Patent Grant
11827028
The present application is based on, and claims priority from JP Application Serial Number 2020-107503, filed Jun. 23, 2020, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to a liquid discharging apparatus and a liquid filling method.
In relation to a liquid discharging apparatus, a technology that initially fills a recording head with an ink by using a pump is disclosed in, for example, in JP-A-2019-14253.
In the technology described in JP-A-2019-14253, a wait is made for a predetermined time, starting from when the recording head starts to be filled with ink, after which the pump is stopped to complete the filling. However, a time taken until the filling of ink is completed may vary depending on various factors such as the type of liquid to be filled, temperature in the environment, and error in the performance of the pump. Even when a wait is made for a predetermined time, therefore, a discharge failure may occur due to an insufficient amount of filled liquid or liquid may be unnecessarily discharged because liquid is filled more than necessary.
According to a first aspect of the present disclosure, a liquid discharging apparatus is provided. This liquid discharging apparatus has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; a detection circuit that detects a signal related to residual vibration in the pressure chamber; and a control section that controls a filling operation to supply liquid from the outside into the liquid discharging head. The control section terminates the filling operation according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
According to a second aspect of the present disclosure, a liquid discharging apparatus is provided. This liquid discharging apparatus has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; a detection circuit that detects a signal related to temperature in the pressure chamber; and a control section that controls a filling operation to supply liquid from the outside into the liquid discharging head. The control section terminates the filling operation according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
According to a third aspect of the present disclosure, a liquid filling method is provided, the method being executed by a liquid discharging apparatus that has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; and a detection circuit that detects a signal related to residual vibration in the pressure chamber. In this liquid filling method, after a filling operation to supply liquid from the outside into the liquid discharging head is started, the filling operation is terminated according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
According to a fourth aspect of the present disclosure, a liquid filling method is provided, the method being executed by a liquid discharging apparatus that has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; and a detection circuit that detects a signal related to temperature in the pressure chamber. In this liquid filling method, after a filling operation to supply liquid from the outside into the liquid discharging head is started, the filling operation is terminated according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
The liquid discharging apparatus 100 has a liquid storage section 14, a transport mechanism 22 that feeds the medium 12, a control section 80, a head moving mechanism 24, and a head unit 3. The liquid storage section 14 individually stores a plurality of types of ink to be supplied to the head unit 3. As the liquid storage section 14, a bag-like pack formed from a flexible film, an ink tank in which ink can be replenished, a detachable ink cartridge, or the like can be used.
The control section 80 includes a processing circuit formed from, for example, one or a plurality of central processing units (CPUs) or field programmable gate arrays (FPGAs) and also includes a storage circuit such as a semiconductor memory. The control section 80 controls the entire operation of the liquid discharging apparatus 100. The control section 80 has a function for executing printing processing and a function for controlling a filling operation to fill ink, in which the head unit 3 is externally filled with ink.
The transport mechanism 22, which operates under control of the control section 80, transports the medium 12 in the +Y direction. The head moving mechanism 24 has a transport belt 23 stretched across a print range on the medium 12 in the X direction, and also has a carriage 25 that stores the head unit 3 and secures them to the transport belt 23. The head moving mechanism 24, which operates under control of the control section 80, bidirectionally moves the head unit 3 along the X direction, which is the main scanning direction, with the head unit 3 mounted in the carriage 25. When the carriage 25 is bidirectionally moved, the carriage 25 is guided along a guide rail (not illustrated). The liquid storage section 14 may be mounted in the carriage 25 together with the head unit 3.
Each head unit 3 has a plurality of nozzles N used to discharge ink. Nozzles N form nozzle rows Ns, in each of which nozzles N are aligned along the Y direction. Each nozzle N has a discharge port, from which ink is discharged, at a position at which the discharge port faces the medium 12. The head unit 3 is provided for each color of ink stored in the liquid storage section 14. Under control of the control section 80, the head unit 3 discharges ink supplied from the liquid storage section 14 from a plurality of nozzles N toward the medium 12. When liquid is discharged from nozzles N while the head unit 3 is bidirectionally moved, an image or the like is printed on the medium 12. The arrows indicated by dashed lines in
The supply flow path 251 couples the liquid storage section 14 and a pressure chamber 213, which will be described later, together, the pressure chamber 213 being included in the head unit 3, so that ink in the liquid storage section 14 is supplied to the pressure chamber 213. The ejection flow path 253 couples the pressure chamber 213 and liquid storage section 14 together so that ink in the pressure chamber 213 is collected into the liquid storage section 14. In the description below, it will be assumed that the upstream of the supply flow path 251 is on the same side as the liquid storage section 14 and the downstream is on the same side as the head unit 3; and the upstream of the ejection flow path 253 is on the same side as the head unit 3 and the downstream is on the same side as the liquid storage section 14.
The pressurizing section 10, which is provide in the supply flow path 251, operates in response to a control signal from the control section 80 and feeds, to the pressure chamber 213, ink supplied from the liquid storage section 14. The depressurizing section 11, which is provided in the ejection flow path 253, operates in response to a control signal from the control section 80 and feeds, to the liquid storage section 14, ink ejected from the pressure chamber 213. In this embodiment, a positive pressure is applied to the pressurizing section 10 and a negative pressure is applied to the depressurizing section 11, so ink is circulated in the circulation mechanism 250. The pressurizing section 10 and depressurizing section 11 are each a positive displacement pump. Instead of a positive displacement pump, however, the pressurizing section 10 and depressurizing section 11 may be a rotary pump such as a gear pump or vane pump, may be a reciprocating pump such as a plunger pump or piston pump, or may be a diaphragm pump.
In this embodiment, it will be assumed that the liquid discharging apparatus 100 has one or a plurality of head units 3, one or a plurality of driving signal creating units 4, which are in one-to-one correspondence with the one or a plurality of head units 3. For convenience of explanation, however, the description below will focus on one head unit 3 of the one or plurality of head units 3 and one driving signal creating unit 4 provided in correspondence with the one head unit 3, as illustrated in
The control section 80 receives image data Img representing an image to be formed by the liquid discharging apparatus 100 from a computer coupled to the liquid discharging apparatus 100 or from any of various types of recording media. The control section 80 executes print processing in which an image represented by the image data Img supplied to the control section 80 is formed on the medium 12.
The control section 80 creates a print signal SI, a waveform specifying signal dCom, and other signals that control the operations of individual sections in the liquid discharging apparatus 100. The waveform specifying signal dCom is a digital signal that stipulates the waveform of the driving signal Com. The driving signal Com is an analog signal that drives the discharging section D. In this embodiment, driving signals Com include a first driving signal Com-A and a second driving signal Com-B. The driving signal creating unit 4, which includes a DA conversion circuit, creates the driving signal Com having a waveform stipulated by the waveform specifying signal dCom. The print signal SI is a digital signal that specifies the type of operation of the discharging section D. Specifically, the print signal SI specifies whether to supply the driving signal Com to the discharging section D to specify the type of operation of the discharging section D.
The head unit 3 has a liquid discharging head 32, a driving circuit 31, and a detection circuit 33.
The liquid discharging head 32 has M discharging sections D. Here, the value M is a natural number greater than or equal to 1. In the description below, to distinguish each of the M discharging sections D in the liquid discharging head 32, they may be sequentially referred to as a first discharging section D, a second discharging section D, . . . , and an M-th discharging section D. In the description below, of the M discharging sections D provided in the liquid discharging head 32, an m-th discharging section D may be represented as a discharging section D[m]. Here, the variable m is a natural number greater than or equal to 1 and smaller than or equal to M. In the description below, when a signal, a constituent element in the liquid discharging apparatus 100, or the like that corresponds to the discharging section D[m] of the M discharging sections D, the reference characters representing the constituent element, the signal, or the like may be suffixed with [m].
As illustrated in
In plan view from the Z direction, the flow path substrate 212 is a plate-like member elongated in the Y direction, as illustrated in
As illustrated in
As illustrated in
As illustrated in
The diaphragm 219 is a thin-plate member that undergoes displacement in response to the driving of the piezoelectric element PZ. On the diaphragm 219, the piezoelectric element PZ is provided at a portion facing the pressure chamber 213.
Piezoelectric elements PZ are individually provided in correspondence with pressure chambers 213. Each piezoelectric element PZ has an upper electrode Zu, a lower electrode Zd, and a piezoelectric body Zm disposed between the upper electrode Zu and the lower electrode Zd. The lower electrode Zd is electrically coupled to a feed line Lb set to a potential VBS indicated in
In plan view from the Z direction, the first compliance substrate 221 is a plate-like member elongated in the Y direction. The first compliance substrate 221 is a thin-film member formed from poly-phenylene sulfide (PPS), aromatic polyamide, or the like. The first compliance substrate 221 absorbs pressure vibration that would otherwise propagate from each pressure chamber 213 to the interior of the first common liquid chamber 234 when an ink droplet is discharged from the relevant nozzle N.
The nozzle communicating path 229 passes through the flow path substrate 212 in the Z direction. The nozzle communicating path 229 causes the relevant nozzle N and the pressure chamber 213 corresponding to the nozzle N to communicate with each other.
The nozzle substrate 220 is joined to the face of the flow path substrate 212 in the —Z direction, closing the openings of the nozzle communicating paths 229 and second individual communicating paths 230. A plurality of nozzles N are formed in the nozzle substrate 220 so as to be arranged side by side by, for example, performing dry etching, wet etching, or the like for a monocrystalline silicon (Si) substrate. Each nozzle N is a substantially circular through-hole that extends through the nozzle substrate 220 in the Z direction.
One second individual communicating path 230 is formed in correspondence to each nozzle N. The second individual communicating path 230 is formed like a groove by performing wet etching or the like for the flow path substrate 212. The end of the second individual communicating path 230 in the +X direction communicates with the relevant nozzle communicating path 229, and the end in the —X direction communicates with the second liquid chamber 233.
As illustrated in
The leading-out flow path substrate 218 internally has a lead-in liquid chamber 235. The lead-in liquid chamber 235 is open to the face of the leading-out flow path substrate 218 in the —Z-direction and communicates with the second liquid chamber 233 in the flow path substrate 212, forming a second common liquid chamber 236. Ink in the second common liquid chamber 236 is fed out of the first outlet 231 to the ejection flow path 253 and is then returned to the liquid storage section 14, as indicated by the hatched arrow.
The second compliance substrate 222, which is formed from a material similar to the material of the first compliance substrate 221, is a plate-like member elongated in the Y direction. The second compliance substrate 222 absorbs pressure vibration that would otherwise propagate from each pressure chamber 213 to the second common liquid chamber 236 when an ink droplet is discharged from the relevant nozzle N.
The protection substrate 216 is formed in correspondence with areas in which the piezoelectric elements PZ disposed on the diaphragms 219 are formed. The protection substrate 216 internally has a storage space 238. In the storage space 238, the piezoelectric elements PZ are stored and are joined to the surface of the pressure chamber substrate 214 in the in the +Z direction. The protection substrate 216 has lead electrodes 240 drawn out from the piezoelectric elements PZ, and also has a through-opening 239 passing through the protection substrate 216 in the Z direction.
Referring again to
The detection circuit 33 has a detection signal creating section 331 and a measurement information creating section 332. The detection signal creating section 331 creates a detection signal SK according to the detection potential signal VX supplied from the eligible-for-decision discharging section DS through the driving circuit 31. Specifically, the detection circuit 33 creates the detection signal SK by amplifying the detection potential signal VX and removing a noise component. The detection signal SK is equivalent to a signal detected by the detection circuit 33 after the driving element has been driven by the driving circuit 31. The measurement information creating section 332 then creates, from the detection signal SK, measurement information JS that represents the cycle NTC of the detection signal SK. The cycle NTC is, for example, a time during which the voltage of the detection signal SK rises from 0, reaches a peak with a positive value, drops, reaches a peak with a negative value, rises again, and reaches 0. For example, the measurement information creating section 332 calculates an average value for cycles included in the detection signal SK as the cycle NTC of the detection signal SK. Instead of the average value for cycles included in the detection signal SK, however, the measurement information creating section 332 may calculate a representative value such as the maximum value or median value as the cycle NTC of the detection signal SK.
The control section 80 executes filling state decision processing in a filling operation, which will be described later. In filling state decision processing, the discharging section D[m] is driven by the eligible-for-decision discharging section DS and a decision is made about the filling state of ink in the discharging section D[m] driven as the eligible-for-decision discharging section DS. In this filling state decision processing, the control section 80 supplies the print signal SI to the driving circuit 31 so that the discharging section D[m] is driven as the eligible-for-decision discharging section DS. The control section 80 then supplies the print signal SI to the driving circuit 31 so that the detection potential signal VX is supplied from the discharging section D[m] to be driven as the eligible-for-decision discharging section DS to the detection circuit 33. Then, the detection circuit 33 creates the detection signal SK according to the detection potential signal VX supplied from the eligible-for-decision discharging section DS through the driving circuit 31, and further creates measurement information JS that represents the cycle NTC of the detection signal SK according to the detection signal SK. The control section 80 makes a decision about the filling state of ink in the discharging section D according to the measurement information JS supplied from the detection circuit 33.
The head unit 3 has: a first line Lc1 through which the first driving signal Com-A is supplied from the driving signal creating unit 4; a second line Lc2 through which the second driving signal Com-B is supplied from the driving signal creating unit 4; and a third line Ls through which the detection potential signal VX is supplied to the detection circuit 33.
The driving circuit 31 has: M first switches Wa[1] to Wa[M], which are in one-to-one correspondence with M discharging sections D[1] to D[M]; M second switches Wb[1] to Wb[M], which are in one-to-one correspondence with M discharging sections D[1] to D[M]; M third switches Ws[1] to Ws[M], which are in one-to-one correspondence with M discharging sections D[1] to D[M]; and a coupling state specifying circuit 310 that specifies the coupling state of each switch. The coupling state specifying circuit 310 creates a first coupling state specifying signal Qa[m] that specifies whether to turn on or off the first switch Wa[m], a second coupling state specifying signal Qb[m] that specifies whether to turn on or off the second switch Wb[m], and a third coupling state specifying signal Qs[m] that specifies whether to turn on or off the third switch Ws[m], in response to at least part of the print signal SI, a latch signal LAT, a period specifying signal Tsig, and a change signal CH, which are supplied from the control section 80.
The first switch Wa[m] selectively creates or breaks an electrical coupling between the first line Lc1 and the upper electrode Zu[m] of the piezoelectric element PZ[m] disposed in the discharging section D[m], according to the first coupling state specifying signal Qa[m]. In this embodiment, the first switch Wa[m] is turned on when the first coupling state specifying signal Qa[m] is high and is turned off when the signal is low. When the first switch Wa[m] is turned on, the first driving signal Com-A supplied to the first line Lc1 is supplied to the upper electrode Zu[m] of the discharging section D[m] as the supply driving signal Vin[m].
The second switch Wb[m] selectively creates or breaks an electrical coupling between the second line Lc2 and the upper electrode Zu[m] of the piezoelectric element PZ[m] disposed in the discharging section D[m], according to the second coupling state specifying signal Qb[m]. In this embodiment, the second switch Wb[m] is turned on when the second coupling state specifying signal Qb[m] is high and is turned off when the signal is low. When the second switch Wb[m] is turned on, the second driving signal Com-B supplied to the second line Lc2 is supplied to the upper electrode Zu[m] of the discharging section D[m] as the supply driving signal Vin[m].
The third switch Ws[m] selectively creates or breaks an electrical coupling between the third line Ls and the upper electrode Zu[m] of the piezoelectric element PZ[m] disposed in the discharging section D[m], according to the third coupling state specifying signal Qs[m]. In this embodiment, the third switch Ws[m] is turned on when the third coupling state specifying signal Qs[m] is high and is turned off when the signal is low. When the third switch Ws[m] is turned on, the potential Vout[m] of the upper electrode Zu[m] of the discharging section D[m] is supplied to the detection circuit 33 through the third line Ls as the detection potential signal VX.
According to the detection potential signal VX supplied from the third line Ls, the detection circuit 33 creates the detection signal SK having a waveform matching the waveform of the detection potential signal VX.
As illustrated in
The control section 80 outputs the change signal CH having a pulse PLC in a unit period TP. The control section 80 divides the unit period TP into a control period TQ1 from the rising edge of the first pulse PLL to the rising edge of the pulse PLC and a control period TQ2 from the rising edge of the pulse PLC to the rising edge of the second pulse PLL.
The control section 80 outputs the period specifying signal Tsig having a pulse PLT1 and a pulse PLT2 in a unit period TP. The control section 80 divides the unit period TP into a control period TT1 from the rising edge of the first pulse PLL to the rising edge of the pulse PLT1, a control period TT2 from the rising edge of the pulse PLT1 to the rising edge of the pulse PLT2, and a control period TT3 from the rising edge of the pulse PLT2 to the rising edge of the second pulse PLL.
The print signal SI in this embodiment includes M individually specifying signals Sd[1] to Sd[M] in one-to-one correspondence with M discharging sections D[1] to D[M]. When the liquid discharging apparatus 100 executes print processing or a filling operation, the individually specifying signal Sd[m] specifies a mode in which the discharging section D[m] is driven in each unit period TP.
Before each unit period TP starts, the control section 80 supplies the print signal SI including individually specifying signals Sd[1] to Sd[M] to the coupling state specifying circuit 310 in synchronization with a clock signal CL, as illustrated in
In this embodiment, it will be assumed that the discharging section D[m] can form any of a large dot, a medium dot smaller than the large dot, and a small dot smaller than the medium dot in a unit period TP. In this embodiment, it will also be assumed that the individually specifying signal Sd[m] can take any one of five values 1 to 5 that specify, in the unit period TP, the discharging section D[m] as a large-dot forming discharging section DP-1, which is a not-eligible-for-decision discharging section DP that discharges ink by an amount equivalent to a large dot (when 1 is taken), a medium-dot forming discharging section DP-2, which is a not-eligible-for-decision discharging section DP that discharges ink by an amount equivalent to a medium dot (when 2 is taken), a small-dot forming discharging section DP-3, which is a not-eligible-for-decision discharging section DP that discharges ink by an amount equivalent to a small dot (when 3 is taken), a dot non-forming discharging section DP-B, which is a not-eligible-for-decision discharging section DP that does not discharge ink (when 4 is taken), and the eligible-for-decision discharging section DS (when 5 is taken).
In this embodiment, the first driving signal Com-A has a waveform PP1 present in the control period TQ1 and a waveform PP2 present in the control period TQ2, as illustrated in
In this embodiment, it will be assumed as an example that when the potential of the supply driving signal Vin[m] supplied to the discharging section D[m] is high, the volume of the pressure chamber 213 included in the discharging section D[m] is smaller than when the potential is low. Therefore, when the discharging section D[m] is driven by the supply driving signal Vin[m] having the waveform PP1 or waveform PP2, the potential of the supply driving signal Vin[m] changes from low to high, so ink in the discharging section D[m] is discharged from the nozzle N.
In this embodiment, the second driving signal Com-B has a waveform PS present in a unit period TP, as illustrated in
In this embodiment, it will be assumed as an example that the waveform PS is defined so that when the supply driving signal Vin[m] having the waveform PS is supplied to discharging section D[m], ink is not discharged from the discharging section D[m]. In this embodiment, for example, it will be assumed as an example that when the discharging section D[m] is driven by the supply driving signal Vin[m] having the waveform PS, the waveform PS is defined so that the pressure chamber 213 in the discharging section D[m] has a smaller volume when the potential of the supply driving signal Vin[m] is the potential VS1 than when the potential of the supply driving signal Vin[m] is the potential VS2.
When the individually specifying signal Sd[m] indicates a value of 2, which specifies the discharging section D[m] as the medium-dot forming discharging section DP-2 in a unit period TP, the coupling state specifying circuit 310 sets the first coupling state specifying signal Qa[m] to the high level in the control period TQ1. In this case, the first switch Wa[m] is turned on in the control period TQ1. In the unit period TP, therefore, the discharging section D[m] is driven by the supply driving signal Vin[m] having the waveform PP1 and discharges ink by an amount equivalent to a medium dot.
When the individually specifying signal Sd[m] indicates a value of 3, which specifies the discharging section D[m] as the small-dot forming discharging section DP-3 in a unit period TP, the coupling state specifying circuit 310 sets the first coupling state specifying signal Qa[m] to the high level in the control period TQ2. In this case, the first switch Wa[m] is turned on in the control period TQ2. In the unit period TP, therefore, the discharging section D[m] is driven by the supply driving signal Vin[m] having the waveform PP2 and discharges ink by an amount equivalent to a small dot.
When the individually specifying signal Sd[m] indicates a value of 4, which specifies the discharging section D[m] as the dot non-forming discharging section DP-B in a unit period TP, the coupling state specifying circuit 310 sets the first coupling state specifying signal Qa[m], second coupling state specifying signal Qb[m], and third coupling state specifying signal Qs[m] to the low level across the unit period TP. In this case, the first switch Wa[m], second switch Wb[m], and third switch Ws[m] are turned off across the unit period TP. In the unit period TP, therefore, the supply driving signal Vin[m] is not supplied to the discharging section D[m] and ink is not thereby discharged from the discharging section D[m].
When the individually specifying signal Sd[m] indicates a value of 5, which specifies the discharging section D[m] as the eligible-for-decision discharging section DS in a unit period TP, the coupling state specifying circuit 310 sets the second coupling state specifying signal Qb[m] to the high level in the control period TT1 and control period TT3 and also sets the third coupling state specifying signal Qs[m] to the high level in the control period TT2. In this case, the first switch Wa[m] is turned on in the control period TT1 and control period TT3, and the third switch Ws[m] is turned on in the control period TT2. In the control period TT1, therefore, the discharging section D[m] specified as the eligible-for-decision discharging section DS is driven by the supply driving signal Vin[m] having the waveform PS, and as a result, vibration occurs in the discharging section D[m]. The vibration remains in the control period TT2, immediately following the control period TT1, as well. In the control period TT2, the potential of the upper electrode Zu[m] disposed in the discharging section D[m] changes due to vibration remaining in the discharging section D[m]. In the control period TT2, therefore, the potential Vout[m] of the upper electrode Zu[m] is supplied to the detection circuit 33 through the third switch Ws[m] as the detection potential signal VX. The waveform of the detection potential signal VX detected from the discharging section D[m] in the control period TT2 indicates the waveform of vibration remaining in the discharging section D[m] in the control period TT2. The waveform of the detection signal SK created according to the detection potential signal VX detected from the discharging section D[m] in the control period TT2 indicates the waveform of vibration remaining in the discharging section D[m] in the control period TT2.
The detection circuit 33 measures the cycle NTC of the waveform of the detection signal SK and creates measurement information JS indicating the measured cycle NTC.
When this filling operation starts to be executed, the control section 80 first pressurizes the supply flow path 251 by using the pressurizing section 10 to start to supply ink from the liquid storage section 14 to the discharging section D in step S100.
After having started to supply ink, the control section 80 starts filling state decision processing described above in step S110. In this filling state decision processing, the control section 80 repeatedly causes the driving circuit 31 to drive the piezoelectric element PZ and the detection circuit 33 to detect the detection signal SK alternately to acquire measurement information JS from the detection circuit 33 for each unit period TP, the measurement information JS indicating the cycle of the waveform of the detection signal SK matching residual vibration in the discharging section D.
In step S120, the control section 80 decides whether the cycle of the detection signal SK has changed, according to measurement information JS obtained from the detection circuit 33. When the control section 80 decides that the cycle of the detection signal SK has not changed, the control section 80 determines that the discharging section D is not filled, in which case the control section 80 executes step S120 again and continues to execute the filling state decision processing.
In step S120, when the control section 80 decides that the cycle of the detection signal SK has changed, specifically when the control section 80 decides that the cycle of the detection signal SK has become longer that the cycle of a previous detection signal SK., the control section 80 determines that the discharging section D is filled. The control section 80 then controls the depressurizing section 11 to start to depressurize the ejection flow path 253 in step S130, after which the control section 80 terminates the filling operation. Pressure in depressurization by the depressurizing section 11 is determined according to a balance with pressure in pressurization by the pressurizing section 10. Specifically, pressure in depressurization has been set so as to be enough to prevent ink from being discharged from the nozzle N due to the difference between pressure in depressurization and pressure in pressurization. In step S120, when the cycle of the recent detection signal SK has become longer than the cycle of the previous detection signal SK or the average of the cycles of a predetermined number of detection signals SK counted up to the previous detection signal SK by a predetermined ratio or higher, it can be determined that the cycle of the detection signal SK has become longer.
In this embodiment, upon termination of the filling operation, the pressurizing section 10 and depressurizing section 11 remain driven, that is, ink is circulated. However, the pressurizing section 10 and depressurizing section 11 may be stopped to stop circulation of ink.
According to the first embodiment described so far, the filling operation, in which the liquid discharging head 32 is filled with ink, is terminated according to the detection signal SK detected by the detection circuit 33 after the piezoelectric element PZ is driven by the driving circuit 31. This enables the liquid discharging head 32 to be filled with ink without excess or deficiency. Particularly, in this embodiment, driving by the driving circuit 31 and detection by the detection circuit 33 are alternately performed, the driving waveform and detection waveform can be separated from each other. This can increase precision in detection of the detection signal SK. In addition, since the filling operation is terminated when a change occurs in a signal detected by the detection circuit 33, specifically when the cycle of residual vibration, the cycle being indicated by the detection signal SK, changes to a longer cycle, it can be precisely detected that the liquid discharging head 32 has been filled with ink.
The liquid discharging apparatus 100 in this embodiment has the supply flow path 251 that supplies ink to the pressure chamber 213, and also has the pressurizing section 10 that pressurizes the supply flow path 251. The control section 80 causes the pressurizing section 10 to perform pressurization during a filling operation. This enables the liquid discharging head 32 to be efficiently filled with ink.
The liquid discharging apparatus 100 in this embodiment has the ejection flow path 253 through which ink is ejected from the pressure chamber 213, and also has the depressurizing section 11 that depressurizes the ejection flow path 253. The control section 80 causes the depressurizing section 11 to perform depressurization during a filling operation. This can suppresses leak of ink from the liquid discharging head 32. Particularly, in this embodiment, the pressure chamber 213 is depressurized after the liquid discharging head 32 has been filled with ink, so it is possible to restrain foreign matter from being drawn from the nozzle N. Furthermore, since the pressure chamber 213 is depressurized after the liquid discharging head 32 has been filled with ink, filling of ink can be speeded up. Furthermore, upon completion of filling of ink, it is possible to efficiently restrain ink from drooping from the nozzle N.
As illustrated in
When the control section 80 does not decide that the discharging section D has been fully filled, the control section 80 repeats decision processing in step S140. When the control section 80 decides that the discharging section D has been fully filled, the control section 80 terminates the filling operation.
According to the second embodiment described so far, after the cycle of the detection signal SK has changed, depressurization in the ejection flow path 253 is started. Then, it is decided according to the detection signal SK whether the liquid discharging head 32 has been fully filled before the filling operation is terminated. Therefore, the liquid discharging head 32 can be more reliably filled with ink.
As illustrated in
According to the third embodiment described so far, after the liquid discharging head 32 has been filled with ink, not only the ejection flow path 253 is depressurized but also pressure in pressurization of the supply flow path 251 is raised concurrently. Therefore, pressure in the liquid discharging head 32 can be stabilized at an earlier time than when only depressurization in the ejection flow path 253 is performed.
In the filling operation in the fourth embodiment, after the supply flow path 251 has been pressurized in step S100, it is decided in step S102 whether a predetermined time has elapsed. The predetermined time is determined in advance so as to be shorter than a time taken to complete the filling operation for the discharging section D. When the control section 80 decides that the predetermined time has not elapsed, the control section 80 repeats decision processing in step S102 until the predetermined time elapses. When the control section 80 decides that the predetermined time has elapsed, the control section 80 lowers pressure in step S104, the pressure being applied to pressurize the supply flow path 251, below pressure applied in step S100. In steps S110 to S130c, the control section 80 then executes similar processing as in the third embodiment.
According to the fourth embodiment described so far, pressure with which the supply flow path 251 is pressurized is temporarily raised immediately after the filling operation has been started. Therefore, filling of ink into the liquid discharging head 32 can be speeded up.
In step S130c in this embodiment, pressure in pressurization by the pressurizing section 10 is raised as in the third embodiment. However, pressure in pressurization may not be raised as in the first and second embodiments.
In the filling operation in the fifth embodiment, the control section 80 decides whether there is a match between cycle 1 and cycle 2 included in detection signal SK, according to measurement information JS acquired from the detection circuit 33. In this embodiment, cycle 1 is one cycle of residual vibration at a certain time. For example, cycle 1 is a cycle in which a voltage rises from 0, reaches a peak with a positive value, drops, reaches a peak with a negative value, rises again, and reaches 0 (see P1 and P2 in
Referring again to
In view of this, in the filling operation in the fifth embodiment, when there is a match between cycle 1 and cycle 2 in step S120e, that is, the cycles of residual vibration are regular, the control section 80 decides that the discharging section D has been filled and proceeds to step S130. When there is no match between cycle 1 and cycle 2, that is, the cycles of residual vibration are not regular, the control section 80 decides that the discharging section D has not been filled, in which case the control section 80 executes step S120e again. When saying that there is a match between cycle 1 and cycle 2, they do not necessarily have to completely match each other. An approximate match is only necessary between cycle 1 and cycle 2. Here, it will be assumed that cycle 1 is A, for example. Then, when cycle 2 is included in the range indicated by A±A×1/10, it may be decided that there is a match between cycle 1 and cycle 2. Other processing is similar as in the first embodiment.
In the filling operation in the sixth embodiment, in step S120f, the control section 80 compares the waveform itself of residual vibration, the waveform being obtained according to the detection signal SK acquired from the detection circuit 33, with an ideal waveform of residual vibration, the ideal waveform being assumed to be formed during ink filling and being stored in a storage circuit in advance. The control section 80 then decides whether the obtained residual vibration waveform matches the stored ideal waveform. When saying that the residual vibration waveform matches the ideal waveform, the residual vibration waveform does not necessarily have to completely match the ideal waveform. The residual vibration waveform only needs to approximately match the ideal waveform. When, for example, parameters, such as voltage, of these waveforms match at various times within a range of 10%, it may be determined that the residual vibration waveform approximately matches the ideal waveform. When the residual vibration waveform matches the ideal waveform, the control section 80 proceeds to step S130. When the residual vibration waveform does not match the ideal waveform, the control section 80 executes step S120f again. Other processing is similar as in the first embodiment.
The liquid discharging head 32g has a silicon (Si) substrate 321 at a position at which the Si substrate 321 faces the nozzle N. The temperature sensor TS, which is formed from a thin-film resistive element made of aluminum (Al), platinum (Pt), titanium (Ti) or the like, is disposed on the −Z-direction side of the Si substrate 321, with a heat storage layer 322, formed from a thermally-oxidized film (silicon dioxide (SiO2)) or the like, intervening between the Si substrate 321 and the temperature sensor TS. In addition, a wire 324 coupled to the heater HT and driving circuit 31, a passivation layer 325 made of silicon nitride (SiN) or the like, and a cavitation-resistant film 326 made of tantalum (Ta) or the like are laminated on the −Z-direction of the Si substrate 321, with an inter-layer insulating film 323 intervening between the Si substrate 321 and these laminated elements.
When ink is to be discharged or it is checked whether ink is filled, the driving circuit 31 in this embodiment supplies a single rectangular wave to the heater HT in a unit period TP. Then, ink in the discharging section D is heated by the heater HT, generating a bubble immediately below the l cavitation-resistant film 326. When the bubble grows, ink is pushed out of the nozzle N.
Upon starting to supply ink, the control section 80 starts filling state decision processing in step S110g. In filling state decision processing in this embodiment, the control section 80 supplies a single rectangular wave to the heater HT for each unit period TP by using the driving circuit 31. The amplitude of this rectangular wave has been set so as to be enough to prevent ink from being discharged from the nozzle N. In addition, the control section 80 acquires temperature, measured by the temperature sensor TS, of the discharging section D by using the detection circuit 33.
In step S120g, the control section 80 decides whether a time at which the inclination largely changed has appeared within a predetermined period in the temperature falling process for temperature change in the discharging section D. To set the predetermined period, a time taken until the inclination in temperature change largely changes is obtained in advance in a measurement or experiment in a state in which the discharging section D is normally filled with ink.
In step S120g, when the control section 80 decides that a time at which the inclination largely changes has not appeared within the predetermined period, the control section 80 decides that the discharging section D is not filled, in which case the control section 80 executes step S120g again and continues to execute filling state decision processing.
In step S120g, when the control section 80 decides that a time at which the inclination largely changes has appeared within the predetermined period, the control section 80 determines that the discharging section D is filled. The control section 80 then controls the depressurizing section 11 to start depressurization in the ejection flow path 253 in step S130, and terminates the filling operation.
Even when the heater HT is used as a driving element that causes ink to be discharged is used as in the seventh embodiment described above, the liquid discharging head 32g can be filled with ink without excess or deficiency, as in the first embodiment.
In this embodiment, the temperature sensor TS is disposed immediately above the heater HT with the inter-layer insulating film 323 intervening between the heater HT and the temperature sensor TS. When the discharging section D is not filled with ink, therefore, heat is not transmitted from the heater HT to ink, so temperature measured by the temperature sensor TS is high. However, when the discharging section D is filled with ink, heat is transmitted to the ink, so temperature measured by the temperature sensor TS is low. In step S120g described above, therefore, whether the discharging section D has been filled with ink can also be decided by detecting that the maximum temperature measured by the temperature sensor TS has changed from high to low.
In the seventh embodiment, only processing in steps S110g and S120g illustrated in
In the seventh embodiment, the temperature sensor TS is placed in the vicinity of the heater HT. However, when a different temperature change can be detected depending on whether the pressure chamber 213 is filled with ink, the temperature sensor TS may be placed at a distance from the heater HT.
H-1. The liquid discharging apparatus 100 in the above embodiments has the depressurizing section 11 and ejection flow path 253. Instead of this, the liquid discharging apparatus 100 may have neither the depressurizing section 11 nor the ejection flow path 253. That is, the liquid discharging apparatus 100 may be such that ink is not circulated. In this case, the filling operations described in the above embodiments are terminated without the ejection flow path 253 being depressurized.
H-2. The liquid discharging apparatus 100 in the above embodiments has the pressurizing section 10. Instead of this, the liquid discharging apparatus 100 may not have the pressurizing section 10. In this case, the liquid discharging apparatus 100 may supply ink from the liquid storage section 14 to the liquid discharging head 32 by using the difference in hydraulic head between the liquid discharging head 32 and the liquid storage section 14.
H-3. In the liquid discharging apparatus 100 in the above embodiments, ink ejected from the ejection flow path 253 is collected into the liquid storage section 14 to circulate the ink. Instead of this, the liquid discharging apparatus 100 may be such that ink ejected from the ejection flow path 253 is not collected.
H-4. In the filling operations described in the above embodiments, after the liquid discharging head 32 has been filled with ink, the ejection flow path 253 is depressurized. Instead of this, immediately after the start of the filling operation, the control section 80 may start to depressurize the ejection flow path 253 concurrently with pressurizing the supply flow path 251. However, pressure in depressurization is set so as to be enough to supply ink to the discharging section D.
H-5. In the above first to fourth embodiments, a single piezoelectric element PZ doubles as the element that applies vibration to the pressure chamber 213 and the element that detects residual vibration. Instead of this, the element that applies vibration to the pressure chamber 213 and the element that detects residual vibration may be different elements placed at different positions.
The present disclosure is not limited to the above embodiments. The present disclosure can be implemented with various other structures, without departing from the intended scope of the present disclosure. For example, technical features, in the above embodiments, corresponding to technical features in the aspects described below can be appropriately replaced or combined to solve part or all of the problems described above or achieve part or all of the effects described above. When these technical features are not described in this specification as being essential, the technical features can be appropriately deleted.
1. According to a first aspect of the present disclosure, a liquid discharging apparatus is provided. This liquid discharging apparatus has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; a detection circuit that detects a signal related to residual vibration in the pressure chamber; and a control section that controls a filling operation to supply liquid from the outside into the liquid discharging head. The control section terminates the filling operation according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
According to this aspect, the filling operation is terminated according to a signal detected by the detection circuit after the driving element is driven by the driving circuit. Therefore, the liquid discharging head can be filled with liquid without excess or deficiency
2. According to a second aspect of the present disclosure, a liquid discharging apparatus is provided. This liquid discharging apparatus has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; a detection circuit that detects a signal related to temperature in the pressure chamber; and a control section that controls a filling operation to supply liquid from the outside into the liquid discharging head. The control section terminates the filling operation according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
According to this aspect, the filling operation is terminated according to a signal detected by the detection circuit after the driving element is driven by the driving circuit. Therefore, the liquid discharging head can be filled with liquid without excess or deficiency
3. In the above aspects, the liquid discharging apparatus may further have: a supply flow path through which liquid is supplied to the pressure chamber; and a pressurizing section that pressurizes the supply flow path. The control section may cause the pressurizing section to perform pressurization in the filling operation. In this aspect, the pressurizing section can be used to efficiently fill liquid.
4. In the above aspects, the liquid discharging apparatus may further have: an ejection flow path through which liquid is ejected from the pressure chamber; and a depressurizing section that depressurizes the ejection flow path. The control section may cause the depressurizing section to perform depressurization in the filling operation. In this aspect, it is possible to fill the liquid discharging head with liquid while the pressure chamber is being depressurized.
5. In the above aspects, the control section may cause the pressurizing section to start pressurization, and after the start of the pressurization, may terminate the filling operation according to a signal detected by the detection circuit after the driving element is driven by the driving circuit. In this aspect, liquid can be efficiently filled.
6. In the above aspects, the control section: may cause the pressurizing section to start pressurization; after the start of the pressurization, may cause the depressurizing section to start depressurization according to a signal detected by the detection circuit after the driving element is driven by the driving circuit; and after the start of the depressurization, may terminate the filling operation. In this aspect, the depressurizing section can be used to restrain liquid from leaking from the liquid discharging head.
7. In the above aspects, the control section: may cause the pressurizing section to start pressurization; after the start of the pressurization, may cause the depressurizing section to start depressurization according to a signal detected by the detection circuit after the driving element is driven by the driving circuit; and after the start of the depressurization, may terminate the filling operation according to a signal detected by the detection circuit after the driving element is driven by the driving circuit. In this aspect, since the filling operation is terminated according to a signal detected by the detection circuit after depressurization, liquid can be more reliably filled.
8. In the above aspects, the control section: may cause the pressurizing section to start pressurization; after the start of the pressurization, may cause the depressurizing section to start depressurization and raise pressure in the pressurization by the pressurizing section, according to a signal detected by the detection circuit after the driving element is driven by the driving circuit; and after a rise in pressure in the pressurization, may terminate the filling operation. In this aspect, after the start of depressurization, pressure in the pressure chamber can be stabilized at an early time.
9. In the above aspects, the control section: may cause the pressurizing section to start pressurization; after the start of the pressurization, may reduce pressure in the pressurization by the pressurizing section; after a reduction in pressure in the pressurization, may cause the depressurizing section to start depressurization and may cause by the pressurizing section to raise pressure in the pressurization, according to a signal detected by the detection circuit after the driving element is driven by the driving circuit; and after a rise in pressure in the pressurization, may terminate the filling operation. In this aspect, since pressure in pressurization can be raised immediately after the start of filling, the filling of liquid can be speeded up.
10. In the above aspects, the control section may alternately cause the driving of the driving element by the driving circuit and the detection of the signal by the detection circuit. In this aspect, precision in the detection of the signal can be raised.
11. In the above aspects, when a change occurs in the signal detected by the detection circuit, the control section may terminate the filling operation. In this aspect, it can be precisely detected that the liquid discharging head has been filled with liquid.
12. In the above aspects, after the driving element is driven by the driving circuit, when the cycle of residual vibration, the cycle being indicated by the signal detected by the detection circuit, changes to a cycle longer than the cycle of residual vibration so far, the control section may terminate the filling operation. In this aspect, it can be precisely detected that the liquid discharging head has been filled with liquid.
13. In the above aspects, after the driving element is driven by the driving circuit, when a match occurs between the cycle of residual vibration at a time, the cycle being indicated by the signal detected by the detection circuit, and the cycle of residual vibration at another time, the control section may terminate the filling operation.
14. In the above aspects, after the driving element is driven by the driving circuit, when a match occurs between the waveform of residual vibration, the waveform being indicated by the signal detected by the detection circuit, and a prestored ideal residual vibration waveform taken while the filling operation is terminated, the control section may terminate the filling operation.
15. According to a third aspect of the present disclosure, a liquid filling method is provided, the method being executed by a liquid discharging apparatus that has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; and a detection circuit that detects a signal related to residual vibration in the pressure chamber. In this liquid filling method, after a filling operation to supply liquid from the outside into the liquid discharging head is started, the filling operation is terminated according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
16. According to a fourth aspect of the present disclosure, a liquid filling method is provided, the method being executed by a liquid discharging apparatus that has: a liquid discharging head that has a driving element and a pressure chamber in which liquid is pressurized when the driving element is driven; a driving circuit that drives the driving element; and a detection circuit that detects a signal related to temperature in the pressure chamber. In this liquid filling method, after a filling operation to supply liquid from the outside into the liquid discharging head is started, the filling operation is terminated according to a signal detected by the detection circuit after the driving element is driven by the driving circuit.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-107503 | Jun 2020 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 10703098 | Okazawa | Jul 2020 | B2 |
| 10843479 | Takahashi | Nov 2020 | B2 |
| 10913267 | Kaneko | Feb 2021 | B2 |
| 11230115 | Shinoda | Jan 2022 | B2 |
| 20190009563 | Tokisawa et al. | Jan 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 2019-014253 | Jan 2019 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20210394522 A1 | Dec 2021 | US |
