JP2012020428A - Liquid ejection apparatus and liquid ejection method - Google Patents

Abstract

A liquid ejecting apparatus and a liquid ejecting method capable of satisfactorily preventing cavitation from occurring.
A liquid ejecting apparatus includes a liquid ejecting head that ejects a liquid supplied from a liquid storage means based on application of a drive signal based on drive signal information, and the liquid ejecting apparatus. Based on the time information, the air pressure measuring means 5 for measuring the atmospheric pressure of the place, the air pressure difference calculating means 6 for calculating the air pressure difference between the historical air pressure and the operating air pressure, the time measuring means 53 for generating time information, Measurement interval calculation means 6 for calculating a measurement interval that is a time interval at the time of measurement of the pressure and the atmospheric pressure during use, pressure difference correlation information indicating the relationship between the drive signal information associated with the gas saturation amount and the pressure difference And a control means 6 for selecting drive signal information based on the pressure difference and the measurement interval and controlling the drive of the liquid jet head 14.
[Selection] Figure 6

Description

  The present invention relates to a liquid ejecting apparatus and a liquid ejecting method.

  Patent Document 1 discloses a technical content in which an IC chip included in an ink cartridge stores information related to the time of manufacture and information related to ink sedimentation, and the degree of flushing is changed based on the information. Has been. Further, in Patent Document 2, as the elapsed time from the manufacture of the ink cartridge becomes longer, the amount of ink sucked in the recovery operation (cleaning operation) is increased, or the number of ink ejections is increased. Such technical contents are disclosed.

JP 2007-168452 A JP 2007-79694 A

  By the way, in the flow path through which the ink inside the print head circulates, a phenomenon called so-called cavitation, in which bubbles grow in the print head, occurs due to a decrease in pressure. This cavitation occurs due to the flow rate of ink, the atmospheric pressure, and the dissolved gas, for example, the saturation amount of ink with respect to the ink, but when such cavitation occurs, the ink cannot be ejected across a large number of nozzles. This happens.

  Such cavitation is difficult to prevent even if the configurations of Patent Document 1 and Patent Document 2 are adopted.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide a liquid ejecting apparatus and a liquid ejecting method capable of satisfactorily preventing the occurrence of cavitation. .

  In order to solve the above problems, a liquid ejecting apparatus according to the present invention includes a liquid ejecting head that ejects liquid supplied from a liquid storage unit based on application of a drive signal based on drive signal information, and a liquid ejecting apparatus. Pressure measurement means for measuring the atmospheric pressure of the place where it is used, the historical atmospheric pressure which is the atmospheric pressure measured before the current use of the liquid ejecting apparatus, and the in-use atmospheric pressure which is the atmospheric pressure measured in the current use of the liquid ejecting apparatus A pressure difference calculating means for calculating a pressure difference with the time, a time measuring means for measuring time by generating time information, a time when the historical pressure is measured based on the time information generated by the time measuring means, and Measurement interval calculation means for calculating a measurement interval that is a time interval from when the atmospheric pressure during use is measured, and drive signal information associated with the amount of gas saturation in the liquid that varies according to the pressure difference , Based on the information storage unit storing the pressure difference correlation information indicating the relationship with the pressure difference, the pressure difference and the measurement interval, the drive signal information is selected, and the liquid jet head is driven based on the drive signal information. And control means for controlling.

  When the liquid ejecting apparatus is configured in this way, the control unit can select drive signal information that exhibits an appropriate drive waveform corresponding to the gas saturation amount based on the pressure difference and the measurement interval. Based on the drive signal information, it becomes possible to control the drive of the liquid jet head. Accordingly, it is possible to select drive signal information corresponding to the amount of gas saturation with respect to the liquid, and it is possible to prevent generation of bubbles in the liquid ejecting head. By preventing the generation of air bubbles, it is possible to prevent the occurrence of cavitation.

  In addition, according to another aspect of the present invention, in the above-described invention, the drive signal information in the atmospheric pressure difference correlation information includes first drive signal information and second drive signal information. The liquid ejection amount based on the second drive signal information in the cycle is provided smaller than the liquid ejection amount based on the first drive signal information, and the liquid ejection head based on the second drive signal information by the control unit In the state where the generation of bubbles in the liquid is suppressed as compared with the case where the liquid jet head is controlled based on the first drive signal information. The maximum atmospheric pressure difference, which is the largest atmospheric pressure difference among the atmospheric pressure differences calculated for the historical atmospheric pressure measured within the predetermined time interval or shorter than the predetermined time interval, is the first atmospheric pressure difference threshold value. Or exceed Alternatively, when it is determined that the pressure difference is equal to or greater than the first atmospheric pressure difference threshold value, the second drive signal information is selected instead of the first drive signal information, and the liquid jet head is based on the second drive signal information. It is preferable to control the driving of.

  When the liquid ejecting apparatus is configured as described above, the control unit selects the second drive signal information instead of the first drive signal information to control the driving of the liquid ejecting head. Under the situation where the difference exceeds the first atmospheric pressure difference threshold value, it is possible to reduce bubbles generated from the liquid existing inside the liquid ejecting head, and to effectively prevent the occurrence of cavitation. Further, the maximum atmospheric pressure difference is calculated for the history atmospheric pressure measured at a measurement interval shorter than or within a predetermined time interval. Therefore, the number of historical atmospheric pressures to be calculated can be reduced, and the processing for calculating the maximum atmospheric pressure difference can be speeded up.

  In addition, according to another aspect of the present invention, in the above-described invention, the drive signal information in the atmospheric pressure difference correlation information includes first drive signal information and second drive signal information. The liquid ejection amount based on the second drive signal information in the cycle is provided smaller than the liquid ejection amount based on the first drive signal information, and the liquid ejection head based on the second drive signal information by the control unit In the state where the generation of bubbles in the liquid is suppressed as compared with the case where the liquid jet head is controlled based on the first drive signal information. It has an inclination value calculation means for calculating an inclination value of a change in atmospheric pressure based on the measurement interval, and the control means corresponds to an inclination value determined that the inclination value exceeds a predetermined threshold value or is equal to or higher than a predetermined threshold value. In the pressure difference When it is determined that the maximum atmospheric pressure difference, which is the largest atmospheric pressure difference, exceeds the first atmospheric pressure difference threshold value or is equal to or larger than the first atmospheric pressure difference threshold value, the second driving signal information is used instead of the second driving signal information. It is preferable that the drive signal information is selected and the drive of the liquid jet head is controlled based on the second drive signal information.

  When the liquid ejecting apparatus is configured as described above, the control unit selects the second drive signal information instead of the first drive signal information to control the driving of the liquid ejecting head. Under the situation where the difference exceeds the first atmospheric pressure difference threshold value, it is possible to reduce bubbles generated from the liquid existing inside the liquid ejecting head, and to effectively prevent the occurrence of cavitation. The maximum atmospheric pressure difference is determined for an atmospheric pressure difference that is an inclination value at which the inclination value is determined to be greater than or equal to a predetermined threshold value. Therefore, the number of pressure differences to be calculated can be reduced, and the processing for calculating the maximum pressure difference can be accelerated.

  Further, according to another aspect of the present invention, in the above-described invention, the driving signal information in the atmospheric pressure difference correlation information is provided with third driving signal information, and a specific period based on the third driving signal information. The number of unit drive waveforms is less than the number of unit drive waveforms in a specific period based on the second drive signal information, and the control means has a maximum atmospheric pressure difference equal to the first atmospheric pressure difference threshold value. Instead of the first drive signal information or the second drive signal information when it is determined that the second pressure difference threshold value is higher than the second pressure difference threshold value or greater than the second pressure difference threshold value. Preferably, driving signal information 3 is selected, and driving of the liquid jet head is controlled based on the third driving signal information.

  When the liquid ejecting apparatus is configured as described above, the amount of ejected liquid is reduced as compared with the case based on the second drive signal information. However, in a situation where the maximum atmospheric pressure difference is large, the amount of liquid is increased accordingly. Bubbles generated from the liquid present in the ejection head can be further reduced, and the occurrence of cavitation can be effectively prevented.

  Further, according to another aspect of the present invention, in the above-described invention, the driving signal information in the atmospheric pressure difference correlation information is provided with third driving signal information, and a specific period based on the third driving signal information. The number of unit drive waveforms is set to be smaller than the number of unit drive waveforms in a specific period based on the second drive signal information, and the control means has a slope value exceeding a predetermined threshold or a predetermined value. The second atmospheric pressure difference threshold value, in which the maximum atmospheric pressure difference, which is the largest atmospheric pressure difference among the atmospheric pressure differences corresponding to the slope value determined to be equal to or greater than the threshold value, is higher than the first atmospheric pressure difference threshold value. If it is determined that the value exceeds or exceeds the second atmospheric pressure difference threshold, the third drive signal information is selected instead of the first drive signal information or the second drive signal information, and the third drive Based on the signal information It is preferable to control the movement.

  When the liquid ejecting apparatus is configured as described above, the amount of ejected liquid is reduced as compared with the case based on the second drive signal information. However, in a situation where the maximum atmospheric pressure difference is large, the amount of liquid is increased accordingly. Bubbles generated from the liquid present in the ejection head can be further reduced, and the occurrence of cavitation can be effectively prevented.

  Furthermore, according to another aspect of the present invention, in each of the above-described inventions, it is preferable that the control unit reflects information relating to application of the drive signal based on input image data input from the outside in selection of the drive signal information. .

  In such a configuration, when input image data is input from the outside and information on application of the drive signal based on the input image data is generated, information on application of the drive signal is selected when selecting the drive signal information. Is reflected. For example, depending on the input image data, it may be assumed that the liquid ejecting head does not need to be driven so much (that is, the degree of application of the driving signal is small), and bubbles are not generated so much. On the contrary, depending on the input image data, the liquid ejecting head is almost fully driven (that is, the driving signal is almost fully applied), and it is assumed that many bubbles are generated. is there. For this reason, when selecting the drive signal information as described above, it is possible to select more appropriate drive signal information by reflecting the information related to the application of the drive signal based on the input image data.

  Further, according to another aspect of the present invention, in the above-described invention, the control unit calculates input image data and an index value indicating the ease of bubble generation based on the input image data, and the index value is predetermined. If the threshold value is less than or less than the predetermined threshold value, the control means selects the first drive signal information regardless of the measurement result of the atmospheric pressure measurement means, and the liquid ejection is performed based on the first drive signal information. It is preferable to control the driving of the head.

  In such a configuration, an index value indicating the ease of bubble generation is calculated based on the input image data, and the first driving is performed when the index value is equal to or less than a predetermined threshold value or less than a predetermined threshold value. Signal information is selected. Therefore, in the case of input image data in which bubbles are not expected to occur so much, it is not necessary to select the second drive signal information that reduces the liquid ejection amount, so that the printing speed can be ensured. That is, it is possible to appropriately maintain a balance between the prevention of the generation of bubbles and the securing of the printing speed according to the input image data.

  According to another aspect of the present invention, in each of the above-described inventions, a cap member for forming a sealed space in contact with the nozzle forming surface of the liquid ejecting head is provided, and the liquid is ejected from the liquid ejecting head to the cap member. A maintenance execution means for discharging is provided, and the control means determines that the maximum atmospheric pressure difference exceeds the first atmospheric pressure difference threshold or is equal to or higher than the first atmospheric pressure difference threshold, or the maximum atmospheric pressure difference is When it is determined that the pressure exceeds the second pressure difference threshold or is greater than or equal to the second pressure difference threshold, cleaning for operating the maintenance execution means to discharge the bubbles present inside the liquid ejecting head to the outside It is preferable to perform control to execute the operation.

  When configured in this way, the control unit can execute a cleaning operation for discharging bubbles present inside the liquid ejecting head to the outside according to the maximum pressure difference. Thereby, the occurrence of cavitation can be more effectively prevented. Further, even when the maximum atmospheric pressure difference is large, it is possible to more effectively prevent cavitation.

  According to another aspect of the present invention, in each of the above-described inventions, a liquid ejecting apparatus including a liquid ejecting head that ejects the liquid supplied from the liquid storing unit by applying a drive signal based on the drive signal information is installed. The atmospheric pressure measurement step for measuring the atmospheric pressure of the location where the pressure is present, the historical atmospheric pressure that is the atmospheric pressure measured before the current use of the liquid ejecting apparatus, and the in-use atmospheric pressure that is the atmospheric pressure that is measured in the current use of the liquid ejecting apparatus A pressure difference calculating step for calculating a pressure difference, a measurement interval calculating step for calculating a measurement interval that is a time interval between when the historical pressure is measured and when the pressure during use is measured, Based on the measurement interval, any drive signal information that is associated with the saturation amount of the gas in the liquid that fluctuates according to the atmospheric pressure difference and is the basis of the drive signal is selected, and the drive is selected. It is preferred to comprise a control step for controlling the driving of the liquid ejecting head on the basis of the signal information.

  When configured in this way, it is possible to select drive signal information that exhibits an appropriate drive waveform corresponding to the gas saturation amount based on the atmospheric pressure difference and the measurement interval, and the liquid can be selected based on the drive signal information. It becomes possible to control the drive of the ejection head. Accordingly, it is possible to select drive signal information corresponding to the amount of gas saturation with respect to the liquid, and it is possible to prevent generation of bubbles in the liquid ejecting head. By preventing the generation of air bubbles, it is possible to prevent the occurrence of cavitation.

1 is a perspective view illustrating a configuration of a printer according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic configuration of the printer of FIG. 1. It is a disassembled perspective view which shows the structure of a print head. It is a top view which shows the composition of a printing head transparently. FIG. 3 is a partial cross-sectional view illustrating a configuration of a print head. It is a block diagram which shows schematic structure centering on a control part. It is a figure which shows schematic structure of a computer. It is a figure which shows an example of a display window. It is a graph which shows the relationship between a measurement interval and an atmospheric pressure difference. It is a figure which shows the drive waveform based on 1st, 2nd drive signal information. It is a figure which shows the drive waveform based on 3rd drive signal information. It is a figure which shows the drive waveform based on the drive signal information which concerns on a modification. It is a figure which shows the drive waveform based on the drive signal information which concerns on a modification.

<First Embodiment>
Hereinafter, a printer 1 and a liquid ejecting method as a liquid ejecting apparatus according to a first embodiment of the invention will be described with reference to FIGS. 1 to 11. The printer 1 according to the present embodiment is an ink jet printer. However, the ink jet printer may be an apparatus that employs any ejection method as long as it can print by ejecting ink.

  In the following description, the lower side refers to the side where the printer 1 is installed, and the upper side refers to the side away from the installed side. Further, the opening side of the nozzle opening 38 (see FIG. 3) with respect to the pressure generating chamber 21 (see FIG. 3) is the lower side, and the opposite side is the upper side. Further, the side on which the print medium P is supplied is described as a feeding side (rear end side), and the side on which the print medium P is discharged is described as a paper discharge side (front side). In addition, a direction in which a carriage 7 described later moves is a main scanning direction, a direction orthogonal to the main scanning direction, and a direction in which the print medium P is conveyed is a sub-scanning direction.

<Schematic configuration of printer 1>
As shown in FIG. 1, the printer 1 includes a casing (not shown), a carriage mechanism 2, a paper transport mechanism 3, and a cleaning mechanism 4. In addition, as shown in FIG. The control unit 6 and the like are provided.

  Among these, the carriage mechanism 2 includes a carriage 7, a carriage motor (CR motor 8), a belt 9, a gear pulley 10, a driven pulley 11, and a carriage shaft 12. Among these, the carriage 7 can mount the ink cartridges 13 of the respective colors. Further, as shown in FIG. 2, a print head 14 (corresponding to an example of a liquid ejecting head) capable of ejecting ink droplets is provided on the lower surface of the carriage 7. Details of the configuration of the print head 14 will be described later. Ink corresponds to an example of a liquid.

  The belt 9 is an endless belt, and a part of the belt 9 is fixed to the back surface of the carriage 7. The belt 9 is stretched by a gear pulley 10 and a driven pulley 11.

  As shown in FIG. 2, the paper transport mechanism 3 includes a PF motor 15 for transporting the print medium P (corresponding to the ejection target), and a paper feed roller 16 for paper feeding such as plain paper. Yes. A pair of PF rollers (not shown) for conveying / clamping the print medium P is provided on the paper discharge side with respect to the paper supply roller 16. A platen (not shown) and the above-described print head 14 are arranged on the paper discharge side of the PF roller pair so as to face each other in the vertical direction.

<Details of Configuration of Print Head 14>
Details of the configuration of the print head 14 of the carriage mechanism 2 described above will be described with reference to FIGS. As shown in FIG. 3, the print head 14 includes an actuator unit 17 and a flow path unit 18. Among these, the actuator unit 17 includes a pressure generation chamber forming substrate 19 and a diaphragm 20. A space (long hole portion 22) for forming the pressure generation chamber 21 is formed in the pressure generation chamber forming substrate 19, and a number of long holes are formed along a direction orthogonal to the length of the long hole portion 22. The parts 22 are arranged.

  The pressure generation chamber 21 includes a long hole portion 22, a vibration plate 20 that closes the long hole portion 22 from the upper surface side, and a supply port forming plate 23 that closes the long hole portion 22 from the lower surface side. Yes.

  A lower electrode 24 is formed on the upper surface of the diaphragm 20. Each of the lower electrodes 24 is formed in a portion covering the upper portion of the pressure generating chamber 21. A plate-shaped piezoelectric vibrator 25 is formed on the upper surface of the lower electrode 24, and an upper electrode 26 is formed on the upper surface of the piezoelectric vibrator 25.

  The flow path unit 18 includes a supply port forming plate 23, a storage chamber forming substrate 27, and a nozzle plate 28. Among these, the supply port forming plate 23 is located on the upper surface of the storage chamber forming substrate 27. The supply port forming plate 23 is provided with a first ink supply port 29, a second ink supply port 30, a communication port 31, and an ink introduction port 32.

  Among these, the first ink supply port 29 is an opening for supplying ink from a first ink storage chamber 36 to be described later to the pressure generating chamber 21. Similarly, the second ink supply port 30 is an opening for supplying ink from a second ink storage chamber 37 to be described later to the pressure generating chamber 21. In the present embodiment, the first ink storage chamber 36 is provided closer to the center of the storage chamber forming substrate 27 than the second ink storage chamber 37. Therefore, the first ink supply port 29 is provided closer to the center of the supply port forming plate 23 than the second ink supply port 30. The first ink supply port 29 and the second ink supply port 30 are provided so as to be aligned along the direction in which the pressure generation chambers 21 are aligned (that is, the direction perpendicular to the longitudinal direction of the pressure generation chambers 21). Yes. However, when the pressure generating chambers 21 travel in the direction in which they are arranged, the first ink supply ports 29 and the second ink supply ports 30 are alternately arranged, whereby the first ink supply ports 29 and the second ink supply ports 30 are arranged. The ink supply ports 30 are arranged in a staggered pattern.

  A communication port 31 is provided at a position closer to the center of the supply port forming plate 23 than the first ink supply port 29. The communication port 31 communicates the pressure generation chamber 21 and a nozzle opening 38 described later via a nozzle communication port 35 described later. An ink introduction port 32 is provided on one end side of the supply port forming plate 23 in the longitudinal direction. The ink introduction ports 32 are openings for introducing ink from the ink cartridge 13 into the ink storage chambers 36 and 37. In the present embodiment, the four ink introduction ports 32 are provided on the supply port forming plate 23. Arranged in a row along the short direction.

  The storage chamber forming substrate 27 is provided with a first long groove 33, a second long groove 34, and a nozzle communication port 35. The upper surface side of the first long groove 33 and the second long groove 34 is blocked by the supply port forming plate 23, and the lower surface side of the first long groove 33 and the second long groove 34 is blocked by the nozzle plate 28. A chamber 36 and a second ink storage chamber 37 are configured. Here, the first ink storage chamber 36 communicates with the first ink supply port 29, and the second ink storage chamber 37 communicates with the second ink supply port 30. One end side of the first ink storage chamber 36 communicates with the ink introduction port 32 located on the center side of the supply port forming plate 23, and one end side of the second ink storage chamber 37 is connected to the supply port forming plate 23 communicates with the ink inlet 32 located on the end side of the head 23. The nozzle communication port 35 is an opening portion that communicates with the nozzle opening 38.

  A nozzle opening 38 is formed in the nozzle plate 28. The nozzle opening 38 communicates with the pressure generating chamber 21 through the nozzle communication port 35. For this reason, the actuator unit 17 (piezoelectric vibrator 25) bends and vibrates so that ink can be ejected from the nozzle openings 38.

  Note that the first ink storage chamber 36 and the second ink storage chamber 37 may be configured to store the same ink, or may be configured to store different types of ink.

<Barometric pressure sensor>
As shown in FIG. 6, the printer 1 according to the present embodiment includes an atmospheric pressure sensor 5. The atmospheric pressure sensor 5 corresponds to an example of atmospheric pressure measuring means, and is for measuring the atmospheric pressure of the environment where the printer 1 is installed. As the atmospheric pressure sensor 5, a semiconductor or the like that outputs a digital signal relating to atmospheric pressure is preferable. Examples of such an atmospheric pressure sensor 5 include a capacitance type and a vibration type. The capacitance type atmospheric pressure sensor 5 is a chamber in which a chamber made of silicon or the like forms a capacitor, and detects a change in the distance between the electrodes of the capacitor as a change in capacitance by the atmospheric pressure. The vibration-type atmospheric pressure sensor 5 applies vibration from a piezoelectric element such as quartz to a chamber made of metal, silicon, or the like. Then, the atmospheric pressure is measured by detecting the tension of the chamber surface that changes with the change of the atmospheric pressure as the change of the resonance frequency.

  The atmospheric pressure sensor 5 is attached to a desired location such as a circuit board, a chassis, or a housing of the printer 1. The number of pressure sensors 5 may be only one, but a plurality of pressure sensors 5 may be attached.

  As the atmospheric pressure sensor 5, other types of sensors may be used. Examples of other methods include a liquid column method, an aneroid type, and a method using a Bourdon tube.

<Ink cartridge>
The carriage 7 can mount an ink cartridge 13 (corresponding to an example of a liquid storage unit) that stores inks (corresponding to liquids) of respective colors (for example, cyan, magenta, yellow, and black). The number of colors of the ink cartridge 13 is not limited to the above four colors, and may be three colors of cyan, magenta, and yellow, or five or more colors.

  A circuit board 40 is attached to the casing 39 of the ink cartridge 13 so as to be integrated with the casing 39. The circuit board 40 is, for example, an IC chip or the like, and includes a memory 41 (storage element) that stores information about ink in a writable manner. The memory 41 stores, as information about the ink, historical pressure and measurement time data regarding the time when the historical pressure was measured. The historical atmospheric pressure is an atmospheric pressure measured by the atmospheric pressure sensor 5 when the printer 1 has been used in the past, that is, when the printer 1 has been used before the current use of the printer 1. The measurement data is data for calculating the time interval between the measurement of the atmospheric pressure during use and the measurement of the historical atmospheric pressure, which is the atmospheric pressure measured when using the printer 1 this time. This is data based on the obtained time information. The measurement time data is not stored in the memory 41 in advance, but the main control unit 43 instructs the cartridge memory control unit 42 to access the memory 41 based on the time measurement information in the timer 53. As a result, it is stored in the memory 41. In addition, the measurement time data may indicate a temporal element that can calculate the time interval (measurement interval) between when the historical atmospheric pressure is measured and when the atmospheric pressure is measured during use. Any measure may be used, and for example, the measured date and time or the measured date can be used.

  Information on ink includes information on ink characteristics. Examples of information relating to such characteristics include information relating to ink production time and information relating to the saturation amount of gas such as air that can be dissolved in the ink. Other information on the ink characteristics includes ink color type data stored in the ink cartridge 13, pigment / dye ink type data, and the amount of ink initially filled in the ink cartridge 13. Ink capacity data, remaining ink data, serial number data, expiration date data, target model data that can use the ink cartridge 13, and the like.

<About the cleaning mechanism>
A cleaning mechanism 4 as shown in FIGS. 1 and 6 is provided in the chassis. The cleaning mechanism 4 includes a cap 44, an ink discharge tube 45, a waste liquid tank 46, and a suction pump 47. The cleaning mechanism 4 corresponds to an example of a maintenance execution unit.

  Among these, the cap 44 corresponds to an example of a cap member. The cap 44 is a part that abuts against the nozzle forming surface of the print head 14 to form one or a plurality of sealing spaces. Therefore, the cap 44 can be moved up and down by a lifting mechanism (not shown).

  The ink discharge tube 45 has one end connected to the cap 44 and the other end connected to the waste tank 46. The waste liquid tank 46 is a portion that stores ink discharged from the nozzle openings 38 of the print head 14 to the cap 44. The suction pump 47 is connected to the middle part of the ink discharge tube 45. Therefore, when the suction pump 47 is activated, the ink can be discharged from the nozzle opening 38 toward the waste liquid tank 46. Further, by this ink suction operation, bubbles mixed in the flow path of the print head 14 and the like are forcibly discharged, and / or the thickened ink existing in the nozzle openings 38 is forcibly discharged. A so-called maintenance operation can be executed.

  The suction pump 47 is provided so as to be able to generate a negative pressure in the ink discharge tube 45, and when the suction pump 47 is operated, the print is ejected from the print head 14 via the ink discharge tube 45 or the like. Ink unrelated to the ink is discharged to the waste liquid tank 46. In addition, by this ink suction operation, it is possible to execute a so-called cleaning operation for forcibly discharging bubbles mixed in the print head 14 and an ink supply path (not shown).

<Configuration of control unit>
As shown in FIGS. 1 and 6, the printer 1 is provided with a control unit 6. The control unit 6 includes a CPU 48, a ROM 48, a memory 48 such as a non-volatile memory (not shown), an ASIC (Application Specific Integrated Circuit), a bus, a timer, a communication interface 49, and the like. Signals from various sensors including detection signals from the atmospheric pressure sensor 5 are input to the control unit 6 described above. The control unit 6 controls driving of the CR motor 8, the print head 14 (the vibration plate 20), the PF motor 15, the suction pump 47, and the like based on signals from these sensors. Further, the control unit 6 constitutes an atmospheric pressure difference calculation unit and a measurement interval calculation unit. That is, the control unit 6 can calculate a pressure difference from the signal from the pressure sensor 5, the history pressure stored in the memory 41, and the operating pressure that is measured when the printer 1 is used this time. it can. Further, the control unit 6 measures the time interval between the measurement of the historical atmospheric pressure and the measurement of the atmospheric pressure during use based on the time measurement information of the timer 53 and the measurement time data stored in the memory 41. The interval can be calculated. The control unit 6 corresponds to an example of a control unit.

  The data and program in the memory 48 are executed by the CPU in order to control the above-described units, and the components of the control unit 6 cooperate to functionally show the block diagram of FIG. Is realized. As shown in FIG. 6, the control unit 6 includes a communication interface 49, a main control unit 43, a memory 48, a PTS generation unit 50, a head control unit 51, a pump control unit 52, and a cartridge memory control unit. 42, a timer 53, a head drive circuit 54, and a pump drive circuit 55.

  Among these, the communication interface 49 is a circuit for performing communication with the computer 100.

  The main control unit 43 is a part that controls the entire printer 1, receives commands from the computer 100, and reads a control program and various data stored in the memory 48. Further, the main control unit 43 performs an operation as described later based on a command (print signal) from the computer 100 and detection signals input from various sensors such as the atmospheric pressure sensor 5.

  The memory 48 corresponds to an example of an information storage unit. The memory 48 corresponds to, for example, a ROM, a RAM, a nonvolatile memory, and the like, and various control programs and various data are stored in the ROM and the nonvolatile memory. Examples of programs stored in the memory 48 include a print control program 48A that controls the operation of each unit of the printer 1, an atmospheric pressure difference variation control program 48B, and atmospheric pressure difference variation drive waveform data 48C (corresponding to an example of atmospheric pressure correlation information). It is remembered.

  Here, the control program 48B for changing the atmospheric pressure difference is a program for controlling the driving of the print head 14 (the diaphragm 20) based on a later-described maximum atmospheric pressure difference and measurement interval calculated by the control unit 6. More specifically, the control program 48B for changing the atmospheric pressure difference selects an appropriate one of the data relating to the drive waveform applied to the print head 14 (the diaphragm 20) based on the maximum atmospheric pressure difference and the measurement interval. . The details of the control by the atmospheric pressure difference variation control program 48B will be described later.

  The pressure difference variation drive waveform data 48C is data relating to drive signal information when the drive of the print head 14 (the diaphragm 20) is changed by the control based on the pressure difference variation control program 48B, the first atmospheric pressure. It is data regarding a difference threshold value and a second atmospheric pressure difference threshold value. One example of data relating to such drive signal information is shown in FIG. The drive signal information as shown in FIG. 10 is two or more assuming that the degree of saturation of the gas dissolved in the ink tends to be supersaturated as the maximum pressure difference increases. Existing. Such drive signal information is stored in the memory 48 together with identification data for distinguishing from other drive signal information.

  The PTS generator 50 generates a drive timing signal (Print Timing Signal; hereinafter abbreviated as PTS) of the print head 14. The PTS generator 50 receives an encoder signal from the linear encoder 56 shown in FIG. 1 and a clock signal from a clock (not shown). Based on these signals, a timing signal PTS as shown in FIG. 11 is generated.

  Further, the head control unit 51 drives the print head 14 (the vibration plate 20) via the head drive circuit 54 based on a command from the main control unit 43 to eject ink droplets. Here, the commands received by the head control unit 51 from the main control unit 43 include a printing operation command based on print data and a flushing operation command which is a kind of maintenance operation based on the above-described maintenance table. .

  Further, the pump control unit 52 controls the suction pump 47 via the pump drive circuit 55 in a state where the print head 14 (the diaphragm 20) is sealed with the cap 44 based on a command from the main control unit 43. Control drive is performed and predetermined cleaning is executed.

  The cartridge memory control unit 42 is a part for controlling access to the memory 41 existing in the ink cartridge 13 based on a command from the main control unit 43. The cartridge memory control unit 42 accesses the memory 41 and reads each information related to ink as described above. The cartridge memory control unit 42 stores the atmospheric pressure measured by the atmospheric pressure sensor 5 in the memory 41 as the historical atmospheric pressure when the printer 1 is operated. Further, measurement time data relating to the time point at which the history atmospheric pressure is measured is stored in the memory 41. The measurement of the historical pressure and the acquisition of measurement data and the storage of the historical pressure and measurement data are performed each time the printer 1 is operated.

  Specifically, for example, when the printer 1 is turned on, the cartridge memory control unit 42 reads from the memory 41 historical pressure data, measurement time data, and other information related to ink that are already stored. Then, the cartridge memory control unit 42 stores the atmospheric pressure measured by the atmospheric pressure sensor 5 in the memory 41 as the historical atmospheric pressure at the next use of the printer 1 when the printer 1 is turned on. Further, the cartridge memory control unit 42 stores, in the memory 41, measurement time data when the atmospheric pressure is measured when the printer 1 is turned on as historical atmospheric pressure measurement data. The measurement of the historical pressure and the acquisition of the measurement time data and the storage of the historical pressure and the measurement time data in the memory 41 may be performed when the printer 1 is turned off. When the printer 1 is powered off, the historical pressure measurement, the acquisition of measurement data, and the storage of the historical pressure measurement and measurement data in the memory 41 are actually performed after the power-off button is pressed. There is something to do until the power is turned off. In addition, the atmospheric pressure measured as the atmospheric pressure during use and the measurement data regarding this measurement may be stored in the memory 41 so as to be used as the historical atmospheric pressure and measurement data during the next use of the printer 1.

  The timer 53 corresponds to an example of a time measuring unit, and outputs time information obtained by receiving a signal from a clock (not shown) to the main control unit 43 and / or the cartridge memory control unit 42. The measurement time data acquired using the timer 53 is the time from when the printer 1 is first used to the time when the historical pressure is measured, or the historical pressure is measured from when the printer 1 is manufactured. It can be the time to do. Moreover, the date obtained based on these times can be used as measurement time data, or the date can be used as measurement time data.

  Further, the head drive circuit 54 generates a predetermined voltage in response to a command from the head control unit 51, and applies the voltage to the diaphragm 20 in the print head 14. Further, the pump drive circuit 55 generates a predetermined voltage in accordance with a command from the pump control unit 52 and applies the voltage to the suction pump 47.

<Schematic configuration of computer>
As shown in FIG. 7, the printer 1 is connected to a computer 100 via a communication interface 49. The computer 100 includes a CPU 101, a ROM 102, a RAM 103, an HDD (Hard Disk Drive) 104, a video circuit 105, an interface 106, a display device 107, and the like.

  Among these, the HDD 104 reads data or a program recorded on a hard disk as a recording medium in response to a request from the CPU 101, and records data generated as a result of arithmetic processing of the CPU 101 on the hard disk described above. Device. In the present embodiment, the HDD 104 stores a video driver program 104A, a printer driver program 104B, and the like.

  Of these, the video driver program 104A is a program for driving the video circuit 105. For example, the video driver program 104A performs a predetermined adjustment on information for a predetermined window display supplied from the printer driver program 104B. Thereafter, a video signal is generated and supplied to the display device 107. Thereby, a window 120 as shown in FIG. 8 is displayed.

  The printer driver program 104B corresponds to an example of a part of input means. When the printer driver program 104B operates under a predetermined operating system (OS) and receives information indicating that the window 120 as shown in FIG. 8 is displayed from the printer 1, the information about the display window 120 is displayed on the HDD 104. Or the like, and transfer it to the video driver program 104A side.

  Note that a window 120 shown in FIG. 8 includes a display unit 121 indicating that the printing speed has been slowed due to a drive waveform change as will be described later, and a display unit 122 indicating that the replacement of the ink cartridge 13 is recommended. Is provided.

  The video circuit 105 is a circuit that executes a drawing process in accordance with a drawing command supplied from the CPU 101, converts the obtained image data into a video signal, and outputs the video signal to the display device 107. The interface 106 outputs image data to the printer 1 and signals output from the external input device 108 (keyboard, mouse, etc.) and the external storage device 109 (magnetic disk, optical disk, magneto-optical disk, flash memory, etc.). This is a circuit for appropriately converting and inputting the expression format.

<Control based on atmospheric pressure fluctuation>
Details of the control when the atmospheric pressure fluctuates in the printer 1 having the above configuration will be described below. This control is performed to prevent the occurrence of cavitation in the print head 14.

  In the control described below, when the maximum atmospheric pressure difference (described later) calculated for any one of the ink cartridges 13 exceeds the first atmospheric pressure difference threshold value or becomes equal to or larger than the first atmospheric pressure difference threshold value, The following control is performed. Similarly, when the maximum pressure difference calculated for any one of the ink cartridges 13 exceeds the second pressure difference threshold or becomes equal to or greater than the second pressure difference threshold, the following control is performed. . However, when the maximum pressure difference (described later) calculated for two or more ink cartridges 13 exceeds the first pressure difference threshold or exceeds the first pressure difference threshold, the following control is performed. Anyway. Further, when the maximum atmospheric pressure difference (described later) calculated for two or more ink cartridges 13 exceeds the second atmospheric pressure difference threshold value or exceeds the second atmospheric pressure difference threshold value, the following control is performed. Anyway.

  When the printer 1 is in a power-on state, the main control unit 43 configured by a CPU (not illustrated) reading the control program 48B for changing the pressure difference performs a control based on the control program 48B for changing the pressure difference. It has become. That is, the main control unit 43 can execute the following control.

  The main control unit 43 outputs a command to the cartridge memory control unit 42 when the printer 1 is turned on. In response to this command, the cartridge memory control unit 42 reads the history pressure and the measurement data when the history pressure is measured from the memory 41 included in the ink cartridge 13, and outputs it to the main control unit 43. The historical atmospheric pressure and the measurement time data when the historical atmospheric pressure is measured are data acquired each time the printer 1 is used in the past, and exist at least one by one. Specifically, for example, if the current use (power on) of the printer 1 is the sixth use, five historical atmospheric pressures and five measurement time data when these historical atmospheric pressures are measured are stored in the memory 41. Read from.

  Further, the main control unit 43 measures the atmospheric pressure of the place where the printer 1 is installed based on the detection signal from the atmospheric pressure sensor 5 when the printer 1 is turned on, and obtains the atmospheric pressure during use. Further, the main control unit 43 obtains measurement time data from the timer 53 when the atmospheric pressure during use is measured. Then, the main control unit 43 calculates a measurement interval that is a time interval between the measurement of the historical atmospheric pressure and the measurement of the atmospheric pressure during use for each measurement of the historical atmospheric pressure. Further, the main control unit 43 calculates the atmospheric pressure difference between the historical atmospheric pressure and the in-use atmospheric pressure for each historical atmospheric pressure.

<Measurement interval and pressure difference>
The measurement interval and the atmospheric pressure difference will be described with reference to FIG. FIG. 9 is a graph showing the relationship between the atmospheric pressure measured when the printer 1 has been used in the past and when the power is turned on and when the atmospheric pressure is measured. The vertical axis represents the measured atmospheric pressure, and the horizontal axis represents the time when the atmospheric pressure was measured. The horizontal axis indicates the time from when the printer 1 is first used to when the atmospheric pressure (historical atmospheric pressure and atmospheric pressure during use) is measured. In FIG. 9, n corresponds to the current use of the printer 1, and the atmospheric pressure corresponding to n is the in-use atmospheric pressure. On the other hand, n-1 corresponds to the previous use of the printer 1, and the atmospheric pressure corresponding to this n-1 is the history atmospheric pressure. Similarly, before n-2 corresponds to the previous use of the printer 1, and the atmospheric pressure corresponding to the n-2th, n-3th,. The measurement intervals are time intervals indicated as T (n−1), T (n−2),... In FIG. Further, the atmospheric pressure difference is shown as P (n−1), P (n−2),... In FIG. The main control unit 43 obtains the measurement interval and the atmospheric pressure difference for each past history atmospheric pressure.

  Then, the main controller 43 determines that the maximum atmospheric pressure difference, which is the largest atmospheric pressure difference among the atmospheric pressure differences for the historical atmospheric pressure whose measurement interval is shorter than the predetermined time interval, exceeds the first atmospheric pressure difference threshold value ( Or is it equal to or greater than a first atmospheric pressure difference threshold value). In addition, the main control unit 43 also determines whether or not the maximum atmospheric pressure difference exceeds the second atmospheric pressure difference threshold (or is greater than or equal to the second atmospheric pressure difference threshold). For example, if the predetermined time interval of the measurement interval is the time after the n-5th, the atmospheric pressure difference P (n-4) becomes the maximum atmospheric pressure difference. Note that the data related to the first atmospheric pressure difference threshold value and the second atmospheric pressure difference threshold value may exist in the atmospheric pressure difference variation drive waveform data 48C, or may be stored in the memory 48 as separate data. The first atmospheric pressure difference threshold value and the second atmospheric pressure difference threshold value may be stored in the memory 41 as information about ink. In this case, when the printer 1 is turned on, the cartridge memory control unit 42 reads information about the first atmospheric pressure difference threshold value and the second atmospheric pressure difference threshold value from the memory 41, and sends the information to the main control unit 43. Output.

<About the first atmospheric pressure difference threshold>
Here, the first atmospheric pressure difference threshold is set as follows. The amount of gas that can be dissolved in the ink is larger as the atmospheric pressure is higher, and conversely, it is smaller as the atmospheric pressure is lower. Therefore, when the pressure at the place where the printer 1 is installed changes from a high state to a low state, the amount of gas that can be dissolved in the ink decreases, and the degree of saturation of the gaseous ink increases. That is, when the history atmospheric pressure> the atmospheric pressure at the time of use, the degree of saturation of the gaseous ink when using the printer 1 this time is biased to a supersaturated state according to the atmospheric pressure difference. When the gas is supersaturated with respect to the ink, even if the print head 14 (vibrating plate 20) is driven for a certain short time W1, bubbles are likely to be generated in the ink (cavitation is likely to occur). It has become. Considering this point, the first atmospheric pressure difference threshold is set.

  Note that the historical atmospheric pressure> the atmospheric pressure during use is, for example, that the installation location of the printer 1 is moved from a low altitude to a high location, or that the installation location of the printer 1 is high atmospheric pressure when measuring historical atmospheric pressure. What was below may be in low-pressure weather when measuring atmospheric pressure during use. Note that when the history atmospheric pressure is less than the atmospheric pressure during use, the degree of saturation of the gas ink during use of the printer 1 this time is low, and it is biased toward the side where it is difficult to saturate. When the history atmospheric pressure = the atmospheric pressure during use, the degree of saturation of the gas ink due to the change in atmospheric pressure does not change.

<About the second atmospheric pressure difference threshold>
In addition, the second atmospheric pressure difference threshold value is a pressure difference that is larger than the first atmospheric pressure difference threshold value. When the calculated maximum pressure difference exceeds the second pressure difference threshold or is equal to or greater than the second pressure difference threshold, the degree of saturation of the gaseous ink is more supersaturated than the first pressure difference threshold. It is in a state biased to the side. Therefore, even if the print head 14 (the vibration plate 20) is driven for a time W2 shorter than the time W1, bubbles are generated from the ink. Considering such a state, the second pressure difference threshold is set.

  The first atmospheric pressure difference threshold value and the second atmospheric pressure difference threshold value are provided for each type of ink cartridge 13. However, the first atmospheric pressure difference threshold value and the second atmospheric pressure difference threshold value may be common to all the ink cartridges 13 or two or more ink cartridges 13.

<About the predetermined time interval for the measurement interval>
The predetermined time interval with respect to the measurement interval is set as follows. The degree of saturation of the gaseous ink changes with changes in atmospheric pressure. Then, after the change of the atmospheric pressure, the degree of saturation of the gaseous ink changes toward the saturated state with the passage of time. That is, when the atmospheric pressure changes in a low direction, immediately after the atmospheric pressure changes, the degree of saturation of the gaseous ink is biased to supersaturation, but after the atmospheric pressure changes, it is balanced to a saturated state over time. Therefore, as the predetermined time interval with respect to the measurement interval, the gas is applied to the ink with respect to the maximum pressure difference assumed for the printer 1 (the maximum pressure difference assumed when the history pressure> the use pressure). In contrast, it is set to the time (time interval) until saturation occurs. By setting a predetermined time interval in this way, it is sufficient to calculate the atmospheric pressure difference for the historical atmospheric pressure measured within the measurement interval where a supersaturated state is expected, and to calculate the maximum atmospheric pressure difference. Can be faster.

  As an assumed maximum atmospheric pressure difference, for example, when an atmospheric pressure is assumed, 900 hpa to 1020 hpa (that is, 1020 hpa−900 hpa = 120 hpa) can be assumed as an example. In addition, when it is assumed that the printer 1 is moved from, for example, the vicinity of the coast (altitude 0 m) to a high altitude of 4000 m, the maximum atmospheric pressure that is assumed to have an atmospheric pressure difference (about 400 hpa) corresponding to the altitude difference. It can be assumed as a difference. Further, it is possible to assume a pressure difference corresponding to the weather and the height difference of the movement of the printer 1. Even when these atmospheric pressure differences (the maximum atmospheric pressure difference assumed when the historical atmospheric pressure> the atmospheric pressure during use) occur, the time during which the gas can be in a saturated state from a supersaturated state with respect to ink Can be set as a predetermined time interval with respect to the measurement interval.

<Mode 1 of Changing Drive Signal Information>
When the main control unit 43 determines that the calculated maximum atmospheric pressure difference exceeds the first atmospheric pressure difference threshold value (or is greater than or equal to the first atmospheric pressure difference threshold value), the main control unit 43 determines that the print head 14 (drive signal information) related to the drive waveform applied to the vibration plate 20 is read from the pressure difference variation drive waveform data 48C and changed as follows (mode 1 of change of drive signal information). .

  In the state before the change, a waveform having a drive waveform corresponding to the first drive signal information as a basic waveform is applied, and after the change, the drive waveform corresponding to the first drive signal information is applied. The basic waveform is changed to one having the drive waveform corresponding to the second drive signal information as the basic waveform. Here, the first drive signal information and the second drive signal information are information related to a drive waveform serving as a base for generating a drive signal based on print data.

  Here, the data related to the drive waveform is changed so as to reduce the amount of ejected ink droplets. In other words, the unit drive waveform T is changed so as to reduce the number of ink droplets ejected. Specifically, drive waveform data (first drive signal information) applied to the print head 14 (the diaphragm 20) in a state where the first pressure difference threshold value is exceeded (or is equal to or greater than the first pressure difference threshold value). If the corresponding drive waveform data) exhibits the drive waveform indicated by the broken line in FIG. 10, the drive waveform data that exhibits the drive waveform indicated by the solid line in FIG. 10 (drive waveform data corresponding to the second drive signal information). Change to

  Here, in the drive waveform indicated by the solid line in FIG. 10, the change when the print head 14 (the vibration plate 20) bends in the direction of drawing ink changes more than the drive waveform indicated by the broken line in FIG. It is set so as not to be sudden (the change per unit time in FIG. 10 does not become large).

  Further, when the print head 14 (vibrating plate 20) returns to the original unbent state after performing the operation of discharging ink, the drive waveform indicated by the solid line in FIG. 10 is indicated by the broken line in FIG. It is set so that the change does not become abrupt as compared with the drive waveform (the change per unit time in FIG. 10 does not become large).

  In FIG. 10, the drive waveform indicated by the solid line and the drive waveform indicated by the broken line may have the same or different potential at “65%”. However, in FIG. 10, the potential difference from the lowest potential to the highest potential is 100% in the drive waveform indicated by the broken line, and the potential difference from the lowest potential to the highest potential is 80% in the drive waveform indicated by the solid line. Thus, the number of ejected ink droplets is reduced.

  As described above, the main control unit 43 determines that the calculated atmospheric pressure difference exceeds the first atmospheric pressure difference threshold value (or is greater than or equal to the first atmospheric pressure difference threshold value) but is less than or equal to the second atmospheric pressure difference threshold value. (Or the second atmospheric pressure difference threshold value is not exceeded), the data relating to the drive waveform indicated by the solid line (second drive signal information) (the second drive signal information indicated by the broken line in FIG. 10) Drive signal information).

<Mode 2 of Changing Drive Signal Information>
Further, when the main control unit 43 determines that the calculated maximum atmospheric pressure difference exceeds the second atmospheric pressure difference threshold value (or is equal to or greater than the second atmospheric pressure difference threshold value), the main control unit 43 Data relating to the drive waveform applied to the print head 14 (vibrating plate 20) is read from the drive waveform data 48C for changing the atmospheric pressure difference and changed as follows (mode 2 of change of drive signal information).

  As shown in FIG. 11, the main control unit 43 controls the print head 14 (the diaphragm 20 so that the number of unit drive waveforms T existing in one cycle (corresponding to a specific cycle) of the timing signal PTS is changed. ) To control.

  Here, in the case shown in FIG. 11A, in the drive waveform A shown based on the data (first drive signal information) regarding the drive waveform before the change, four (4) within one cycle of the timing signal PTS. There is a unit drive waveform T of the cycle. In this state, as shown in FIGS. 11B and 11C, the data related to the drive waveform so as to lengthen the wait time until the next unit drive waveform T arrives after each unit drive waveform T elapses. Change to (third drive signal information). As a result of this change, the print head 14 (the vibration plate 20) of the print head 14 (vibrating plate 20) has a drive waveform B after the change as shown in FIG. The drive is controlled. Further, as shown in FIG. 11C, the main control unit 43 sets the time length for each unit drive waveform T (that is, the period of the unit drive waveform T) as compared with that shown in FIG. By increasing the length, the number of unit drive waveforms T existing within one cycle of the timing signal PTS is controlled to be further reduced.

  When the main control unit 43 determines that the calculated maximum atmospheric pressure difference exceeds the second atmospheric pressure difference threshold (or is greater than or equal to the second atmospheric pressure difference threshold), a solid line in FIG. From the data relating to the drive waveform shown (second drive signal information), the data shown by drive waveform B (third drive signal information) in FIG. 11B or the drive waveform C shown in FIG. Change to data (third drive signal information). Note that the main control unit 43 converts the data (third drive signal) indicated by the drive waveform B in FIG. 11B from the data indicated by the drive waveform A in FIG. 11A (first drive signal information). Information) or the data (third drive signal information) indicated by the drive waveform C in FIG. 11C may be controlled.

  In the above-described (Aspect 2 of changing drive signal information), the main control unit 43 increases the wait time between the unit drive waveforms T, so that the unit drive waveforms existing in one cycle of the timing signal PTS. The number of T is reduced.

  As described above, the drive waveform is changed, and ink droplets are ejected from the print head 14 toward the print medium P. As a result, a print image is formed on the print medium P. The drive waveform may be changed not only when a print image is formed on the print medium P but also during flushing for cleaning purposes.

  Further, when the drive waveform is changed as described above, a display window 120 as shown in FIG. 8 is displayed. As a result, the display unit 121 that the printing speed is slowed down and the display unit 122 that recommends replacement of the ink cartridge 13 are displayed to the user.

<Other maximum pressure differences>
In the above example, the maximum atmospheric pressure difference is calculated for the historical atmospheric pressure when the measurement period is within a predetermined time interval. On the other hand, based on the pressure difference and the measurement interval, the inclination value of the atmospheric pressure change is calculated by the control unit 6 as the inclination value calculating means, and this inclination value exceeds or exceeds a predetermined threshold value. Of the pressure differences, the largest pressure difference may be set as the maximum pressure difference.

  The threshold value of the slope value can be set as follows. When the atmospheric pressure changes in a low direction, the degree of saturation of the gas ink tends to be oversaturated. However, when the time required for the change is long with respect to the change amount of the atmospheric pressure, that is, when the slope value is small. The atmospheric pressure changes while maintaining a saturated state. Therefore, the threshold value of the slope value is set to a slope value at which the atmospheric pressure changes while the gas is saturated with respect to the ink. By setting the threshold value of the inclination value in this way, the calculation process can be speeded up because the process of calculating the maximum atmospheric pressure difference is sufficient for the atmospheric pressure difference in which a supersaturated state is expected.

<Main effects of the present embodiment>
The printer 1 having the above-described configuration includes a print head 14 as a liquid ejecting head that ejects ink as liquid supplied from an ink cartridge 13 as liquid storage means by applying a drive signal based on drive signal information. . In addition, the printer 1 includes a barometric pressure sensor 5 serving as a barometric pressure measuring unit that measures the barometric pressure at a place where the printer 1 is installed, a historical barometric pressure that is measured before the printer 1 is used, and a printer 1 A control unit 6 as a pressure difference calculating means for calculating a pressure difference from the operating pressure, which is a pressure measured at the time of use this time, and a timer 53 as a time measuring means for generating time information by measuring time. As a measurement interval calculation means for calculating a measurement interval that is a time interval between when the historical atmospheric pressure is measured and when the atmospheric pressure during use is measured based on the timing information generated by the timer 53 And a control unit 6. Further, the printer 1 stores pressure difference variation drive waveform data 48C as drive signal information associated with the gas saturation amount with respect to ink that varies according to the pressure difference based on the pressure difference and the measurement interval. A memory 48 is provided as an information storage unit. Then, the control unit 6 selects drive signal information corresponding to the atmospheric pressure difference and the measurement interval from the atmospheric pressure difference variation driving waveform data 48 </ b> C stored in the memory 48.

  Therefore, the control unit 6 can select drive signal information that exhibits an appropriate drive waveform corresponding to the gas saturation amount based on the atmospheric pressure difference and the measurement interval, and the print head 14 can be selected based on the drive signal information. Can be controlled. Accordingly, it is possible to select drive signal information corresponding to the amount of gas saturation with respect to the ink, and it is possible to prevent the generation of bubbles in the print head 14. By preventing the generation of air bubbles, it is possible to prevent the occurrence of cavitation.

  In the present embodiment, the drive signal information includes first drive signal information and second drive signal information, and second drive signal information within one cycle of the timing signal PTS. When ink droplets are ejected from the print head 14 based on (the drive waveform indicated by the solid line in FIG. 10), the ink is output from the print head 14 based on the first drive signal information (the drive waveform indicated by the broken line in FIG. 10). The ink amount is set to be smaller than that in the case of ejecting droplets. In addition, the ink droplet ejection based on the second drive signal information is provided in a state in which the generation of bubbles in the ink in the print head 14 is suppressed compared to the ink droplet ejection based on the first drive signal information. It has been. And the control part 6 has the largest atmospheric pressure difference which is the largest atmospheric | air pressure difference among the atmospheric | air pressure differences calculated about the historical atmospheric | air pressure which a measurement interval is shorter than a predetermined time interval, or was measured within a predetermined time interval, When it is determined that the first atmospheric pressure difference threshold value is exceeded or greater than the first atmospheric pressure difference threshold value, the second driving signal information is selected instead of the first driving signal information, and the second driving is performed. Based on the signal information, the driving of the liquid jet head is controlled.

  Therefore, when the control unit 6 selects the second driving signal information instead of the first driving signal information to control the driving of the print head 14, the maximum atmospheric pressure difference exceeds the first atmospheric pressure difference threshold value. Under the circumstances, it is possible to reduce bubbles generated from the ink existing inside the print head 14 and effectively prevent cavitation. Further, the maximum atmospheric pressure difference is calculated for the history atmospheric pressure measured at a measurement interval shorter than or within a predetermined time interval. Therefore, the number of historical atmospheric pressures to be calculated can be reduced, and the processing for calculating the maximum atmospheric pressure difference can be speeded up.

  The printer 1 is provided with first drive signal information and second drive signal information as drive signal information, and second drive signal information within one cycle of the timing signal PTS (FIG. 10). When the ink droplets are ejected from the print head 14 based on the drive waveform indicated by the solid line in FIG. 10, the ink droplets are ejected from the print head 14 based on the first drive signal information (the drive waveform indicated by the broken line in FIG. 10). The amount of ink is set to be smaller than that in the case where the ink is used. In addition, the ink droplet ejection based on the second drive signal information is provided in a state in which the generation of bubbles in the ink in the print head 14 is suppressed compared to the ink droplet ejection based on the first drive signal information. It has been. In addition, the printer 1 includes an inclination value calculation unit that calculates an inclination value of a change in atmospheric pressure based on an atmospheric pressure difference and a measurement interval. Then, the control unit 6 determines that the maximum atmospheric pressure difference, which is the largest atmospheric pressure difference among the atmospheric pressure differences corresponding to the inclination value determined that the inclination value exceeds the predetermined threshold value or is greater than or equal to the predetermined threshold value, is the first. In the case where it is determined that the pressure difference threshold value exceeds or exceeds the first pressure difference threshold value, the second drive signal information is selected instead of the first drive signal information, and the second drive signal information is selected. The drive of the liquid jet head is controlled based on the above.

  Therefore, when the control unit 6 selects the second driving signal information instead of the first driving signal information to control the driving of the print head 14, the maximum atmospheric pressure difference exceeds the first atmospheric pressure difference threshold value. Under the circumstances, it is possible to reduce bubbles generated from the ink existing inside the print head 14 and effectively prevent cavitation. The maximum atmospheric pressure difference is determined for an atmospheric pressure difference that is an inclination value at which the inclination value is determined to be greater than or equal to a predetermined threshold value. Therefore, the number of pressure differences to be calculated can be reduced, and the processing for calculating the maximum pressure difference can be accelerated.

  Further, when the maximum atmospheric pressure difference exceeds the second atmospheric pressure difference threshold value or is equal to or larger than the second atmospheric pressure difference threshold value, the printer 1 causes the control unit 6 to perform the first driving signal information or the second driving signal. Instead of the information, the third drive signal information is selected. Here, within one cycle of the timing signal PTS, the number of unit drive waveforms T of the third drive signal information is set smaller than the number of unit drive waveforms T of the second drive signal information.

  For this reason, the ink ejection amount is reduced as compared with the case based on the second drive signal information. However, in a situation where the maximum atmospheric pressure difference is large, bubbles generated from the ink existing in the print head 14 correspondingly. Can be further reduced, and the occurrence of cavitation can be effectively prevented.

  Further, the liquid ejecting method according to the present embodiment is a print head 14 as a liquid ejecting head that ejects ink as liquid supplied from an ink cartridge 13 as liquid storing means by applying a drive signal based on drive signal information. The atmospheric pressure at the place where the printer 1 as a liquid ejecting apparatus is installed is measured, the atmospheric pressure measured before the printer 1 is used this time, and the atmospheric pressure measured when the printer 1 is used this time. The atmospheric pressure difference from the atmospheric pressure during use is calculated, and the measurement interval that is the time interval between when the historical atmospheric pressure is measured and when the atmospheric pressure is measured is calculated. Then, based on the atmospheric pressure difference and the measurement interval, select one of the driving signal information that is associated with the gas saturation amount in the liquid that varies according to the atmospheric pressure difference and becomes the basis of the driving signal, and The drive of the print head 14 is controlled based on the drive signal information.

  Therefore, drive signal information that exhibits an appropriate drive waveform corresponding to the gas saturation amount can be selected based on the pressure difference and the measurement interval, and the drive of the print head 14 is controlled based on the drive signal information. It becomes possible. Accordingly, it is possible to select drive signal information corresponding to the amount of gas saturation with respect to the ink, and it is possible to prevent the generation of bubbles in the print head 14.

  As described above, the printer 1 and the liquid ejecting method according to the present embodiment can effectively prevent the occurrence of cavitation due to the variation in the atmospheric pressure difference. Therefore, it is possible to stabilize the printing quality. In other words, when cavitation occurs, ink cannot be ejected over a large number of nozzles (so-called dosage loss occurs, in which ink cannot be ejected from a large number of nozzles and printing is lost). However, by preventing the occurrence of cavitation as described above, the ejection of ink droplets becomes stable and the quality of printing can be stabilized.

  Further, by effectively preventing the occurrence of cavitation, it is possible to prevent the inside of the print head 14 from being damaged due to cavitation and to improve the maintainability of the print head 14.

  Furthermore, by effectively preventing the occurrence of cavitation, it is possible to prevent unnecessary cleaning from being performed multiple times. That is, when cavitation occurs, cleaning must be performed by operating the suction pump 47 or the like to remove bubbles inside the print head 14. In this case, the ink is unnecessarily discharged during cleaning. However, by effectively preventing the occurrence of cavitation, it is possible to prevent ink from being wasted. Even when air bubbles are generated in a specific color ink, the ink is discharged by the operation of the suction pump 47 in all color inks including other color inks. Is in a state of being wasted. However, by effectively preventing cavitation as described above, it is possible to satisfactorily prevent ink from being discharged wastefully.

<Modification>
In the above-described embodiment, only the one corresponding to the first atmospheric pressure difference threshold exists as shown in FIG. 10 to change the drive waveform so as to reduce the amount of ejected ink droplets. ing. However, as shown in FIG. 12, the present invention relates to a drive waveform that corresponds to the second atmospheric pressure difference threshold and that makes the amount of ejected ink droplets smaller than the drive waveform corresponding to the first atmospheric pressure difference threshold. Third drive signal information may be provided. Then, the third drive signal information in which the amount of ink droplets is further reduced may be used instead of the information in the above-described (Mode 2 of changing drive signal information).

  Even in this case, it is possible to execute printing that effectively suppresses the occurrence of cavitation based on the maximum pressure difference.

  Further, in the above-described embodiment, what is described in (Mode 2 of changing drive signal information) is described as corresponding to the third drive signal information. However, the drive signal information that exhibits the drive waveform described in (Modification 2 of the drive signal information) may be used as the second drive signal information. In this case, the number of unit drive waveforms T existing in one cycle (corresponding to a specific cycle) of the timing signal PTS is larger in the second drive signal information than in the third drive signal information. To do. Even with this configuration, the amount of ink ejected can be reduced, and cavitation can be effectively prevented even when the atmospheric pressure drops.

  In the above-described embodiment, drive signal information as shown in FIGS. 10 and 11 is selected. On the other hand, drive signal information indicated by a drive waveform as shown in FIG. 13 may be selected based on the maximum atmospheric pressure difference. Here, the drive waveform shown in FIG. 13A corresponds to the first drive signal information, and the specific period is T1. The drive waveform shown in FIG. 13B corresponds to the second drive signal information, and the specific period is T2 larger than T1. The drive waveform shown in FIG. 13C corresponds to the third drive signal information, and the specific period is T3 larger than T2. As described above, the specific period is set to be greater than the specific period corresponding to the first drive signal information, and the specific period corresponding to the second drive signal information is further set to correspond to the third drive signal information. The occurrence of cavitation is also effectively prevented by setting the specific period to be larger than the specific period corresponding to the first drive signal information and the specific period corresponding to the second drive signal information. Is possible.

  In the above-described embodiment, the first drive signal information, the second drive signal information, and the third drive signal information exist in the atmospheric pressure difference variation drive waveform data 48C. However, the drive waveform corresponding to the second drive signal information and / or the third drive signal information may be calculated by calculation.

  Furthermore, in the above-described embodiment, when the information related to the application of the drive signal based on the input image data input from the outside such as the computer 100 is generated, the control unit 6 performs the input when selecting the drive signal information. Information regarding application of the drive signal based on the image data may be reflected. Specifically, for example, depending on the input image data, it may be assumed that the print head 14 does not need to be driven so much (that is, the degree of application of the drive signal is small) and bubbles are not generated so much. On the contrary, depending on the input image data, the print head 14 is almost in a state of being fully driven (that is, a state in which the drive signal is almost fully applied) and it is assumed that many bubbles are generated. is there.

  For this reason, when selecting the drive signal information as described above, it is possible to select more appropriate drive signal information by reflecting the information related to the application of the drive signal based on the input image data. Further, it is possible to more effectively prevent the generation of bubbles in the print head 14 and to maintain a balance with the printing speed.

  Furthermore, the control unit 6 may calculate the input image data and an index value indicating the ease with which bubbles are generated based on the input image data. When the index value is equal to or less than the predetermined threshold value or less than the predetermined threshold value, the control unit 6 selects the first drive signal information regardless of the maximum atmospheric pressure difference, and the first drive signal The drive of the print head 14 may be controlled based on the information.

  In this case, in the case of input image data in which it is assumed that bubbles are not generated so much, it is not necessary to select the second drive signal information that reduces the ink ejection amount. Therefore, it is possible to ensure the printing speed. That is, it is possible to appropriately maintain a balance between the prevention of the generation of bubbles and the securing of the printing speed according to the input image data.

  In the above example, after the input image data is converted into data represented by CMYK, an average of CMYK gradation values is calculated in a certain area of the input image data, and the average value is a predetermined threshold value. There is something to judge whether or not. Further, at the stage of RGB input image data, an average of gradation values may be calculated, and it may be determined whether or not the average value exceeds a predetermined threshold value.

  In the above-described embodiment, the control unit 6 determines that the maximum atmospheric pressure difference exceeds the first atmospheric pressure difference threshold or is equal to or greater than the first atmospheric pressure difference threshold, or the maximum atmospheric pressure difference exceeds the first atmospheric pressure difference. When it is determined that the pressure difference threshold value of 2 is exceeded or equal to or greater than the second pressure difference threshold value, the cleaning mechanism 4 is operated to perform a cleaning operation for discharging bubbles present inside the print head 14 to the outside. You may make it perform control to perform.

  In this case, it is possible to execute a cleaning operation for discharging the bubbles existing inside the print head 14 to the outside according to the maximum pressure difference. Thereby, the occurrence of cavitation can be more effectively prevented. Further, even when the ambient atmospheric pressure is low, the occurrence of cavitation can be more effectively prevented.

  For this cleaning, a display part for asking whether or not to perform cleaning is provided in the display window 120 as shown in FIG. 8, and a button part corresponding to execution of cleaning is provided in the display part. Cleaning may be executed by clicking. The cleaning may be any type of cleaning including flushing, pump suction, and the like.

  In the above-described embodiment, the historical pressure and the measurement time data when the historical pressure is measured are measured when the printer 1 is turned on and when the printer 1 is turned off. explained. However, for example, by using a power source such as a backup power source, regardless of whether the printer 1 is turned on or off, for example, every hour or every 6 hours, the historical pressure is periodically measured and the measurement time data May be obtained. With this configuration, it is possible to acquire the maximum pressure difference that accurately corresponds to the change in atmospheric pressure at the place where the printer 1 is installed, and effectively suppress the occurrence of cavitation.

  In the above-described embodiment, the operation of the print head 14 is controlled based on the maximum atmospheric pressure difference. However, a temperature sensor for measuring the ambient temperature of the printer 1 or the temperature of the ink inside the print head 14 is separately provided, and the measurement result of this temperature sensor is driven as described in the above embodiment. You may make it consider in selection of signal information. That is, because the gas is less soluble at higher temperatures due to the temperature dependence of the solubility of the gas in the ink, the drive signal information is corrected by correcting the maximum atmospheric pressure difference by the ratio of the temperature change with respect to the reference temperature. May be selected.

  In this case, the selection of drive signal information is further optimized, and it is possible to effectively prevent the generation of bubbles, thereby further reducing the occurrence of cavitation and maintaining a good balance with the printing speed. It becomes possible.

  Furthermore, in the above-described embodiment, the atmospheric pressure difference variation control program 48B and the atmospheric pressure difference variation drive waveform data 48C may be stored on the computer 100 side, and are stored in the IC chip included in the ink cartridge 13. Also good. If the control program 48B for pressure difference variation and the drive waveform data 48C for pressure difference variation are stored on the computer 100 side, the control program 48B for pressure difference variation and the drive waveform for pressure difference variation are included in the printer driver program 104B. Preferably, data 48C is incorporated. In addition, it is desirable to store the pressure information such as the history pressure and the pressure at the time of use, and the storage destination of the time information at the time of pressure measurement, and the ink cartridge memory. By providing information in the memory of the ink cartridge, the state of the ink and the information stored in the memory are paired, so that the drive of the print head 14 can be accurately controlled, and the same ink is used. Even when the cartridge is mounted in another printer, it is possible to perform the same control as that described above for the print head.

  In the above-described embodiment, the control unit 6 may be realized by software, or may be realized by a circuit.

  Further, the liquid ejecting apparatus according to the above-described embodiment may include both the printer 1 and the computer 100 functions.

  In addition, the printer 1 may be a multifunction device including a scanner device, a fax device, a copy device, and the like other than the printing function as the printer of the present invention.

  Further, the concept of the printer 1 in the above-described embodiment includes fluids such as liquids other than ink (liquids themselves, liquids obtained by dispersing or mixing functional material particles in liquids, and gels). It is also possible to include a fluid ejecting apparatus that ejects or ejects (including a material). As such, a liquid containing a material such as an electrode material or a color material (pixel material) used for manufacturing a liquid crystal display, an EL (electroluminescence) display, and a surface emitting display is dispersed or dissolved. There are a liquid ejecting apparatus, a fluid ejecting apparatus that ejects a bio-organic matter used for biochip manufacturing, a fluid ejecting apparatus that ejects a liquid that is used as a precision pipette and serves as a sample.

  Further, the concept of the printer 1 of the present invention includes a micro hemispherical lens (optical lens) used in a fluid ejecting apparatus, an optical communication element, and the like that ejects lubricating oil pinpoint to a precision machine such as a watch or a camera. A fluid ejecting apparatus that ejects a transparent resin liquid such as an ultraviolet curable resin onto a substrate to form a substrate, a fluid ejecting apparatus that ejects an etchant such as an acid or an alkali to etch the substrate, etc., a gel (for example, a physical gel ) And the like.

DESCRIPTION OF SYMBOLS 1 ... Printer (liquid ejecting apparatus) 4 ... Cleaning mechanism (maintenance execution means) 13 ... Ink cartridge (liquid storage means) 14 ... Print head (liquid ejecting head) 5 ... Pressure sensor (atmospheric pressure measuring means) 6 ... Control part (atmospheric pressure) Difference calculation means, measurement interval calculation means, inclination value calculation means) 44... Cap (cap member) 48... Memory (information storage unit) 48 C .. Pressure waveform fluctuation drive waveform data (drive signal information, drive signal, pressure difference correlation information) 53 ... Timer (time measuring means)

Claims (9)

A liquid ejecting apparatus including a liquid ejecting head that ejects a liquid supplied from a liquid storing unit based on application of a drive signal based on drive signal information,
Atmospheric pressure measuring means for measuring the atmospheric pressure of the place where the liquid ejecting apparatus is installed;
Pressure difference calculation for calculating the pressure difference between the historical pressure, which is the atmospheric pressure measured before the current use of the liquid ejecting apparatus, and the operating air pressure, which is the atmospheric pressure, measured when the liquid ejecting apparatus is used this time. Means,
A time measuring means for measuring time and generating time information;
Based on the timekeeping information generated by the timekeeping means, a measurement interval calculation means for calculating a measurement interval that is a time interval between the time when the historical atmospheric pressure is measured and the time when the atmospheric pressure is measured. When,
An information storage unit that stores the drive signal information associated with the saturation amount of the gas in the liquid that fluctuates according to the pressure difference and the pressure difference correlation information indicating the relationship between the pressure difference;
Control means for selecting the drive signal information based on the pressure difference and the measurement interval, and controlling the drive of the liquid jet head based on the drive signal information;
A liquid ejecting apparatus comprising: The liquid ejecting apparatus according to claim 1,
The drive signal information in the atmospheric pressure difference correlation information includes first drive signal information and second drive signal information,
The liquid ejection amount based on the second drive signal information within a specific period is provided to be smaller than the liquid ejection amount based on the first drive signal information, and the second drive is performed by the control means. When the liquid ejecting head is controlled based on the signal information, bubbles are generated in the liquid more than when the liquid ejecting head is controlled based on the first drive signal information. It is provided in a state that can be suppressed,
The control means has a maximum atmospheric pressure difference which is the largest atmospheric pressure difference among the atmospheric pressure differences calculated for the history atmospheric pressure, wherein the measurement interval is shorter than a predetermined time interval or measured within the predetermined time interval. Is determined to exceed the first atmospheric pressure difference threshold value or greater than or equal to the first atmospheric pressure difference threshold value, the second driving signal information is selected instead of the first driving signal information. Controlling the driving of the liquid jet head based on the second drive signal information.
A liquid ejecting apparatus. The liquid ejecting apparatus according to claim 1,
The drive signal information in the atmospheric pressure difference correlation information includes first drive signal information and second drive signal information,
The liquid ejection amount based on the second drive signal information within a specific period is provided to be smaller than the liquid ejection amount based on the first drive signal information, and the second drive is performed by the control means. When the liquid ejecting head is controlled based on the signal information, bubbles are generated in the liquid more than when the liquid ejecting head is controlled based on the first drive signal information. It is provided in a state that can be suppressed,
Inclination value calculating means for calculating an inclination value of atmospheric pressure change based on the atmospheric pressure difference and the measurement interval,
The control means has a maximum atmospheric pressure difference which is the largest atmospheric pressure difference among the atmospheric pressure differences corresponding to the inclination value determined that the inclination value exceeds a predetermined threshold value or is equal to or more than the predetermined threshold value. When it is determined that the first pressure difference threshold is exceeded or greater than the first pressure difference threshold, the second drive signal information is selected instead of the first drive signal information, and Controlling the driving of the liquid jet head based on second drive signal information;
A liquid ejecting apparatus. The liquid ejecting apparatus according to claim 2,
The drive signal information in the atmospheric pressure difference correlation information is provided with third drive signal information,
The number of unit drive waveforms in the specific period based on the third drive signal information is less than the number of unit drive waveforms in the specific period based on the second drive signal information,
The control means determines that the maximum pressure difference exceeds a second pressure difference threshold value that is higher than the first pressure difference threshold value or is equal to or greater than the second pressure difference threshold value. Instead of the first driving signal information or the second driving signal information, the third driving signal information is selected, and the driving of the liquid ejecting head is controlled based on the third driving signal information. ,
A liquid ejecting apparatus. The liquid ejecting apparatus according to claim 3,
The drive signal information in the atmospheric pressure difference correlation information is provided with third drive signal information,
The number of unit drive waveforms in the specific period based on the third drive signal information is less than the number of unit drive waveforms in the specific period based on the second drive signal information,
The control means has a maximum atmospheric pressure difference, which is the largest atmospheric pressure difference among the atmospheric pressure differences corresponding to the inclination value determined that the inclination value exceeds the predetermined threshold value or is greater than or equal to the predetermined threshold value. When it is determined that the second pressure difference threshold value, which is higher than the first pressure difference threshold value, is greater than or equal to or greater than the second pressure difference threshold value, the first drive signal information or the above In place of the second drive signal information, the third drive signal information is selected, and the driving of the liquid jet head is controlled based on the third drive signal information.
A liquid ejecting apparatus. The liquid ejecting apparatus according to any one of claims 2 to 5,
The control means reflects information related to the application of the drive signal based on input image data input from the outside in the selection of the drive signal information.
A liquid ejecting apparatus. The liquid ejecting apparatus according to claim 6,
The control means calculates the index value indicating the ease of bubble generation based on the input image data and the input image data,
When the index value is less than or equal to a predetermined threshold value or less than a predetermined threshold value, the control means selects the first drive signal information regardless of the atmospheric pressure difference, and uses the first drive signal information as the first drive signal information. Controlling the driving of the liquid jet head based on
A liquid ejecting apparatus. The liquid ejecting apparatus according to any one of claims 2 to 7,
A cap member for contacting the nozzle forming surface of the liquid ejecting head to form a sealed space, and a maintenance execution means for ejecting or discharging the liquid from the liquid ejecting head to the cap member;
The control means determines that the maximum atmospheric pressure difference exceeds the first atmospheric pressure difference threshold value or is greater than or equal to the first atmospheric pressure difference threshold value, or the largest atmospheric pressure difference is the second atmospheric pressure difference. When it is determined that the threshold value is exceeded or greater than or equal to the second atmospheric pressure difference threshold value, the maintenance execution unit is operated to execute a cleaning operation for discharging bubbles present inside the liquid ejecting head to the outside. Do control,
A liquid ejecting apparatus. A pressure measuring step for measuring a pressure at a place where a liquid ejecting apparatus including a liquid ejecting head that ejects the liquid supplied from the liquid storing means by applying a driving signal based on driving signal information is installed;
Pressure difference calculation for calculating the pressure difference between the historical pressure, which is the atmospheric pressure measured before the current use of the liquid ejecting apparatus, and the operating air pressure, which is the atmospheric pressure, measured when the liquid ejecting apparatus is used this time. Steps,
A measurement interval calculation step for calculating a measurement interval that is a time interval between when the historical atmospheric pressure is measured and when the in-use atmospheric pressure is measured;
Based on the atmospheric pressure difference and the measurement interval, select one of the driving signal information that is associated with the saturation amount of the gas in the liquid that varies according to the atmospheric pressure difference and that is the basis of the driving signal. A control step for controlling the driving of the liquid jet head based on the drive signal information;
A liquid ejecting method comprising:

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