JP2007245619A - Liquid jet device and flushing method in liquid jet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet device and a flushing method in liquid jet device capable of suppressing the excessive consumption of a liquid by controlling the jet quantity of the liquid when flushing. <P>SOLUTION: The control section of the inkjet type printer measures a first lapse time from the time of completion of last cleaning and measures a second lapse time T2 from the time of completion of last flushing. The control section determines a flushing pattern such that the longer the second lapse time T2 is the larger the jet quantity from the recording head in the next flushing time is. The control section executes cleaning when the first lapse time is a cleaning time threshold value or more. While the control section executes the flushing executed prior to jetting the ink to the recording paper based on the flushing pattern determined based on the long or short state of the second lapse time T2 when the first lapse time is less than the cleaning time threshold value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer, and a flushing method of the liquid ejecting apparatus.

  In general, as a liquid ejecting apparatus that ejects liquid from a recording head as a liquid ejecting head to a target, an ink jet printer that ejects ink (liquid) onto a recording sheet (target) (hereinafter simply referred to as “printer”). )It has been known. The printer includes a recording head mounted on a carriage that reciprocates along the main scanning direction, and a recording paper conveyance mechanism that conveys the recording paper in the sub-scanning direction. The recording head is supplied from within the cartridge. Nozzles for ejecting ink toward the recording paper are formed.

  By the way, in such a printer, there is a possibility that an ink ejection defect may occur due to bubbles generated in the nozzles of the recording head or the thickened ink adhering to the nozzle openings. . Therefore, in order to solve such a problem, in such a printer, cleaning is performed to suck ink from the nozzles of the recording head by driving the suction pump in a state where the nozzle forming surface of the recording head is sealed with a cap. It has become so. That is, in this printer, in addition to when the cleaning switch is operated, when the printer is turned on, when the elapsed time from the end of the previous cleaning exceeds a predetermined time or when the printer is turned on, Cleaning is performed when the elapsed time is equal to or longer than a predetermined time in a power-on state (for example, Patent Document 1).

  In addition, in the printer described in Patent Document 1, by applying a drive signal unrelated to printing (liquid ejection to a target) to the recording head, for example, ink is ejected from the nozzles of the recording head into the cap (empty ejection). Flushing is performed. This flushing may be executed by appropriately interrupting the printing operation during printing, and is also executed immediately before the start of printing on the recording paper (hereinafter referred to as “before printing”).

Regarding the pre-print flushing executed before printing, in the printer described in Patent Document 1, a plurality of types (for example, four types) of flushing patterns corresponding to the elapsed time from the end of the previous cleaning are displayed on the control unit of the printer. Is set in the ROM provided in. That is, the ROM has a plurality of types of flushing corresponding to the length of the elapsed time so that the longer the elapsed time from the end of the previous cleaning, the greater the amount of ink ejected from the nozzles of the recording head. A pattern was set. When performing the pre-printing flushing, the flushing based on the flushing pattern selected from the respective flushing patterns according to the length of the elapsed time is performed.
JP 2000-289229 A

  By the way, in the printer described in Patent Document 1, when performing pre-printing flushing, one of the flushing patterns is selected based on the elapsed time from the end of the previous cleaning. When the elapsed time is long, the flushing pattern with the largest ink discharge amount is selected, and powerful flushing based on the flushing pattern is executed.

  For this reason, when printing is performed again on the recording paper after the pre-printing flushing is completed and before a new cleaning is performed, the elapsed time from the end of the previous cleaning is still long. The flushing pattern with the largest ink discharge amount is selected again. Then, powerful flushing based on the selected flushing pattern is continuously executed.

  That is, it was based on the flushing pattern with the largest ink discharge amount even though the adhering matter (thickened ink, dust, etc.) adhering to the vicinity of the recording head nozzle opening was removed by the previous powerful flushing. Intense flushing is performed again, resulting in excessive ink ejection. Therefore, in the printer described in Patent Document 1, there is a possibility that ink is consumed more than necessary due to excessive ejection of ink during such flushing.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid ejecting apparatus and a liquid ejecting apparatus that can suppress excessive consumption of liquid by adjusting the amount of liquid ejected during flushing. To provide a flushing method.

  In order to achieve the above object, the liquid ejecting apparatus of the present invention causes the cleaning unit to perform cleaning for sucking the liquid from the nozzle of the liquid ejecting head, and before the liquid ejecting onto the target, A liquid ejecting apparatus that performs flushing, wherein a first elapsed time measuring unit that measures a first elapsed time from the end of the previous cleaning, and a second elapsed time that measures a second elapsed time from the end of the previous flushing Time measuring means, pattern determining means for determining a flushing pattern so that the amount of the liquid ejected from the liquid ejecting head at the next flushing time increases as the second elapsed time increases, and the first elapsed time measurement Whether the first elapsed time measured by the means is equal to or greater than a preset cleaning time threshold value And when the determination result by the cleaning determination unit is negative, the control unit controls the cleaning unit to perform cleaning while the determination result by the cleaning determination unit is negative. Comprises control means for controlling the liquid ejecting head in order to perform flushing executed before liquid ejection to the target based on the flushing pattern determined by the pattern determining means.

  According to the present invention, the flushing pattern is determined such that the amount of liquid ejected from the liquid ejecting head at the next flushing increases as the second elapsed time from the end of the previous flushing is longer. When the first elapsed time from the end of the previous cleaning is less than the cleaning time threshold, the flushing based on the flushing pattern determined according to the length of the second elapsed time is performed before the liquid is jetted onto the target. To be executed. That is, unlike the conventional case in which the flushing pattern is determined based on the first elapsed time from the end of the previous cleaning, flushing (strong flushing) in which the amount of liquid ejected from the liquid ejecting head is relatively large is executed. As a result, it is avoided that powerful flushing is performed again in the state where the adhering material (such as thickened liquid or dust) adhering to the vicinity of the nozzle opening of the liquid ejecting head has already been removed. Therefore, excessive consumption of the liquid can be suppressed by adjusting the liquid ejection amount during the flushing.

  In the liquid ejecting apparatus according to the aspect of the invention, the cleaning unit may include a cap capable of sealing the nozzle forming surface of the liquid ejecting head, and a nozzle inside the nozzle forming surface in a state where the cap seals the nozzle forming surface. And a suction means that is driven to suck the liquid from, and the control means injects an amount of liquid into the cap based on the flushing pattern determined by the pattern determination means during the flushing. The liquid jet head is controlled so that

  According to the present invention, the liquid ejected from the nozzle of the liquid ejecting head during flushing is received in the cap of the cleaning means. Therefore, unlike the case where a member for receiving the liquid ejected from the liquid ejecting head at the time of flushing is separately provided in addition to the cap, an increase in the number of parts is suppressed satisfactorily.

  In the liquid ejecting apparatus according to the aspect of the invention, the second elapsed time measuring unit may measure a second elapsed time from the end of flushing performed before the liquid ejecting head ejects the liquid onto the target.

  In general, flushing may be performed during printing as well as before liquid jetting to a target (so-called printing). Here, if the second elapsed time from the end of the flushing executed during printing is measured, the time that is the starting point for measuring the second elapsed time during printing is stored, 2 It is necessary to reset the elapsed time to “0 (zero)”. Therefore, the control load of the second elapsed time measuring means during printing increases, and as a result, there is a possibility that the time spent for printing on the target by the liquid ejecting apparatus becomes longer. However, in the present invention, the second elapsed time from the end of the flushing executed before printing is measured without measuring the second elapsed time from the end of the flushing executed during printing. Therefore, as a result of reducing the control load of the second elapsed time measuring means during printing, it is possible to suppress an increase in printing time.

  The liquid ejecting apparatus of the present invention stores a plurality of flushing patterns set so that the ejection amount of the liquid differs according to the length of the second elapsed time measured by the second elapsed time measuring unit. The apparatus further includes a storage unit, and the pattern determination unit reads out the flushing pattern corresponding to the second elapsed time measured by the second elapsed time measurement unit from the storage unit.

  According to this invention, each flushing pattern is set and stored in the storage unit in correspondence with the length of the second elapsed time measured by the second elapsed time measuring unit. Therefore, in order to set the flushing pattern corresponding to the length of the second elapsed time, it is not necessary to perform a complicated calculation using a relational expression or the like. Therefore, the processing load of the pattern determining means is reduced well.

  On the other hand, the flushing method for a liquid ejecting apparatus according to the present invention is executed before the liquid ejecting to the target in the liquid ejecting head separately from the cleaning for sucking the liquid from the nozzle formed on the nozzle forming surface of the liquid ejecting head. The flushing method of the liquid ejecting apparatus according to the present invention measures the first elapsed time from the end of the previous cleaning and also measures the second elapsed time from the end of the previous flushing. A flushing pattern is determined so that the amount of the liquid ejected from the liquid ejecting head at the next flushing is increased, and cleaning is performed when the first elapsed time is equal to or greater than a preset cleaning time threshold. On the other hand, if the first elapsed time is less than the cleaning time threshold, the target The flushing is performed in prior to the liquid jet, and so as to execute on the basis of the flushing pattern determined in accordance with the length degree of the second elapsed time.

  According to the present invention, the flushing pattern is determined such that the amount of liquid ejected from the liquid ejecting head at the next flushing increases as the second elapsed time from the end of the previous flushing is longer. When the first elapsed time from the end of the previous cleaning is less than the cleaning time threshold, the flushing based on the flushing pattern determined according to the length of the second elapsed time is performed before the liquid is jetted onto the target. To be executed. That is, unlike the conventional case in which the flushing pattern is determined based on the first elapsed time from the end of the previous cleaning, flushing with a relatively large amount of liquid ejected from the liquid ejecting head (strong flushing) is executed. As a result, it is avoided that powerful flushing is performed again in the state where the adhering material (such as thickened liquid or dust) adhering to the vicinity of the nozzle opening of the liquid ejecting head has already been removed. Therefore, excessive consumption of the liquid can be suppressed by adjusting the liquid ejection amount during the flushing.

  Hereinafter, an embodiment in which the present invention is embodied in an ink jet printer will be described with reference to FIGS. In the following description of the present specification, the terms “front-rear direction”, “left-right direction”, and “up-down direction” indicate the front-rear direction, left-right direction, and up-down direction indicated by arrows in FIG. .

  As shown in FIG. 1, an ink jet printer 11 as a liquid ejecting apparatus includes a frame 12 having a rectangular shape in plan view. A platen 13 extending in the left-right direction is provided in the frame 12, and the recording paper P is fed onto the platen 13 by a paper feed mechanism configured to have a paper feed motor 14 outside the frame 12. It has become so. A rod-shaped guide member 15 is installed above the platen 13 in the frame 12 in parallel with the longitudinal direction (left-right direction) of the platen 13.

  A carriage 16 is supported on the guide member 15 such that the carriage 16 can reciprocate in the axial direction (left-right direction) with respect to the guide member 15. A part of the carriage 16 is fixed to a timing belt 17 stretched between a pair of pulleys 17 a provided on the rear surface in the frame 12. The carriage 16 is reciprocated along the guide member 15 as the timing belt 17 is reciprocated by driving the carriage motor 18.

  A recording head 19 as a liquid ejecting head is mounted on the lower surface of the carriage 16, and the lower surface of the recording head 19 includes a plurality of nozzles 20 (only four are shown in FIG. 2) as shown in FIG. 2. The nozzle forming surface 19a is formed. A cartridge 21 is detachably mounted on the carriage 16 above the recording head 19, and ink as a liquid is accommodated in the cartridge 21 so as to be supplied to the recording head 19.

  The ink in the cartridge 21 is supplied from the cartridge 21 to the recording head 19 by driving a piezoelectric element (not shown) provided in the recording head 19, and is fed onto the platen 13 from each nozzle 20 of the recording head 19. The recording paper P is discharged (jetted). That is, printing is performed on the recording paper P. Also, a cleaning mechanism (cleaning means) 23 for cleaning the nozzle forming surface 19a of the recording head 19 at the time of non-printing is provided near the home position region provided in the non-printing region located at the right end portion in the frame 12. It has been.

Next, the cleaning mechanism 23 will be described below with reference to FIGS.
As shown in FIG. 2, the cleaning mechanism 23 includes a cap (sealing means) 24 having a bottomed square box shape, and an elevating device 25 for moving the cap 24 in the vertical direction. When the carriage 16 is moved to the home position area, the cleaning mechanism 23 raises the cap 24 by the lifting device 25 so that the nozzle formation surface 19 a (each nozzle 20) of the recording head 19 is moved by the cap 24. It is designed to be sealed. Further, a protrusion 27 projects downward from the bottom wall of the cap 24, and a discharge path 27 a for discharging ink from the cap 24 extends along the vertical direction in the protrusion 27. Is formed through.

  An upper end portion 29 a of a discharge tube 29 made of a flexible material is connected to the protrusion 27, and a lower end portion 29 b of the discharge tube 29 is inserted into the waste ink tank 30. Further, a suction pump 31 as a suction means is disposed in the middle portion of the discharge tube 29 between the cap 24 and the waste ink tank 30. When the suction pump 31 is driven, the ink in each nozzle 20 of the recording head 19 is sucked and flows in the discharge tube 29, and is discharged into the waste ink tank 30 from the lower end portion 29 b of the discharge tube 29. It has come to be. In the waste ink tank 30, a waste ink absorbing material 32 made of a porous member is accommodated.

Next, the electrical configuration of the ink jet printer 11 will be described with reference to FIG.
As shown in FIG. 3, the ink jet printer 11 includes a control unit 40 as a control unit, and the control unit 40 includes a paper feed motor 14, a carriage motor 18, a lifting device 25, a suction pump 31, and the like. Connected. The motors 14 and 18, the lifting device 25, the suction pump 31, and the like are controlled by the control unit 40 in their driving states.

  The control unit 40 includes an interface 41, a CPU 42, a ROM 43, a RAM 44, an EEPROM (Electrically Erasable and Programmable Read Only Memory) 45, an RTC (Real Time Clock) 46, and the like. The ROM 43 stores various control programs for controlling the ink jet printer 11, various information (tables indicating respective flushing patterns and threshold values described later), and the like. The RAM 44 stores various information that can be appropriately rewritten while the ink jet printer 11 is being driven. Further, the EEPROM 45 stores various information that should not be erased even when the ink jet printer 11 is turned off (such as an end time at the end of cleaning and an end time at the end of flushing, which will be described later). It is like that.

  The RTC 46 keeps time in the ink jet printer 11. Further, a capacitor (not shown) is arranged in the controller 40 so as to be in parallel with the RTC 46. Therefore, even when the power supply from the external power source to the ink jet printer 11 is stopped, the RTC 46 can measure the time while the power is supplied from the capacitor.

Next, the table stored in the ROM 43 will be described with reference to FIG.
The table shown in FIG. 4 shows a plurality of types (four types in this embodiment) of flushing patterns FL1, FL2, FL3, and FL4 that are applied in the next flushing performed by the recording head 19. That is, in the predetermined area of the ROM 43, the respective flushing patterns FL1 to FL4 are set and stored so that the ejection amount (ejection amount) of ink from each nozzle 20 of the recording head 19 at the time of flushing is different. Therefore, in this embodiment, the control part 40 provided with ROM43 functions also as a memory | storage means. Each of the flushing patterns FL1 to FL4 indicates a flushing pattern of flushing that is executed immediately before the printing by the ink jet printer 11 is started.

  Specifically, the first flushing pattern FL1 is selected when the second elapsed time T2 since the last flushing based on the respective flushing patterns FL1 to FL4 is less than the first threshold value KTfl1 (for example, 48 hours). Pattern. The first flushing pattern FL1 is set so that the ink ejection amount (and the number of ink ejections) from each nozzle 20 of the recording head 19 is the smallest among the flushing patterns FL1 to FL4.

  Subsequently, in the second flushing pattern FL2, the second elapsed time T2 after the previous flushing based on the respective flushing patterns FL1 to FL4 is performed is equal to or longer than the first threshold value KTfl1, and the second threshold value KTfl2 (for example, 120 hours). It is a pattern selected when it is less than. The second flushing pattern FL2 is set so that the ink ejection amount (and the number of ink ejections) from each nozzle 20 of the recording head 19 among the flushing patterns FL1 to FL4 is the second smallest. Yes.

  The third flushing pattern FL3 has a second elapsed time T2 that is equal to or longer than the second threshold value KTfl2 and less than the third threshold value KTfl3 (for example, 240 hours) since the last flushing based on the respective flushing patterns FL1 to FL4 is executed. This pattern is selected when The third flushing pattern FL3 is set so that the ink ejection amount (and the number of ink ejections) from each nozzle 20 of the recording head 19 among the flushing patterns FL1 to FL4 is the third smallest. Yes.

  In the fourth flushing pattern FL4, the second elapsed time T2 after the previous flushing based on the respective flushing patterns FL1 to FL4 is performed is not less than the third threshold KTfl3 and less than the cleaning time threshold KTcl (for example, 480 hours). This pattern is selected when The fourth flushing pattern FL4 is set so that the ink ejection amount (and the number of ink ejections) from each nozzle 20 of the recording head 19 is the largest among the flushing patterns FL1 to FL4.

  Each of the threshold values KTfl1 to KTfl3 described above is a value for adjusting the amount of ink discharged from each nozzle 20 of the recording head 19 at the time of flushing according to the second elapsed time T2. Respectively. The cleaning time threshold value KTcl is a value for causing the cleaning mechanism 23 to perform cleaning at predetermined intervals (for example, every 480 hours), and is set in advance through experiments, simulations, or the like.

  Further, in the ink jet printer 11 of the present embodiment, flushing is executed immediately before printing on the recording paper P, and flushing is also executed during printing on the recording paper P. Then, immediately before printing on the recording paper P, flushing based on the above-described flushing patterns FL1 to FL4 is executed. On the other hand, during printing on the recording paper P, flushing for discharging a predetermined amount of ink set in advance from each nozzle 20 of the recording head 19 is executed regardless of the second elapsed time T2.

  Next, a maintenance execution processing routine among the control processing routines executed by the control unit 40 of the present embodiment will be described below based on flowcharts based on FIGS. 5 and 6. The term “maintenance” here refers to cleaning or flushing for removing bubbles generated in the nozzles 20 of the recording head 19 and deposits (such as thickened ink and dust) near the openings of the nozzles 20. It is a general term.

  Now, the control part 40 performs a maintenance execution process routine for every predetermined period (for example, every 0.1 second). In this maintenance execution processing routine, the control unit 40 reads the current time T from the RTC 46, and sets the read current time T in a predetermined area of the RAM 44 (step S10). Subsequently, the control unit 40 reads the cleaning end time information indicating the end time Tcl when the previous cleaning is ended from the EEPROM 45, and sets the end time Tcl in a predetermined area of the RAM 44 (step S11). As will be described in detail later, the cleaning end time Tcl is a time at the end of cleaning by the cleaning mechanism 23, and is stored in the EEPROM 45 as cleaning end time information at the end of cleaning.

  Then, the control unit 40 calculates the first elapsed time T1 by subtracting the cleaning end time Tcl read in step S11 from the current time T read in step S10 (step S12). . Therefore, in this embodiment, the control part 40 functions also as a 1st elapsed time measurement means. Then, the control unit 40 determines whether or not the first elapsed time T1 calculated in step S12 is equal to or greater than the cleaning threshold value KTcl (step S13). Therefore, in the present embodiment, the control unit 40 also functions as a cleaning determination unit.

  When the determination result in step S13 is affirmative (T1 ≧ KTcl), the control unit 40 causes the cleaning mechanism 23 to perform cleaning (step S14). That is, the control unit 40 confirms that the carriage 16 is located in the home position region and drives the lifting device 25 to seal the nozzle forming surface 19a of the recording head 19 with the cap 24, and this state Then, the suction pump 31 is driven. And the control part 40 determines whether the cleaning by the cleaning mechanism 23 was complete | finished (step S15). When this determination result is a negative determination, the control unit 40 repeatedly executes the determination process of step S15 until the determination result of step S15 becomes a positive determination.

  On the other hand, when the determination result of step S15 is affirmative, the control unit 40 reads the current time T from the RTC 46 (step S16). Then, the control unit 40 sets the current time T read in step S16 as the cleaning end time Tcl, and stores the end time Tcl in the EEPROM 45 as the cleaning end time information (step S17). That is, the control unit 40 updates the cleaning end time Tcl. Thereafter, the control unit 40 ends the maintenance execution processing routine.

  On the other hand, if the determination result in step S13 is negative (T1 <KTcl), the control unit 40 determines whether a print command has been input to the control unit 40 (step S18). When this determination result is a negative determination, the control unit 40 ends the maintenance execution processing routine. On the other hand, if the determination result in step S18 is affirmative, the control unit 40 performs the flushing indicating the end time Tfl of the flushing before the previous printing (flushing based on any one of the flushing patterns FL1 to FL4) from the EEPROM 45. The end time information is read, and the end time Tfl is set in a predetermined area of the RAM 44 (step S19). As will be described in detail later, the flushing end time Tfl is the time when the flushing immediately before printing ends, and is stored in the EEPROM 45 as the flushing end time information when flushing before printing ends.

  Subsequently, the control unit 40 calculates the second elapsed time T2 by subtracting the flushing end time Tfl read in step S19 from the current time T read in step S10 (step S20). ). Therefore, in this point, in this embodiment, the control unit 40 also functions as a second elapsed time measuring unit. Then, the control unit 40 determines whether or not the second elapsed time T2 calculated in step S20 is less than the first threshold value KTfl1 (step S21).

  If the determination result is affirmative (T2 <KTfl1), the control unit 40 drives the elevating device 25 to move the cap 24 to a position separated from the nozzle forming surface 19a of the recording head 19. Then, the control unit 40 selects the first flushing pattern FL1 from the table shown in FIG. 4 in the ROM 43, and controls the recording head 19 to execute the first flushing corresponding to the first flushing pattern FL1 (step S22). ). Thereafter, the control unit 40 proceeds to step S28, which will be described later.

  On the other hand, when the determination result in step S21 is negative (T2 ≧ KTfl1), the control unit 40 determines whether or not the second elapsed time T2 calculated in step S20 is less than the second threshold value KTfl2. (Step S23). When the determination result is affirmative (KTfl1 ≦ T2 <KTfl2), the control unit 40 drives the lifting device 25 to separate the cap 24 from the nozzle formation surface 19a of the recording head 19. Then, the control unit 40 selects the second flushing pattern FL2 from the table shown in FIG. 4 in the ROM 43, and controls the recording head 19 to execute the second flushing corresponding to the second flushing pattern FL2 (step S24). ). Thereafter, the control unit 40 proceeds to step S28, which will be described later.

  On the other hand, when the determination result in step S23 is negative (T2 ≧ KTfl2), the control unit 40 determines whether or not the second elapsed time T2 calculated in step S20 is less than the third threshold value KTfl3. (Step S25). When the determination result is affirmative (KTfl2 ≦ T2 <KTfl3), the control unit 40 drives the lifting device 25 to separate the cap 24 from the nozzle formation surface 19a of the recording head 19. Then, the control unit 40 selects the third flushing pattern FL3 from the table shown in FIG. 4 in the ROM 43, and controls the recording head 19 to execute the third flushing corresponding to the third flushing pattern FL3 (step S26). ). Thereafter, the control unit 40 proceeds to step S28, which will be described later.

  On the other hand, when the determination result in step S25 is negative (KTfl3 ≦ T2 <KTcl), the control unit 40 drives the lifting device 25 to move the cap 24 away from the nozzle formation surface 19a of the recording head 19. Then, the control unit 40 selects the fourth flushing pattern FL4 from the table shown in FIG. 4 in the ROM 43, and controls the recording head 19 to execute the fourth flushing corresponding to the fourth flushing pattern FL4 (step S27). ). That is, the control unit 40 selects (determines) the flushing patterns FL1 to FL4 such that the longer the second elapsed time T2, the greater the amount of ink ejected from the recording head 19 during flushing. Therefore, in this point, in this embodiment, the control unit 40 also functions as a pattern determination unit. Thereafter, the control unit 40 proceeds to step S28, which will be described later.

  In step S28, the control unit 40 determines whether or not the flushing based on the flushing patterns FL1 to FL4 selected in steps S22, S24, S26, and S27 is completed. When this determination result is a negative determination, the control unit 40 determines that the flushing has not been completed yet, and repeatedly executes the determination process of step S28 until the determination result of step S28 becomes an affirmative determination. On the other hand, if the determination result of step S28 is affirmative, the control unit 40 reads the current time T from the RTC 46 and sets it in a predetermined area of the RAM 44 (step S29). Then, the control unit 40 sets the current time T read in step S29 as the flushing end time Tfl, and stores the end time Tfl in the EEPROM 45 as the flushing end time information (step S30). That is, the control unit 40 updates the flushing end time Tfl. Thereafter, the control unit 40 ends the maintenance execution processing routine.

  Next, the flushing method of the ink jet printer 11 in this embodiment will be described below. As a premise for explanation, the first elapsed time T1 from the end of the previous cleaning is “450 hours”, and the second elapsed time T2 from the end of the flushing immediately before the previous printing is “300 hours”. Shall.

  When the first elapsed time T1 from the end of the previous cleaning is “450 hours” and a print command is input from an external device (not shown) (for example, a host computer), the flushing immediately before the previous print is completed. The fourth flushing pattern FL4 is selected based on the second elapsed time T2 from time (= “300 hours”). Then, when the lifting device 25 is driven, the cap 24 is disposed at a position slightly separated from the nozzle formation surface 19a of the recording head 19 (see FIG. 2B).

  Then, based on the driving of each piezoelectric element in the recording head 19, the ink in the cartridge 21 is supplied into the recording head 19 and discharged from the nozzles 20 of the recording head 19 toward the cap 24. That is, the recording head 19 performs the fourth flushing with the largest number of ink ejections from the nozzles 20 among the flushing patterns based on the flushing patterns FL1 to FL4. Therefore, deposits (thickened ink, dust, etc.) adhering to the vicinity of the openings of the nozzles 20 of the recording head 19 between the end of the previous flushing and the elapse of the second elapsed time T2 are satisfactorily removed. In this state, printing on the recording paper P is executed.

  After that, when the second elapsed time T2 after the completion of the fourth flushing is “1 hour” and the first elapsed time T1 is “451 hours”, the external device has the inside of the control unit 40. Suppose that a print command is input to. Then, the first flushing pattern FL1 is selected based on the second elapsed time T2 (= “1 hour”), and the first flushing based on the first flushing pattern FL1 is executed immediately before printing. Specifically, when the elevating device 25 is driven, the cap 24 moves to a position slightly separated from the nozzle forming surface 19a of the recording head 19, and then each nozzle 20 of the recording head 19 drives the piezoelectric element. Based on this, ink is ejected into the cap 24. Note that the first flushing executed here is the flushing in which the number of ink ejections from each nozzle 20 is the smallest among the flushings based on the respective flushing patterns FL1 to FL4.

  In other words, when the second elapsed time T2 from the end of the previous flushing is relatively short, flushing is performed based on the flushing pattern set so that the number of ink ejections from each nozzle 20 of the recording head 19 is small. . Therefore, the fourth flushing based on the fourth flushing pattern FL4 similar to the flushing performed “one hour” is avoided, and as a result, excessive consumption of ink due to the flushing is suppressed. .

Therefore, in this embodiment, the following effects can be obtained.
(1) In the flushing patterns FL1 to FL4, the discharge amount of ink (liquid) from the recording head (liquid ejecting head) 19 at the next flushing is longer as the second elapsed time T2 from the end of the flushing before the previous printing is longer. It is determined so that (injection amount) increases. When the first elapsed time T1 from the end of the previous cleaning is less than the cleaning time threshold value KTcl, flushing based on the flashing patterns FL1 to FL4 determined according to the length of the second elapsed time T2 is performed. Executed immediately before printing. That is, when the first elapsed time T1 is “450 hours”, for example, and the second elapsed time T2 is “300 hours”, the fourth flushing is executed immediately before printing. Further, at the time of printing several hours later (for example, “1 hour”), the first flushing with less ink consumption is executed immediately before the printing compared to the fourth flushing. Therefore, excessive ink consumption can be suppressed by adjusting the ink ejection amount during flushing.

  (2) Ink (liquid) ejected from each nozzle 20 of the recording head (liquid ejecting head) 19 at the time of flushing is received in the cap 24 of the cleaning mechanism (cleaning means) 23. Therefore, unlike the case where a member for receiving the ink ejected from the recording head 19 at the time of flushing is separately provided in addition to the cap 24, an increase in the number of parts can be suppressed satisfactorily.

  (3) In general, flushing may be performed not only before the liquid is discharged onto the recording paper (target) P (just before printing) but also during printing. Here, if the second elapsed time T2 from the end of the flushing executed during printing is measured, the current time T that is the starting point for measuring the second elapsed time T2 during printing is stored. It is necessary to let Therefore, the control load of the control unit (second elapsed time measuring means) 40 during printing increases, and as a result, the time spent on printing on the recording paper (target) P by the ink jet printer (liquid ejecting apparatus) 11 is as follows. There is a possibility that the length becomes longer than in the case of the present embodiment. However, in the present embodiment, the second elapsed time T2 from the end of the flushing executed immediately before printing is measured without measuring the second elapsed time T2 from the end of the flushing executed during printing. . Therefore, as a result of reducing the control load of the control unit 40 during printing, it is possible to suppress an increase in printing time.

  (4) The flashing patterns FL1 to FL4 are set and stored in the ROM (storage means) 43 corresponding to the length of the second elapsed time T2 measured by the control unit (second elapsed time measuring means) 40. . For this reason, it is not necessary to perform a complicated calculation using a relational expression or the like in order to execute the flushing based on the flushing patterns FL1 to FL4 corresponding to the length of the second elapsed time T2. Therefore, the processing load of the control unit (pattern determining means) 40 can be reduced well.

The above embodiment may be changed to another embodiment (another example) as follows.
In the above embodiment, as shown in FIG. 7, the ROM 43 stores a map indicating the relationship between the second elapsed time T2 and the ink ejection amount from the recording head 19, and the recording head 19 uses the map based on this map. The ink discharge amount (flushing pattern) may be set. Further, the ROM 43 stores a relational expression between the second elapsed time T2 and the ink discharge amount from the recording head 19, and sets the ink discharge amount (flushing pattern) from the recording head 19 based on this relational expression. You may do it.

In the above embodiment, the flushing end time Tfl may be updated even when the flushing executed during printing is completed.
In the above embodiment, a member for storing ink ejected from each nozzle 20 of the recording head 19 during flushing may be provided separately from the cap 24.

In the above embodiment, a timer for measuring the first elapsed time T1 may be provided.
Similarly, a timer for measuring the second elapsed time T2 may be provided.
In the above embodiment, the liquid ejecting apparatus is embodied as the ink jet printer 11, but for example, it is embodied in a liquid ejecting apparatus used for manufacturing a color filter such as a liquid crystal display or pixel formation such as an organic EL display. Also good.

1 is a schematic perspective view of an ink jet printer according to an embodiment. (A) is a schematic diagram of the cleaning mechanism in the present embodiment, (b) is a schematic diagram showing a state in which the cap is moved to a position away from the recording head. The block circuit diagram which shows the electric constitution in this embodiment. A table showing each flushing pattern. The flowchart which shows a maintenance execution process routine (first half part). The flowchart which shows a maintenance execution process routine (second half part). The map which shows the relationship between the 2nd elapsed time and the discharge amount of the ink from a recording head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Inkjet printer (liquid ejecting apparatus), 19 ... Recording head (liquid ejecting head), 19a ... Nozzle formation surface, 20 ... Nozzle, 23 ... Cleaning mechanism (cleaning means), 24 ... Cap, 31 ... Suction pump (suction) Means), 40 ... control unit (first elapsed time measuring means, second elapsed time measuring means, pattern determining means, cleaning determining means, control means, storage means), FL1 to FL4 ... flushing pattern, KTcl ... cleaning time threshold value, P: target, T1: first elapsed time, T2: second elapsed time.

Claims (5)

A liquid ejecting apparatus that causes a cleaning unit to perform cleaning for sucking liquid from the nozzles of the liquid ejecting head and causes the liquid ejecting head to perform flushing before liquid ejection to a target,
First elapsed time measuring means for measuring a first elapsed time from the end of the previous cleaning;
A second elapsed time measuring means for measuring a second elapsed time from the end of the previous flushing;
Pattern determining means for determining a flushing pattern so that the amount of ejection of the liquid from the liquid ejecting head at the next flushing increases as the second elapsed time becomes longer;
Cleaning determining means for determining whether or not the first elapsed time measured by the first elapsed time measuring means is equal to or greater than a preset cleaning time threshold;
When the determination result by the cleaning determination unit is affirmative determination, the cleaning unit is controlled to perform cleaning, while when the determination result by the cleaning determination unit is negative determination, A liquid ejecting apparatus comprising: control means for controlling the liquid ejecting head so that flushing performed before liquid ejection is performed based on the flushing pattern determined by the pattern determining means. The cleaning unit includes a cap capable of sealing the nozzle formation surface of the liquid ejecting head, and is driven to suck liquid from the nozzles of the nozzle formation surface when the cap seals the nozzle formation surface. And a suction means that is configured to cause the liquid ejecting head to eject the amount of liquid ejected into the cap based on the flushing pattern determined by the pattern determining means during the flushing. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is controlled. The said 2nd elapsed time measurement means measures either the 2nd elapsed time from the time of completion | finish of the flushing performed before the liquid jet to the said target by the said liquid jet head. The liquid ejecting apparatus according to 1. Storage means for storing a plurality of flushing patterns set so that the ejection amount of the liquid is different corresponding to the length of the second elapsed time measured by the second elapsed time measuring means;
4. The liquid according to claim 1, wherein the pattern determination unit reads a flushing pattern corresponding to the second elapsed time measured by the second elapsed time measurement unit from the storage unit. 5. Injection device. A flushing method for a liquid ejecting apparatus that is performed before liquid ejection to a target in the liquid ejecting head, separately from cleaning that sucks liquid from the nozzle formed on the nozzle forming surface of the liquid ejecting head,
The first elapsed time from the end of the previous cleaning is measured, and the second elapsed time from the end of the previous flushing is measured. The longer the second elapsed time, the longer the time from the liquid jet head at the time of the next flushing. When a flushing pattern is determined so that the amount of liquid ejected is increased and the first elapsed time is equal to or greater than a preset cleaning time threshold, cleaning is performed, while the first elapsed time is the cleaning time. When the time is less than the time threshold, the liquid ejecting apparatus is configured to perform the flushing performed before the liquid ejection to the target based on the flushing pattern determined according to the length of the second elapsed time. Flushing method.

Images