JP4228526B2 - Inkjet recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus having a function of performing a purge operation for sucking ink from an ink ejection nozzle and an ink flushing operation.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, for example, an inkjet printer is known as an inkjet recording apparatus that performs recording such as printing by ejecting ink onto a recording medium such as paper. In this ink jet printer, an ink cartridge for containing ink is provided so as to be replaceable with respect to a recording head unit including a recording head, ink is supplied from the replaced ink cartridge to the recording head, and ink is ejected from each ejection nozzle. Recording.
[0003]
  In addition, during the use of the ink jet printer, for example, the ink is ejected from the front end side of the ejection nozzle, that is, the nozzle surface where the ejection nozzle opens, for example, by a user's switch operation or when a predetermined condition is satisfied. A so-called purge operation for suction is performed.
[0004]
  This purging operation is an operation in which a suction cap is placed on the nozzle surface, and negative pressure is applied to the inside of the suction cap by a suction pump, whereby ink is sucked from the recording head through the suction cap and removed to the outside. .
[0005]
  In the ink jet printer that performs the purge operation, the nozzle surface of the recording head is moved by bringing the wipe member into contact with the nozzle surface of the recording head and moving the recording head in order to wipe off ink adhering to the nozzle surface during the purging operation. Wiping operation is performed. Further, since the ink mixes between the ejection nozzles of different colors by the wiping operation, the flushing operation is performed subsequent to the wiping operation in order to remove the mixed ink by the ejection.
[0006]
[Problems to be solved by the invention]
  However, ink adheres to the nozzle surface immediately after the purge operation by suction using the negative pressure described above. This ink contains a lot of minute bubbles generated by the intense ink flow caused by the purge operation. On the other hand, since the negative pressure (back pressure) in the direction of pulling back acts on the ink in the recording head by the function of the porous body in the ink cartridge as is well known, the bubbles adhering to the nozzle surface The ink containing the ink is drawn into the recording head by the back pressure. Thereafter, a wiping operation for wiping off the ink on the nozzle surface is performed, but bubbles drawn together with the ink in the recording head cannot be removed. In addition, when the nozzle surface has a plurality of colors of ink ejection nozzles, ink of other colors may be pushed into the nozzles by the wiping operation.
[0007]
  In this way, an ejection operation for discharging bubbles or other colors of ink that have entered the recording head, that is, a flushing operation, is performed. The meniscus will be destroyed and it will not be possible to shift to the recording operation. If jetting is performed at a low frequency, there is a problem that it takes a lot of time to discharge bubbles and ink of other colors.
[0008]
  SUMMARY An advantage of some aspects of the invention is that it provides an ink jet printer capable of stably performing a flushing operation for discharging bubbles and preventing color mixing.
[0009]
[Means for Solving the Problems]
  In order to achieve the above object, an ink jet recording apparatus according to claim 1 is provided.
Has a plurality of ejection nozzles with different colors of ejected inkIn order to improve the ink ejection state with respect to a recording head that performs recording by ejecting ink onto a recording medium, a purge operation for sucking ink in the recording head from the ejection side of the recording head, and the purge In an inkjet recording apparatus that performs a wiping operation for wiping off ink adhering to the nozzles of the recording head performed after the operation and a flushing operation for ejecting ink in the recording head performed after the wiping operation.Determination means for determining whether or not to perform the purge process for each color injection nozzle, and performing the purge operation and the wipe operation only for the injection nozzle determined to perform the purge process by the determination means, After that, only for the injection nozzle that performed the purge operationFlushing operation by a small waveform in which a driving voltage having a waveform that reduces the amount of ink droplets ejected for one dot during recording is applied to the recording head.After that, for the injection nozzle that has performed the purge operation and the injection nozzle that has not performed the purge operationA flushing operation using a large corrugated waveform in which a drive voltage having a waveform in which the amount of ink droplets ejected for one dot is larger than the amount of ink having a small corrugated waveform is applied to the recording head.In the flushing operation using the large ball waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation.It is the structure characterized by this.
[0010]
  In the ink jet recording apparatus of this configuration,The purge operation and the wipe operation are performed only for the ejection nozzles that are determined to perform the purge process, and then only for the ejection nozzles that have performed the purge operation.Flushing operation by a small waveform in which a driving voltage having a waveform that reduces the amount of ink droplets ejected for one dot during recording is applied to the recording head.After that, for the injection nozzle that has performed the purge operation and the injection nozzle that has not performed the purge operationA flushing operation using a large corrugated waveform in which a drive voltage having a waveform in which the amount of ink droplets ejected for one dot is larger than the amount of ink having a small corrugated waveform is applied to the recording head.In the flushing operation using the large ball waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation.Therefore, it is possible to eject the ink necessary for discharging the bubbles and preventing color mixing in a relatively short time, and the flushing by the large corrugation can be suppressed in a short time, so that the meniscus is not destroyed.
[0011]
  In addition, in the ink jet recording apparatus of the invention according to claim 2, in addition to the configuration of the ink jet recording apparatus according to claim 1, the large ball waveform has more ejection pulses than the small ball waveform for the one dot. It has the structure characterized by having.
[0012]
  In the ink jet recording apparatus having this configuration, in addition to the operation of the ink jet recording apparatus according to claim 1, the large ball waveform can be realized by increasing the pulses of the small ball waveform.
[0013]
  In the ink jet recording apparatus of the invention according to claim 3,Has a plurality of ejection nozzles with different colors of ejected inkIn order to improve the ink ejection state with respect to a recording head that performs recording by ejecting ink onto a recording medium, a purge operation for sucking ink in the recording head from the ejection side of the recording head, and the purge In an inkjet recording apparatus that performs a wiping operation for wiping off ink adhering to the nozzles of the recording head performed after the operation and a flushing operation for ejecting ink in the recording head performed after the wiping operation.Determination means for determining whether or not to perform the purge process for each color injection nozzle, and performing the purge operation and the wipe operation only for the injection nozzle determined to perform the purge process by the determination means, After that, only for the injection nozzle that performed the purge operationFlushing operation by a stable waveform in which a driving voltage having a waveform with small pressure fluctuation of ink in the recording head is applied to the recording headAfter that, the injection nozzle that performed the purge operation and the For injection nozzles that have not been purgedFlushing operation by an unstable waveform in which a drive voltage having a waveform with large pressure fluctuation of ink in the print head is applied to the print headIn the flushing operation using the unstable waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation.It is the structure characterized by this.
[0014]
  In the ink jet recording apparatus of this configuration,The purge operation and the wipe operation are performed only for the ejection nozzles that are determined to perform the purge process, and then only for the ejection nozzles that have performed the purge operation.Flushing operation by a stable waveform in which a driving voltage having a waveform with small pressure fluctuation of ink in the recording head is applied to the recording headAfter that, for the injection nozzle that has performed the purge operation and the injection nozzle that has not performed the purge operationFlushing operation by an unstable waveform in which a drive voltage having a waveform with large pressure fluctuation of ink in the print head is applied to the print headIn the flushing operation using the unstable waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation.Therefore, it is possible to eject ink as much as necessary for discharging bubbles and preventing color mixing in a relatively short time, and flushing by an unstable waveform can be suppressed in a short time, so that the meniscus is not destroyed.
[0015]
  In addition, in the ink jet recording apparatus of the invention according to claim 4, in addition to the configuration of the ink jet recording apparatus according to claim 3, the unstable waveform has more ejection pulses than the stable waveform for one dot. It is the structure characterized by this.
[0016]
  In the ink jet recording apparatus having this configuration, in addition to the operation of the ink jet recording apparatus according to the third aspect, the unstable waveform can be realized by increasing the number of ejection pulses for one dot than the stable waveform.
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, an embodiment of a recording apparatus of the present invention will be described with reference to the drawings. First, the internal configuration of an ink jet printer 1 which is an embodiment of a recording apparatus of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing an internal structure of the ink jet printer 1. FIG. 2 is an enlarged view of the maintenance / recovery mechanism RM.
[0017]
  As shown in FIG. 1, a carriage 8 is provided inside a housing 2 of the inkjet printer 1, and the carriage 8 is slidably supported by a guide rod 11 and a guide member 12, and is supported by a belt 13. It is fixed and driven by the CR motor 16 to reciprocate. A recording head unit 17 having a recording head 18 for recording such as printing is attached to the carriage 8. The recording head 18 is an ink jet type that performs recording operation by ejecting ink droplets of four colors of ink (cyan c, magenta m, yellow y, black b) onto a recording paper P that is a recording medium. On the recording paper P side, four ejection nozzle groups of cyan, magenta, yellow, and black are provided in order to eject each color ink.
[0018]
  The recording head unit 17 is detachably mounted with four ink cartridges 22y, 22m, 22c, and 22b that supply ink of each color to each ejection nozzle. In the recording head 18, a large number of (for example, 64) channels (not shown) serving as ink flow paths are formed by cutting a large number of concave portions in parallel and linearly on the material of the piezoelectric element. . This channel opens at the nozzle surface 23 to form a large number of injection nozzles (injection holes).
[0019]
  Therefore, ink can be ejected from a desired ejection nozzle by applying a voltage of a predetermined frequency using the piezoelectric element at the position constituting the wall surface of each channel as an actuator.
[0020]
  Further, in the ink jet printer 1 of the present embodiment, as shown in FIG. 1, a platen roller 25 that conveys the recording paper P is provided at a position facing the recording head 18, and the platen roller 25 is configured as shown in FIG. The recording paper P is conveyed in the direction of the arrow shown in FIG. 1 by the rotation of the LF motor 24 shown in FIG.
[0021]
  As shown in FIGS. 1 and 2, a maintenance / recovery mechanism RM that performs maintenance / recovery of the ink ejection operation of the recording head 18 is provided in the lower left portion (in FIG. 1) of the housing 2. . This maintenance / recovery mechanism RM may cause ink to dry during use of the recording head 18, bubbles may be generated inside the ink, or ink droplets may adhere to the nozzle surface 23 of the ejection nozzle. A suction means 26 for eliminating the ejection failure that occurs, a storage cap 27 that covers the nozzle surface 23 to prevent ink drying when the inkjet printer 1 is not used, and a wiper member 28 that wipes the nozzle surface 23 are provided. Further, as shown in FIG. 1, a flushing receiving member 7 that receives ink ejected from the recording head 18 is provided at the right end (in FIG. 1) in the housing 2. The flushing receiving member 7 is made of a material having high hygroscopicity of ink such as felt.
[0022]
  The suction means 26 has a suction cap 33 that can be brought into close contact with or separated from the surface 23 of each ejection nozzle of the recording head 18, and the suction cap 33 when the suction cap 33 is in close contact with the recording head 18. And a suction pump 34 for sucking ink through the. The suction means 26 drives the suction cap 33 and the wiper member 28 forward and backward toward the recording head 18 by a cam member 36 and a cam drive motor (not shown), and drives the suction pump 34 to drive the suction cap 33. Through the suction operation (purge operation).
[0023]
  Next, with reference to FIG. 3, the electrical configuration of the ink jet printer 1 of the present embodiment will be described. FIG. 3 is a block diagram showing an electrical configuration of the ink jet printer 1.
[0024]
  As shown in FIG. 3, the inkjet printer 1 is provided with a one-chip CPU 50 that controls the entire inkjet printer 1, and the CPU 50 temporarily receives data via a data bus B1 and an address bus B2. A RAM 51 for storage and a ROM 52 for storing various control programs are connected. The CPU 50 is connected to a control circuit 57 composed of a gate array via a data bus B1 and an address bus B2. The control circuit 57 includes an image memory 58 for developing print data and a personal computer 60. The connected Centronics interface 59 is connected.
[0025]
  Here, the CPU 50 generates the print timing signal TS and the control signal RS according to the program stored in the ROM 52 and transfers them to the control circuit 57. In the control circuit 57, based on the image data stored in the image memory 58 in accordance with the print timing signal TS and the control signal RS, transfer data DATA for printing for forming the image data on the recording paper P, and the transfer A transfer clock TCK, a strobe signal STB, and a print clock ICK that are synchronized with the data DATA are generated and transferred to the drive circuit 61. The control circuit 57 generates a Centronics data interrupt signal WS based on the Centronics data transferred from the external device such as the personal computer 60 via the Centronics interface 59, and transfers the generated data to the CPU.
[0026]
  The drive circuit 61 is connected to the control circuit 57 via the harness cable 62, and the transfer data DATA for printing, the transfer clock TCK, the strobe signal STB, and the print clock ICK are input from the control circuit 57 to the drive circuit 61. The These transfer data DATA for printing, transfer clock TCK, strobe signal STB, and print clock ICK are low voltage signals of approximately 5V.
[0027]
  Further, the drive circuit 61 is connected to the recording head 18 via a harness cable 63. Since the recording head 18 is composed of a shear mode piezoelectric actuator, a signal flowing through the harness cable 63 is approximately The signal is a relatively high voltage of 20V. The harness cables 62 and 63 are formed of a flexible printed circuit board.
[0028]
  The CPU 50 is connected to an operation panel 53 for inputting various commands. Further, the CPU 50 is connected to the CR motor 16 that drives the carriage 8 via the CR motor drive circuit 54, and the CPU 50 is connected to the LF motor 24 that drives the platen roller 25 via the LF motor drive circuit 55. Is connected. Further, a maintenance / recovery mechanism drive circuit 56 is connected to the CPU 50, and the maintenance / recovery mechanism drive circuit 56 is configured to control the maintenance / recovery mechanism RM.
[0029]
  Next, the configuration of the drive circuit 61 will be described with reference to FIG. FIG. 4 is a diagram illustrating an internal configuration of the drive circuit 61.
[0030]
  As shown in FIG. 4, the drive circuit 61 includes a serial / parallel converter 71, a data latch 72, an AND gate 73, and an output circuit 74. The serial-parallel converter 71 is composed of a shift register having the same number of bit lengths as the ink flow paths in the recording head 18, and transfers the transfer data DATA for printing serially transferred from the control circuit 57 in synchronization with the transfer clock TCK. Input and convert to parallel data PD0 to PD63. The data latch 72 latches the parallel data PD0 to PD63 in accordance with the rising edge of the strobe signal STB transferred from the control circuit 57.
[0031]
  The AND gate 73 calculates the logical product of each parallel data PD0 to PD63 output from the data latch 72 and the print clock ICK transferred from the control circuit 57, and generates drive data A0 to A63. The output circuit 74 generates a 20V pulse signal based on the drive data A0 to A63, and outputs the output signal to the actuator of the piezoelectric element provided in the print head 18.
[0032]
  Next, the maintenance process of the inkjet printer 1 of the present embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing a maintenance process of the ink jet printer 1, and FIG. 6 is a drive waveform diagram of ink ejection used in the ink jet printer 1. The maintenance processing program shown in FIG. 5 is stored in the ROM 52 shown in FIG.
[0033]
  In the inkjet printer 1, after the ink cartridges 22y, 22m, 22c, and 22b are replaced, a maintenance process (initial purge) at the time of initial introduction is performed. In addition, even when the user finds a missing pixel in printing, a maintenance process is performed by operating a purge button (not shown) provided on the operation panel 53. Further, when a predetermined time has elapsed since the previous maintenance process, the maintenance process is automatically performed.
[0034]
  As shown in FIG. 5, when the maintenance process is started, it is determined which color of the ejection nozzle has been replaced by the ink cartridge or instructed for the purge process by a purge button or the like (S1, S5, S9, S13). When the ejection nozzle to be purged is a black ink ejection nozzle (S1: YES), the carriage 8 is moved so that the black ink ejection nozzle of the recording head 18 faces the suction cap 33. (S2).
[0035]
  Next, the suction cap 33 is brought into contact with the black ink ejection nozzle of the recording head 18, and the suction pump 34 is driven to perform a purge operation (suction operation) through the suction cap 33 (S3). Next, the carriage 8 is moved, and the wiper member 28 wipes the black ink ejection nozzle surface of the recording head 18 (S4), and the process proceeds to S5. If it is determined in S1 that the purge operation of the black ink ejection nozzle of the recording head 18 is not performed (S1: NO), the process proceeds to S5.
[0036]
  When the ejection nozzle to be purged is a yellow ink ejection nozzle (S5: YES), the carriage 8 is moved so that the yellow ink ejection nozzle of the recording head 18 faces the suction cap 33. (S6).
[0037]
  Next, the suction cap 33 is brought into contact with the yellow ink ejection nozzle of the recording head 18, and the suction pump 34 is driven to perform a purge operation (suction operation) through the suction cap 33 (S7). Next, the carriage 8 is moved, the wiper member 28 wipes the yellow ink ejection nozzle surface of the recording head 18 (S8), and the process proceeds to S9. If it is determined in S5 that the yellow ink ejection nozzle purge operation of the recording head 18 is not performed (S5: NO), the process proceeds to S9.
[0038]
  When the ejection nozzle to be purged is a cyan ink ejection nozzle (S9: YES), the carriage 8 is moved so that the cyan ink ejection nozzle of the recording head 18 faces the suction cap 33. (S10).
[0039]
  Next, the suction cap 33 is brought into contact with the cyan ink ejection nozzle of the recording head 18, and the suction pump 34 is driven to perform a purge operation (suction operation) through the suction cap 33 (S11). Next, the carriage 8 is moved, and the wiper member 28 wipes the cyan ink ejection nozzle surface of the recording head 18 (S12), and the process proceeds to S13. If it is determined in S9 that the purge operation of the cyan ink ejection nozzle of the recording head 18 is not performed (S9: NO), the process proceeds to S13.
[0040]
  When the ejection nozzle to be purged is a magenta ink ejection nozzle (S13: YES), the carriage 8 is moved so that the magenta ink ejection nozzle of the recording head 18 faces the suction cap 33. (S14).
[0041]
  Next, the suction cap 33 is brought into contact with the magenta ink ejection nozzle of the recording head 18, and the suction pump 34 is driven to perform a purge operation (suction operation) through the suction cap 33 (S15). Next, the carriage 8 is moved to wipe the magenta ink ejection nozzle surface of the recording head 18 by the wiper member 28 (S16), and the process proceeds to S17.
[0042]
  Next, the recording head 18 is moved to the flushing position (S17). Specifically, in the housing 2, the carriage 8 is moved to the right end (in FIG. 1), and the recording head 18 is opposed to the flushing receiving member 7 (S17).
[0043]
  Next, the process of S18 is performed. In S18, a flushing operation of 500 ink droplets with a small corrugated waveform is set for the ejection nozzle that has been purged (S18). This setting is stored in the RAM 51 shown in FIG. The drive waveform data for performing the flushing operation using the small ball waveform is stored in the ROM 52 shown in FIG. A specific example of the Kodama waveform will be described later.
[0044]
  Next, when the process of S18 is completed, a flushing operation of 500 ink droplets with a small ball waveform is performed on the ejection nozzle that has been previously purged (S19). In this process, the CPU 50 shown in FIG. 3 performs a drive signal from the drive circuit 61 to the print head 18 via the control circuit 57 based on the ejection data of the ink droplets 500 from the small waveform stored in the RAM 51 in S18. As shown in FIG. 7A, ink droplets are ejected from the corresponding ejection nozzle onto the flushing receiving member 7 (S19).
[0045]
  When the flushing operation of S19 ends, the process of S20 is then performed. In S20, a flushing operation for 1000 ink droplets with a large corrugated waveform in which the ink amount is larger than the ink amount of the small corrugated waveform is set for the ejection nozzle that has performed the purge operation (S20). This setting is stored in the RAM 51 shown in FIG. Note that drive waveform data for performing a flushing operation using a large ball waveform is stored in the ROM 52 shown in FIG. A specific example of the large ball waveform will be described later.
[0046]
  In the process of S20, in order to perform the flushing operation with the large corrugation waveform even for the ejection nozzle that has not been purged, the ejection of 500 ink droplets with the large corrugation waveform is set (S20). This setting is stored in the RAM 51 shown in FIG.
[0047]
  Next, when the process of S20 is completed, a flushing operation is performed on the ejection nozzles that are set to eject 1000 or 500 ink droplets using a large corrugated waveform (S21). This processing is performed by the CPU 50 shown in FIG. 3 in S20 from the drive circuit 61 via the control circuit 57 based on the ejection data of 1000 or 500 ink droplets by the large ball waveform stored in the RAM 51. As shown in FIG. 7B, ink droplets are ejected from the corresponding ejection nozzles onto the flushing receiving member 7 by sending a driving signal having a large waveform to (S21). Thereafter, the maintenance process ends, and the inkjet printer 1 enters a standby state.
[0048]
  Next, the small ball waveform and the large ball waveform will be described with reference to FIGS. 6 and 7. 6A shows a driving waveform of a small ball waveform for driving the recording head 18, and FIG. 6B shows a driving waveform of a large ball waveform for driving the recording head 18.
[0049]
  Here, the length (depth) of the channel in the ejection nozzles of cyan, magenta, yellow, and black of the recording head 18 is “L”, and the sound velocity in the ink in the channel is “a”. Then, the one-way propagation time T = L / a of the pressure wave in the channel. Using this “T”, the small ball waveform and the large ball waveform will be described. An example of T is “8 μsec”.
[0050]
  As shown in FIG. 6 (A), when the small ball waveform first rises, it turns on at a voltage value of approximately 20V, continues for 1T time, then falls and turns off. At this falling timing, as shown in FIG. 7A, only one drop of ink is ejected from the ink nozzle. Then, after 2.5T time from the falling timing, the voltage value is turned ON at about 20V, and after 0.5T time it falls and turned OFF. This pulse lasting for 0.5 T is a cancel pulse for canceling the residual pressure fluctuation in the channel. Note that the Kodama waveform is a single cycle of the printing clock 1CK, that is, one dot, and is ejected as described above, and the pressure fluctuation in the channel is small. It is a waveform.
[0051]
  Next, the large wave waveform will be described. As shown in FIG. 6 (B), when the large waveform first rises, it turns on at a voltage value of approximately 20V, continues for 1T time, falls, and turns off. At this falling timing, as shown in FIG. 7B, only one drop of ink is ejected from the ink nozzle. Then, after 1T time from the fall timing, it is turned ON again at a voltage value of about 20V, and after continuing for 1T time, it falls and turns OFF. At the falling timing, as shown in FIG. 7B, the second drop of ink is ejected from the ink nozzle. Then, after 1T time from the fall timing, it is turned ON again at a voltage value of about 20V, and after continuing for 1T time, it falls and turns OFF. At the falling timing, as shown in FIG. 7B, the third drop of ink is ejected from the ink nozzle.
[0052]
  Then, after 1T time from the fall timing, it is turned ON again at a voltage value of about 20V, and after continuing for 1T time, it falls and turns OFF. At the falling timing, as shown in FIG. 7B, the fourth drop of ink is ejected from the ink nozzle. After 2.5T time from the last falling timing, the voltage value is turned ON at about 20V, and after 0.5T time it falls and turned OFF. This pulse lasting for 0.5 T is a cancel pulse for canceling the residual pressure fluctuation in the channel. In the large ball waveform, the above waveform is output within one cycle of the printing clock 1CK, and eventually four drops of ink are ejected to one dot, and as shown in FIG. In this case, a large dot is formed as compared with a dot by a small corrugated waveform. The large waveform is a waveform with a large pressure fluctuation in the channel.
[0053]
  In more detail, when the operation of outputting a plurality of pulses for one dot is continued, the residual vibration of the ink itself is gradually amplified, and a rapidly changing ink flow is generated in the channel and the manifold. If this operation is continued for a very large number of dots (for example, 10,000 shots or more, or one line or more of the printer), the meniscus of the nozzle is excessively dented, and air may be drawn in as it is, resulting in non-ejection. In this sense, the large waveform of the present embodiment is an unstable waveform in the sense that there is a possibility of non-injection.
[0054]
  As described above, in the ink jet printer according to the present embodiment, at the time of the flushing operation, first, the flushing operation is performed by the small ball waveform which is a waveform in which the pressure fluctuation in the channel is small with respect to the ejection nozzle subjected to the purge operation. . Since the air bubbles are drawn into the channel by the back pressure together with the ink adhering to the nozzle surface by this purging operation, air bubbles that are relatively close to the nozzle surface or relatively large air bubbles are discharged. Next, a flushing operation with a large corrugated waveform, which is a waveform with a large pressure fluctuation in the channel, is performed for all the ejection nozzles, and the ink pushed into each nozzle by the wiping operation is discharged, that is, only necessary for preventing color mixing. Ink is ejected and bubbles remaining in the channel and manifold and bubbles adhering to the wall surface are discharged by a violent flow. At this time, the flushing operation of the large corrugation is not continued so that the meniscus of the nozzle is excessively dented and falls into non-injection.
[0055]
  In addition, this invention is not limited to the said embodiment, Of course, it can implement in various aspects within the range which does not deviate from the summary of this embodiment. For example, in the above-described embodiment, the ink jet printer has been described. However, the present invention can be applied to other recording apparatuses such as a fax machine. Note that, instead of the above-described small ball waveform and large ball waveform, the recording head may be driven at a low frequency at the time of flushing, and then the recording head may be driven at a high frequency.
[0056]
【The invention's effect】
  As described above in detail, in the ink jet recording apparatus of the invention according to claim 1,The purge operation and the wipe operation are performed only for the ejection nozzles that are determined to perform the purge process, and then only for the ejection nozzles that have performed the purge operation.Flushing operation by a small waveform in which a driving voltage having a waveform that reduces the amount of ink droplets ejected for one dot during recording is applied to the recording head.And then the above-mentioned purge operation And for the injection nozzle that did not perform the purge operationA flushing operation using a large corrugated waveform in which a drive voltage having a waveform in which the amount of ink droplets ejected for one dot is larger than the amount of ink having a small corrugated waveform is applied to the recording head.In the flushing operation using the large ball waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation.Therefore, it is possible to eject the ink necessary for bubble discharge and color mixing prevention in a relatively short time, and flushing with a large corrugation can be suppressed in a short time, so that the meniscus is not destroyed.
[0057]
  In the ink jet recording apparatus of the invention according to claim 2, in addition to the effect of the ink jet recording apparatus according to claim 1, the large ball waveform can be realized by increasing the pulses of the small ball waveform. Therefore, it is not necessary to provide a special additional circuit in the injection pulse control circuit.
[0058]
  In the ink jet recording apparatus of the invention according to claim 3,The purge operation and the wipe operation are performed only for the ejection nozzles that are determined to perform the purge process, and then only for the ejection nozzles that have performed the purge operation.Flushing operation by a stable waveform in which a driving voltage having a waveform with small pressure fluctuation of ink in the recording head is applied to the recording headAfter that, for the injection nozzle that has performed the purge operation and the injection nozzle that has not performed the purge operationFlushing operation by an unstable waveform in which a drive voltage having a waveform with large pressure fluctuation of ink in the print head is applied to the print headIn the flushing operation using the unstable waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation.Therefore, it is possible to eject the ink necessary for discharging the bubbles and preventing color mixing in a relatively short time, and the flushing due to the unstable waveform can be suppressed in a short time, so that the meniscus is not destroyed.
[0059]
  In the ink jet recording apparatus of the invention according to claim 4, in addition to the effect of the ink jet recording apparatus according to claim 3, the unstable waveform has more ejection pulses for one dot than the stable waveform. Can be realized. Therefore, it is not necessary to provide a special additional circuit in the injection pulse control circuit.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an internal structure of an ink jet printer.
FIG. 2 is an enlarged view of a maintenance / recovery mechanism RM.
FIG. 3 is a block diagram showing an electrical configuration of the ink jet printer.
4 is a diagram showing an internal configuration of a drive circuit 61. FIG.
FIG. 5 is a flowchart showing maintenance processing of the inkjet printer 1;
6 is a drive waveform diagram of ink ejection used in the inkjet printer 1. FIG.
FIG. 7 is a diagram showing small ball injection and large ball injection.
[Explanation of symbols]
  1 Inkjet printer
  2 Case
  7 Flushing receiving member
  8 Carriage
18 Recording head
22y, 22m, 22c, 22b Ink cartridge
23 Nozzle surface
25 Platen roller
RM maintenance / recovery mechanism
26 Suction means
27 Storage cap
28 Wiper member
33 Suction cap
36 Cam member
50 CPU
51 RAM
52 ROM
53 Operation panel
57 Control circuit
58 Image memory
61 Drive circuit
  P Recording paper

Claims (4)

In order to improve the ink ejection state for a recording head that has a plurality of ejection nozzles with different colors of ink to be ejected and performs recording by ejecting ink onto a recording medium, the ejection side of the recording head A purge operation for sucking ink in the recording head, a wiping operation for wiping off ink adhering to the nozzles of the recording head performed after the purge operation, and an ejection of ink in the recording head performed after the wiping operation In an inkjet recording apparatus that performs a flushing operation for performing
A determination means for determining whether or not to perform a purge process for each ejection nozzle of each color;
The purge operation and the wipe operation are performed only for the injection nozzles determined to perform the purge process by the determination means,
After that, only the ejection nozzle that has performed the purge operation has a waveform driving voltage in which the amount of ink droplets ejected for one dot at the time of recording is small due to the small-drum waveform applied to the recording head. Perform by flushing operation ,
Thereafter, a waveform in which the amount of ink droplets ejected for one dot to the ejection nozzle that has performed the purge operation and the ejection nozzle that has not performed the purge operation is larger than the ink amount of the small-drum waveform. Perform a flushing operation with a large corrugated waveform applied to the recording head ,
In the flushing operation using the large corrugated waveform, the number of droplets ejected from the ejection nozzle that has performed the purge operation is greater than the number of droplets ejected from the ejection nozzle that has not performed the purge operation. Recording device.   The inkjet recording apparatus according to claim 1, wherein the large corrugation waveform has more ejection pulses than the small corrugation waveform for the one dot. In order to improve the ink ejection state for a recording head that has a plurality of ejection nozzles with different colors of ink to be ejected and performs recording by ejecting ink onto a recording medium, the ejection side of the recording head A purge operation for sucking ink in the recording head, a wiping operation for wiping off ink adhering to the nozzles of the recording head performed after the purge operation, and an ejection of ink in the recording head performed after the wiping operation In an inkjet recording apparatus that performs a flushing operation for performing
A determination means for determining whether or not to perform a purge process for each ejection nozzle of each color;
The purge operation and the wipe operation are performed only for the injection nozzles determined to perform the purge process by the determination means,
Thereafter, only the ejection nozzle that has performed the purge operation is performed by a flushing operation using a stable waveform in which a drive voltage having a waveform in which the pressure fluctuation of the ink in the recording head is small is applied to the recording head ,
Thereafter, a drive voltage having a waveform in which the pressure variation of the ink in the recording head is large with respect to the ejection nozzle that has performed the purge operation and the ejection nozzle that has not been purged is caused by an unstable waveform applied to the recording head. Perform the flushing action ,
In the flushing operation using the unstable waveform, the number of droplet ejection from the ejection nozzle that has performed the purge operation is greater than the number of droplet ejection from the ejection nozzle that has not performed the purge operation. Inkjet recording device.   The inkjet recording apparatus according to claim 3, wherein the unstable waveform has more ejection pulses than the stable waveform for one dot.

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