JP5145748B2 - Liquid ejection device and recovery operation control method - Google Patents

Description

  The present invention relates to a liquid ejection apparatus and a recovery operation control method.

  A recording head of an ink jet printer has a structure in which pressure is applied to ink stored in a cavity using a piezoelectric element or the like, and the ink is ejected as ink droplets from a nozzle opening. For this reason, if air bubbles are mixed into the cavity from the nozzle opening, the pressure applied is absorbed by the air bubbles, making it impossible to eject ink droplets, or the flight speed is reduced and print quality is impaired. Occurs. Therefore, this type of printer is equipped with a function for executing an operation for removing bubbles from the cavity, such as a cleaning operation, a flushing operation, and a degassing ink addition operation. The cleaning operation is an operation of sucking ink containing bubbles from the cavity by applying a negative pressure after sealing the nozzle opening with a cap. The flushing operation is an operation in which the piezoelectric element is driven and ink containing bubbles is ejected while the print signal is not supplied. The degassing ink addition operation is an operation of dissolving and absorbing bubbles by adding sufficiently degassed ink to the cavity or the flow path leading to the cavity.

Patent Documents 1 and 2 disclose a mechanism for removing bubbles in a printer cavity and maintaining a good discharge environment. The ink jet printer disclosed in Patent Document 1 is configured to add deaerated ink only when severe air bubbles are mixed that cannot be eliminated by the flushing operation. The ink jet printer disclosed in Patent Document 2 stores a history of a cleaning operation performed by a user's own instruction and a history of a cleaning operation performed every time a predetermined time set by a timer elapses in a memory of the ink cartridge. It can be done.
Japanese Patent Laid-Open No. 10-44468 JP 2005-224980 A

  As disclosed in Patent Document 2, many printers of this type are equipped with a so-called timer cleaning function that automatically performs a cleaning operation every time a predetermined period elapses. Unless otherwise, only the cleaning operation for every predetermined period by the timer cleaning function is periodically executed.

  However, the bubble mixed in the cavity grows in size or dissolves in the ink depending on various conditions such as temperature and consumption. Therefore, according to the conventional mechanism in which the cleaning operation is periodically repeated every predetermined period according to the timer cleaning function, the cleaning operation is performed even though there are almost no bubbles in the cavity, or there are many bubbles. There is a possibility that inconveniences such as the cleaning operation not being performed may occur.

  The present invention has been devised under such a background, and an object of the present invention is to provide a mechanism that can dynamically perform a cleaning operation in accordance with the state of generation of bubbles in a cavity.

A liquid ejection apparatus which is a preferred embodiment of the present invention includes: a discharge head having a nozzle opening for discharging the cavity and the liquid for storing the liquid supplied from a liquid supply source, a temperature detecting means for detecting a temperature of the liquid If a consumption detecting means for detecting the consumption of liquid discharged from the discharge head, and means for performing a recovery operation for recovering the operation of ejecting the liquid, a timing for performing the recovery operation the Recovery means for determining the temperature according to the relationship between the liquid consumption and the first correlation data indicating the relationship between the growth rate of bubbles generated in the cavity and the temperature of the liquid, and storing the nozzle A memory for storing second correlation data indicating a relationship between a discharge speed of the liquid from the opening and a dissolution speed of bubbles dissolved in the liquid, and the recovery means includes The bubble growth rate corresponding to the temperature detected by the degree detection means is specified based on the first correlation data stored in the memory, and the liquid consumption is detected based on the liquid consumption detected by the consumption detection means. And the bubble dissolution rate corresponding to the discharge rate is specified based on the second correlation data stored in the memory, and the difference between the specified growth rate and the specified dissolution rate is obtained. The timing for causing the recovery means to perform the recovery operation is specified according to the obtained difference .

According to the present invention, the bubble growth rate is calculated from the temperature of the liquid, the bubble dissolution rate is calculated from the discharge speed, and the timing of the recovery operation is specified according to the difference therebetween. Therefore, the amount of bubbles mixed in the liquid can be specified more precisely, and the recovery operation can be performed at an appropriate timing.

  Further, the growth rate specifying means specifies the growth rate during that period every time a predetermined period elapses, and the dissolution rate specifying means specifies the dissolution rate during that period every time the period elapses, and specifies the timing. Each time the growth rate and dissolution rate are specified, the means adds the difference between the growth rate and dissolution rate to the sum of the differences obtained so far, and restores the timing when the total after the addition exceeds the threshold. You may make it specify as a timing which performs. According to this, every time a predetermined period elapses, the bubble growth rate and the dissolution rate thereof are specified, and the timing of the recovery operation is specified according to the sum of the difference between the two. Therefore, the bubbles mixed in the liquid can be kept below a certain amount without performing the recovery operation at unnecessary timing.

  In addition, the dissolution rate specifying unit may calculate the liquid discharge rate by dividing the consumption detected by the consumption detection unit during the predetermined period by the predetermined period. According to this, by using the detection value of the consumption detection means, the dissolution rate of the liquid during a predetermined period can be accurately obtained.

  Further, the recovery operation may be a cleaning operation in which the nozzle opening is sealed with a cap, and the liquid in the cavity is sucked by applying a negative pressure to the airtight space formed by the sealing. According to this, it is possible to maintain good discharge characteristics even if a mechanism for performing a stronger recovery operation that can remove all the bubbles in the liquid is not installed.

  According to another aspect of the present invention, there is provided a recovery operation control method comprising: an ejection head having a cavity for storing liquid; a nozzle opening for ejecting liquid; a temperature detecting means for detecting the temperature of the liquid; and an ejection from the ejection head. Consumption detecting means for detecting the amount of liquid consumed, and means for performing a recovery operation for recovering the operation of ejecting the liquid, the timing of performing the recovery operation being related to the relationship between temperature and liquid consumption The first correlation data indicating the relationship between the recovery means determined in accordance with the growth speed of the bubbles generated in the cavity and the temperature of the liquid is stored, and the discharge speed of the liquid from the nozzle opening and the liquid are dissolved in the liquid. A memory that stores second correlation data indicating a relationship with the dissolution rate of bubbles, and a method that is executed by the apparatus, the bubble growth corresponding to the temperature detected by the temperature detection means The liquid discharge speed is calculated based on the growth speed specifying process for specifying the degree based on the first correlation data stored in the memory and the liquid consumption detected by the consumption detection means, and the liquid discharge speed is determined according to the discharge speed. The dissolution rate specifying process for specifying the dissolution rate of the bubble generated based on the second correlation data stored in the memory, the difference between the specified growth rate and the specified dissolution rate is obtained, and the recovery means is used according to the obtained difference. And a timing specifying step for specifying a timing for performing the recovery operation. Also according to the present invention, the bubble growth rate is determined from the temperature of the liquid, the bubble dissolution rate is determined from the discharge rate, and the timing of the recovery operation is specified according to the difference therebetween. Therefore, the amount of bubbles mixed in the liquid can be specified more precisely, and the recovery operation can be performed at an appropriate timing.

  (Embodiment of the Invention)

  Hereinafter, a printer 10 as a liquid ejection apparatus according to first to third embodiments of the present invention will be described with reference to the drawings. In the following description, the lower side refers to the side where the printer 10 is installed, and the upper side refers to the side away from the installed side. The direction in which the carriage 31 moves is the main scanning direction, and the direction perpendicular to the main scanning direction and the direction in which the print target P is conveyed is the sub-scanning direction. Further, the side on which the print target P is supplied will be described as a paper feed side, and the side on which the print target P is discharged will be described as a paper discharge side.

  Since the configuration according to each embodiment is basically the same, the configuration common to each embodiment will be described first. The configuration according to the first embodiment is different in that the temperature detector 84 is necessary, whereas the second embodiment does not require the temperature detector 84. There is. The configuration according to the third embodiment is different in that the ink consumption calculation unit 78 does not have to exist.

<Schematic configuration of printer>
First, an outline of the configuration of the printer 10 will be described. FIG. 1 is a perspective view showing a schematic configuration of a printer 10 according to an embodiment of the present invention, in which an upstream side of paper feeding is arranged on the front side, and a downstream side (paper discharging side) of paper feeding is arranged on the back side. FIG. FIG. 2 is a schematic diagram showing the configuration of the printer 10. The printer 10 according to the present embodiment includes a chassis 21, a housing 22, a carriage mechanism 30, a paper feed mechanism 40, an ink supply mechanism 50, a cleaning mechanism 60, and a control unit 70.

  Among these, the chassis 21 is a part where the lower surface side is in contact with the installation surface and a part on which various units are mounted. Further, a housing 22 indicated by a two-dot chain line in FIG. 1 is attached to the chassis 21.

  As shown in FIGS. 1 and 2, the carriage mechanism 30 includes a carriage 31, a carriage shaft 32 on which the carriage 31 slides, and a print head 33 (corresponding to the “ejection head” in the claims). It has. The carriage mechanism 30 includes a carriage motor (CR motor) 34, a gear pulley 35 attached to the CR motor 34, an endless belt 36, and the endless belt 36 between the gear pulley 35. And a driven pulley 37 to be provided. Among these, the ink supplied from the print head 33 via the ink supply mechanism 50 described later is ejected to the print object P.

  As shown in FIG. 2, the paper feed mechanism 40 includes a paper feed motor (PF motor) 41 and a paper feed roller 42 to which the driving force from the paper feed motor 41 is transmitted.

  The printer 10 according to the present embodiment is a so-called off-carriage type in which an ink cartridge 51 (corresponding to “liquid supply source” in the claims) is mounted on the chassis 21 side. Therefore, as shown in FIG. 1, the ink supply mechanism 50 of the printer 10 includes a cartridge holder 52, a pressure pump 53, a plate tube 54, a flexible tube 55, a sub tank 56, and an ink supply valve 57. (See FIG. 6).

  Among these, the cartridge holder 52 shown in FIG. 3 is a portion on which the ink cartridge 51 shown in FIG. 4 is mounted, and is fixedly attached to the chassis 21. The cartridge holder 52 is provided with an insertion port 52 a for inserting the ink cartridge 51. In the present embodiment, one (two in total) cartridge holders 52 are provided inside the printer 10 and on the end side in the main scanning direction. Further, the mounting position of the cartridge holder 52 with respect to the chassis 21 is provided at a portion that is out of the moving space area of the carriage 31. Specifically, the cartridge holder 52 is attached to the paper feed side of the printing object P rather than the reciprocating region of the carriage 31.

  In addition, a plurality (three in this embodiment) of ink cartridges 51 are detachably attached to the pair of cartridge holders 52 via the insertion ports 52a. As shown in FIG. 4, the ink cartridge 51 includes an air chamber 51b inside a casing 51a, and an ink pack 51c that fills the inside of the air chamber 51b. The ink pack 51c is a highly airtight bag-like member such as an aluminum pack, for example, and ink is accommodated inside the ink pack 51c.

  As will be described later, the ink in the ink pack 51c flows / stores in the flow path (in this embodiment, the ink is supplied from the ink cartridge 51 and discharged from the print head 33). It is possible to dissolve bubbles that are present inside and discharge them to the outside. Therefore, the ink in the ink pack 51c is, for example, a deaeration ink in which the dissolution of air is suppressed in advance, and a predetermined amount of bubbles can be dissolved. Further, since the ink pack 51c has high airtightness as described above, it is possible to maintain a state in which the bubbles (air) can be dissolved without saturating the solubility of the bubbles (air) for a very long period of time. It is said.

  As shown in FIG. 4, the casing 51a is provided with an ink supply port 51d into which an ink supply needle (not shown) is inserted. As shown in FIG. 6, a circuit board 51e is attached to the casing 51a so as to be integrated with the casing 51a. The circuit board 51e is, for example, an IC chip or the like, and has a memory 51f (storage element) that stores information about ink in a writable manner. Examples of the information relating to the ink include ink color type data stored in the ink cartridge 51, pigment / dye type ink type data, and ink capacity data indicating the amount of ink initially filled in the ink cartridge 51. , Remaining ink data, serial number data, expiration date data, target model data that can use the ink cartridge 51, and the like.

  As shown in FIG. 1, a pressure pump 53 is connected to the cartridge holder 52. The pressurizing pump 53 sends air into the air chamber 51 b in the ink cartridge 51. Then, by increasing the pressure of the air chamber 51b, the ink pack 51c is deformed so as to be crushed. As a result of this deformation, the ink present in the ink pack 51c is pushed into the ink flow path of the plate tube 54, and the ink flows through the ink flow path.

  As shown in FIG. 1, one end side of the flexible tube 55 is connected to the downstream end portion of the ink flow in the plate-like tube 54. The flexible tube 55 is made of a flexible material such as an elastomer resin. Thereby, the flexible tube 55 is flexibly soft and does not hinder the reciprocation of the carriage 31 in the main scanning direction. Further, the flexible tube 55 has a hollow tube line (not shown) penetrating in the longitudinal direction. The ink flow path and the tube pipe line communicate with each other so that ink can be circulated satisfactorily.

  A sub tank 56 is connected to the other end of the flexible tube 55. In principle, the same number of sub-tanks 56 as the ink cartridges 51 are provided above the carriage 31. The sub tank 56 temporarily stores ink that has circulated through the ink flow path and the tube line. The ink stored in the sub tank 56 is ejected from the nozzle openings 33a (see FIG. 5) of the print head 33 to the lower surface side of the carriage 31.

  The ink supply valve 57 is provided, for example, in the vicinity of the ink outlet from the ink cartridge 51, and can be opened and closed electrically based on the output of a sensor (not shown) in the sub tank 56. For example, if it is determined by the sensor output that the amount of ink in the sub tank 56 has decreased, the ink supply valve 57 is opened, and ink can be supplied to the sub tank 56.

  Further, the chassis 21 is provided with a cleaning mechanism 60 as shown in FIGS. The cleaning mechanism 60 includes a cap 61, a partition wall 62, an ink discharge tube 63, a control valve 64, and a suction pump 65 (see FIGS. 5 and 6). Among these, the cap 61 is a portion that seals the nozzle opening 33a of the print head 33 from the outside. The partition wall 62 is a member that subdivides the space inside the cap 61, and is a member that enables the nozzle openings 33a of the nozzle rows that discharge ink of each color to be sealed independently for each color. In addition, the ink discharge tube 63 is provided for each color nozzle row in the present embodiment.

  The control valve 64 is a valve that is provided in the middle of the ink discharge tube 63 and can be electrically controlled. When the valve is open, ink can flow through the ink discharge tube 63 and is closed. In the valve state, the ink distribution in the ink discharge tube 63 is disabled. Further, the suction pump 65 (corresponding to a part of the recovery means) is provided so as to be able to generate a negative pressure in the ink discharge tube 63. When the suction pump 65 is operated, the ink discharge tube 63 is passed through the ink discharge tube 63. The ink is discharged to a waste liquid tank (not shown). In addition, by this ink suction operation, a so-called cleaning operation for forcibly discharging bubbles mixed in the flow path of the plate tube 54, the flexible tube 55, the print head 33, or the like can be executed. ing.

<Configuration of control unit>
As shown in FIGS. 2 and 6, the printer 10 is provided with a control unit 70. The control unit 70 includes a CPU (not shown), a memory (ROM, RAM, nonvolatile memory, etc.), an ASIC (Application Specific Integrated Circuit), a bus, a timer, an interface 85, and the like.

  Signals from various sensors are input to the control unit 70, and based on the signals from the sensors, the control unit 70 includes a CR motor 34, a PF motor 41, a pressure pump 53, a suction pump 65, and Controls driving of the print head 33 and the like.

  Further, the data and the program in the memory described above are executed by the CPU, and the components shown in the block diagram of FIG. 6 are functionally realized by the cooperation of the components of the control unit 70. . As shown in FIG. 6, the control unit 70 includes a main control unit 71, a memory 72, a head control unit 73, a pump control unit 74, a CR motor control unit 75, a valve control unit 76, a CL timer 77, and ink consumption calculation. And a cartridge memory controller 79, a head drive circuit 80, a pump drive circuit 81, a CR motor drive circuit 82, and a valve drive circuit 83.

  Of these, the main control unit 71, together with the memory 72, corresponds to the main part of the recovery means, the growth rate specifying means, the dissolution rate specifying means, and the timing specifying means in the claims, and controls the entire printer 10. 2, a command from the computer 90 side shown in FIG. 2, a timing output from the CL timer 77, and an output from the ink consumption calculation unit 78 are input. The main control unit 71 is supplied with a detection signal from a temperature detection unit 84 described later.

  Here, the CL timer 77 is a timer that measures the time from the cleaning with the previous suction. The CL timer 77 is used to measure the time on the basis of the time when the bubble is discharged by the previous cleaning, and to predict the growth of the bubble by the time measurement. Therefore, the CL timer 77 is reset when cleaning with suction is performed, but is not reset in a flushing operation without suction, and time measurement is continued.

  The memory 72 in the present embodiment stores first correlation data and second correlation data. The first correlation data is data indicating the relationship between the growth speed of bubbles generated in a cavity (not shown) of the print head 33 and the ink temperature. Each pair of the value indicating the growth rate and the value indicating the temperature of the ink, which constitutes the first correlation data, is obtained based on the experiment results or calculation results of the designers. The second correlation data is data indicating the relationship between the ejection speed of ink from the nozzle openings 33a and the dissolution speed of bubbles in the ink. Each pair of the value indicating the discharge speed and the value indicating the dissolution speed, which constitutes the second correlation data, is also obtained based on the experiment results or calculation results of the designers.

  Further, the head control unit 73 drives the print head 33 via the head drive circuit 80 based on a command from the main control unit 71 to eject ink droplets. Here, the commands received by the head control unit 73 from the main control unit 71 include a print operation command based on print data and a flushing operation command which is a kind of maintenance operation.

  The pump control unit 74 corresponds to a part of the recovery means, and is based on a command from the main control unit 71 via the pump drive circuit 81 when the print head 33 is sealed with the cap 61. The suction pump 65 is controlled to perform predetermined cleaning. Further, the CR motor control unit 75 drives the CR motor 34 via the CR motor drive circuit 82 based on a command from the main control unit 71. The CR motor control unit 75 drives the CR motor 34 in conjunction with the operation of the print head 33 when performing printing. Further, when performing the flushing operation, the CR motor control unit 75 drives the CR motor 34 prior to the flushing operation of the print head 33 to move the carriage 31 to the cap 61 side.

  The valve controller 76 controls and drives at least one of the ink supply valve 57 and the control valve 64 via the valve drive circuit 83 based on a command from the main controller 71 to control the circulation of ink.

  The ink consumption calculation unit 78 is a part that calculates the ink consumption by counting the operation of ejecting large, medium, or small ink droplets. The ink consumption calculation unit 78 can calculate the ink consumption by referring to print data including raster data indicating the dot formation state, and is configured to be realized by a CPU, an ASIC, or the like. . However, if the ink remaining amount of the ink cartridge 51 can be detected by a detection sensor (such as an optical sensor), the ink consumption calculation unit 78 calculates the ink consumption based on the ink remaining amount. May be. In the present embodiment, the ink consumption calculation unit 78 calculates the ink consumption individually for each nozzle row.

  The cartridge memory control unit 79 is a part for controlling access to the memory 51 f existing in the ink cartridge 51 based on a command from the main control unit 71. The cartridge memory control unit 79 accesses the memory 51f and reads each piece of information related to ink as described above. Further, the cartridge memory control unit 79 updates the ink remaining amount data in the memory 51f based on the ink consumption calculated by the ink consumption calculation unit 78.

  The head drive circuit 80 generates a predetermined voltage in response to a command from the head control unit 73 and applies the voltage to the piezo element in the print head 33. Further, the pump drive circuit 81 generates a predetermined voltage in response to a command from the pump control unit 74 and applies the voltage to the suction pump 65. The CR motor drive circuit 82 generates a predetermined voltage in response to a command from the CR motor control unit 75 and applies the voltage to the CR motor 34. In addition, the valve drive circuit 83 generates a predetermined voltage in response to a command from the valve control unit 76 and applies the voltage to at least one of the ink supply valve 57 and the control valve 64.

  Further, the temperature detection unit 84 (corresponding to “temperature detection means” in the claims) detects the temperature of the print head 33 each time a predetermined time (for example, 1 hour, for example) elapses, and relates to the detected temperature. The signal is supplied to the main control unit 71.

  The control unit 70 is connected to a computer 90 via an interface 85, and can transmit and receive various data such as print data. Further, the computer 90 may be configured to have the same function as the control unit 70 described above.

<Operation according to the first embodiment>
FIG. 7 is a flowchart showing a specific procedure for the timing of the cleaning operation. The main control unit 71 sequentially stores the temperature value indicated by the signal supplied from the temperature detection unit 84 and the signal supplied from the ink consumption calculation unit 78 in association with the supply time in its own memory 72 or the like. Then, a series of processing shown in FIG. 7 is executed using those values.

  The series of processing shown in FIG. 7 is repeatedly executed with the trigger of either cleaning by a user command or timer cleaning being performed. When any of the cleaning operations is performed (S100: Yes), the main control unit 71 resets the value of the CL timer 77 to 0. At this time, the value of the CL timer 77 read to the memory 72 is also set to 0 ( S110). When the determination result in step S100 is No, that is, when the cleaning operation is not performed, the process proceeds to the next step S120 without executing step S110.

  When one day (24 hours) has elapsed since the value of the CL timer 77 was set to 0 (S120: Yes), the main control unit 71 calculates an average TAV of temperatures during the day (S130). Furthermore, the main control unit 71 specifies the bubble growth rate VS per day by referring to the first correlation data in the memory 72 based on the average TAV of the temperatures obtained in step S120 (S140). As described above, the first correlation data is data indicating the relationship between the growth speed VS of bubbles generated in the cavity of the print head 33 and the ink temperature.

  FIG. 8 is a graph showing the correlation between the bubble growth rate and the ink temperature. As shown in this graph, the bubble growth rate per day is constant at 0.005 cubic millimeters until the temperature of the ink exceeds 10 ° C., and is constant at 0.005 cubic millimeters. It has been shown to rise. In the present embodiment, each pair of a value indicating a temperature and a value indicating a bubble growth rate that has the characteristics shown in this graph is prepared as first correlation data, and the first correlation data is used as the first correlation data. The bubble growth rate according to the temperature is specified by referring.

  Note that data indicating the graph of FIG. 8 may be stored in the memory 72 as a stepwise value for each predetermined temperature, for example, every time. Further, the memory 72 may be stored in the form of a function indicating the graph of FIG.

  When one day has elapsed since the value of the CL timer 77 was set to 0 (step S120: Yes), the main control unit 71 calculates the ink consumption amount calculation result from the point of power-on in the ink consumption amount calculation unit 78. Based on the above, the ink consumption during the day is calculated (S150). The main control unit 71 that has obtained the ink consumption per day specifies the ink ejection speed from the nozzle openings 33a during the day (S160). The ink ejection speed per day from the nozzle openings 33a is a value (consumption / day) obtained by dividing the ink consumption during that period by time (one day). The main control unit 71 that has obtained the ink ejection speed refers to the second correlation data in the memory 72 based on the ejection speed, and specifies the ink dissolution speed VY per day (S170). As described above, the second correlation data is data indicating the relationship between the ejection speed of the ink from the nozzle openings 33a and the dissolution speed of the bubbles in the ink.

  Here, the measurement result regarding this Embodiment is as follows. That is, when the discharge speed is 0.1 (gram / hour) or more and 1 (gram / hour) or less, the bubble dissolution speed is 1 (cubic millimeter / hour), and the discharge speed is 1 (gram / hour). The dissolution rate of bubbles when it was less than 10 (gram / hour) was 0.5 (cubic millimeter / hour). Further, when the discharge rate was more than 10 (gram / hour), the bubble dissolution rate was 0.2 (cubic millimeter / hour). From this, there was a correlation between the dissolution rate of bubbles in ink and the discharge rate of ink, and the idea was that the slower the discharge rate, the faster the dissolution rate, and the faster the discharge rate, the slower the dissolution rate. . In addition, when the same measurement was tried by setting the discharge speed to less than 0.1 (gram / hour), the dissolution speed was 0 (cubic millimeter / hour). However, this is considered to be caused by the fact that the dissolution of bubbles in the ink is saturated and there is no room for further dissolution in an environment where ejection is hardly performed. Therefore, it is considered that the above idea is not overturned by the result that the discharge speed is 0.1 (gram / hour) or less. In the present embodiment, each pair of a value indicating a discharge speed and a value indicating a dissolution speed, which is determined by extrapolation based on the measurement result described above, is prepared as second correlation data, and this data is referred to. By doing this, the dissolution rate corresponding to the discharge rate is specified.

  In addition, when the above-mentioned 1st correlation data takes a step value for every predetermined temperature like every time, for example, this 1st correlation data and the above-mentioned 2nd correlation data (above-mentioned In the example, there are four levels, but the number is not limited to four.) May be stored in the memory 72 as a matrix table.

  The main control unit 71 that has determined the growth rate VS and the dissolution rate VY adds the difference between the two to the total difference thus far determined, and determines whether or not the total after the addition exceeds the bubble margin threshold. When the sum after addition exceeds the threshold (S180: Yes), a cleaning operation is performed (S190). And it returns to step S100, and after resetting the value of CL timer 77 in the following step S110, the subsequent processes are repeated. On the other hand, when the sum after the addition does not exceed the threshold value (S180: No), the process returns to step S100 without executing step S190.

  Note that FIG. 9 showing an example of the measurement result will be described in detail. FIG. 9 shows a line indicating the pressure loss of the print head 33, a line indicating the discharge speed during a predetermined cleaning operation (a straight line), and a line indicating the correlation between the discharge speed and the bubble volume (substantially proportional line). ) And is shown. As described above, even after the cleaning operation is performed, bubbles of a predetermined volume (for example, about 20 cubic meters) remain in the cavity, and the bubbles of the predetermined volume depend on the discharge speed. And grow up. On the other hand, as shown in this graph, the discharge speed of the ink from the nozzle opening 33a decreases depending on the size of the bubble volume in the ink, and the bubble volume exceeds a certain value (for example, 32 cubic meters). Then, the pressure loss rapidly increases toward infinity (this corresponds to the rising portion of the line indicating the pressure loss of the print head 33). From this, the printer 10 according to the present embodiment has a difference between the bubble volume immediately after the cleaning operation (20 cubic meters in FIG. 9) and the boundary (32 cubic meters in FIG. 9) where the pressure loss rapidly increases. (12 cubic meters in FIG. 9) is set as the bubble margin threshold, and the integrated value of the difference between the bubble growth volume per day determined from the bubble growth rate and the bubble dissolution volume per day determined from the bubble dissolution rate is this The cleaning operation is performed every time the threshold value is exceeded.

Here, when the determination in step S180 is expressed as a mathematical formula, the following calculation formula (1) is obtained. N in this calculation formula (1) is the number of loop iterations from step S110 to step S180.

  The calculation formula (1) shows a case where the bubble margin threshold is 12, and this state corresponds to FIG. However, the bubble margin threshold 12 in the calculation formula (1) is merely an example, and can be set to various values under the environment around the printer 10.

<Effect when the invention according to the first embodiment is applied>
As described above, in the present embodiment (the first embodiment), the bubble growth rate and the dissolution rate are specified based on the consumption amount and the temperature of the ink ejected from the print head 33, respectively. The cleaning operation is performed every time the sum of the differences between the two exceeds the bubble margin threshold. That is, the execution of the cleaning operation is dynamically controlled based on the ink consumption and temperature. Therefore, it is possible to prevent the occurrence of inconveniences such as the cleaning operation being performed even though there are almost no bubbles in the cavity, or the cleaning operation not being performed even though there are many bubbles.

<Configuration Specific to Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. In the present embodiment, the memory 72 stores a table related to maintenance (hereinafter referred to as a maintenance table) as shown in FIG. Here, in the maintenance table shown in FIG. 10, the maintenance operation to be executed and its processing rank are described in a matrix format based on the cleaning timer (CL timer T1) on the horizontal axis and the ink consumption M on the vertical axis. Has been. In this embodiment, the ink is deaerated ink as will be described later.

  Here, in the horizontal axis of FIG. 10, the time of the CL timer T1 increases from left to right. In addition, in the vertical axis of FIG. 10, the ink consumption M increases from the top to the bottom. As can be seen from FIG. 10, in this embodiment, (1) the higher the ink consumption M, the more bubbles are dissolved, so the maintenance is low in rank (low ink consumption). (2) Since the bubbles are in a direction to accumulate as the time count in the CL timer 77 increases, a maintenance operation with higher rank (more ink consumption) is performed. , And is designed based on the idea.

  On the other hand, a conventional maintenance table is shown in FIG. The maintenance table shown in FIG. 11 is designed to execute a maintenance operation with a higher rank as the cumulative printing time elapses, although the timing in the CL timer 77 is the same. For this reason, even if deaeration ink is used, the deaeration ink cannot be effectively used.

<About the operation according to the second embodiment>
(1) Operation Flow at Power-On Hereinafter, the operation flow at power-on among the operations related to cleaning of the printer 10 will be described based on the flowchart shown in FIG. When the printer 10 is powered on, an initialization operation is executed (S200). In this initialization operation, the main control unit 71 determines whether, for example, the ink flow path is initially filled with ink and whether each color ink cartridge 51 is in a mounted state.

  Subsequently, the type of maintenance operation to be performed when the power is turned on is selected (S210). In this selection, the main control unit 71 performs data based on the time measurement data in the CL timer 77 and the ink consumption data in the ink consumption calculation unit 78. Further, when making this selection, the main control unit 71 reads the maintenance table stored in the memory 72, refers to the maintenance table, and corresponds to which maintenance operation from the above-mentioned time measurement and ink consumption. Judge whether to do.

  Here, in this embodiment, deaeration ink is used as the supplied ink. Since the deaerated ink dissolves bubbles, it is considered that as the ink consumption increases, a larger amount of deaerated ink is supplied and the bubbles in the flow path are dissolved and the bubbles disappear. Therefore, if the time counted by the CL timer 77 is the same, the larger the ink consumption, the more bubbles are dissolved, so a large maintenance operation is unnecessary. The smaller the ink consumption, the larger the maintenance operation is necessary. Yes. In other words, when the power is turned on, a slightly larger maintenance operation is set.

  Subsequently, the maintenance operation selected in step S210 is executed (S220). Here, in this embodiment, since the nozzle row can be sealed independently for each color, the main control unit 71 performs control so that this maintenance operation is performed independently for each color. . Further, when the selected maintenance operation is a flushing operation, an operation of ejecting ink droplets by a predetermined number of shots (empty ejection) is performed. For example, in FIG. 10, assuming that a small Fl (flushing operation with a small number of shots) is selected and this small Fl is 1000 shots, ink droplets are ejected by 1000 shots, and a large Fl (flushing operation). Assuming that the large Fl is 10,000 shots, ink droplets are ejected by 10,000 shots.

  Further, when the selected maintenance operation is any one of TCL2 to TCL4, the cleaning operation of the selected rank is performed. The ink discharge amount in TCL2 to TCL4 is TCL2 <TCL3 <TCL4. Further, the discharge amount of bubbles is also TCL2 <TCL3 <TCL4.

  Here, FIG. 13 shows the relationship between the cleaning flow rate of each rank, the bubble volume, and the pressure loss. FIG. 13 is a detailed description of FIG. 9 in the first embodiment described above, and is an experimental result using ink in a saturated state, not deaerated ink. Of the straight lines in FIG. 13 (straight line 1, straight line 2, straight line 3), straight line 1 is a flow velocity (flow velocity line; flushing operation) when the printing duty (ratio of time during which print head 33 is driven) is 100%. The straight line 2 indicates the flow velocity in the case of TCL2, and the straight line 3 indicates the flow velocity in the case of TCL3. Further, the substantially inversely proportional lines (curve 1 and curve 2) in FIG. 13 indicate the remaining bubble volume when ink is sucked at each flow rate and cleaning is performed (flow rate-bubble volume line). Further, in FIG. 13, the lines (rise line 1 and rise line 2) that rise sharply from the middle part indicate the relationship between the bubble volume and the pressure loss (bubble-pressure loss line). The curved line 1 and the rising line 1 indicate characteristics relating to a specific type (first type) of the print head 33, and the curved line 2 and the rising line 2 are different from the first type (second type). The characteristic regarding the print head 33 is shown. In FIG. 13, the bubble volume at the intersection of the straight lines 2 and 3 and the curves 1 and 2 is the bubble volume that remains (cannot be discharged) even after each cleaning. Yes.

  Further, when the bubble volume increases up to the rising portions of the rising lines 1 and 2, the pressure loss rapidly increases toward infinity. For this reason, if the bubble volume increases beyond this rising portion, it becomes difficult to eject ink droplets even if pressure is applied to eject ink droplets. In FIG. 13, the bubble volume can be increased by the difference between the bubble volume at the rising portions of the rising lines 1 and 2 and the currently remaining bubble volume (hereinafter referred to as the bubble volume). Margin.)

  As described above, when any one of TCL2 and TCL3 is cleaned in FIG. 13, bubbles remaining in the flow path can be reduced by cleaning according to the rank. From another point of view, this indicates that even when cleaning at a predetermined rank, excluding very strong choke suction, bubbles remain by a predetermined amount.

  However, in the present embodiment, as the printing is started and the deaerated ink is supplied, the bubbles are dissolved. For this reason, after cleaning or flushing each rank, bubbles existing in the flow path are considered to decrease as the amount of deaerated ink increases, and the bubble margin is considered to increase. .

  When a maintenance operation is executed in step S220 shown in FIG. 12, the CL timer 77 is reset (S230). However, while the power is on, the ink consumption is not reset and remains as it is. Note that the ink consumption may also be reset (the count is cleared to zero) as the CL timer 77 is reset.

(2) Operation Flow at the Time of Printing Next, of the operations related to cleaning of the printer 10, the operation flow at the start of printing will be described based on the flowchart shown in FIG. In this operation flow, when an instruction to start printing is given (S201), the type of maintenance operation to be performed at that time is selected (S211). This selection is performed with reference to the maintenance table described above. The other processes are the same as those in FIG. 12 described above, and a description thereof will be omitted.

<Effect when the invention according to the second embodiment is applied>
According to the printer 10 described above, the maintenance operation executed by the print head 33 or the suction pump 65 is controlled based on the liquid consumption calculated by the ink consumption calculation unit 78. Here, since the ink in the present embodiment is a deaerated ink in a deaerated state, bubbles existing in the flow path can be dissolved. Therefore, if the maintenance operation is controlled based on the consumption amount of the deaerated ink, it is possible to appropriately reduce the bubbles existing in the flow path and increase the bubble margin, so that the gas dissolved in the deaerated ink is dissolved. It is possible to make effective use of sex.

  In particular, in the present embodiment, if the CL timer T1 is the same, control is performed such that the consumption of liquid in the maintenance operation decreases as the consumption of deaerated ink increases. For this reason, it is possible to effectively utilize the gas solubility of the deaerated ink and to reduce the amount of ink discharged unnecessarily during the maintenance operation.

  Further, if the amount of deaerated ink consumed before the maintenance operation is the same, it is considered that the gas solubility of the deaerated ink decreases as the CL timer T1 elapses (the gas solubility is saturated). It is thought that many bubbles remain without melting bubbles anymore). In this embodiment, if the ink consumption M before maintenance is the same, the amount of deaerated ink consumed in the maintenance operation is increased as the CL timer T1 elapses. It becomes possible to increase the amount of bubbles discharged together with the ink. That is, by supplying a large amount of degassed ink with high bubble solubility over time, more bubbles remaining in the flow path can be dissolved.

  Furthermore, in the present embodiment, since the maintenance operation executed by the print head 33 or the suction pump 65 or the like is controlled based on a matrix-like table that changes stepwise, the amount of data can be reduced. At the same time, the calculation can be simplified.

  In the present embodiment, when the maintenance operation is performed, the print head 33 is ejected idle or the suction pump 65 is operated to discharge more deaerated ink. Here, when the print head 33 is idle, a small amount of liquid can be discharged, and when the suction pump 65 is operated, a larger amount of deaerated ink can be discharged, and various maintenance operations can be performed.

  Furthermore, the cap 61 seals the nozzle row corresponding to each type separately from the other nozzle rows, and sucks the nozzle rows individually in the sealed state. The ink consumption amount calculation unit 78 calculates the consumption amount of deaerated ink individually for each nozzle row, and the main control unit 71 calculates the consumption amount of liquid separately for each nozzle row based on the consumption amount of liquid calculated for each nozzle row. Maintenance operation is selected. For this reason, it is possible to execute an optimum maintenance operation in consideration of bubble solubility of the deaerated ink corresponding to each nozzle row. Further, since the nozzle rows can be sucked individually, it is not necessary to suck the degassed ink wastefully, which is economical for the user.

<Configuration Specific to Third Embodiment>
Hereinafter, a third embodiment of the present invention will be described. The present embodiment has a unique cleaning mechanism 60 that is different from the first and second embodiments. The chassis 21 is provided with a cleaning mechanism 60 as shown in FIGS. The cleaning mechanism 60 includes a cap 61, a partition wall 62, an ink discharge tube 63, a control valve 64, and a suction pump 65.

  Among these, the cap 61 is a portion that seals the nozzle opening 33a of the print head 33 from the outside. The partition wall 62 divides the space inside the cap 61 into two. Here, unlike the first and second embodiments, the space in the cap 61 is divided into two by the partition wall 62 and is individually sealed. In the following description, of the two internal spaces, the one for sucking ink supplied from the ink cartridge 51 of the first cartridge group 51A is referred to as the internal space 61A, and the ink of the second cartridge group 51B. A space for sucking ink supplied from the cartridge 51 is referred to as an internal space 61B. Further, in the present embodiment, the ink discharge tubes 63 are provided by the number of the internal spaces 61A and the internal spaces 61B.

  The control valve 64 is a valve that is provided in the middle of the ink discharge tube 63 and can be electrically controlled. When the valve is open, ink can flow through the ink discharge tube 63 and is closed. In the valve state, the ink distribution in the ink discharge tube 63 is disabled. The suction pump 65 is provided so as to be able to generate a negative pressure in the ink discharge tube 63, and when the suction pump 65 is operated, the ink is supplied to a waste liquid tank (not shown) via the ink discharge tube 63. Discharged. In addition, by this ink suction operation, a so-called cleaning operation for forcibly discharging bubbles mixed in the flow path of the plate tube 54, the flexible tube 55, the print head 33, or the like can be executed. ing.

  FIG. 16 shows the control unit 70A in the present embodiment. This control unit 70A is different from the control unit 70 in the first embodiment described above in the presence or absence of the ink consumption calculation unit 78.

  In the present embodiment, the table stored in the memory 72 is different from that in the second embodiment described above. That is, in the present embodiment, a table relating to maintenance (hereinafter referred to as a maintenance table) as shown in FIG. 17 is stored. Here, in the maintenance table shown in FIG. 17, the horizontal axis is a cleaning timer (CL timer T1), and the vertical axis indicates whether the ink is light-colored ink and which print mode is selected. Show. In the maintenance table, the maintenance operation to be executed and its processing rank are described in a matrix format based on these.

  Here, on the horizontal axis in FIG. 17, the time of the CL timer T1 increases from left to right. Also, in the high-quality printing mode on the vertical axis in FIG. 17, the light-colored ink performs a maintenance operation with a lower rank (lower ink consumption) than the dark-colored ink. It has been designed. In the high-speed printing mode on the vertical axis in FIG. 17, in contrast to the high-quality printing mode, the dark ink has a lower rank than the light ink (the ink consumption is lower). ) Designed to perform maintenance operations.

  Here, in the high-quality print mode, the consumption of light-colored ink is increased. On the other hand, the consumption of dark-colored ink is relatively smaller than the consumption of light-colored ink. Further, in the present embodiment, the ink is deaerated ink, and the more the consumed amount of the deaerated ink, the more the bubbles are directed to decrease. For this reason, in the high quality printing mode, it is considered that the flow path for distributing the light-colored ink has fewer bubbles than the flow path for distributing the dark-colored ink. The flow path through which the ink flows is designed so that a lower rank (lighter) maintenance operation is sufficient.

  In the high-speed printing mode, light-colored ink is not consumed or is relatively small even if consumed. For this reason, in the high-speed printing mode, it is considered that bubbles in the dark color ink are reduced compared to the light color ink, and the dark ink has a lower rank (lighter). Designed to do maintenance operations.

  The conventional maintenance table as a reference is shown in FIG. 11, and as described above, the maintenance table shown in FIG. As it does, it is designed to perform high-ranking maintenance operations. For this reason, even if deaeration ink is used, the deaeration ink cannot be effectively used.

<About the operation according to the third embodiment>
(1) Operation Flow at Power-On Hereinafter, of the operations related to cleaning of the printer 10, the operation flow at power-on will be described. The operation in the present embodiment is basically the same as that in the second embodiment described above, and therefore the operation flow based on FIG. 12 is performed. Therefore, the following operation flow will be schematically described.

  First, in the initialization operation (S200) executed when the printer 10 is powered on, for example, it is determined whether or not the ink flow path is initially filled with ink, and whether or not each color ink cartridge 51 is in a mounted state. Performed by the controller 71.

  In the subsequent step S210, the main control unit 71 selects the type of maintenance operation based on the time measurement data in the CL timer 77 and the current print mode specified in the command transmitted from the computer 90. Do. Further, when making this selection, the main control unit 71 reads the maintenance table (see FIG. 17) stored in the memory 72 and refers to the maintenance table to determine from the above-mentioned time measurement and the current print mode. Determine which maintenance operation is applicable.

  Here, in this embodiment, deaeration ink is used as the supplied ink. Since the deaerated ink dissolves bubbles, it is considered that as the ink consumption increases, a larger amount of deaerated ink is supplied and the bubbles in the flow path are dissolved and the bubbles disappear. Therefore, if the time counted by the CL timer 77 is the same, the larger the ink consumption, the more bubbles are dissolved, so a large maintenance operation is unnecessary. The smaller the ink consumption, the larger the maintenance operation is necessary. Yes. In other words, when the power is turned on, a slightly larger maintenance operation is set.

  In the subsequent execution of the maintenance operation (S220), if the selected maintenance operation is a flushing operation, an operation of ejecting ink droplets by a specified number of shots (empty ejection) is performed. Thereafter, the process proceeds to step S230, and the CL timer 77 is reset. For example, in FIG. 17, assuming that a small Fl (a flushing operation with a small number of shots) is selected and this small Fl is 1000 shots, ink droplets are ejected by 1000 shots, and a large Fl (flushing operation). Assuming that the large Fl is 10,000 shots, ink droplets are ejected by 10,000 shots. In this flushing operation, since ink droplets can be ejected for each nozzle row, unlike the cleaning operations of TCL2 to TCL4 described below, the internal space 61A and the internal space 61B are made independent of each other. It is no longer necessary to seal in the closed state.

  In addition, when the selected maintenance operation is a cleaning operation involving the operation of the suction pump 65 (in the case of any of TCL2 to TCL4), the cap 61 is brought into close contact with the print head 33. At this time, the internal space 61A corresponding to the first cartridge group 51A and the internal space 61B corresponding to the second cartridge group 51B can be independently sealed. Then, the main control unit 71 controls the maintenance operation to be executed independently in the internal space 61A and the internal space 61B.

  In this cleaning operation, a cleaning operation of a selected rank (any one of TCL2 to TCL4) is performed. The ink discharge amount in TCL2 to TCL4 is TCL2 <TCL3 <TCL4. Further, the discharge amount of bubbles is also TCL2 <TCL3 <TCL4.

  Here, when one of TCL2 and TCL3 is cleaned as shown in FIG. 13, bubbles remaining in the flow path can be reduced by cleaning according to the rank. From another point of view, this indicates that even when cleaning at a predetermined rank, excluding very strong choke suction, bubbles remain by a predetermined amount.

  However, in the present embodiment, as the printing is started and the deaerated ink is supplied, the bubbles are dissolved. For this reason, after cleaning or flushing each rank, bubbles existing in the flow path are considered to decrease as the amount of deaerated ink increases, and the bubble margin is considered to increase. .

(2) Operation Flow at the Time of Printing Next, an operation flow at the start of printing among operations related to cleaning of the printer 10 will be described. In this operation flow, the basic operation is the same as that in FIG. 14 in the second embodiment described above. That is, when the start of printing is instructed (S201), the type of maintenance operation specific to the present embodiment to be executed at that time is selected (S211). This selection is made with reference to a maintenance table similar to that shown in FIG. The other processes are the same as those in FIG. 14 (FIG. 12) described above, and the description thereof is omitted.

<Effect in the case where the invention according to the third embodiment is applied>
According to the printer 10 described above, the maintenance operation executed by the print head 33 or the suction pump 65 is controlled according to the print mode. For this reason, if an appropriate maintenance operation according to this print mode is executed, the ink ejection state from the print head 33 can be kept good. In addition, by performing a maintenance operation according to the print mode, it is possible to reduce the amount of ink that is wasted.

  In the present embodiment, deaeration ink that can maintain a deaeration state is used as the ink. By using such deaerated ink, it is possible to dissolve bubbles present in the flow path from the ink cartridge 51 to the print head 33. Therefore, if control is performed so that an appropriate maintenance operation is executed according to the print mode, it is possible to reduce bubbles existing in the flow path and increase the bubble margin, and the gas solubility of the deaerated ink Can be effectively utilized. Moreover, since it is not necessary to use a special configuration for deaeration, it is possible to suppress an increase in cost.

  Further, in the present embodiment, in the high quality printing mode, the supply amount of light-colored ink (deaerated ink) is relatively large. Therefore, in the high quality printing mode, bubbles are reduced in the light-color ink flow path. Therefore, by controlling the maintenance operation so that the discharge amount or discharge amount of light-colored ink is less than the discharge amount or discharge amount of dark-colored ink, it is possible to prevent the light-color ink from being wasted. It becomes possible to do. In the printing in the high quality mode, the supply amount of dark ink is relatively small. For this reason, by controlling the maintenance operation so that the discharge amount or discharge amount of the dark color ink is larger than the discharge amount or discharge amount of the light color ink, air bubbles are generated in the flow path of the dark ink. Can be reduced.

  In the high-speed printing mode, light-colored ink (deaerated ink) is not consumed or is relatively small even if consumed. For this reason, by controlling the maintenance operation so that the discharge amount or discharge amount of light-colored ink is larger than the discharge amount or discharge amount of dark-color ink, bubbles are generated in the flow path of light-color ink. It becomes possible to decrease. In the high-speed printing mode, the supply amount of dark color ink (deaeration ink) is relatively large. Therefore, in the high-speed printing mode, bubbles are reduced in the dark ink channel. Therefore, by controlling the maintenance operation so that the discharge amount or discharge amount of dark color ink is smaller than the discharge amount or discharge amount of light color ink, the dark color ink can be wasted. It becomes possible to prevent.

  That is, in the present embodiment, if the CL timer T1 shown in FIG. 17 is the same, the liquid consumption in the maintenance operation is higher when the amount of deaeration ink consumed is larger between the light color ink and the dark color ink. Controls to reduce consumption. For this reason, it is possible to effectively utilize the gas solubility of the deaerated ink and to reduce the amount of ink discharged unnecessarily during the maintenance operation.

  In the present embodiment, when the maintenance operation is performed, the print head 33 is ejected idle or the suction pump 65 is operated to discharge more deaerated ink. Here, when the print head 33 is idle, a small amount of liquid can be discharged, and when the suction pump 65 is operated, a larger amount of deaerated ink can be discharged, and various maintenance operations can be performed.

  In the present embodiment, the cap 61 is provided with a partition wall 62, and the inside of the cap 61 corresponds to the internal space 61A corresponding to the first cartridge group 51A and the second cartridge group 51B. It is partitioned off from the internal space 61B. The internal space 61A and the internal space 61B can be sealed independently. For this reason, an optimum maintenance operation (cleaning operation) can be executed in correspondence with the nozzle rows of the respective cartridge groups 51A and 51B. Further, since the internal spaces 61A and 61B corresponding to the respective cartridge groups 51A and 51B can be sucked independently, it is not necessary to suck ink wastefully, which is economical for the user.

  Further, since the amount of deaerated ink consumed in the maintenance operation is increased as the CL timer T1 elapses, the amount of bubbles discharged together with the deaerated ink can be increased. That is, by supplying a large amount of degassed ink with high bubble solubility over time, more bubbles remaining in the flow path can be dissolved.

  Further, in the present embodiment, since the maintenance operation executed by the print head 33 or the suction pump 65 is controlled based on a table that changes stepwise, the amount of data can be reduced and the calculation can be performed. It can be simplified.

<Modification of the present invention>
Although the first to third embodiments of the present invention have been described above, the present invention can be variously modified in addition to this. This will be described below.

  In the ink jet printer 10 according to the first embodiment described above, the temperature detection unit 84 that detects the temperature of the print head 33 is mounted, the temperature detected by the temperature detection unit 84 is regarded as the temperature of the ink, and then It is used for various processes. In contrast, the temperature detection unit 84 is provided at a position in contact with the ink on the flow path from the ink cartridge 51 to the print head 33, and the temperature of the ink itself detected by the temperature detection unit 84 is used for each subsequent process. Also good.

  In the first embodiment described above, the main control unit 71 resets the value of the CL timer 77 to 0 when the cleaning operation is performed, and every time one day (24 hours) elapses from that time, the main control unit 71 in FIG. The timing for executing the next cleaning operation is specified through a series of processes. On the other hand, the time interval for executing a series of processes for specifying the timing of execution of the cleaning operation need not be every day, and can be set to an appropriate date and time.

  In the first embodiment described above, a mechanism for executing a cleaning operation which is one of the operations for recovering the ink storage environment in the cavity of the print head 33 is mounted, and this cleaning operation is executed. The timing is specified from the relationship between the ink consumption and the temperature. On the other hand, a mechanism for executing an operation for recovering the ink storage environment, such as a flushing operation and a deaeration ink addition operation, is installed, and the timing of executing the operation is determined as an ink consumption amount. You may make it identify from the relationship of temperature.

  Further, in the second or third embodiment described above, a stepwise matrix type as shown in FIGS. 10 and 17 is used as the maintenance table. However, the maintenance table is not in a matrix form, and may be designed so that any maintenance operation exists between areas existing between straight lines (or curves) as shown in the graph of FIG. Good.

  In each of the above-described embodiments, the printer 10 is a so-called off-carriage type printer 10 in which the ink cartridge 51 is mounted on the chassis 21 side. However, the printer 10 is not limited to the off-carriage type, and may be a so-called on-carriage type in which the ink cartridge 51 is mounted on the carriage 31.

  In the second and third embodiments described above, the maintenance table is described as having a five-stage maintenance operation of Fl small, Fl large, timer CL2, timer CL3, and timer CL4. However, the maintenance operation is not limited to five stages, and may be any number of stages as long as it is two or more stages. Further, chalk cleaning may or may not be included in the maintenance operation.

  In addition to the configurations of the above-described embodiments, the pressure pump 53 may pressurize the deaerated ink in the flow path by a predetermined amount so as to accelerate the dissolution of bubbles in the deaerated ink. . In addition, as a configuration for accelerating dissolution, a configuration including a means for applying an ultrasonic wave (ultrasonic wave generator) inside the flow path, or a means for controlling a temperature (such as a Peltier element) is used. May be adopted. By adopting these configurations and operating each means, it is possible to further accelerate (accelerate) the bubble dissolution rate.

  In addition, the printer 10 in each of the above-described embodiments may be a part of a complex device such as a configuration including functions (scanner function, copy function, etc.) other than the printer function. Further, the liquid ejection device is not limited to the printer 10. Examples of the liquid ejecting apparatus other than the printer 10 include a liquid ejecting apparatus used for manufacturing a liquid crystal display, an EL display, and the like. In addition, the liquid may be a liquid other than ink. For example, in a device for ejecting a liquid used for a liquid crystal display or an EL display, the color material and the electrode material are liquid. In addition, the liquid is not limited to deaerated ink, and ink in which bubbles are dissolved by a predetermined amount (saturated ink or the like) may be used. When using saturated ink, additional work such as pressurization or cooling is required.

1 is a perspective view illustrating a schematic configuration of a printer according to a first embodiment of the present invention. It is a figure which shows schematic structure of the printer of FIG. FIG. 2 is a perspective view illustrating a configuration of a cartridge holder in the printer of FIG. 1. FIG. 2 is a perspective view illustrating a configuration of an ink cartridge in the printer of FIG. 1. It is a figure which shows schematic structure of the cleaning mechanism in the printer of FIG. FIG. 2 is a diagram illustrating a schematic configuration centering on a control unit of the printer of FIG. 1. It is a flowchart which shows the procedure of cleaning operation | movement. It is a graph which shows the correlation between the bubble growth rate and the ink temperature. It is a graph which shows the relationship between the volume of a bubble, the flow velocity of ink, and a pressure loss. It is a figure which shows the maintenance table which concerns on 2nd Embodiment. It is a figure which shows the conventional maintenance table. It is a figure which shows the flow regarding the maintenance operation | movement at the time of power-on. It is a figure which shows the relationship between the flow rate of cleaning, bubble volume, and pressure loss. It is a figure which shows the flow regarding the maintenance operation | movement at the time of a printing start. It is a figure which shows schematic structure of the cleaning mechanism which concerns on 3rd Embodiment. It is a figure which shows schematic structure centering on the control part which concerns on 3rd Embodiment. It is a figure which shows the maintenance table which concerns on 3rd Embodiment. It is a figure which shows the modification of a maintenance table.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printer, 30 ... Carriage mechanism, 31 ... Carriage, 33 ... Print head (corresponding to discharge head), 50 ... Ink supply mechanism, 51 ... Ink cartridge, 60 ... Cleaning mechanism, 61 ... Cap, 62 ... Septum, 64 ... Control valve, 65 ... suction pump (corresponding to a part of the recovery means), 70 ... control unit (corresponding to a part of the recovery means, growth rate specifying means, dissolution rate specifying means, consumption detecting means and timing specifying means), 72: Memory, 73: Head control unit, 74: Pump control unit (corresponding to a part of the recovery means), 75 ... CR motor control unit, 76 ... Valve control unit, 77 ... CL timer, 78 ... Ink consumption calculation unit (Corresponding to consumption detecting means), 79 ... cartridge memory control section, 84 ... temperature detecting section (corresponding to temperature detecting means), 90 ... computer

Claims (3)

An ejection head having a nozzle opening for discharging the cavity and the liquid for storing the liquid supplied from a liquid supply source,
Temperature detecting means for detecting the temperature of the liquid;
Consumption detecting means for detecting consumption of liquid discharged from the discharge head;
Means for performing a recovery operation for recovering the operation of discharging the liquid,
Recovery means for determining the timing of performing the recovery operation according to the relationship between the temperature and the consumption amount of the liquid ;
The first correlation data indicating the relationship between the growth speed of bubbles generated in the cavity and the temperature of the liquid is stored, and the discharge speed of the liquid from the nozzle opening and the dissolution speed of bubbles dissolved in the liquid are stored. Memory for storing second correlation data indicating the relationship between
The recovery means identifies the bubble growth rate according to the temperature detected by the temperature detection means based on the first correlation data stored in the memory, and the consumption of the liquid detected by the consumption detection means The discharge speed of the liquid is calculated based on the amount, and the bubble dissolution speed corresponding to the discharge speed is specified based on the second correlation data stored in the memory, and the specified growth speed is specified. A liquid ejecting apparatus characterized in that a difference in dissolution rate is obtained, and a timing at which the recovery means performs a recovery operation according to the determined difference .   The liquid ejecting apparatus according to claim 1, wherein the liquid is deaerated ink. A discharge head having a cavity for storing liquid and a nozzle opening for discharging the liquid; temperature detecting means for detecting the temperature of the liquid; consumption detecting means for detecting the consumption of liquid discharged from the discharge head; Recovery means for recovering the operation of discharging the liquid, the recovery means for determining the timing for performing the recovery operation according to the relationship between the temperature and the consumption amount of the liquid, and the inside of the cavity The first correlation data indicating the relationship between the growth rate of bubbles generated in the liquid and the temperature of the liquid is stored, and the relationship between the discharge rate of the liquid from the nozzle opening and the dissolution rate of bubbles dissolved in the liquid And a memory for storing second correlation data indicating:
A growth rate specifying step of specifying a bubble growth rate according to the temperature detected by the temperature detection means based on the first correlation data stored in the memory;
The liquid discharge speed is calculated based on the liquid consumption detected by the consumption detection means, and the bubble dissolution speed corresponding to the liquid discharge speed is calculated based on the second correlation data stored in the memory. A specific process for determining the dissolution rate, and
Obtaining a difference between the specified growth rate and the specified dissolution rate, and a timing specifying step for specifying a timing for causing the recovery means to perform a recovery operation according to the determined difference;
A recovery operation control method.

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