JP2007210234A - Device and method for determining proper driving voltage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for determining a proper driving voltage, which enables a driving voltage of a driving pulse for a liquid jet head to be set with a high degree of accuracy, and a method for determining the proper driving voltage. <P>SOLUTION: The quantity of ink remaining in an ink pack 30 when a specified quantity of ink droplet is ejected during driving at such a proper driving voltage that the specified quantity of ink droplet is ejected is set as a reference remaining quantity for a reference head with the predetermined proper driving voltage; a deviation of the remaining quantity of the ink, detected by a weight sensor 31 for the pack, from the reference remaining quantity is determined; a correction value is computed by multiplying the deviation by a coefficient which indicates the tendency of the fluctuation of the driving voltage with respect to a change in the remaining quantity of the ink; and the proper driving voltage is determined by adding the correction value to the driving voltage which is temporarily determined according to an ejection quantity measured by a weight sensor 29 for the ink, so as to correct the driving voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an appropriate drive voltage determining device and an appropriate drive voltage determining method for setting an appropriate voltage of a drive pulse for driving a liquid jet head such as an ink jet recording head.

  A liquid ejecting head is capable of ejecting liquid in the form of liquid droplets. A typical example is a recording head that is used in an image recording apparatus such as an ink jet printer and ejects liquid ink. In addition to this, a color material ejecting head for discharging liquid color materials of R (Red), G (Green), and B (Blue), which is used in a display manufacturing apparatus for manufacturing a color filter such as a liquid crystal display, an organic EL (Electro Luminescence) Used for electrode forming devices for forming electrodes such as displays and FEDs (surface emitting displays), and manufactures electrode material ejection heads that eject liquid electrode materials and biochips (biochemical elements) There are organic substance ejecting heads that are used in biochip manufacturing apparatuses and eject liquid bioorganic substances.

  One type of liquid ejecting head includes a configuration in which a pressure chamber communicates with a nozzle opening, and ink droplets are ejected from the nozzle opening by utilizing pressure fluctuation generated in the liquid in the pressure chamber. In this liquid ejecting head, pressure generating means such as a piezoelectric vibrator is provided corresponding to each pressure chamber, and a pressure pulse is generated in the liquid in the pressure chamber by supplying a driving pulse to the pressure generating means. Ink droplets can be ejected by controlling the pressure fluctuation. The drive pulse is set in various shapes depending on the type of pressure generating means used, but the drive voltage (which means a potential difference from the lowest potential to the maximum potential; hereinafter the same) is used regardless of the shape. It is important to define with high accuracy. This is because the amount of droplets to be ejected changes depending on the magnitude of the driving voltage. Further, since the optimum value of the driving voltage differs for each liquid ejecting head, the same value cannot be set uniformly. This is because the optimum value of the drive voltage varies due to the dimensional accuracy of the parts, the positional accuracy at the time of mounting, and the like. Therefore, it is necessary to determine the optimum value of the drive voltage for each ejection head.

  In order to determine the drive voltage, for example, at least two types of measurement drive pulses having different drive voltages are separately supplied to the pressure generating unit, and the amount of droplets corresponding to each measurement drive pulse is acquired. Then, the driving voltage is set on one axis and the amount of droplets is set on the other axis, and the measurement result is plotted to create a calibration curve. From this calibration curve, the driving voltage corresponding to the designed droplet volume is calculated. Obtain (for example, refer to Patent Document 1).

JP 2003-011369 A (FIG. 5)

  By the way, in the above-described liquid ejecting head, there is a liquid jet head configured to introduce liquid stored in a liquid storage member such as a liquid storage pack into a pressure chamber using a water head difference. Specifically, the relative positional relationship between the nozzle formation surface of the liquid ejecting head and the liquid storage member in the gravitational direction is determined so that the ink surface (meniscus) exposed to the nozzle opening is positioned slightly closer to the pressure chamber than the nozzle formation surface. In this state, ink is supplied to the pressure chamber and droplets are ejected from the nozzle openings using the pressure change caused by the driving of the pressure generating means.

  However, when the liquid level in the liquid storage member is lower than when the liquid is consumed as the liquid is consumed, that is, when the water head value with respect to the nozzle formation surface increases in the negative direction, the liquid ejecting head is moved. The liquid supply amount is insufficient, and the amount of liquid droplets ejected from the liquid ejecting head varies accordingly. When setting the drive voltage, the voltage is determined based on the amount of droplets that are actually ejected. Therefore, if the amount of ejected droplets fluctuates due to a change in the head value, the appropriate drive voltage is There is a risk that it will not be obtained.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an appropriate drive voltage determination device capable of setting the drive voltage of a liquid ejection head drive pulse with high accuracy, and an appropriate drive. It is to provide a voltage determination method.

In order to achieve the above object, an appropriate drive voltage determination device of the present invention includes a liquid storage member that stores liquid to be supplied to a pressure chamber of a liquid ejecting head,
A head drive that causes a pressure fluctuation to occur in the pressure chamber by applying a measurement drive pulse to the pressure generating means of the liquid ejecting head to drive the pressure generating means, and discharges the liquid in the pressure chamber as droplets from the nozzle opening. Means,
A discharge amount measuring means for measuring a discharge amount of droplets discharged from the liquid ejecting head;
Drive voltage determining means for determining the drive voltage of the liquid ejection head drive pulse based on the discharge amount measured by the discharge amount measuring means;
An appropriate drive voltage determination device comprising:
A liquid remaining amount detecting means for detecting a liquid remaining amount of the liquid storage member is provided;
The drive voltage determining means includes
The liquid storage member of the liquid storage member when the specified amount of liquid droplets are discharged when the appropriate driving voltage for discharging the specified amount of liquid droplets is driven with the appropriate driving voltage with respect to a predetermined reference head. Using the remaining amount of liquid as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
The proper drive voltage is determined by adding the correction value to the drive voltage that is provisionally determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage.

Further, the appropriate drive voltage determination device of the present invention includes a liquid storage member that stores liquid to be supplied to the pressure chamber of the liquid jet head,
A head drive that causes a pressure fluctuation to occur in the pressure chamber by applying a measurement drive pulse to the pressure generating means of the liquid jet head to drive the pressure generating means, and discharges the liquid in the pressure chamber as droplets from the nozzle opening. Means,
A discharge amount measuring means for measuring the amount of liquid droplets discharged from the liquid ejecting head;
Drive voltage determining means for determining the drive voltage of the liquid ejection head drive pulse based on the discharge amount measured by the discharge amount measuring means;
An appropriate drive voltage determination device comprising:
A liquid remaining amount detecting means for detecting a liquid remaining amount of the liquid storage member is provided;
The drive voltage determining means includes
The amount of the effective liquid obtained by subtracting the invalid remaining amount that cannot be finally used from the remaining amount of liquid when the liquid storage member is full is set as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
The proper drive voltage is determined by adding the correction value to the drive voltage that is provisionally determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage.

  According to each of the above configurations, a correction value is obtained by obtaining a deviation of the remaining liquid amount detected by the remaining liquid amount detecting unit from the reference remaining amount, and multiplying the deviation by a coefficient indicating a variation tendency of the driving voltage with respect to the change in the remaining liquid amount. And the appropriate drive voltage is determined by adding the correction value to the drive voltage tentatively determined based on the discharge amount measured by the discharge amount measuring means and correcting it, so that the liquid in the liquid storage member It is possible to suppress the drive voltage from deviating from an appropriate value in accordance with the remaining amount, whereby the drive voltage of the drive pulse can be set with high accuracy.

  In the above-described configuration, it is desirable that the liquid remaining amount detecting means is a weight sensor and detects the liquid weight excluding the weight of the liquid storage member main body as the liquid remaining amount.

  According to this configuration, since the liquid remaining amount is detected using the weight sensor, for example, based on the calculated liquid consumption obtained by multiplying the number of droplet discharges by the design value (designed liquid amount). Compared with the case of obtaining the remaining liquid amount, it is possible to detect the remaining liquid amount with less error. Thereby, the accuracy of the appropriate drive voltage can be further increased.

In the method for determining an appropriate driving voltage according to the present invention, the liquid stored in the liquid storage member is supplied to the pressure chamber of the liquid ejecting head, and a measurement driving pulse is applied to the pressure generating means of the liquid ejecting head to apply the pressure. By driving the generating means, pressure fluctuation is caused in the pressure chamber, the liquid in the pressure chamber is discharged as a droplet from the nozzle opening, the amount of the discharged droplet is measured, and based on the measured discharge amount, An appropriate drive voltage determination method for determining a drive voltage of a liquid ejection head drive pulse,
A liquid remaining amount of the liquid storage member is detected by a liquid remaining amount detecting means;
The liquid storage member of the liquid storage member when the specified amount of liquid droplets are discharged when the appropriate driving voltage for discharging the specified amount of liquid droplets is driven with the appropriate driving voltage with respect to a predetermined reference head. Using the remaining amount of liquid as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
The proper drive voltage is determined by adding the correction value to the drive voltage that is provisionally determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage.

According to the method for determining an appropriate driving voltage of the present invention, the liquid stored in the liquid storage member is supplied to the pressure chamber of the liquid ejecting head, and a measurement driving pulse is applied to the pressure generating means of the liquid ejecting head to thereby apply the pressure generating means. Is caused to cause a pressure fluctuation in the pressure chamber, the liquid in the pressure chamber is discharged as a droplet from the nozzle opening, the amount of the discharged droplet is measured, and the liquid ejection is performed based on the measured discharge amount. An appropriate drive voltage determining method for determining a drive voltage of a head drive pulse,
A liquid remaining amount of the liquid storage member is detected by a liquid remaining amount detecting means;
The amount of the effective liquid obtained by subtracting the invalid remaining amount that cannot be finally used from the remaining amount of liquid when the liquid storage member is full is set as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
The proper drive voltage is determined by adding the correction value to the drive voltage that is provisionally determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage.

  According to the above configuration, the deviation of the liquid remaining amount detected by the liquid remaining amount detecting means is obtained with respect to the reference remaining amount, and the correction value is obtained by multiplying the deviation by the coefficient indicating the drive voltage fluctuation tendency with respect to the change in the remaining liquid amount. The appropriate drive voltage is determined by adding the correction value to the drive voltage that has been calculated and tentatively determined based on the discharge amount measured by the discharge amount measuring means, and correcting it. It is possible to suppress the drive voltage from deviating from an appropriate value according to the amount, whereby the drive voltage of the drive pulse can be set with high accuracy.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following description, an ink jet recording head (a type of liquid ejecting head of the present invention, hereinafter referred to as a recording head) used in an image recording apparatus such as an ink jet printer will be exemplified.

  First, the configuration of the recording head 1 will be described with reference to FIG. The illustrated recording head 1 includes a vibrator unit 5 in which a plurality of piezoelectric vibrators 2, a fixing plate 3, a flexible cable 4, and the like are unitized, a case 6 that can store the vibrator units 5, And a flow path unit 7 joined to the bottom surface.

  The case 6 is a synthetic resin block-like member in which the storage space 8 is formed. The storage space 8 is a space for storing the vibrator unit 5, and the vibrator unit 5 is stored and fixed in the storage space 8 by bonding the fixing plate 3 to the wall surface of the storage space 8. Yes. In this storage state, the tip surface of the piezoelectric vibrator 2 faces the opening on the tip side of the storage space 8 and is joined to the island portion 9 of the flow path unit 7 as described later. In addition, the case 6 is provided with an ink supply path 11 that communicates from the upper surface side to the reservoir 10 of the flow path unit 7 so as to penetrate the height direction of the case 6. The ink supply path 11 communicates with the ink supply needle 12 (see FIG. 2) in a liquid-tight state on the upper surface side.

  The piezoelectric vibrator 2 is a kind of pressure generating means according to the present invention, and in the present embodiment, the piezoelectric vibrator 2 is formed in a comb-teeth shape cut into an extremely narrow width of about several tens of μm to 100 μm. Each piezoelectric vibrator 2 is attached in a cantilever state in which a free end portion is projected outward from the edge of the fixed plate 3. The piezoelectric vibrator 2 is a laminated piezoelectric vibrator configured by alternately laminating piezoelectric bodies and internal electrodes, and can expand and contract in the vertical direction perpendicular to the electric field direction. This is a type of piezoelectric vibrator that can vibrate in the direction. Therefore, the piezoelectric vibrator 2 has its free end contracted in the longitudinal direction of the vibrator by charging, and the free end contracted in the longitudinal direction of the element by discharge. The flexible cable 4 is electrically connected to each piezoelectric vibrator 2 at the base end of the vibrator.

  In the flow path unit 7, a nozzle plate (nozzle forming substrate) 15 is disposed on one surface of the flow path forming substrate 16, and the vibration plate 17 is disposed on the other surface opposite to the nozzle plate 15 for bonding or the like. It is comprised by integrating by. The nozzle plate 15 is a thin plate made of stainless steel in which a plurality of nozzle openings 18 are opened in a row at a pitch corresponding to the dot formation density. In the present embodiment, 180 nozzle openings 18 are opened at a pitch of 180 dpi, and a nozzle row is configured by these nozzle openings 18. The flow path forming substrate 16 is a plate-like member formed in plural in a state in which empty portions that become pressure chambers 19 are partitioned by partition walls so as to correspond to the respective nozzle openings 18 of the nozzle plate 15. In addition, the flow path forming substrate 16 in the present embodiment is formed with an empty portion that becomes the pressure chamber 19 and an empty portion that becomes the ink supply port 20 and the reservoir 10. The flow path forming substrate 16 is produced, for example, by etching a silicon wafer or plastic processing a metal plate such as nickel. The pressure chamber 19 is configured as a long and narrow chamber in a direction orthogonal to the direction in which the nozzle openings 18 are arranged (nozzle row direction). Then, a nozzle communication port 21 is provided at one end in the longitudinal direction of the pressure chamber 19 far from the reservoir 10 so as to penetrate the plate thickness direction, and the pressure chamber 19 and the nozzle opening 18 are communicated with each other. Further, the ink supply port 20 is a groove-like portion formed between the other longitudinal end of the pressure chamber 19 and the reservoir 10, and the flow path width is provided sufficiently narrower than the pressure chamber 19.

  The diaphragm 17 has a double structure in which an elastic film 23 made of a resin film such as PPS (polyphenylene sulfide) is laminated on a support plate 22 such as stainless steel, and seals one opening surface of the pressure chamber 19. The diaphragm part and the compliance part which seals one opening surface of the reservoir | reserver 10 are provided. And the diaphragm part is produced by carrying out the etching process of the support plate 22 of the part corresponding to the pressure chamber 19, and the island part 9 is formed in the ring. The compliance portion is manufactured by removing only the elastic film 23 by removing the support plate 22 corresponding to the reservoir 10 by etching.

  In the recording head 1 configured as described above, the island portion 9 is pressed toward the nozzle plate 15 by extending the piezoelectric vibrator 2 in the longitudinal direction of the vibrator. By this pressing, the elastic film 23 constituting the diaphragm portion is deformed and the pressure chamber 19 is contracted. When the piezoelectric vibrator 2 is contracted in the longitudinal direction of the vibrator, the pressure chamber 19 is expanded by the elasticity of the elastic film 23. Since the internal ink pressure fluctuates due to the expansion and contraction of the pressure chamber 19, by controlling the expansion and contraction, an ink droplet (a kind of droplet of the present invention) can be ejected from the nozzle opening 18. . The amount of ink droplets can be changed depending on the type of drive pulse supplied to the piezoelectric vibrator 2.

  By the way, since the recording head 1 has a very fine structure in units of μm, some variation occurs regardless of how accurately each component such as the vibrator unit 5 and the flow path unit 7 is attached. For this reason, even if drive signals (drive pulses) having the same shape are supplied to the piezoelectric vibrator 2, some variation occurs in the amount of ink droplets ejected from the nozzle openings 18. In order to prevent such a variation in the ejection amount, a drive voltage is individually set for each drive pulse. This drive voltage is set by actually ejecting ink droplets. For example, a temporary drive voltage is set, and ink droplets are ejected a specified number of times (tens of thousands to hundreds of thousands) using this temporary drive voltage. The value of the drive voltage that is actually used is determined from the difference between the total amount of ejected ink droplets (ejection amount) and the target ejection amount (specified amount).

  However, even if such a method is adopted, the amount of ink droplets may deviate from the design value when the recording head is mounted on a printer and actually used. For example, during the drive voltage setting process, the water head value of the ink pack liquid level relative to the nozzle formation surface of the recording head changes according to the remaining amount of the ink pack (a type of liquid storage member) that stores the measurement ink. As a result, the ink supply pressure to the pressure chamber fluctuates, thereby increasing or decreasing the amount of ink droplets ejected from the recording head. Conventionally, the drive voltage of the drive pulse is set based only on the measured discharge amount without considering such a difference in discharge amount according to the remaining amount of the ink pack. In such a printer, even when ink droplets are ejected from the recording head using the drive pulse, the amount of ejected ink droplets may vary from the design value. Therefore, in the present embodiment, attention is paid to this point, and when the drive voltage is set, the drive voltage is corrected according to the remaining amount of the ink pack. Hereinafter, the appropriate drive voltage determination process for determining the drive voltage will be described.

First, an appropriate drive voltage determination device used in the appropriate drive voltage determination step will be described with reference to FIG.
As illustrated in FIG. 2, the appropriate drive voltage determination device 27 in the present embodiment is generally configured by a control device 28, an ink weight sensor 29, an ink pack 30, and a pack weight sensor 31. The control device 28 includes an interface unit (I / F) 33 that inputs and outputs signals from the recording head 1, the ink weight sensor 29, and the pack weight sensor 31, and a drive signal that can generate a drive signal. A main control unit 37 that includes a circuit 34, a nonvolatile memory element 35 (for example, a flash memory) that stores various data for determining an appropriate voltage of the drive signal, and a ROM, RAM, CPU, and the like and controls each unit. And have.

  The drive signal generation circuit 34 generates, for example, a measurement drive pulse having a waveform shape defined by signal data under the control of the main control unit 37, and supplies this to the recording head 1 through the I / F unit 33. To do. That is, the drive signal generation circuit 34 and the main control unit 37 function as a kind of head drive means in the present invention. The measurement drive pulse includes two types of measurement drive pulses (first measurement drive pulse DP1, second measurement drive pulse DP2) having different drive voltages for each dot size of the recording mode set by the printer. Each is prepared, and the drive voltage is individually set using the corresponding measurement drive pulses DP1 and DP2. The measurement drive pulses DP1 and DP2 are obtained by expanding and contracting the reference drive pulse DP in the voltage axis direction based on the shape of the reference drive pulse DP. The reference drive pulse DP is designed when the recording head selected as the reference for all the recording heads of the same type (hereinafter referred to as the reference head) is driven under certain environmental conditions (conditions such as temperature and humidity). This is a drive pulse in which the waveform shape and the drive voltage are determined so that the value of the ink droplet is ejected.

  FIG. 3 shows an example of drive pulses used in the present embodiment, where (a) is a reference drive pulse DP, (b) is a first measurement drive pulse, and (c) is a second measurement drive. Each pulse is shown. The reference drive pulse DP includes an expansion element P1 that raises the potential with a constant gradient that does not cause ink droplets to be ejected from the intermediate potential Vm to the first maximum potential Vh, an expansion hold element P2 that holds the maximum potential Vh for a predetermined time, A discharge element P3 that drops the potential steeply from the potential Vh to the lowest potential VL, a vibration suppression hold element P4 that holds the lowest potential VL for a predetermined time, and a vibration control element P5 that raises the potential from the lowest potential VL to the intermediate potential Vm. It consists of and. The first measurement drive pulse DP1 is set to a drive voltage Vh1 smaller than the drive voltage Vh of the reference drive pulse DP based on the waveform shape of the reference drive pulse DP. Further, the second measurement drive pulse DP2 is set to a drive voltage Vh2 larger than the drive voltage Vh of the reference drive pulse DP. In this way, by changing the drive voltage, the designed ejection amount of the ejected ink droplets changes.

  The ink weight sensor 29 is electrically connected to the main control unit 37 via the I / F unit 33, acquires the weight of ink ejected from the recording head 1, and uses the main control unit as ejection amount information. 37. As the ink weight sensor 29, for example, a sensor that can accurately measure the weight in milligram units is used. A control signal from the main control unit 37 is input to the ink weight sensor 29, and the measured weight when the start signal indicating the start of measurement is received and the measured weight when the end signal indicating the end of measurement is received. Each is output to the main control unit 37. In the present embodiment, a petri dish (a tray) 29 ′ for collecting ink droplets ejected from the recording head 1 is placed on the ink weight sensor 29, and the petri dish 29 ′ has a collecting oil. Is stored. That is, the recording head 1 ejects ink droplets toward the collecting oil in the petri dish 29 '. When the ink droplets land on the collecting oil, the ink enters the oil due to the difference in specific gravity, and evaporation is prevented. The ink weight sensor 29 and the main control unit 37 function as a kind of discharge amount measuring means for measuring the amount (discharge amount) of ink droplets discharged from the recording head 1.

  Similar to the ink weight sensor 29, the pack weight sensor 31 is electrically connected to the control device 28, obtains the weight of the ink pack 30 placed on the top plate 31 ', and stores the remaining ink information. To the main control unit 37. The pack weight sensor 31 is adjusted so that the detected value when the weight of the empty ink pack 30 in which ink is not stored is measured becomes zero. Therefore, the pack weight sensor 31 is an ink weight (corresponding to the liquid weight) excluding the weight of the ink pack main body (in the case of having an absorber such as a sponge that absorbs ink, this absorber is also included as the ink pack main body). Is detected as ink remaining amount information (corresponding to the remaining amount of liquid) and output to the main control unit 37. That is, in the present embodiment, the pack weight sensor 31 functions as the liquid remaining amount detecting means in the present invention.

  The ink pack 30 is a flexible bag-like member, and is a kind of liquid storage member that stores liquid ink used for measurement. The ink pack 30 has a larger capacity than a general ink storage member actually used in a printer so that it can be continuously used without being replaced each time in a driving voltage determination process for a plurality of recording heads. A lot of ink is stored. As the ink (liquid) to be stored, for example, the same ink as that actually used for recording, or a liquid dedicated to measurement having the same viscosity and surface tension as this ink is used. The ink pack 30 is provided with an ink tube 40 for delivering ink. The tip of the ink tube 40 opposite to the ink pack 30 is connected to the ink supply needle 12 of the recording head 1. As a result, the ink pack 30 and the recording head 1 communicate with each other via the ink tube 40, and the ink can be supplied.

  Further, when the ink pack 30 is set on the pack weight sensor 31, the meniscus exposed to the nozzle opening 18 of the recording head 1 is positioned slightly on the pressure chamber side with respect to the nozzle forming surface. The relative positional relationship in the gravity direction with respect to the nozzle forming surface is adjusted. The liquid storage member is not limited to the ink pack 30 as long as ink can be stored. For example, it may be a cartridge-type storage member molded from synthetic resin or the like.

  The main control unit 37 functions as a control unit, and controls operations of the drive signal generation circuit 34, the ink weight sensor 29, the pack weight sensor 31, and the like. The main control unit 37 also functions as a drive voltage determination unit, and is used for the recording head 1 based on the ink weight information from the ink weight sensor 29 and the ink remaining amount information from the pack weight sensor 31. The appropriate voltage of the drive pulse for the determination is determined.

  Next, the appropriate drive voltage determination step will be described based on the flowchart of FIG. Prior to this step, the operator sets the recording head 1 to be set with the drive voltage in the appropriate drive voltage determination device 27. Specifically, the recording head 1 is fixed with a jig, the recording head 1 and the control device 28 are electrically connected by a wiring member, and the tip portion of the ink tube 40 is attached to the ink supply needle 12 of the recording head 1. . When the recording head 1 is set in the apparatus, the worker operates a work start button (not shown) provided in the control device 28 to start the operation of the control device 28, for example. By the operation of the work start button, first, an ink filling process is performed in step S1. In this ink filling process, the flow path in the recording head 1 set in the apparatus is filled with ink. That is, the main control unit 37 controls a capping mechanism (not shown), and makes the inside of the cap have a negative pressure with the nozzle surface sealed by the capping mechanism. As a result, the air in the recording head 1 is sucked out from the nozzle openings 18, the ink in the ink pack 30 flows into the recording head 1 through the ink tube 40, and the flow path in the recording head 1 is filled with ink. If the ink is sucked for a predetermined time, the nozzle surface is wiped with a wiper member or the like to make it clean.

  In the ink filling step, for example, dozens of g to several tens of g of ink are consumed, so that the remaining amount of ink in the ink pack 30 varies compared to the previous step. Therefore, when this ink filling process is completed, the main control unit 37 acquires the ink remaining amount Rx of the ink pack 30 from the pack weight sensor 31 in the ink remaining amount acquiring process of step S2. This remaining ink amount Rx is information on the weight of only the stored ink excluding the weight of the ink pack body as described above.

  When the ink remaining amount acquisition process is completed, the process proceeds to the ejection amount measurement process in step S3. In this ejection amount measurement step, the ink droplet ejection amount is measured using two types of measurement drive pulses having different drive voltages, that is, the first measurement drive pulse DP1 and the second measurement drive pulse DP2. . In this ejection amount measurement step, the main control unit 37 (control unit) transmits a start signal to the ink weight sensor 29 immediately before ejection of the ink droplets. Upon receiving this start signal, the ink weight sensor 29 transmits the weight information (the weight of the petri dish or oil) at the time of signal reception to the main control unit 37 as the start time weight information.

  Subsequently, the main control unit 37 controls the drive signal generation circuit 34 and the electric drive system (not shown) of the recording head 1, and repeatedly supplies the first measurement drive pulse DP1 to the piezoelectric vibrator 2 a predetermined number of times. As a result, ink droplets are ejected from the nozzle openings 18 toward the collecting oil in the petri dish 29 'by the number corresponding to the number of times of supply of the first measurement drive pulse DP1. When the first measurement drive pulse DP1 is supplied a predetermined number of times, the main control unit 37 transmits an end signal to the ink weight sensor 29. Upon receiving this end signal, the ink weight sensor 29 transmits weight information at the time of signal reception to the main control unit 37 as end-time weight information. The main control unit 37 calculates the ink droplet ejection amount from the difference between the end-time weight information and the start-time weight information and sets it as the first ejection amount. If the discharge amount by the first measurement drive pulse DP1 is measured, the main control unit 37 measures the discharge amount for the second measurement drive pulse DP2 in the same procedure and sets this as the second discharge amount. This discharge amount measurement process is terminated.

  When the discharge amount measurement process is completed, the process proceeds to step S4, and a drive voltage calculation process is performed. In this drive voltage calculation step, the main control unit 37 (calculation means) calculates the drive voltage from the correlation between the drive voltage of the measurement drive pulse and the ejection amount corresponding to the drive voltage. For example, as shown in FIG. 5, the main control unit 37 determines from the drive voltage Vh1 and the first discharge amount of the first measurement drive pulse DP1 and the drive voltage Vh2 and the second discharge amount of the second measurement drive pulse DP2. A linear expression (calibration curve) with the weight of the ink droplet as a variable is derived, and the drive voltage VhX that becomes the target ink amount is tentatively determined by calculation from the linear expression.

  In the appropriate drive voltage determination device 27 according to the present invention, the drive voltage VhX determined in the drive voltage calculation step is not directly adopted as an appropriate voltage, and an error occurs in the drive voltage according to the ink remaining amount of the ink pack 30 as described above. In consideration of the occurrence of this, a drive voltage correction step is performed in step S5.

  Here, FIG. 6 is a graph showing the relationship between the remaining amount of ink in the ink pack 30 and the drive voltage determined in the drive voltage calculation step. As shown in the figure, as the remaining amount of ink increases, the ink supply pressure to the recording head 1 increases, so the amount of ink droplets ejected from the recording head 1 increases, and as a result, in the drive voltage calculation step. The determined drive voltage is lowered. On the other hand, since the ink supply pressure to the recording head 1 becomes smaller as the remaining amount of ink decreases, the amount of ink droplets ejected from the recording head 1 decreases, and as a result, the driving voltage determined in the driving voltage calculation step Becomes higher.

  For this reason, in the present embodiment, the drive voltage calculation process is performed in advance with the ink packs 30 having different ink remaining amounts X1 and X2, and the drive voltages Y1 and Y2 determined respectively are acquired to obtain the remaining ink amount X1. , X2 and the drive voltages Y1, Y2, the slope of the linear expression shown in the graph of FIG. 6, that is, (Y2-Y1) / (X2-X1) is calculated. This inclination is stored in the non-volatile storage element 35 as a coefficient Cf indicating the fluctuation tendency of the drive voltage with respect to the change in the remaining amount of ink. In addition, when the above-mentioned reference head having an appropriate driving voltage determined so that the ink droplet of the design value is ejected is set in the appropriate driving voltage determining device 27, the reference head is driven with the driving pulse of the appropriate driving voltage. The remaining ink amount of the ink pack 30 when the ejection amount matches the specified amount is acquired as the reference remaining amount Ra, and this reference remaining amount Ra is stored in the nonvolatile storage element 35. That is, the reference remaining amount Ra is an optimal ink remaining amount when setting the drive voltage.

  In the drive voltage correction process of step S5, the main control unit 37 reads the reference remaining amount Ra stored in the nonvolatile storage element 35, and the ink remaining amount Rx acquired in the ink remaining amount acquiring step from the reference remaining amount Ra. Is subtracted to obtain a deviation D of the ink remaining amount Rx from the reference remaining amount Ra (D = Ra-Rx). Subsequently, the deviation D is multiplied by the coefficient Cf to calculate a correction value Cv (Cv = D × Cf). Then, an appropriate drive voltage VhX ′ is finally determined (VhX ′ = VhX + Cv) by adding the correction value Cv to the drive voltage VhX tentatively determined in the ejection amount measurement step and the drive voltage calculation step to correct the drive voltage VhX ′. ).

  Then, when the setting of the appropriate drive voltage for the drive pulse corresponding to each dot size in all print modes is completed for the print head 1, the proper drive voltage determination step is finished.

As described above, in the present embodiment, the drive voltage VhX determined in the drive voltage calculation step is corrected according to the ink remaining amount in the ink pack 30. Thereby, the precision of a suitable drive voltage can be raised. That is, it is possible to suppress the drive voltage from deviating from an appropriate value in accordance with the remaining amount of ink in the ink pack 30, thereby making it possible to set the drive voltage of the drive pulse with high accuracy. As a result, when the recording head 1 is mounted on a printer and ink droplets are actually ejected, the amount of ink droplets can be prevented from varying from the design value.
In this embodiment, since the remaining ink amount is detected using the pack weight sensor 31, for example, the remaining ink amount is calculated based on the calculated consumption obtained by multiplying the number of ink droplet ejections by the design value. As compared with the case of obtaining the ink, it is possible to detect the remaining amount of ink with less error. Thereby, the accuracy of the appropriate drive voltage can be further increased.

  By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims.

  For example, in the above embodiment, the ink droplet ejection amount is measured using two types of measurement drive pulses with different drive voltages, but three or more types of measurement drive pulses with different drive voltages may be used.

  Further, in the above-described embodiment, the example in which the total weight of the ejected ink droplets is measured by the ink weight sensor as the ejection amount has been described. However, if the ejection amount of the ink droplets is known, the weight may not be used. . For example, the volume of the ejected ink droplet may be measured.

  In the above embodiment, the ink pack 30 is set when the reference head is set in the appropriate drive voltage determination device 27 and the ejection amount when the reference head is driven with the drive pulse set to the appropriate drive voltage matches the specified amount. Although an example in which the remaining ink amount is used as the reference remaining amount Ra is shown, the present invention is not limited to this. For example, the effective liquid amount 1 obtained by subtracting the invalid remaining amount that cannot be finally used (the remaining amount in a state where ink cannot be supplied to the recording head 1) from the ink remaining amount when the ink pack 30 is full. The amount of / 2 can also be used as the reference remaining amount Ra. This half of the effective liquid amount roughly matches the remaining amount of ink in the ink pack 30 when the discharge amount when the reference head is driven with the drive pulse set to the appropriate drive voltage matches the specified amount. I know that.

  Furthermore, regarding the pressure generating means, the piezoelectric vibrator 2 is exemplified in the above embodiment, but the present invention is not limited to this. The pressure generating means may be any element that can cause a pressure fluctuation in the liquid in the pressure chamber 19, and may be, for example, a heating element that bumps the ink in the pressure chamber 19.

  In the above description, the recording head 1 is described as an example of the liquid ejecting head. However, the present invention can also be applied to the case where the voltage of the driving signal of another liquid ejecting head is set. For example, a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an electrode material ejecting head used for forming an electrode such as an organic EL (Electro Luminescence) display, an FED (surface emitting display), a biochip (biochemical element) The present invention is also suitable for bioorganic matter ejecting heads and the like used in the production of

FIG. 3 is a cross-sectional view illustrating the structure of a recording head. It is a block diagram explaining the structure of the appropriate drive voltage determination apparatus. (A) is a reference drive pulse, (b) is a first measurement drive pulse, and (c) is a second measurement drive pulse. It is a flowchart explaining an appropriate drive voltage determination process. It is a figure explaining the correlation of the drive voltage of a measurement drive pulse, and discharge amount. FIG. 6 is a diagram for explaining a relationship between an ink remaining amount of an ink pack and a driving voltage determined in a driving voltage calculating step.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Recording head, 2 ... Piezoelectric vibrator, 18 ... Nozzle opening, 19 ... Pressure chamber, 27 ... Appropriate drive voltage determination device, 28 ... Control device, 29 ... Ink weight sensor, 30 ... Ink pack, 31 ... For pack Weight sensor, 34... Drive signal generation circuit, 35... Nonvolatile memory element, 37.

Claims (5)

A liquid storage member storing liquid to be supplied to the pressure chamber of the liquid ejecting head;
A head drive that causes a pressure fluctuation to occur in the pressure chamber by applying a measurement drive pulse to the pressure generating means of the liquid ejecting head to drive the pressure generating means, and discharges the liquid in the pressure chamber as droplets from the nozzle opening. Means,
A discharge amount measuring means for measuring a discharge amount of droplets discharged from the liquid ejecting head;
Drive voltage determining means for determining the drive voltage of the liquid ejection head drive pulse based on the discharge amount measured by the discharge amount measuring means;
An appropriate drive voltage determination device comprising:
A liquid remaining amount detecting means for detecting a liquid remaining amount of the liquid storage member is provided;
The drive voltage determining means includes
The liquid storage member of the liquid storage member when the specified amount of liquid droplets is discharged when the appropriate driving voltage for discharging the specified amount of liquid droplets is driven with the appropriate driving voltage with respect to a predetermined reference head. Using the remaining amount of liquid as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
An appropriate drive voltage determining apparatus, wherein an appropriate drive voltage is determined by adding the correction value to a drive voltage provisionally determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage. A liquid storage member storing liquid to be supplied to the pressure chamber of the liquid ejecting head;
A head drive that causes a pressure fluctuation to occur in the pressure chamber by applying a measurement drive pulse to the pressure generating means of the liquid ejecting head to drive the pressure generating means, and discharges the liquid in the pressure chamber as droplets from the nozzle opening. Means,
A discharge amount measuring means for measuring the amount of liquid droplets discharged from the liquid ejecting head;
Drive voltage determining means for determining the drive voltage of the liquid ejection head drive pulse based on the discharge amount measured by the discharge amount measuring means;
An appropriate drive voltage determination device comprising:
A liquid remaining amount detecting means for detecting a liquid remaining amount of the liquid storage member is provided;
The drive voltage determining means includes
The amount of the effective liquid obtained by subtracting the invalid remaining amount that cannot be finally used from the remaining amount of liquid when the liquid storage member is full is set as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
An appropriate drive voltage determination apparatus, wherein an appropriate drive voltage is determined by adding the correction value to a drive voltage provisionally determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage.   3. The appropriate drive voltage determination according to claim 1, wherein the remaining liquid amount detection unit is a weight sensor, and detects the liquid weight excluding the weight of the liquid storage member main body as the remaining liquid amount. apparatus. The liquid stored in the liquid storage member is supplied to the pressure chamber of the liquid ejecting head, and the pressure generating means is applied to the pressure generating means of the liquid ejecting head to drive the pressure generating means, thereby changing the pressure in the pressure chamber. The liquid in the pressure chamber is discharged as a droplet from the nozzle opening, the amount of the discharged droplet is measured, and the drive voltage of the liquid ejection head drive pulse is determined based on the measured discharge amount An appropriate driving voltage determination method,
A liquid remaining amount of the liquid storage member is detected by a liquid remaining amount detecting means;
The liquid storage member of the liquid storage member when the specified amount of liquid droplets are discharged when the appropriate driving voltage for discharging the specified amount of liquid droplets is driven with the appropriate driving voltage with respect to a predetermined reference head. Using the remaining amount of liquid as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
An appropriate drive voltage determination method, wherein an appropriate drive voltage is determined by adding the correction value to a drive voltage tentatively determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage. . The liquid stored in the liquid storage member is supplied to the pressure chamber of the liquid ejecting head, and the pressure generating means is applied to the pressure generating means of the liquid ejecting head to drive the pressure generating means, thereby changing the pressure in the pressure chamber. The liquid in the pressure chamber is discharged as a droplet from the nozzle opening, the amount of the discharged droplet is measured, and the drive voltage of the liquid ejection head drive pulse is determined based on the measured discharge amount An appropriate driving voltage determination method,
A liquid remaining amount of the liquid storage member is detected by a liquid remaining amount detecting means;
The amount of the effective liquid obtained by subtracting the invalid remaining amount that cannot be finally used from the remaining amount of liquid when the liquid storage member is full is set as the reference remaining amount,
Obtaining a deviation of the remaining amount of liquid detected by the remaining liquid amount detecting means from a reference remaining amount;
The correction value is calculated by multiplying the deviation by a coefficient indicating the fluctuation tendency of the driving voltage with respect to the change in the remaining amount of liquid,
An appropriate drive voltage determination method, wherein an appropriate drive voltage is determined by adding the correction value to a drive voltage tentatively determined based on the discharge amount measured by the discharge amount measuring means and correcting the drive voltage. .

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