereinafter, also referred to as high potential) than the common electrode 33 in advance. Then, with the control unit 14, each time a discharge request is made, the individual electrodes 34 are set to the same potential as the common electrode 33 (hereinafter referred to as low potential), and then are again set to the high potential at a predetermined timing.
Thus, at the timing when the individual electrodes 34 shift to the low potential, the piezoceramic layers 31 and 32 return to their original shape, and the volume of the first pressurizing chambers 43 and second pressurizing chambers 53 increases over that in the initial state, that is, the state with the high potential.
In this process, negative pressure is applied to the first pressurizing chamber 43 and the second pressurizing chamber 53. As a result, liquid in the supply manifold 40 is sucked into the interior of the first pressurizing chamber 43 and the second pressurizing chamber 53.
Then, the piezoceramic layers 31 and 32 deform so as to protrude toward the first pressurizing chamber 43 and the second pressurizing chamber 53 at the timing when the individual electrodes 34 are again set to the high potential.
In other words, the first pressurizing chamber 43 and the second pressurizing chamber 53 have positive pressure as a result of the volume of the first pressurizing chamber 43 and the second pressurizing chamber 53 decreasing. Thus, the pressure of the liquid inside the first pressurizing chamber 43 and the second pressurizing chamber 53 rises, and droplets are discharged from the first discharge holes 45 and the second discharge holes 55.
In other words, the control unit 14 supplies a drive signal including pulses based on the high potential to the individual electrode 34 to discharge the droplets from the first discharge holes 45 and the second discharge holes 55. The pulse width need only be an acoustic length (AL), corresponding to the length of time required for pressure waves to propagate from the first aperture 41 to the first discharge holes 45 (or from the second aperture 52 to the second discharge holes 55).
With this configuration, when the inside of the first pressurizing chambers 43 and the second pressurizing chambers 53 transition from the negative pressure state to the positive pressure state, the pressures under the states are combined, so that the droplets can be discharged with higher pressure.
For gradient printing, the gradient is expressed based on the number of droplets continuously discharged from the first discharge holes 45 and the second discharge holes 55, that is, the amount (volume) of droplets adjusted based on the number of times the droplets are discharged. Thus, the droplets are discharged by a number of times corresponding to the designated gradient to be expressed, through the first discharge holes 45 and the second discharge holes 55 corresponding to the designated dot region.
Generally, when the liquid is continuously discharged, the interval between the pulses supplied for discharging the droplets may be designated as AL. As a result, periods match between a residual pressure wave of the pressure produced for the previous discharging of droplets and the pressure wave of the pressure produced for the subsequent discharging of the droplets.
Thus, the residual pressure wave and the pressure wave are superimposed, whereby the droplets can be discharged with a higher pressure. Note that in this case, the later discharging involves a higher speed of the droplets and a closer distance between the landing points of the plurality of droplets.
Various modifications of the head main body 20 according to the embodiment will be described with reference to
Note that, in the various modifications below, redundant explanations are omitted, with parts that are the same as those in the embodiment described above denoted by the same reference numerals.
As illustrated in
In the first modification, there is a portion where the first aperture 41 of the first individual flow channel C1 and the second pressurizing chamber 53 of the second individual flow channel C2 overlap in plan view. As a result, the first individual flow channel C1 and the second individual flow channel C2 can be formed in the flow channel member 24 with high space efficiency.
Thus, with the first modification, even when a large number of the first discharge holes 45 and the second discharge holes 55 are provided, the flow channel member 24 can be downsized, whereby the head main body 20 can be downsized.
Furthermore, in the first modification, a plate in which the second aperture 52 is formed is located below the second pressurizing chamber 53, whereby rigidity directly below the second pressurizing chamber 53 can be guaranteed.
As illustrated in
Thus, with the second modification, the connection portion between the supply manifold 40 and the first individual flow channel C1 and the second individual flow channel C2 can be simplified. Furthermore, with the second modification, the number of connection portions can be reduced, whereby the rigidity of the plate in which such connection portions are formed can be guaranteed.
As illustrated in
Thus, according to the third modification, even when a large number of the first discharge holes 45 and the second discharge holes 55 are provided, the flow channel member 24 can be downsized, whereby the head main body 20 can be downsized.
As illustrated in
Specifically, a first collection flow channel 46 branches from the first vertical flow channel 44 located on the upstream side of the first discharge holes 45, and the first collection flow channel 46 is connected to the collection manifold 40R. A second collection flow channel 56 branches from the second vertical flow channel 54 located on the upstream side of the second discharge holes 55, and the second collection flow channel 56 is connected to the collection manifold 40R.
Thus, in the fourth modification, the first individual flow channel C1 includes the first aperture 41, the first connection flow channel 42, the first pressurizing chamber 43, the first vertical flow channel 44, and the first collection flow channel 46. In the fourth modification, the second individual flow channel C2 includes the second connection flow channel 51, the second aperture 52, the second pressurizing chamber 53, the second vertical flow channel 54, and the second collection flow channel 56.
When bubbles are contained in the liquid supplied from the supply manifold 40 through the first individual flow channel C1, the bubbles are collected in the collection manifold 40R through the first collection flow channel 46.
Similarly, when bubbles are contained in the liquid supplied from the supply manifold 40 through the second individual flow channel C2, the bubbles are collected in the collection manifold 40R through the second collection flow channel 56.
Thus, in the fourth modification, the collection manifold 40R, the first collection flow channel 46, and the second collection flow channel 56 are provided, so that bubbles can be prevented from remaining in the first vertical flow channel 44 or the second vertical flow channel 54. Thus, with the fourth modification, a negative impact of the remaining bubbles on the pressure waves propagating from the first pressurizing chamber 43 or the second pressurizing chamber 53 can be suppressed.
Furthermore, in the fourth modification, as illustrated in
In the fourth modification, in plan view, preferably, the first pressurizing chamber 43 is located farther from the supply manifold 40 than the second pressurizing chamber 53, and the first collection flow channel 46 is located closer to the first surface 24a than the second collection flow channel 56.
With this configuration, in the fourth modification, the first collection flow channel 46 and the second collection flow channel 56 can be formed in the flow channel member 24 with even higher space efficiency.
Thus, with the fourth modification, even when a large number of the first discharge holes 45 and the second discharge holes 55 are provided, the flow channel member 24 can be downsized, whereby the head main body 20 can be downsized.
The first collection flow channel 46 is connected to the first discharge hole 45 side of the first vertical flow channel 44 in the first direction D1, and the second collection flow channel 56 is connected to the second discharge hole 55 side of the second vertical flow channel 54 in the first direction D1. As a result, the liquid near the first discharge holes 45 and the second discharge holes 55 can be collected, whereby the first discharge holes 45 and the second discharge holes 55 are less likely to become clogged.
The first collection flow channel 46 and the second collection flow channel 56 are disposed at the same height in the first direction D1. In other words, the height at which the first collection flow channel 46 branches from the first vertical flow channel 44 and the height at which the second collection flow channel 56 branches from the second vertical flow channel 54 are the same. As a result, the first collection flow channel 46 and the second collection flow channel 56 can impose similar effects on the first vertical flow channel 44 and the second vertical flow channel 54, whereby the droplets can be discharged with similar characteristics from the first discharge hole 45 and the second discharge hole 55.
Although embodiments of the present disclosure are described above, the present disclosure is not limited to the embodiments described above, and various modifications can be made without departing from the spirit thereof. For example, in the example described in the above embodiment, the flow channel member 24 includes a plurality of stacked plates. However, the flow channel member 24 is not limited to the configuration where a plurality of plates are stacked.
For example, the flow channel member 24 may be configured with the supply manifold 40, the first individual flow channel C1, the second individual flow channel C2, and the like formed by etching.
As described above, the liquid discharge head 8 according to the embodiment includes the flow channel member 24 including the first surface 24a and the second surface 24b located opposite to the first surface 24a, and the pressing unit (displaced elements 38) located on the first surface 24a. The flow channel member 24 includes a first discharge hole 45 and a second discharge hole 55 located in the second surface 24b, a first individual flow channel C1 connected to the first discharge hole 45; a first pressurizing chamber 43 located more on an upstream side than the first discharge hole 45 in the first individual flow channel C1; a second individual flow channel C2 connected to the second discharge hole 55; a second pressurizing chamber 53 located more on an upstream side than the second discharge hole 55 in the second individual flow channel C2; and a manifold (supply manifold 40) commonly connected to an upstream side of first individual flow channel C1 and an upstream side of the second individual flow channel C2. The first individual flow channel C1 and the second individual flow channel C2 have an overlapping portion in plan view. With this configuration, the head main body 20 can be downsized.
In the liquid discharge head 8 according to the embodiment, the first individual flow channel C1 includes the first aperture 41 connecting the first pressurizing chamber 43 and the manifold (supply manifold 40) to each other, the second individual flow channel C2 includes the second aperture 52 connecting the second pressurizing chamber 53 and the manifold (supply manifold 40) to each other, and the first aperture 41 and the second aperture 52 have an overlapping portion in plan view. With this configuration, the liquid can be efficiently discharged from the first discharge hole 45 and the second discharge hole 55, and the first individual flow channel C1 and the second individual flow channel C2 can be formed in the flow channel member 24 with high space efficiency.
In the liquid discharge head 8 according to the embodiment, in plan view, the first pressurizing chamber 43 is located farther from the manifold (supply manifold 40) than the second pressurizing chamber 53, and the second aperture 52 is located closer to the first surface 24a than the first aperture 41. With this configuration, the first individual flow channel C1 can be formed in the flow channel member 24 with even higher space efficiency.
In the liquid discharge head 8 according to the embodiment, the first individual flow channel C1 includes the first aperture 41 connecting the first pressurizing chamber 43 and the manifold (supply manifold 40) to each other, the second individual flow channel C2 includes the second aperture 52 connecting the second pressurizing chamber 53 and the manifold (supply manifold 40) to each other, the second pressurizing chamber 53 and the second aperture 52 are located closer to the first surface 24a than the first aperture 41, and the second pressurizing chamber 53 and the first aperture 41 have an overlapping portion in plan view. With this configuration, the head main body 20 can be downsized, and the rigidity directly below the second pressurizing chamber 53 can be guaranteed.
In the liquid discharge head 8 according to the embodiment, when the direction from the first surface 24a toward the second surface 24b is defined as the first direction D1, the first individual flow channel C1 includes the first connection flow channel 42 connecting the first pressurizing chamber 43 and the first aperture 41 to each other in the first direction D1, the second individual flow channel C2 includes the second connection flow channel 51 connecting the second aperture 52 and the manifold (supply manifold 40) to each other in the first direction D1. The volume of the second pressurizing chamber 53 is larger than the volume of the first pressurizing chamber 43. With this configuration, the characteristics of discharging as a result of application of pressure from the displaced element 38 to the first pressurizing chamber 43 and the characteristics of discharging as a result of application of pressure to the second pressurizing chamber 53 from the displaced element 38 can be equalized.
In the liquid discharge head 8 according to the embodiment, when the direction from the first surface 24a toward the second surface 24b is defined as the first direction D1, the second individual flow channel C2 includes the second connection flow channel 51 connecting the second aperture 52 and the manifold (supply manifold 40) to each other in the first direction D1, and the upstream portion of the first aperture 41 and the second connection flow channel 51 overlap in plan view.
With this configuration, the connection portion between the supply manifold 40 and the first individual flow channel C1 and the second individual flow channel C2 can be simplified.
In the liquid discharge head 8 according to the embodiment, the first individual flow channel C1 is connected to the side surface of the manifold (supply manifold 40), and the second individual flow channel C2 is connected to the upper surface of the manifold (supply manifold 40). With this configuration, the head main body 20 can be downsized, and the connection portion between the supply manifold 40 and the first individual flow channel C1 can be simplified.
In the liquid discharge head 8 according to the embodiment, the first individual flow channel C1 includes the first collection flow channel 46 branched from a portion more on the upstream side than the first discharge hole 45, and the second individual flow channel C2 includes the second collection flow channel 56 branched from a portion more on the upstream side than the second discharge hole 55. With this configuration, a negative impact of the remaining bubbles on the pressure wave propagating from the first pressurizing chamber 43 or the second pressurizing chamber 53 can be suppressed.
In the liquid discharge head 8 according to the embodiment, in plan view, the first pressurizing chamber 43 is located farther from the manifold (supply manifold 40) than the second pressurizing chamber 53, and the first collection flow channel 46 is located closer to the first surface 24a than the second collection flow channel 56. With this configuration, the first collection flow channel 46 and the second collection flow channel 56 can be formed in the flow channel member 24 with even higher space efficiency.
The recording apparatus (printer 1) according to the embodiment includes the liquid discharge head 8, the conveying unit (conveying rollers 6) configured to convey the recording medium (printing sheet P) to the liquid discharge head 8, and the control unit 14 configured to control the liquid discharge head 8 as described above. With this configuration, the printer 1 with the head main body 20, which is downsized, can be achieved.
In addition, the recording apparatus (printer 1) according to the embodiment includes the liquid discharge head 8, and the applicator 4 configured to apply the coating agent on the recording medium (printing sheet P) as described above. Thus, the printing quality of the printer 1 can be improved.
In addition, the recording apparatus (printer 1) according to the embodiment includes the liquid discharge head 8, and the dryer 10 that dries the recording medium (printing sheet P) as described above. With this configuration, it is possible to suppress the bonding between the printing sheets P rolled while being overlapped with each other, and rubbing of undried liquid, in the collection roller 13.
The disclosed embodiments should be considered as illustrative and not limiting in any point. In fact, the embodiments described above can be embodied in a variety of forms. Omission, replacement, and change can be made in various forms on the above embodiments without departing from the scope and the spirit of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-053750 | Mar 2019 | JP | national |
This application is a national stage application of International Application No. PCT/JP2020/011846, filed on Mar. 17, 2020, which designates the United States, is based upon and claims the benefit of priority to Japanese Patent Application No. 2019-053750, filed on Mar. 20, 2019.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/011846 | 3/17/2020 | WO | 00 |
