Patent Grant
10611145
This application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2017-244097 filed on Dec. 20, 2017, the entire content of which is hereby incorporated by reference.
The present disclosure relates to a liquid jet head, a liquid jet recording device, a method for driving a liquid jet head, and a program for driving a liquid jet head.
A liquid jet recording device equipped with a liquid jet head is used in a variety of fields.
In the liquid jet head, it is arranged that the capacity (volume) of a pressure chamber varies in accordance with application of a pulse signal to a piezoelectric actuator, and thus, a liquid filling the pressure chamber is jetted from a nozzle (see, e.g., JP-A-2001-246738).
In such a liquid jet head, in general, it is required to improve the printed image quality. It is desirable to provide a liquid jet head, a liquid jet recording device, a method for driving the liquid jet head, and a program for driving the liquid jet head each capable of improving the printed image quality.
The liquid jet head according to an embodiment of the present disclosure is provided with a plurality of nozzles adapted to jet liquid, a piezoelectric actuator having a plurality of pressure chambers communicated individually with the nozzles and each filled with the liquid, and adapted to change a capacity of each of the pressure chambers, and a control section adapted to apply at least one pulse signal to the piezoelectric actuator to thereby expand and contract the capacity of the pressure chambers to jet the liquid filling the pressure chamber. The pressure chambers adjacent to each other in the plurality of the pressure chambers are set so as to belong to a plurality of groups different from each other. The control section makes the pulse signals different in timing between the plurality of groups and sets a shift amount of the timing in the pulse signals between the respective groups so as to approximate an integral multiple of an on-pulse peak (AP) when jetting the liquid.
The liquid jet recording device according to an embodiment of the present disclosure is equipped with the liquid jet head according to an embodiment of the present disclosure described above.
The method for driving a liquid jet head according to an embodiment of the present disclosure includes the steps of setting, when applying at least one pulse signal to a piezoelectric actuator adapted to change a capacity of each of a plurality of pressure chambers communicated respectively with a plurality of nozzles to thereby expand and contract the capacity of the pressure chambers to jet a liquid filling the pressure chamber from the nozzle, the pressure chambers adjacent to each other in the plurality of pressure chambers so as to belong to a plurality of groups different from each other, and making the pulse signals different in timing between the plurality of groups and setting a shift amount of the timing in the pulse signals between the respective groups so as to approximate an integral multiple of an on-pulse peak (AP).
The program for driving a liquid jet head according to an embodiment of the present disclosure is adapted to make a computer perform a process including the steps of setting, when applying at least one pulse signal to a piezoelectric actuator adapted to change a capacity of each of a plurality of pressure chambers communicated respectively with a plurality of nozzles to thereby expand and contract the capacity of the pressure chambers to jet a liquid filling the pressure chamber from the nozzle, the pressure chambers adjacent to each other in the plurality of pressure chambers so as to belong to a plurality of groups different from each other, and making the pulse signals different in timing between the plurality of groups and setting a shift amount of the timing in the pulse signals between the respective groups so as to approximate an integral multiple of an on-pulse peak (AP).
According to the liquid jet head, the liquid jet recording device, the method for driving the liquid jet head, and the program for driving the liquid jet head related to the embodiment of the present disclosure, it becomes possible to improve the printed image quality.
An embodiment of the present disclosure will hereinafter be described in detail with reference to the drawings. It should be noted that the description will be presented in the following order.
1. Embodiment (an example of the case of applying only a single pulse signal)
2. Modified Examples
Modified Example 1 (an example of the case of applying a plurality of pulse signals)
Modified Example 2 (an example of the case of setting presence or absence of the shift amount in accordance with the volume of the droplet size)
Modified Example 3 (an example of the case of adjusting the jetting speed of the liquid in accordance with the jet timing of a liquid)
Modified Example 4 (an example of the case of a structure for supplying a liquid commonly to a plurality of columns of pressure chambers)
3. Other Modified Examples
[Overall Configuration of Printer 1]
As shown in
Here, the printer 1 corresponds to a specific example of the “liquid jet recording device” in the present disclosure, and the inkjet heads 4 (the inkjet heads 4Y, 4M, 4C, and 4B described later) each correspond to a specific example of the “liquid jet head” in the present disclosure. Further, the ink 9 corresponds to a specific example of the “liquid” in the present disclosure. It should be noted that the method for driving a liquid jet head according to an embodiment of the disclosure is embodied in the printer 1 according to the present embodiment, and will therefore be described at the same time. This point also applies to each of the modified examples described later.
The carrying mechanisms 2a, 2b are each a mechanism for carrying the recording paper P along the carrying direction d (an X-axis direction) as shown in
(Ink Tanks 3)
The ink tanks 3 are each a tank for containing the ink 9 inside. As the ink tanks 3, there are disposed 4 types of tanks for individually containing 4 colors of ink 9, namely yellow (Y), magenta (M), cyan (C), and black (B), in this example as shown in
It should be noted that the ink tanks 3Y, 3M, 3C, and 3B have the same configuration except the color of the ink 9 contained, and are therefore collectively referred to as ink tanks 3 in the following description.
(Inkjet Heads 4)
The inkjet heads 4 are each a head for jetting (ejecting) the ink 9 having a droplet shape from a plurality of nozzles (nozzle holes H1, H2) described later to the recording paper P to thereby perform recording of images, characters, and so on. As the inkjet heads 4, there are also disposed 4 types of heads for individually jetting the 4 colors of ink 9 respectively contained by the ink tanks 3Y, 3M, 3C, and 3B described above in this example as shown in
It should be noted that the inkjet heads 4Y, 4M, 4C, and 4B have the same configuration except the color of the ink 9 used, and are therefore collectively referred to as inkjet heads 4 in the following description. Further, the detailed configuration of the inkjet heads 4 will be described later (
(Circulation Mechanism 5)
The circulation mechanism 5 is a mechanism for circulating the ink 9 between the inside of the ink tanks 3 and the inside of the inkjet heads 4. The circulation mechanism 5 is configured including, for example, circulation channels 50 as flow channels for circulating the ink 9, and pairs of liquid feeding pumps 52a, 52b.
As shown in
(Scanning Mechanism 6)
The scanning mechanism 6 is a mechanism for making the inkjet heads 4 perform a scanning operation along the width direction (the Y-axis direction) of the recording paper P. As shown in
The pulleys 631a, 631b are respectively disposed in areas corresponding to the vicinities of both ends in each of the guide rails 61a, 61b along the Y-axis direction. To the endless belt 632, there is connected the carriage 62. On the carriage 62, the four types of inkjet heads 4Y, 4M, 4C, and 4B described above are disposed so as to be arranged side by side along the Y-axis direction.
It should be noted that it is arranged that a moving mechanism for moving the inkjet heads 4 relatively to the recording paper P is constituted by such a scanning mechanism 6 and the carrying mechanisms 2a, 2b described above.
[Detailed Configuration of Inkjet Heads 4]
Then, the detailed configuration example of the inkjet heads 4 will be described with reference to
The inkjet heads 4 according to the present embodiment are each an inkjet head of a so-called side-shoot type for ejecting the ink 9 from a central part in the extending direction (the Y-axis direction) of each of a plurality of channels (channels C1, C2) described later. Further, the inkjet heads 4 are each an inkjet head of a circulation type which uses the circulation mechanism 5 (the circulation channel 50) described above to thereby use the ink 9 while circulating the ink 9 between the inkjet head 4 and the ink tank 3.
As shown in
Further, it is also possible to arrange that a flow channel plate (not shown) having a predetermined flow channel is disposed on an upper surface of the cover plate 43. It should be noted that the flow channels 50a, 50b in the circulation mechanism 5 described above are connected to the flow channel in the flow channel plate so as to achieve inflow of the ink 9 to the flow channel and outflow of the ink 9 from the flow channel, respectively.
(Nozzle Plate 41)
The nozzle plate 41 is formed of a film member made of polyimide or the like having a thickness of, for example, about 50 μm, and is bonded to a lower surface of the actuator plate 42 as shown in
The nozzle column 411 has a plurality of nozzle holes H1 formed in alignment with each other at predetermined intervals along the X-axis direction. These nozzle holes H1 each penetrate the nozzle plate 41 along the thickness direction (the Z-axis direction) of the nozzle plate 41, and are communicated with the respective ejection channels C1e in the actuator plate 42 described later as shown in, for example,
The nozzle column 412 similarly has a plurality of nozzle holes H2 formed in alignment with each other at predetermined intervals along the X-axis direction. Each of these nozzle holes H2 also penetrates the nozzle plate 41 along the thickness direction of the nozzle plate 41, and is communicated with the ejection channel C2e in the actuator plate 42 described later. Specifically, as shown in
It should be noted that such nozzle holes H1, H2 are each formed as a tapered through hole gradually decreasing in diameter in a direction toward the lower side (see
(Actuator Plate 42)
The actuator plate 42 is a plate formed of a piezoelectric material such as lead zirconium titanate (PZT), and is arranged to change the capacity of each of the ejection channels C1e, C2e although the details will be described later. The actuator plate 42 is formed of, for example, a single (unique) piezoelectric substrate having the polarization direction set one direction along the thickness direction (the Z-axis direction) (a so-called cantilever type). It should be noted that the configuration of the actuator plate 42 is not limited to the cantilever type. Specifically, it is possible to constitute the actuator plate 42 by stacking two piezoelectric substrates different in polarization direction from each other on one another along the thickness direction (the Z-axis direction) (a so-called chevron type). It should be noted that the actuator plate 42 corresponds to a specific example of a “piezoelectric actuator” in the present disclosure.
Further, as shown in
In such an actuator plate 42, as shown in
As shown in
As shown in
Here, as shown in
Similarly, as shown in
It should be noted that such ejection channels C1e, C2e each correspond to a specific example of the “ejection chamber” in the present disclosure.
Further, as shown in
Here, as shown in
The pair of common electrodes Edc opposed to each other in the same ejection channel C1e (or the same ejection channel C2e) are electrically connected to each other in a common terminal (not shown). Further, the pair of active electrodes Eda opposed to each other in the same dummy channel C1d (or the same dummy channel C2d) are electrically separated from each other. In contrast, the pair of active electrodes Eda opposed to each other via the ejection channel C1e (or the ejection channel C2e) are electrically connected to each other in an active terminal (not shown).
Here, as shown in
(Cover Plate 43)
As shown in
As shown in
The entrance side common ink chamber 431a is formed in the vicinity of an inner end part along the Y-axis direction in each of the channels C1, and forms a groove section having a recessed shape (see
It should be noted that these entrance side common ink chambers 431a, 432a are each formed as a part constituting an entrance part Tin in the inkjet head 4, and each correspond to a specific example of a “common liquid supply chamber” in the present disclosure.
As shown in
It should be noted that these exit side common ink chambers 431b. 432b each form a part constituting an exit part Tout in the inkjet head 4.
In such a manner, the entrance side common ink chamber 431a and the exit side common ink chamber 431b are each communicated with the ejection channels C1e via the supply slits Sa and the discharge slits Sb, respectively, on the one hand, but are not communicated with the dummy channels C1d on the other hand. Specifically, each of the dummy channels C1d is arranged to be closed by bottom parts of the entrance side common ink chamber 431a and the exit side common ink chamber 431b (see
Similarly, the entrance side common ink chamber 432a and the exit side common ink chamber 432b are each communicated with the ejection channels C2e via the supply slits Sa and the discharge slits Sb, respectively, on the one hand, but are not communicated with the dummy channels C2d on the other hand. Specifically, each of the dummy channels C2d is arranged to be closed by bottom parts of the entrance side common ink chamber 432a and the exit side common ink chamber 432b.
(Control Section 49)
Here, each of the inkjet heads 4 according to the present embodiment is also provided with the control section 49 for performing control of a variety of operations in the printer 1 as shown in
Specifically, as shown in
As shown in
It should be noted that the details of the control operation by the control section 49 will be described later (
In the printer 1, the recording operation (a printing operation) of images, characters, and so on to the recording paper P is performed in the following manner. It should be noted that as an initial state, it is assumed that the four types of ink tanks 3 (3Y, 3M, 3C, and 3B) shown in
In such an initial state, when operating the printer 1, the grit rollers 21 in the carrying mechanisms 2a, 2b each rotate to thereby carry the recording paper P along the carrying direction d (the X-axis direction) between the grit rollers 21 and the pinch rollers 22. Further, at the same time as such a carrying operation, the drive motor 633 in the drive mechanism 63 rotates each of the pulleys 631a, 631b to thereby operate the endless belt 632. Thus, the carriage 62 reciprocates along the width direction (the Y-axis direction) of the recording paper P while being guided by the guide rails 61a, 61b. Then, on this occasion, the four colors of ink 9 are appropriately ejected on the recording paper P by the respective inkjet heads 4 (4Y, 4M, 4C, and 4B) to thereby perform the recording operation of images, characters, and so on to the recording paper P.
Then, the detailed operation (the jet operation of the ink 9) in the inkjet head 4 will be described with reference to
Firstly, when the reciprocation of the carriage 62 (see
Here, as described above, in the actuator plate 42, the polarization direction is set to the one direction, and at the same time, the drive electrodes Ed are not formed beyond the intermediate position in the depth direction on the inner side surfaces in the drive walls Wd. Therefore, application of the drive voltage Vd using the control section 49 results in a flexion deformation of the drive wall Wd having a V shape centered on the intermediate position in the depth direction in the drive wall Wd. Further, due to such a flexion deformation of the drive wall Wd, the ejection channel C1e, C2e deforms as if the ejection channel C1e, C2e bulges (see the expansion directions da shown in
Incidentally, in the case in which the configuration of the actuator plate 42 is not the cantilever type but is the chevron type described above, the drive wall Wd makes the flexion deformation to have the V shape in the following manner. Specifically, in the case of the chevron type, the polarization direction of the actuator plate 42 differs along the thickness direction (the two piezoelectric substrates described above are stacked on one another), and at the same time, the drive electrodes Ed are formed in the entire area in the depth direction on the inner side surface in each of the drive walls Wd. Therefore, application of the drive voltage Vd using the control section 49 described above results in a flexion deformation of the drive wall Wd having a V shape centered on the intermediate position in the depth direction in the drive wall Wd. As a result, also in this case, due to such a flexion deformation of the drive wall Wd, the ejection channel C1e, C2e deforms as if the ejection channel C1e, C2e bulges (see the expansion directions da shown in
As described above, due to the flexion deformation caused by a piezoelectric thickness-shear effect in the pair of drive walls Wd, the capacity of the ejection channel C1e, C2e increases. Further, due to the increase of the capacity of the ejection channel C1e, C2e, it results in that the ink 9 retained in the entrance side common ink chamber 431a, 432a is induced into the ejection channel C1e, C2e (see
Subsequently, the ink 9 having been induced into the ejection channel C1e, C2e in such a manner turns to a pressure wave to propagate to the inside of the ejection channel C1e, C2e. Then, the drive voltage Vd to be applied to the drive electrodes Ed becomes 0 (zero) V at the timing at which the pressure wave has reached the nozzle hole H1, H2 of the nozzle plate 41. Thus, the drive walls Wd are restored from the state of the flexion deformation described above, and as a result, the capacity of the ejection channel C1e, C2e having once increased is restored again (see the contraction directions db shown in
When the capacity of the ejection channel C1e, C2e is restored in such a manner, the internal pressure of the ejection channel C1e, C2e increases, and the ink 9 in the ejection channel C1e, C2e is pressurized. As a result, the ink 9 having a droplet shape is ejected (see
In particular, the nozzle holes H1, H2 of the present embodiment each have the tapered shape gradually decreasing in diameter in the downward direction (see
Then, the circulation operation of the ink 9 by the circulation mechanism 5 will be described in detail with reference to
As shown in
On this occasion, in the inkjet head 4, the ink 9 flowing from the inside of the ink tank 3 via the flow channel 50a inflows into the entrance side common ink chambers 431a, 432a (the entrance parts Tin) (see
Further, the ink 9 in the ejection channels C1e, C2e flows into the exit side common ink chamber 431b, 432b (the exit part Tout) via the discharge slits Sb (see
Here, in the inkjet head of a type other than the circulation type, in the case of using fast drying ink, there is a possibility that a local increase in viscosity or local solidification of the ink occurs due to drying of the ink in the vicinity of the nozzle hole, and as a result, a failure such as an ink ejection failure occurs. In contrast, in the inkjet heads 4 (the circulation type inkjet heads) according to the present embodiment, since the fresh ink 9 is always supplied to the vicinity of the nozzle holes H1, H2, the failure such as the failure in ejection of the ink described above is prevented as a result.
Here, a control operation example by the control section 49 described above will be described in detail with reference to
Firstly, when performing the control operation related to the present embodiment, there is provided a configuration in which the ejection channels C1e (C2e) adjacent to each other out of the plurality of ejection channels C1e (C2e) in the actuator plate 42 respectively belong to a plurality of groups different from each other. Specifically, in the present embodiment, as shown in
The ejection channels C1e, C2e arranged at odd-numbered (1-st, 3-rd, 5-th, . . . ) places starting from one end part along the X-axis direction in the respective channel columns 421, 422 are arranged to belong to the group G1. Specifically, as shown in
In contrast, the ejection channels C1e, C2e arranged at even-numbered (2-nd, 4-th, 6-th, . . . ) places starting from the one end part along the X-axis direction in the respective channel columns 421, 422 are arranged to belong to the group G2. Specifically, as shown in
As described above, it is arranged that the group G1 functions as an odd group Go, and at the same time, the group G2 functions as an even group Ge as described in combination in the parentheses in
Further, in the control operation of the present embodiment, the control section 49 is arranged to set the shift amount Δtd in timing between such groups G1, G2. Specifically, as described hereinafter in detail, the control section 49 sets such a shift amount Δtd between the pulse signal Sp1 applied to the ejection channels C1e, C2e belonging to the group G1 and the pulse signal Sp2 applied to the ejection channels C1e, C2e belonging to the group G2. In other words, in the control operation of the present embodiment, unlike a control operation related to a comparative example (see
Here,
It should be noted that the pulse signals Sp1, Sp2 shown in
Firstly, in the example shown in
Specifically, the pulse signal Sp1 of the group G1 (Go) shown in
Further, in the example of the case in which the pulse signals Sp1, Sp2 shown in
Further, in the example shown in
Specifically, the pulse signal Sp1 of the group G1 (Go) shown in
Further, in the example of the case in which the pulse signals Sp1, Sp2 shown in
Here,
Firstly, in the example shown in
Here, the AP corresponds to a period (1 AP=(characteristic vibration period of the ink 9)/2) half as large as the characteristic vibration period of the ink 9 in the ejection channel C1e, C2e, and it is arranged that the jetting speed of the ink 9 is maximized when ejecting (a droplet of) the ink 9 as much as one normal droplet. Further, the AP is arranged to be defined by, for example, the shape of the ejection channel C1e, C2e and the specific gravity of the ink 9.
In contrast, in the example shown in
Further, in the example shown in
Here,
Firstly, in the example shown in
In contrast, in the example shown in
Then, the functions and the advantages in the inkjet head 4 and the printer 1 according to the present embodiment will be described in detail in comparison with a comparative example (see
As shown in
In the case of using the control operation of such a comparative example, since it results in that the expansion timing and the contraction timing are each common to (coincide in) all of the ejection channels C1e, C2e in the actuator plate 42, there is a possibility that such a problem as described below, for example, arises. Specifically, there is a possibility that instantaneous flow in one direction or the like of the ink 9 occurs in the plurality of ejection channels (the ejection channels C1e, or the ejection channels C2e) adjacent to each other in, for example, the channel column 421, 422, and thus, crosstalk (mutual interference) between the plurality of ejection channels adjacent to each other occurs. Such crosstalk occurs due to the influence on the plurality of ejection channels exerted by repercussions caused by the capacity variation in the ejection channels C1e, C2e and propagating via the ink 9 in the ejection channels C1e, C2e. Further, if such crosstalk occurs, there is a possibility that the variation in the jetting speed of the ink 9, the variation in droplet size of the ink 9 and so on increase between the corresponding nozzles (the nozzle holes H1 or the nozzle holes H2) to degrade the printed image quality.
Incidentally, for example, it is also possible to adopt a method of, for example, reading the printing result to the recording paper P on the printer side, and at the same time, optimizing the drive condition for each of the nozzles in accordance with the reading result, but in such a method, the following problem can arise. That is, there arises a necessity of mounting the reading mechanism of the printing result on the printer, and it becomes necessary to perform cumbersome control of optimizing the drive condition for each of the nozzles on a case-by-case basis.
In contrast, in the inkjet head 4 and the printer 1 according to the present embodiment, the control operation by the control section 49 is performed in such a manner as described below.
That is, firstly, as shown in
Further, unlike the comparative example described above, the control section 49 does not make the timings of the pulse signals Sp1, Sp2 to be concurrently applied, but makes the timings of the pulse signals Sp1, Sp2 to be applied different from each other between the ejection channels C1e (C2e) belonging respectively to such two groups G1, G2. Specifically, as shown in, for example,
More specifically, as shown in
Then, as shown in, for example,
By performing such a control operation, the following occurs in the present embodiment compared to the comparative example described above. That is, since the shift amount Δtd described above is set so as to approximate the integral multiple of the AP in the groups G1, G2 different from each other when jetting the ink 9, it results in that the timing of the expansion and the timing of the contraction of the ejection channels C1e, C2e are appropriately adjusted between the groups G1, G2 (see the expansion directions da and the contraction directions db in the parentheses shown in
Here, the repercussions (described above) propagating to the plurality of ejection channels C1e, C2e adjacent to each other out of the plurality of ejection channels C1e, C2e vary in phase at the wavelength of the AP similarly to each of the ejection channels C1e, C2e. Therefore, by setting the shift amount Δtd so as to approximate the integral multiple of the AP between the plurality of groups G1, G2, it results in that the phase of the repercussions propagating approximates the reversal timing, and thus, the influence of the crosstalk is reduced.
Further, in a different point of view, such a reduction action of the crosstalk can also be said that local scrambling for the ink 9 to the ejection channels C1e (C2e) between the plurality of groups G1, G2 is suppressed by setting the shift amount Δtd.
In such a manner, the instantaneous flow in one direction or the like of the ink 9 is suppressed in the plurality of ejection channels (the ejection channels C1e, or the ejection channels C2e) adjacent to each other, and thus, occurrence of the crosstalk between the plurality of ejection channels adjacent to each other is reduced in the present embodiment compared to the comparative example described above. As a result, the variation in the jetting speed of the ink 9, the variation in droplet size of the ink 9 and so on are suppressed between the corresponding nozzles (the nozzle holes H1 or the nozzle holes H2).
Due to the above, in the present embodiment, it becomes possible to improve the printed image quality compared to the comparative example described above. Further, since the structure itself of the inkjet head 4 is not required to be changed from the existing structure, and it is sufficient to change only the control operation by the control section 49 (the waveforms of the pulse signals), it becomes possible to obtain such an improvement effect of the printed image quality while keeping the structure of the existing inkjet head.
Further, in the present embodiment, as shown in, for example,
Further, in the present embodiment, as shown in, for example,
Further, in the present embodiment, as shown in, for example,
In contrast, in the present embodiment, as shown in, for example,
Further, in the present embodiment, since the ejection channels C1e (C2e) belonging to one of the two groups G1, G2 and the ejection channels C1e (C2e) belonging to the other of the two groups G1, G2 are alternately arranged along the X-axis direction as shown in
It should be noted that the inkjet heads in the liquid jet recording devices generally fall into the general classification of a shuttle type and an in-line type, and it can be said that the control method described in the present embodiment and so on (e.g., the present embodiment and Modified Examples 1 through 4 described later) exert particularly remarkable advantage in the in-line type. Incidentally, the shuttle type is a system for performing a scanning action with the inkjet head when performing printing on the recording target medium, while the in-line type is a system (also referred to as a one-pass system) for carrying the recording target medium when performing printing on the recording target medium. Here, in the case of the in-line type, it is possible to obtain an advantage that the productivity is dramatically improved on the one hand, but the in-line type tends to be inferior in image quality to the shuttle type since a multi-pass effect cannot be obtained. The multi-pass effect denotes the effect that by performing the printing while performing the scanning operation with the inkjet head a plurality of times, it is difficult for the variation inherent in the inkjet head to appear in the image, and thus, an improvement in image quality can be obtained. In other words, in the case of the in-line type, there is a possibility that the individual variation of the inkjet head appears in the image. For example, in the case in which there is a variation in ejection speed or ejection amount of the ink to be ejected from each of the nozzles in the inkjet head, a variation occurs in the landing position and the luminance despite the intention of printing a uniform image, and thus, it results in that the performance as the image quality deteriorates. Therefore, by using the control method described in the present embodiment and so on, it becomes possible to obtain a high image quality equivalent to the shuttle type even in such an in-line type liquid jet recording device, and thus, it becomes possible to achieve both of the high image quality and the high productivity.
Then, some modified examples (Modified Examples 1 through 4) of the embodiment described above will be described. It should be noted that the same constituents as those in the embodiment are denoted by the same reference symbols, and the description thereof will arbitrarily be omitted.
In the embodiment described above, there is described the case of applying one pulse signal (the pulse signal Sp1 or the pulse signal Sp2) alone when jetting one droplet of the ink 9 using the control section 49. In contrast, in Modified Example 1 described below, it is arranged that a plurality of pulse signals is applied as each of the pulse signals Sp1, Sp2 when jetting one droplet of the ink 9 using the control section 49, and it is arranged that the drive method of a so-called “multi-pass system” is performed.
(Setting of Shift Amount ΔTd)
Here, as shown in
It should be noted that also in Modified Example 1, the three pulse signals in each of these pulse signals Sp1, Sp2 are made as follows. That is, these pulse signals are each made as a positive pulse signal for expanding the ejection channel C1e, C2e in the period of the high state, and at the same time, contracting the ejection channel C1e, C2e in the period of the low state.
Further, in Modified Example 1, the control section 49 sets the shift amount Δtd with respect to the following pulse signals out of the plurality of pulse signals (the three pulse signals in this example) in each of the pulse signals Sp1, Sp2. That is, the control section 49 sets the shift amount Δtd in substantially the same manner as in the embodiment between the falling timings in, for example, the last pulse signals (the pulse signals having the ON period Ton3 in this example) making a contribution to the jet of the ink 9 (for expanding the capacity of the ejection channel C1e, C2e). Alternatively, the control section 49 sets the shift amount Δtd in substantially the same manner as in the embodiment between the rising timings in, for example, the first pulse signals (the pulse signals having the ON period Ton1 in this example) making a contribution to the jet of the ink 9.
Here, in the example shown in
Specifically, the pulse signal having the ON period Ton1 in the pulse signal Sp1 of the group G1 (Go) shown in
Further, in the example of the case in which the pulse signals Sp1, Sp2 shown in
Further, in the example shown in
Specifically, the pulse signal having the ON period Ton3 in the pulse signal Sp1 of the group G1 (Go) shown in
Further, in the example of the case in which the pulse signals Sp1, Sp2 shown in
In such a manner as described above, also in Modified Example 1, since the shift amount Δtd is set in substantially the same manner as in the embodiment with respect to the plurality of pulse signals in each of the pulse signals Sp1, Sp2, the following occurs. That is, also in the case of the multi-pass system, it results in that the function of reducing the occurrence of the crosstalk described in the embodiment is exerted. Therefore, also in Modified Example 1, it becomes possible to obtain substantially the same advantages as those of the embodiment. Specifically, it is possible to suppress the variation in the ejection speed of the ink 9, the variation in droplet size of the ink 9 and so on between the plurality of nozzles (the nozzle holes H1 or the nozzle holes H2), and thus, it becomes possible to improve the printed image quality.
Further, in particular in Modified Example 1, since the shift amount Δtd described above is set between the falling timings in the last pulse signals, or between the rising timings in the first pulse signals making a contribution to the jet of the ink 9 (for jetting the ink 9) as described above, the following occurs. That is, in the case of adopting such a configuration, it becomes easy to define the shift amount Δtd between the pulse signals Sp1, Sp2. Further, in particular in the case of the shift amount Δtd between the falling timings in the last pulse signals described above, it becomes possible to more efficiently exert the reduction action of the crosstalk described above. Therefore, in the case of adopting such a configuration, it becomes possible to enhance the convenience in jetting the ink 9.
It should be noted that in Modified Example 1, in the case of the multi-pulse system, the description is presented citing the case of the “three-drop waveform” as an example. However, this example is not a limitation, and it is also possible to arrange that the shift amount Δtd is set in substantially the same manner as in Modified Example 1 with respect also to the case of a “two-drop waveform or four-or-more-drop waveform.”
(Regarding Case of Adding Pulse Signal for Contracting Capacity)
Here, in Modified Example 1, in the case of adding a pulse signal for contracting the capacity of each of the ejection channels C1e, C2e to the pulse signal having a contribution (for expanding the capacity of each of the ejection channels C1e, C2e) to the jet of the ink 9 as described above, the control section 49 performs setting of the shift amount Δtd in, for example, a following manner. It should be noted that it can also be said that the pulse signal for contracting the capacity of each of the ejection channels C1e, C2e is a pulse signal for further contracting the capacity of each of the ejection channels C1e, C2e after once contracting the capacity of each of the ejection channels C1e, C2e having been expanded.
In the example shown in
It should be noted that such a pulse signal for expanding the capacity of each of the ejection channels C1e, C2e corresponds to a specific example of a “first pulse signal” in the present disclosure. Further, the pulse signal for expanding the capacity of each of the ejection channels C1e, C2e corresponds to a specific example of a “second pulse signal” in the present disclosure.
In such a case, the control section 49 sets, for example, the pulse signals (the three pulse signals having the ON periods Ton1 through Ton3 in this example) for expanding the capacity of each of the ejection channels C1e, C2e so as to have the shift amount Δtd as described hereinabove (see
In the case of arranging that such selective setting of the shift amount Δtd is performed, the following occurs. That is, since the pulse signals for expanding the capacity of each of the ejection channels C1e, C2e have a principal contribution to the reduction action of the crosstalk described above, by selectively performing setting of the shift amount Δtd with respect to such pulse signals for expanding the capacity, it becomes possible to more effectively exert the reduction action of the crosstalk. This is because the suction amount of the ink 9 is larger in expanding the capacity of each of the ejection channels C1e, C2e than in contracting the capacity of each of the ejection channels C1e, C2e, and therefore, the repercussions (described above) generated in each of the ejection channels C1e, C2e becomes stronger, and thus, the influence on other adjacent ejection channels C1e, C2e becomes more significant. As a result, in the case of adopting such a configuration, it is possible to suppress the variation in the ejection speed of the ink 9, the variation in droplet size of the ink 9 and so on between the plurality of nozzles (the nozzle holes H1 or the nozzle holes H2), and thus, it becomes possible to further improve the printed image quality.
It should be noted that it is also possible to arrange that such selective setting of the shift amount Δtd is performed not only in the case of Modified Example 1 shown in
(Experimental Results)
Here,
Firstly, in the experimental result related to the comparative example shown in
In contrast, in both of the experimental results related to Modified Example 1 shown in
As shown in
Further, as shown in
In such a manner, in Modified Example 2, since the presence or absence of the shift amount Δtd is set in accordance with the volume of the droplet size Sd to be set in the case of the multi-pulse system (the system of controlling the droplet size in accordance with the number and so on of the pulse signals) described above, the following occurs. That is, it becomes possible to more effectively exert the reduction action of the crosstalk described above in accordance with the droplet size Sd. As a result, in Modified Example 2, since it is possible to further suppress the variation in the jetting speed of the ink 9, the variation in droplet size of the ink 9 and so on between the plurality of nozzles (the nozzle holes H1 or the nozzle holes H2), it becomes possible to further improve the printed image quality.
Further, in Modified Example 2, in the case of arranging that the presence or absence of the shift amount Δtd is set in accordance with the magnitude relationship between the droplet size Sd to be set and the predetermined threshold value Sth as described above, the following occurs. That is, firstly, the crosstalk described above is more effectively reduced due to the setting of the shift amount Δtd in the case in which the droplet size Sd is smaller than the threshold value Sth (the droplet size Sd is relatively small) compared to the case in which the droplet size Sd is no smaller than the threshold value Sth (the droplet size Sd is relatively large), and therefore, it becomes easy to reduce the crosstalk. This is because in the case in which the droplet size Sd is relatively large, a sufficient amount of the ink 9 is applied on the recording paper P (the recording target medium) to saturate the density of the ink 9, and thus, it becomes difficult to generate a difference in thickness. As a result, in the case in which the droplet size Sd is relatively large, it becomes unnecessary to set the shift amount Δtd, and therefore the variation in the jetting speed of the ink 9, the variation in droplet size of the ink 9 and so on are further suppressed between the plurality of nozzles (the nozzle holes H1 or the nozzle holes H2). Therefore, in the case of adopting this configuration, it becomes possible to further improve the printed image quality.
As shown in
That is, firstly, the control section 49 performs the waveform adjustment of the pulse signals Sp1, Sp2 so that the jetting speed V9 of the ink 9 becomes relatively low in the group in which the jet timing of the ink 9 is relatively accelerated due to the setting of the shift amount Δtd out of the plurality of groups G1, G2 compared to the rest of the groups.
Alternatively, the control section 49 performs the waveform adjustment of the pulse signals Sp1, Sp2 so that the jetting speed V9 of the ink 9 becomes relatively high in the group in which the jet timing of the ink 9 is relatively delayed due to the setting of the shift amount Δtd out of the plurality of groups G1, G2 compared to the rest of the groups.
In such a manner, in Modified Example 3, since the waveform adjustment of the pulse signals Sp1, Sp2 is performed so that the jetting speed V9 of the ink 9 varies in accordance with the jet timing of the ink 9 due to the setting of the shift amount Δtd, the following occurs. That is, it results in that the variation in landing position of the droplet of the ink 9 on the recording paper P due to such a shift of the jet timing of the ink 9 is suppressed. Therefore, in Modified Example 3, it is possible to reduce a density variation of the ink 9 on the recording paper P, and thus, it becomes possible to achieve a further improvement of the printed image quality.
In each of the embodiment and Modified Examples 1 through 3 having already been described, the plurality of ejection channels adjacent to each other in each of the channel columns is set so as to respectively belong to the plurality of groups different from each other.
In contrast, in Modified Example 4 described below, there is described the case in which a structure for supplying the ink commonly to the ejection channels in the plurality of channel columns is adopted, and at the same time, the plurality of ejection channels adjacent to each other between the channel columns is also set so as to respectively belong to the plurality of groups different from each other.
(Configuration of Cover Plate 43A)
In the cover plate 43A, one entrance side common ink chamber 430a is provided as shown in
It should be noted that such an entrance side common ink chamber 430a is formed as a part constituting an entrance part Tin in the inkjet head 4A, and corresponds to a specific example of a “common liquid supply chamber” in the present disclosure.
(Regarding Setting of Grouping)
In the case of the control operation of Modified Example 4, as shown in
The ejection channels C1e arranged at odd-numbered (1-st, 3-rd, 5-th, . . . ) places starting from one end part along the X-axis direction in the channel column 421 are arranged to belong to the group G11 (G1o). Specifically, as shown in
Further, the ejection channels C2e arranged at odd-numbered (1-st, 3-rd, 5-th, . . . ) places starting from the one end part along the X-axis direction in the channel column 422 are arranged to belong to the group G21 (G2o). Specifically, as shown in
On the other hand, the ejection channels C1e arranged at even-numbered (2-nd, 4-th, 6-th, . . . ) places starting from the one end part along the X-axis direction in the channel column 421 are arranged to belong to the group G12 (G1e). Specifically, as shown in
Further, the ejection channels C2e arranged at even-numbered (2-nd, 4-th, 6-th, . . . ) places starting from the one end part along the X-axis direction in the channel column 422 are arranged to belong to the group G22 (G2e). Specifically, as shown in
As described above, in Modified Example 4, the ejection channels C1e belonging to the group G11 (G1o) and the ejection channels C1e belonging to the group G12 (G1e) are arranged alternately along the X-axis direction, and at the same time, the ejection channels C2e belonging to the group G21 (G2o) and the ejection channels C2e belonging to the group G22 (G2e) are arranged alternately along the X-axis direction.
(Functions/Advantages)
In such a manner as described above, in Modified Example 4, since there is provided the entrance side common ink chamber 430a for supplying the ink 9 commonly to the plurality of ejection channels C1e, C2e adjacent to each other between the channels columns 421, 422, and it is arranged that the plurality of ejection channels C1e, C2e adjacent to each other between the channel columns 421, 422 respectively belong to the plurality of groups different from each other, the following is achieved. That is, when supplying the ink 9 commonly to the plurality of ejection channels C1e, C2e adjacent to each other from the entrance side common ink chamber 430a, the instantaneous flow in one direction of the ink 9 or the like can be suppressed in the plurality of ejection channels C1e, C2e adjacent to each other. Therefore, even in the case of providing such an entrance side common ink chamber 430a, by setting the shift amount Δtd in substantially the same manner as in the embodiment and so on, it becomes possible to improve the printed image quality.
(Experimental Results)
Here,
Firstly, in the experimental result related to the comparative example shown in
In contrast, in both of the experimental results related to Modified Example 4 shown in
The present disclosure is described hereinabove citing the embodiment and some modified examples, but the present disclosure is not limited to the embodiment and so on, and a variety of modifications can be adopted.
For example, in the embodiment and so on described above, the description is presented specifically citing the configuration examples (the shapes, the arrangements, the number and so on) of each of the members in the printer 1 and the inkjet head 4, but what is described in the above embodiment and so on is not a limitation, and it is possible to adopt other shapes, arrangements, numbers and so on. Further, the values or the ranges, the magnitude relation and so on of a variety of parameters described in the above embodiment and so on are not limited to those described in the above embodiment and so on, but can also be other values or ranges, other magnitude relation and so on.
Specifically, for example, in the embodiment and so on described above, the description is presented citing the inkjet head 4 of the two-column type (having the two nozzle columns 411, 412), but the example is not a limitation. Specifically, for example, it is also possible to adopt an inkjet head of a single-column type (having a single nozzle column), or an inkjet head of a multi-column type (having three or more nozzle columns) with three or more columns.
Further, for example, in the embodiment described above and so on, there is described the case in which the ejection channels (the ejection grooves) and the dummy channels (the non-ejection grooves) each extend along the Y-axis direction in the actuator plate 42, but this example is not a limitation. Specifically, it is also possible to arrange that, for example, the ejection channels and the dummy channels extend along an oblique direction in the actuator plate 42.
Further, the shape of each of the nozzle holes H1, H2 is not limited to the circular shape as described in the above embodiment and so on, but can also be, for example, a polygonal shape such as a triangular shape, an elliptical shape, or a star shape.
In addition, in the embodiment and so on described above, the example of the so-called side-shoot type inkjet head fir ejecting the ink 9 from the central part in the extending direction (the Y-axis direction) of the ejection channels C1e, C2e is described, but the example is not a limitation. Specifically, it is also possible to apply the present disclosure to a so-called edge-shoot type inkjet head for ejecting the ink 9 along the extending direction of the ejection channels C1e, C2e.
Further, in the embodiment described above, the description is presented citing the circulation type inkjet head for using the ink 9 while circulating the ink 9 mainly between the ink tank and the inkjet head as an example, but the example is not a limitation. Specifically, it is also possible to apply the present disclosure to a non-circulation type inkjet head using the ink 9 without circulating the ink 9.
Further, in the embodiment and so on described above, the description is presented specifically citing the method of the control operation by the control section 49, but the example cited in the embodiment and so on described above is not a limitation, and it is also possible to arrange to perform the control operation using other methods. Specifically, for example, the method of grouping the ejection channels C1e, C2e is not limited to the method described in the embodiment and so on described above, but it is also possible to arrange that, for example, the grouping into three or more groups is adopted, or the ejection channels adjacent to each other are defined in a direction different from the direction along each of the channel columns or the direction between the channel columns.
In addition, in the embodiment and so on described above, there is described the case in which the pulse signal for expanding the capacity of the ejection channel C1e, C2e is the pulse signal (the positive pulse signal) for expanding the capacity during the period of the high state, but the case is not a limitation. Specifically, besides the case of the pulse signal for expanding the capacity during the period of the high state and contracting the capacity during the period of the low state, it is also possible to adopt a pulse signal (a negative pulse signal) for expanding the capacity during the period of the low state and contracting the capacity during the period of the high state by contraries.
Further, for example, it is also possible to arrange that a signal for helping the ejection of the droplet is additionally applied during the OFF period immediately after the ON period. As the signal for helping the ejection of the droplet, there can be cited, for example, a pulse signal for contracting the capacity of each of the ejection channels C1e, C2e, and a pulse signal (an auxiliary pulse signal) for pulling back a part of the droplet having been ejected as described above. Further, the pulse signal (the main pulse signal) to be applied immediately before the auxiliary pulse signal as latter one of the pulses has, for example, the pulse width no larger than the width of the on-pulse peak (AP). It should be noted that even if such a signal for helping the ejection of the droplet is added, the content (e.g., the drive method) of the present disclosure described hereinabove is not affected.
Further, the series of processes described in the above embodiment and so on can be arranged to be performed by hardware (a circuit), or can also be arranged to be performed by software (a program). In the case of arranging that the series of processes is performed by the software, the software is constituted by a program group for making the computer perform the functions. The programs can be incorporated in advance in the computer described above, and are then used, or can also be installed in the computer described above from a network or a recording medium and are then used. Further, such a program corresponds to a specific example of a “program for driving a liquid jet head” in the present disclosure.
In addition, in the above embodiment, the description is presented citing the printer 1 (the inkjet printer) as a specific example of the “liquid jet recording device” in the present disclosure, but this example is not a limitation, and it is also possible to apply the present disclosure to other devices than the inkjet printer. In other words, it is also possible to arrange that the “liquid jet head” (the inkjet head 4) of the present disclosure is applied to other devices than the inkjet printer. Specifically, for example, it is also possible to arrange that the “liquid jet head” of the present disclosure is applied to a device such as a facsimile or an on-demand printer.
Further, in the embodiment and so on described above, the description is presented citing the shuttle type printer described above as an example, but this example is not a limitation. It is also possible to apply the control method described in the embodiment and so on described above to, for example, the in-line type printer described above.
Further, it is also possible to apply the variety of examples described hereinabove in arbitrary combination.
It should be noted that the advantages described in the specification are illustrative only but are not a limitation, and other advantages can also be provided.
Further, the present disclosure can also take the following configurations.
<1>
A liquid jet head comprising: a plurality of nozzles adapted to jet liquid; a piezoelectric actuator having a plurality of pressure chambers communicated individually with the nozzles and each filled with the liquid, and adapted to change a capacity of each of the pressure chambers; and a control section adapted to apply at least one pulse signal to the piezoelectric actuator to thereby expand and contract the capacity of the pressure chambers to jet the liquid filling the pressure chamber, wherein the pressure chambers adjacent to each other in the plurality of the pressure chambers are set so as to belong to a plurality of groups different from each other, and the control section makes the pulse signals different in timing between the plurality of groups and sets a shift amount of the timing in the pulse signals between the respective groups so as to approximate an integral multiple of an on-pulse peak (AP), when jetting the liquid.
<2>
The liquid jet head according to <1>, wherein the control section sets the shift amount so as to be an integral multiple of the AP, when jetting the liquid.
<3>
The liquid jet head according to <2>, wherein the control section sets the shift amount so as to be equal to the AP, when jetting the liquid.
<4>
The liquid jet head according to any one of <1> to <3>, wherein the control section sets a droplet size of the liquid to be jetted at a plurality of levels, and the control section sets presence or absence of the shift amount in accordance with a volume of the droplet size to be set.
<5>
The liquid jet head according to <4>, wherein the control section performs setting so that the shift amount is present in a case in which the droplet size to be set is smaller than a predetermined threshold value, and the control section performs setting so that the shift amount is absent in a case in which the droplet size to be set is no smaller than the threshold value.
<6>
The liquid jet head according to any one of <1> to <5>, wherein the plurality of pulse signals includes a first pulse signal adapted to expand the capacity of the pressure chamber, and a second pulse signal adapted to contract the capacity of the pressure chamber, the control section performs setting so that the shift amount is present with respect to the first pulse signal, and the control section performs setting so that the shift amount is absent with respect to the second pulse signal.
<7>
The liquid jet head according to any one of <1> to <6>, wherein the control section adjusts a waveform of the pulse signal so that jetting speed of the liquid becomes relatively low with respect to the group, in which jet timing of the liquid is relatively accelerated due to setting of the shift amount, out of the plurality of groups, or so that jetting speed of the liquid becomes relatively high with respect to the group, in which jet timing of the liquid is relatively delayed due to setting of the shift amount, out of the plurality of groups.
<8>
The liquid jet head according to any one of <1> to <7>, further comprising: at least one common liquid supply chamber adapted to supply the liquid commonly to the plurality of pressure chambers adjacent to each other.
<9>
The liquid jet head according to any one of <1> to <8>, wherein the shift amount is a shift amount between falling timings in last pulse signals adapted to jet the liquid out of the at least one pulse signal, or a shift amount between rising timings in first pulse signals adapted to jet the liquid out of the at least one pulse signal.
<10>
The liquid jet head according to any one of <1> to <9>, wherein the control section stores information related to the shift amount in advance, and the control section generates the pulse signal based on the information related to the shift amount stored therein.
<11>
The liquid jet head according to any one of <1> to <9>, wherein the control section obtains information related to the shift amount from an outside of the liquid jet head, and the control section generates the pulse signal based on the information related to the shift amount obtained from the outside.
<12>
The liquid jet head according to any one of <1> to <11>, wherein the plurality of groups is two groups, the pressure chambers belonging to one of the two groups and the pressure chambers belonging to the other of the two groups being arranged alternately.
<13>
A liquid jet recording device comprising: the liquid jet head according to any one of <1> to <12>.
<14>
A method for driving a liquid jet head, comprising: setting, when applying at least one pulse signal to a piezoelectric actuator adapted to change a capacity of each of a plurality of pressure chambers communicated respectively with a plurality of nozzles to thereby expand and contract the capacity of the pressure chambers to jet a liquid filling the pressure chamber from the nozzle, the pressure chambers adjacent to each other in the plurality of pressure chambers so as to belong to a plurality of groups different from each other; and making the pulse signals different in timing between the plurality of groups and setting a shift amount of the timing in the pulse signals between the respective groups so as to approximate an integral multiple of an on-pulse peak (AP).
<15>
A program for driving a liquid jet head, the program making a computer perform a process comprising: setting, when applying at least one pulse signal to a piezoelectric actuator adapted to change a capacity of each of a plurality of pressure chambers communicated respectively with a plurality of nozzles to thereby expand and contract the capacity of the pressure chambers to jet a liquid filling the pressure chamber from the nozzle, the pressure chambers adjacent to each other in the plurality of pressure chambers so as to belong to a plurality of groups different from each other; and making the pulse signals different in timing between the plurality of groups and setting a shift amount of the timing in the pulse signals between the respective groups so as to approximate an integral multiple of an on-pulse peak (AP).
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-244097 | Dec 2017 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20050073537 | Iwao | Apr 2005 | A1 |
| Number | Date | Country |
|---|---|---|
| 2851200 | Mar 2015 | EP |
| 3118000 | Jan 2017 | EP |
| 2001-246738 | Sep 2001 | JP |
| Entry |
|---|
| IP.com search (Year: 2019). |
| Extended European Search Report in Europe Application No. 18214812.2, dated Apr. 23, 2019, 9 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20190184699 A1 | Jun 2019 | US |
