Patent Application
20180001619
The present invention relates to a liquid discharging apparatus, such as an ink jet type recording device, a control method of a liquid discharging apparatus, a disk driver, and a printing system, and particularly to a liquid discharging apparatus which discharges liquid from a nozzle by driving an actuator and generating pressure oscillation in the liquid in a liquid flow path, a control method of a liquid discharging apparatus, a device driver, and a printing system.
A liquid discharging apparatus is a device which is provided with a liquid discharging head and discharges (ejects) various types of liquid from the liquid discharging head. An example of the liquid discharging apparatus includes an image recording device, such as an ink jet type printer or an ink jet type plotter, but in recent years, the liquid discharging apparatus has also been applied to various types of manufacturing devices by utilizing the advantageous characteristic that it is possible to make an extremely small amount of liquid accurately land at a predetermined position. For example, the liquid discharging apparatus is applied to a display manufacturing device which manufactures a color filter of a liquid crystal display or the like, an electrode forming device which forms an electrode, such as an organic electroluminescence (EL) display or a field emission display (FED), and a chip manufacturing device which manufactures a biochip (biochemical element). In addition, liquid type ink is discharged from a recording head for the image recording device, and the liquid having each color material, such as red (R), green (G), and blue (B) from a color material discharging head for the display manufacturing device. In addition, a liquid type electrode material is discharged from the electrode material discharging head for an electrode forming device, and a solution of the bioorganic matter is discharged from a bioorganic matter discharging head for the chip manufacturing device.
Here, in a printer which is one type of the above-described liquid discharging apparatus, there is a case where the ink (hereinafter, referred to as resin ink) containing thermoplastic resin particles is used (for example, refer to PTL 1). Since the resin ink forms a solid resin film when solidifying on a recording medium, it has an advantage in that its abrasion resistance and weather resistance are excellent compared to water-based ink. Meanwhile, there is a case where resin components contained in the ink gradually become attached to a flow path or a nozzle in the liquid discharging head, and accordingly, there is a concern that the discharging is adversely influenced.
PTL 1: JP-A-2015-009519
Various types of maintenance methods to respond to the above-described problem, and a correction method of a driving pulse which drives an actuator have also been suggested, but it is necessary that an attachment position of the resin components is changed in accordance with whether the attachment position is on an inner wall of the nozzle or the attachment position is on an inner wall of the liquid flow path further on an upstream side than the nozzle, and thus, it is difficult to specify the attachment position of the resin components in the related art.
In consideration of such a situation, it is an object of the present invention to provide a liquid discharging apparatus which can specify an attachment position in a configuration of discharging liquid containing resin, a control method of a liquid discharging apparatus, a device driver, and a printing system.
(Solution 1)
In the present invention suggested for achieving the above-described object, there is provided a liquid discharging apparatus including: a liquid discharging head which includes a nozzle that discharges a liquid containing resin, a liquid flow path that individually communicates with the nozzle, and an actuator that generates pressure oscillation in the liquid in the liquid flow path, and which discharges the liquid from the nozzle by driving of the actuator; a first inspection mechanism which inspects a discharge abnormality of the nozzle; a second inspection mechanism which inspects oscillation of the liquid in the liquid flow path generated by the driving of the actuator; and a control circuit which performs processing of specifying either of attachment of the resin to the liquid flow path or attachment of the resin to the nozzle, in which the control circuit specifies an attachment position of the resin based on an inspection result of the discharge abnormality by the first inspection mechanism, and an inspection result of oscillation of the liquid in the liquid flow path by the second inspection mechanism.
According to the configuration of Solution 1, since the attachment position of the resin which is unlikely to be specified in the related art is specified based on the inspection result by the first inspection mechanism and the inspection result by the second inspection mechanism, it is possible to perform appropriate processing which corresponds to the attachment position of the resin.
(Solution 2)
In the liquid discharging apparatus according to Solution 1, it is preferable that the control circuit performs correction with respect to a driving pulse which drives the actuator in accordance with the specified attachment position of the resin.
According to the configuration of Solution 2, by appropriately correcting the driving pulse in accordance with the attachment position of the resin, even in a case where the attachment of the resin components contained in the liquid is generated, regardless of the attachment position, it is possible to make the amount or the flying speed of the liquid discharged from the nozzle close to a value which is the target of a design.
(Solution 3)
In the liquid discharging apparatus according to Solution 2, it is preferable that the control circuit performs inspection for specifying the attachment position of the resin, on a regular basis or based on an instruction of a user.
According to the configuration of the above-described Solution 3, by performing the inspection for specifying the attachment position of the resin on a regular basis or based on the instruction of the user, it is possible to respond to a change in situation that the attachment of the resin is further increased as time elapses, or the attached resin is peeled.
(Solution 4)
There is provided a control method of a liquid discharging apparatus including a liquid discharging head which includes a nozzle that discharges a liquid containing resin, a liquid flow path that individually communicates with the nozzle, and an actuator that generates pressure oscillation in the liquid flow path, and which discharges the liquid from the nozzle by driving of the actuator; a first inspection mechanism which inspects a discharge abnormality of the nozzle; and a second inspection mechanism which inspects oscillation of the liquid in the liquid flow path generated by the driving of the actuator, the method including: a first inspection step of inspecting the discharge abnormality of the nozzle by the first inspection mechanism; a second inspection step of inspecting the oscillation of the liquid in the liquid flow path by the second inspection mechanism when the discharge abnormality is detected in the first inspection step; a first correction step of performing correction which corresponds to the attachment of the resin inside the liquid flow path with respect to the driving pulse which drives the actuator when an abnormality is detected in the oscillation in the second inspection step; a third inspection step of re-inspecting the discharge abnormality of the nozzle after the first correction step; and a second correction step of performing the correction which corresponds to the attachment of the resin inside the nozzle with respect to the driving pulse when the abnormality is not detected in the oscillation in the second inspection step or when the discharge abnormality is detected in the third in the third inspection step.
According to the method of Solution 4, by specifying the attachment position of the resin components and appropriately correcting the driving pulse in accordance with the attachment position of the specified resin based on the inspection result by the first inspection mechanism and the inspection result by the second inspection mechanism, even when the attachment of the resin components contained in the liquid is generated, regardless of the attachment position, it is possible to make the amount or the flying speed of the liquid discharged from the nozzle close to a value which is the target of a design.
(Solution 5)
There is provided a device driver which can be executed in a host device connected to be communicable to a liquid discharging apparatus including a liquid discharging head which includes a nozzle that discharges a liquid containing resin, a liquid flow path that individually communicates with the nozzle, and an actuator that generates pressure oscillation in the liquid flow path, and which discharges the liquid from the nozzle by driving of the actuator; a first inspection mechanism which inspects a discharge abnormality of the nozzle; and a second inspection mechanism which inspects oscillation of the liquid in the liquid flow path generated by the driving of the actuator, the driver performing each step of the control method of a liquid discharging apparatus according to Solution 4 in the liquid discharging apparatus.
Furthermore, there is provided a printing system including: a host device which can execute the device driver according to Solution 5; and a liquid discharging apparatus connected to be communicable with the host device.
Hereinafter, an embodiment for realizing the present invention will be described with reference to the attached drawings. In addition, in the embodiment which will be described hereinafter, the present invention is restricted in various ways to an appropriate specific example, but the range of the present invention is not limited to the aspects insofar as there is no particular remark on the restriction of the present invention otherwise stated.
In the printing system, a host device, such as a host computer 1 or the like, and an ink jet printer (hereinafter, simply referred to as a printer) 3 are connected so as to be communicable in a wired or wireless manner. The host computer 1 includes a CPU 5, a memory 6, an input/output interface (I/O) 7, and an auxiliary storage device 8, and the members are connected to each other via an inner bus. The auxiliary storage device 8 is configured of, for example, a hard disk drive, and a device driver or the like, such as an operation program, various types of application programs, and a printer driver 9, is stored in the storage device 8. In addition, the CPU 5 performs various types of processing, such as execution of the application program or the printer driver 9, according to the operation system stored in the auxiliary storage device 8. The input/output interface 7 is formed of an interface, such as a USB or an IEEE 1394, is connected to the input/output interface 7 of the printer 3, and outputs a request of recording processing or the like or data or the like related to printing, which is created by the printer driver 9, to the printer 3. The printer driver 9 is a program for performing processing of converting image data (image data or text data) prepared by the application program into dot pattern data (which is also referred to as raster data) used in the printer 3, or various types of printing settings. In addition, the processing of the printer driver 9 will be described later.
The printer 3 in the embodiment includes a CPU 11 (which corresponds to a control circuit in the present invention), a memory 12, an input/output interface 13, a driving signal generation circuit 14, a paper feeding mechanism 16, a carriage moving mechanism 17, a discharge inspection mechanism 40, an oscillation inspection circuit 41, and a recording head 18. The discharge inspection mechanism 40 (which corresponds to a first inspection mechanism in the present invention) is a mechanism which inspects whether or not the ink is normally discharged from a nozzle 27 (refer to
The input/output interface 13 receives and sends various types of data, for example, receives a request of recording processing or the like or data related to printing from the host computer 1 side which is one type of a host device, or outputs information regarding a state of the printer 3 to the host computer 1 side. The CPU 11 is an arithmetic processing device for performing the control of the entire printer. The memory 12 is an element which stores a program of the CPU 11 or data used in various types of control, and examples of which include a ROM, a RAM, and an NVRAM (nonvolatile random access memory). The CPU 11 controls each unit according to the program stored in the memory 12. In addition, the CPU 11 in the embodiment sends dot pattern data from the host device side to the control device 19 of the recording head 18. The driving signal generation circuit 14 (driving pulse generation circuit) generates an analog signal, amplifies the signal, and generates a driving signal illustrated in
In the printer 3 in the embodiment, the recording head 18 is attached to a bottom surface side of a carriage 23 on which an ink cartridge 22 is loaded. In addition, the carriage 23 is configured to be able to be reciprocated along a guide rod 24 by the carriage moving mechanism 17. In other words, the printer 3 sequentially transports a recording medium S, such as recording paper, by the paper feeding mechanism 16, discharges the ink from the nozzle 27 (refer to
One end portion (right hand side in
The recording head 18 in the embodiment is schematically formed of a nozzle plate 28, a flow path substrate 29, and the piezoelectric element 20, and is attached to a case 30 in a state where the members are stacked. The nozzle plate 28 is a member which is formed of a silicon single crystal substrate on which the plurality of nozzles 27 are established in a row along the same direction at a pitch which corresponds to a dot formation density. In the embodiment, the nozzle row (one type of nozzle group) configured of the plurality of nozzles 27 installed in parallel is formed of, for example, 360 nozzles 27. In addition, a surface on a side where the ink of the nozzle plate 28 is discharged corresponds to a nozzle surface.
On the flow path substrates 29, a plurality of hollow portions which become pressure chambers 31 are formed in accordance with each nozzle 27. On the outside of the row of the pressure chambers 31 on the flow path substrate 29, a common liquid chamber 32 which is a hollow portion common to each pressure chamber 31 is formed. The common liquid chamber 32 communicates with each pressure chamber 31 via an ink supply port 33. In addition, the pressure chambers 31 which separately communicate with the nozzles 27 and the ink supply port 33 correspond to a liquid flow path in the present invention (hereinafter, appropriately, referred to as a separate flow path). In addition, the ink from the ink cartridge side is introduced through an ink introduction path 34 of the case 30 to the common liquid chamber 32. On an upper surface which is a side opposite to the nozzle plate 28 side of the flow path substrate 29, the piezoelectric element 20 (one type of actuator) is formed via an elastic film 35. The piezoelectric element 20 is formed by sequentially stacking a metal-made lower electrode film, a piezoelectric layer made of lead zirconate titanate, and a metal upper electrode film (none of these is illustrated). The piezoelectric element 20 is a so-called bending mode piezoelectric element, and is formed so as to cover the upper portion of the pressure chamber 31. The piezoelectric element 20 is deformed in response to the driving signal (driving pulse (refer to
When the driving pulse Pd which is formed as described above is applied to the piezoelectric element 20, first, the piezoelectric element 20 bends toward the outside (side to which the piezoelectric element 20 is separated from the nozzle plate 28) of the pressure chamber 31 by the expansion element p11, and according to this, the pressure chamber 31 expands to an expansion volume which corresponds to the expansion potential VL from a reference volume which corresponds to the reference potential VB. By the expansion, meniscus of the ink in the nozzle 27 is drawn into the pressure chamber 31 side from a standby position (position of the meniscus when the pressure chamber 31 is maintained to have the reference volume) along an axial direction of the nozzle 27. In addition, the expanded state of the pressure chamber 31 is maintained by the expansion hold element p12 for a certain period of time. After being held by the expansion hold element p12, the piezoelectric element 20 is bent to the inside (side which is close to the nozzle plate 28) of the pressure chamber 31 by the contraction element p13. According to this, the pressure chamber 31 is rapidly contracted to the contraction volume which corresponds to the contraction potential VH from the expansion volume. Accordingly, the ink inside the pressure chamber 31 is pressurized, and the meniscus drawn into the pressure chamber 31 side is pushed out passing the standby position along the axial direction of the nozzle 27 to the discharge side opposite to the pressure chamber 31 side. Accordingly, ink droplets are discharged from the nozzle 27. The contraction state of the pressure chamber 31 is maintained across a supply period of the contraction hold element p14, and during the period, the pressure of the ink in the pressure chamber 31 which is reduced by the discharge of the ink is raised again by the pressure oscillation. The time of the contraction hold element p14 is adjusted so that the recovery element p15 is applied to the piezoelectric element 20 in accordance with the raising timing. As the recovery element p15 is applied, the piezoelectric element 20 returns to a normal position which corresponds to the reference potential VB. According to this, the pressure chamber 31 is expansion-recovered to a normal volume, and the pressure oscillation (remaining oscillation) of the ink in the pressure chamber 31 is absorbed.
Regarding the driving pulse Pd (basic pulse), a driving voltage Vd (a potential difference between the expansion potential VL and the contraction potential VH) is set so that the amount of ink discharged from the nozzle 27 becomes a constant value, that is a value which is the target of a design. In addition, a time period (time of expansion hold element p12) Pw1 from a final end of the expansion element p11 to a starting end of the contraction element p13, and a time period (time of the contraction hold element p14) Pw2 from a final end of the contraction element p13 to a starting end of the recovery element p15, are determined based on the Helmholtz period (intrinsic oscillation period of the ink) Tc of the pressure oscillation generated in the ink in the pressure chamber 31. The intrinsic oscillation period Tc can be generally expressed by the following Formula (1).
Tc=2π√[(Mn+Ms)/(Mn×Ms×(Cc+Ci))] (1)
In Formula (1), Mn is inertance (mass of the ink per unit sectional area) of the nozzle 27, Ms is inertance of the ink supply port 33, Cc is compliance (illustrating a level of a volume change per unit pressure, and softness) of the pressure chamber 31, and Ci is compliance of the ink (Ci=Volume V/[density ρ×speed of sound c2]). Accordingly, it is possible to appropriately perform the discharge of the ink in accordance with the pressure oscillation generated in the ink in the pressure chamber 31, or the control of the remaining oscillation after the discharge.
Meanwhile, the printer 3 in the embodiment is configured to discharge the ink (hereinafter, referred to as resin ink) containing the thermoplastic resin particles by the recording head 18. For this reason, there is a problem that the resin components contained in the ink become attached to an inner wall of the nozzle 27 or an inner wall of the ink flow path, such as the pressure chamber 31, as time elapses. When the resin components are attached in the ink flow path or the like, since the dimensions or the rigidity of the flow path changes, the discharge characteristics of the nozzle 27 are influenced. Specifically, in order to reduce the internal diameter of the nozzle 27 when the resin is attached in the nozzle 27, for example, the weight of the discharged ink droplets is reduced compared with that before being attached, and the flying speed of the ink droplets is increased. In addition, since the inertance in the nozzle 27 decreases, there is a tendency for the above-described intrinsic oscillation period Tc to increase. In addition, inertance M is approximately expressed by the following Formula (2) when the density of the ink is p, the sectional area in a direction orthogonal to a direction of ink flow of the flow path is S, and the length of the flow path is L.
M=(ρ×L)/S (2)
In addition, when the resin is attached to separate flow paths of each nozzle 27, that is, in the pressure chamber 31 or the ink supply port 33, there is a tendency that the above-described intrinsic oscillation period Tc decreases. Furthermore, when the resin is attached to the elastic film 35 (diaphragm) which divides the pressure chamber 31, since it becomes unlikely that the elastic film 35 moves when the piezoelectric element 20 is driven and the displacement becomes small, the weight of the ink droplets discharged from the nozzle 27 decreases, and the above-described intrinsic oscillation period Tc decreases. In this manner, the tendency of the change in the discharge characteristics of the ink varies in accordance with the position at which the resin is attached. Here, in the printing system according to the present invention, by using the inspection result by the discharge inspection mechanism 40 and the inspection result by the oscillation inspection circuit 41, the attachment position of the resin in the recording head 18 is specified, and according to this, appropriate correction is performed.
Next, the CPU 11 determines whether or not a discharge abnormality is present, based on the detected signal from the discharge inspection mechanism 40 (step S2). In other words, discharge abnormality, such as deviation of the amount (mass and volume) or the flying speed of the ink discharged from the nozzle 27 from a target value, or failure of ejection of the ink from the nozzle 27, is generated, the value of the detected signal from the discharge inspection mechanism 40 changes from a normal value. The CPU 11 determines that the discharge abnormality is generated regarding the nozzle 27 when the value of the detected signal changes from the normal value. Here, when it is determined that discharge abnormality is not present in step S2 (NO), since the attachment of the resin components is not even generated in either of the inside of the nozzle 27 and the inside of the separate flow path, such as the pressure chamber 31, that communicates with the inside of the nozzle 27, the processing is finished. Meanwhile, when it is determined that a discharge abnormality is present in step S2 (YES), it is ascertained that the attachment of the resin is generated in at least one of the inside of the nozzle 27 and the separate flow path, such as the pressure chamber 31, that communicates with the inside of the nozzle 27. In addition, it is determined whether or not the discharge inspection step is performed for the second time in the current series of processing (step S3), and when it is determined that the discharge inspection step is performed for the first time (NO), then, a remaining oscillation inspection step (step S4) is performed. In addition, a case where the discharge inspection step is performed for the second time will be described later.
In the remaining oscillation inspection step (which corresponds to a second inspection step in the present invention), as the driving pulse Pd is applied to the piezoelectric element 20 that corresponds to the nozzle 27 to be an inspection target, and the piezoelectric element 20 is driven, the pressure oscillation is generated in the corresponding pressure chamber 31. According to attenuation oscillation (remaining oscillation) of the pressure oscillation, an operation surface (elastic film 35) of the pressure chamber 31 and the piezoelectric element 20 also oscillates, and a reverse electromotive force is generated by the piezoelectric element 20 due to the oscillation. The oscillation inspection circuit 41 detects this, and outputs the reverse electromotive force signal to the CPU 11. Specifically, the method is disclosed in JP-A-2014-091295. The CPU 11 determines whether or not an abnormality is present in the remaining oscillation (whether or not an amplitude component or a frequency component of the remaining oscillation has deviated from a reference value) based on the reverse electromotive signal from the oscillation inspection circuit 41 (step S5). Here, in the remaining oscillation detection step, when the attachment of the resin to the inside of the separate flow path, such as the pressure chamber 31, occurs, it is possible to detect the attachment as a change in the amplitude component or a change in the frequency component of the remaining oscillation. Meanwhile, it is not possible to detect the attachment of the resin inside the nozzle 27, since it is difficult to express the attachment as the change of each component of the remaining oscillation. For this reason, when it is determined that an abnormality is present in the remaining oscillation in step S5 (YES), it is determined that the attachment of the resin is generated at least on the inside of the separate flow path. In this case, in step S6, a first correction step according to the attachment inside the separate flow path is performed.
As described above, when the resin is attached to the inside of the separate flow path, such as the pressure chamber 31, the intrinsic oscillation period Tc tends to decrease. When the intrinsic oscillation period Tc becomes short, a discharging timing is shifted by the contraction element p13 in the driving pulse Pd, and a controlling timing is shifted by the recovery element p15. In addition, when the resin is attached to the elastic film 35 which divides the pressure chamber 31, the weight of the ink droplets discharged from the nozzle 27 is reduced. The attachment position of the resin component in the pressure chamber 31 can be ascertained based on the reverse electromotive force signal from the oscillation inspection circuit 41. For example, when only the frequency component of the reverse electromotive force signal is changed from the reference value, it is ascertained that the attachment of the resin occurs at a part other than the elastic film 35 in the pressure chamber 31. In addition, for example, when both the frequency component and the amplitude component of the reverse electromotive force signal have changed from the reference value, it is considered that the attachment occurs at the elastic film 35. In the first correction step, as illustrated in
In step S5, when it is determined that an abnormality is not present in the remaining oscillation (NO), it is ascertained that the discharge abnormality occurred due to the attachment of the resin to the inside of the nozzle 27. In other words, it is specified that the attachment position is inside the nozzle 27. In this case, in step S7, the second correction step is performed in accordance with the attachment inside the nozzle 27.
As described above, when the resin is attached to the inside of the nozzle 27, the weight of the discharged ink droplets is reduced, or the flying speed of the ink droplets increases. For this reason, in the second correction step, as illustrated in
Meanwhile, after the first correction step, the discharge inspection step (which corresponds to a third inspection step in the present invention) is performed for a second time in step S1, because a possibility that the attachment of the resin component is generated not only in the separate flow path, but also inside the nozzle 27, still remains. As a result of the second discharge inspection step, when it is determined that the discharge abnormality is not detected in step S2 (NO), it is ascertained that the attachment of the resin component is present only in the separate flow path, and the processing is finished. Meanwhile, as a result of the second discharge inspection step, when it is determined that the discharge abnormality is detected in step S2 (YES), it is ascertained that the attachment of the resin component is generated not only in the separate flow path but also inside the nozzle 27. In this case, it is determined that the discharge inspection step is performed for the second time in step S3 (YES), and the second correction step is performed in accordance with the attachment inside the nozzle 27 in step S7. In addition, the above-described processing can be performed for every nozzle 27 or for every nozzle row.
Above, since the attachment position of the resin component which was unlikely to be specified in the related art, is specified based on the result of the discharge inspection step by the discharge inspection mechanism 40 and the result of the remaining oscillation inspection step by the oscillation inspection circuit 41, it is possible to perform appropriate processing in accordance with the attachment position of the resin. Specifically, it is possible to appropriately correct the driving pulse Pd in accordance with the attachment position of the resin. Accordingly, regardless of the attachment position even in a case where the attachment of the resin component contained in the ink is generated, it is possible to make the amount or the flying speed of the ink droplets discharged from the nozzle 27 close to the value which is the target of a design.
The processing of inspecting the presence or the absence of the attachment of the resin, specifying the attachment position, and the correcting the driving pulse in accordance with the attachment position, is performed on a regular basis or based on the instruction by the user via the printer driver 9. Since there is a possibility that the attachment of the resin is further increased as time elapses or the attached resin is peeled, it is possible to react to the change in the situation by performing the above-described processing on a regular basis.
In addition, the correction method in the first correction step or the second correction step is not limited to the example, if it is possible to recover the change in the discharge characteristics generated by the attachment of the resin, various known methods can be employed.
In addition, regarding the driving pulse Pd, not being limited to the example in FIG. 4, various known driving pulses can be employed.
In addition, in the above-described embodiment, the so-called bending oscillation type piezoelectric element 20 is described as an example of an actuator, but the present invention is not limited thereto, and can also be employed in a case where various types of actuators, such as a so-called longitudinal oscillation type piezoelectric element, a heating element, and an electrostatic actuator which changes the volume of the pressure chamber by using an electrostatic force.
In addition, if the liquid discharging apparatus discharges the liquid containing the component which is likely to be attached in the flow path, the present invention is not limited to the printer 3, and can also be employed in various ink jet type recording apparatuses, such as a plotter, a facsimile machine, or a copy machine, or a liquid droplet discharging apparatus, such as a printing equipment which performs printing by making the ink from a liquid discharging head land on fabric (material to be printed) which is one type of a landing target.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-060551 | Mar 2015 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2016/001479 | 3/15/2016 | WO | 00 |
