JP2012106394A - Liquid ejecting apparatus, method and program for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a flushing amount is increased depending on the frequency of a flushing when using a method for decreasing position displacement of a ruled line by frequently carrying out the flushing, causing ink to be wasted accordingly.SOLUTION: The apparatus includes a recording mode determination part 16a for detecting a recording mode when a liquid droplet is ejected from a nozzle opening to record on a medium. When a first recording mode is determined by the recording mode determination part 16a, a control part 16 controls a liquid ejection amount per nozzle opening of a center nozzle opening group to be smaller than the liquid ejection amount per nozzle opening of an end nozzle opening group. When a second recording mode is determined, the control part controls to unify the liquid ejection amount per nozzle opening between the end nozzle opening group and the center nozzle opening group.

Description

  The present invention relates to a liquid ejecting apparatus, a control method for a liquid ejecting apparatus, and a control program.

  A liquid ejecting apparatus such as an ink jet printer ejects ink droplets (droplets) from the nozzle openings of the liquid ejecting head while reciprocating the liquid ejecting head in the main scanning direction intersecting the recording paper (medium) conveyance direction. Print on recording paper. The ink droplets are ejected by expanding and contracting a pressure generating chamber communicating with the nozzle opening. In such a liquid ejecting apparatus, since the free surface (meniscus) of the ink in the nozzle opening is exposed to the air, the solvent component of the ink easily evaporates through the nozzle opening. As a result, the thickening of the ink proceeds in the vicinity of the nozzle opening, and a deviation may occur in the flying direction of the ink droplet.

  For this reason, as a measure to suppress the thickening of the ink near the nozzle opening, flushing is performed to forcibly eject ink droplets outside the liquid ejecting head every time a certain time elapses during the printing operation. Measures are widely taken to discharge the thickened ink. Also, a measure for stirring the ink by slightly vibrating the meniscus is widely performed. At this time, in order not to eject the ink droplets, the meniscus is alternately moved in the ink droplet ejection direction and the drawing direction opposite to the ejection direction to give a fine vibration. This fine vibration of the meniscus is also performed by expanding and contracting the pressure generating chamber. Then, by slightly vibrating the meniscus, the ink in the vicinity of the nozzle opening is agitated and the increase in the viscosity of the ink is suppressed. For example, in Patent Document 1, when it is determined that thickening has occurred in the ink near the nozzle opening, the flushing is effectively performed by performing the flushing after slightly vibrating the meniscus.

JP 2004-42314 A

  The phenomenon in which the deviation in the flying direction of the ink droplets described above appears remarkably at the joint portion of the ruled line when the ruled line along the transport direction is printed by band printing and bidirectional printing, for example. Further, when the same ruled line is printed by interlaced printing and bidirectional printing, the width of the ruled line may be increased due to the deviation of the flying direction of the ink droplets.

In band printing (first recording mode), ink droplets are ejected from the nozzle openings, and an image is recorded on the recording paper in one pass in the main scanning direction. That is, in band printing, a band-like raster line (a dot row composed of a plurality of dots along the transport direction) corresponding to the length of the nozzle row is formed in one pass. In the transport operation performed during each pass, the recording paper is transported by the length of the nozzle row. Then, the image recording and the conveying operation in each pass are alternately repeated, whereby the band-like raster lines are joined in the conveying direction to form a printed image.
On the other hand, in interlaced printing (second recording mode), ink droplets are ejected from nozzle openings and an image is recorded on recording paper in a plurality of passes in the main scanning direction. In other words, in interlaced printing, each time the recording paper is transported at a constant transport amount in the transport direction, each nozzle forms a raster line that fills the dot interval in the raster line formed in the immediately preceding pass. Thus, a printed image is formed.

  In order to cope with the problem of the deviation of the flying direction of the ink droplet, there is a method of making the positional deviation of the ruled line inconspicuous by frequently performing flushing. In addition, it is conceivable that the positional deviation of the ruled line is suppressed by increasing the minute vibration applied to the meniscus between the flushings.

  FIG. 17A is a graph showing the relationship between the minute vibration voltage and the ruled line displacement amount, and FIG. 17B is a graph showing the relationship between the minute vibration voltage and the required flushing amount (liquid ejection amount). . As shown in FIG. 6A, the amount of ruled line displacement can be reduced as the micro-vibration voltage is increased. On the other hand, as shown in FIG. 5B, the required flushing amount increases as the micro-vibration voltage is increased. The reason is as follows. By increasing the micro-vibration voltage to increase the micro-vibration of the meniscus, the thick ink is stirred and the area of the ink that touches the air is increased. As a result, the evaporation amount of the solvent component increases and the ink thickens on the contrary, and the flushing amount increases.

  Therefore, in the method of frequently performing flushing to reduce the amount of ruled line displacement, the flushing amount increases according to the number of times of flushing, and ink is wasted accordingly. Also, in the case of the method of increasing the fine vibration applied to the meniscus between each flushing, the flushing amount increases as the fine vibration voltage is increased, and the ink is wasted.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] Pressure that communicates with the nozzle opening by forming a transport mechanism for transporting the medium in the transport direction and a nozzle array in which a plurality of nozzle openings arranged in the transport direction are arranged. A liquid ejecting head that discharges liquid droplets from the nozzle openings by changing the liquid pressure in the chamber, a moving mechanism that reciprocates the liquid ejecting head in the main scanning direction intersecting the transport direction, and driving the pressure generating element A control unit that supplies a signal to control ejection of liquid droplets from the nozzle opening, and a recording mode determination unit that determines a recording mode when performing recording on the medium by ejecting liquid droplets from the nozzle opening The nozzle row includes an end nozzle opening group including the nozzle openings located on the end side in the transport direction, and a central nozzle including the nozzle openings other than the end nozzle opening group. The recording mode includes a first recording mode in which droplets are ejected from the nozzle openings and an image is recorded on the medium in one pass in the main scanning direction, and droplets are ejected from the nozzle openings. And a second recording mode in which an image is recorded on the medium in a plurality of passes in the main scanning direction, and the control unit performs a flushing operation for forcibly discharging droplets from the nozzle openings. When it is determined that the first recording mode is determined by the recording mode determination unit, the nozzle discharge amount of each nozzle opening of the central nozzle opening group is larger than the liquid discharge amount of each nozzle opening of the end nozzle opening group. When the recording mode determination unit determines the second recording mode, the liquid discharge amount for each nozzle opening of the end nozzle opening group and the central portion are controlled. Nozzle opening group A liquid ejecting apparatus characterized by controlling so that the liquid discharge amount of each nozzle opening becomes uniform.

  According to the above-described liquid ejecting apparatus, an image is recorded on the medium in one pass in the main scanning direction in the first recording mode, and a plurality of passes in the main scanning direction in the second recording mode. An image is recorded on the medium. As for the liquid discharge amount for each nozzle opening when the flushing operation is performed, in the first recording mode, the control unit causes the central nozzle opening group to have a smaller amount than the end nozzle opening group. To control. On the other hand, in the second recording mode, the control unit controls the end nozzle opening group and the central nozzle opening group to be uniform.

In the conventional liquid ejecting apparatus, there is a case where a deviation occurs in the flying direction of the ink droplet due to the thickening of the ink near the nozzle opening. As a result, the landing position of the ink droplet on the medium is shifted, and the recorded ruled line may be shifted in the main scanning direction. In order to suppress this shift, there is a countermeasure for frequently performing flushing.
Here, in the first recording mode, since an image is recorded on the medium in one pass, if the number of times of flushing is increased, a delay due to interruption of printing at the time of flushing may be noticed by the user. On the other hand, in the case of the second recording mode, an image is recorded on the medium in a plurality of passes. Therefore, if the number of times of flushing is increased, the delay due to printing interruption at the time of flushing is the case for the first recording mode for the user. I don't care so much.

Therefore, in the first recording mode in which the number of times of flushing cannot be increased, the liquid discharge amount for each nozzle opening in the central nozzle opening group is smaller than the liquid discharge amount for each nozzle opening in the end nozzle opening group. With this control, it is possible to focus on the positional deviation of the joint portion of the ruled line along the transport direction and to cope with the problem of wasting ink. Further, in the second recording mode in which the number of times of flushing can be increased, the liquid discharge amount for each nozzle opening in the end nozzle opening group and the liquid discharge amount for each nozzle opening in the central nozzle opening group are made uniform. In this way, it is possible to control the positional deviation of the entire ruled line and cope with the problem of wasteful consumption of ink.
As described above, by dealing with each of the first recording mode and the second recording mode, it is possible to cope with the problem of wasteful consumption of ink during the flushing operation.

  Application Example 2 The control unit supplies a drive signal to the pressure generating element to further control the fine vibration of the meniscus at the nozzle opening to such an extent that no droplet is discharged from the nozzle opening. When the determination unit determines that the recording mode is the first recording mode, the control unit applies a slight vibration that is weaker than the fine vibration applied to the meniscus in the nozzle openings of the end nozzle opening group. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is controlled so as to be applied to a meniscus at a nozzle opening of the group.

  According to the above-described liquid ejecting apparatus, in the first recording mode, the control unit performs control so as to apply a slight vibration weaker than that of the end nozzle opening group to the meniscus in the nozzle opening of the central nozzle opening group. To do. As a result, for example, the problem of misalignment that appears prominently at the joints of the ruled lines along the transport direction, and the liquid ejection of the entire nozzle array becomes stronger as the micro-vibration at each nozzle opening increases to cope with this misalignment. It is possible to cope with the problem that the amount becomes large. That is, by applying strong fine vibration to the end nozzle opening group that prints the joint portion of the ruled line, the positional deviation of the joint portion of the ruled line can be further suppressed. Further, since a weaker vibration is applied to the central nozzle opening group than to the end nozzle opening group, the liquid discharge amount for each nozzle opening of the central nozzle opening group can be reduced. As a result, it is possible to cope with a problem that the liquid discharge amount of the entire nozzle row becomes large.

  Application Example 3 The recording mode determination unit is configured to perform bidirectional recording mode in which recording is performed on the medium in both directions of the forward path and the return path in the main scanning direction and in one direction of either the forward path or the return path in the main scanning direction. The unidirectional recording mode for recording on the medium is further determined, and the control unit, when determined as the unidirectional recording mode by the recording mode determination unit, than when determined as the bidirectional recording mode In addition, control is performed so as to apply weak micro-vibration to the meniscus at the nozzle opening, and the liquid for each nozzle opening is more than when the bidirectional recording mode is determined when the flushing operation is performed. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is controlled so as to reduce a discharge amount.

  According to the above-described liquid ejecting apparatus, the control unit performs control so as to apply weaker vibration to the meniscus of the nozzle opening in the unidirectional recording mode than in the bidirectional recording mode. When executing the flushing operation, the control unit controls the liquid discharge amount per nozzle opening to be smaller in the unidirectional recording mode than in the bidirectional recording mode.

  In the case of the unidirectional recording mode, since the recording is performed on the medium in one of the forward path and the backward path, the landing positions of the ink droplets are all shifted in a single direction, for example, the entire ruled line may be shifted in a single direction. . On the other hand, in the bidirectional recording mode, since the recording is performed on the medium in both the forward path and the backward path, the landing positions of the ink droplets are shifted in the opposite directions in the forward path and the backward path, and in the first recording mode. For example, the joint portion of the ruled line may be shifted, or the width of the ruled line may be increased in the second recording mode, for example. Therefore, it can be said that the influence of the ink droplet landing position is less in the unidirectional recording mode than in the bidirectional recording mode.

  For this reason, in the case of the unidirectional recording mode in which the influence of the displacement of the ink droplet landing position is small, a weak vibration is applied to the meniscus compared to the case of the bidirectional recording mode, so that the liquid per nozzle opening during the flushing operation The discharge amount can be reduced. In this way, by applying a slight vibration according to each of the unidirectional recording mode and the bidirectional recording mode to the meniscus and controlling the liquid discharge amount according to the slight vibration, the ink is discharged during the flushing operation. The problem of wasted consumption can be dealt with.

  [Application Example 4] Pressure that communicates with the nozzle opening by forming a transport mechanism for transporting the medium in the transport direction and a nozzle array in which a plurality of nozzle openings arranged in the transport direction are arranged. A liquid ejecting apparatus comprising: a liquid ejecting head that changes liquid pressure in a room to eject liquid droplets from the nozzle openings; and a moving mechanism that reciprocates the liquid ejecting head in a main scanning direction that intersects the transport direction. A control method for controlling the supply of a drive signal to the pressure generating element to discharge a droplet from the nozzle opening, and discharging the droplet from the nozzle opening to perform recording on the medium A recording mode determination step for determining a recording mode at the time, and the nozzle row includes an end nozzle opening group including the nozzle openings positioned on the end side in the transport direction, and the end nozzle opening. And a central nozzle opening group including the nozzle openings other than the group, and the recording mode discharges droplets from the nozzle openings and records images on the medium in one pass in the main scanning direction. And a second recording mode in which a droplet is ejected from the nozzle opening and an image is recorded on the medium in a plurality of passes in the main scanning direction. When performing the flushing operation for forcibly ejecting the droplets, if the first recording mode is determined in the recording mode determination step, the liquid discharge amount for each nozzle opening of the end nozzle opening group When the second recording mode is determined in the recording mode determination step, the end nozzle opening group is controlled so that the liquid discharge amount for each nozzle opening of the central nozzle opening group is small. Control method for a liquid ejecting apparatus and controls so that the liquid discharge amount for each nozzle opening, and a liquid discharge amount of each nozzle opening in the central portion nozzle aperture group becomes uniform.

  According to the control method of the liquid ejecting apparatus described above, an image is recorded on the medium in one pass in the main scanning direction in the first recording mode, and a plurality of times in the main scanning direction in the second recording mode. The image is recorded on the medium in the pass. In the first recording mode, the liquid discharge amount for each nozzle opening when performing the flushing operation is such that the central nozzle opening group is smaller than the end nozzle opening group in the control step. To control. On the other hand, in the second recording mode, the control is performed so that the end nozzle opening group and the central nozzle opening group are uniform.

In the conventional liquid ejecting apparatus, there is a case where a deviation occurs in the flying direction of the ink droplet due to the thickening of the ink near the nozzle opening. As a result, the landing position of the ink droplet on the medium is shifted, and the recorded ruled line may be shifted in the main scanning direction. In order to suppress this shift, there is a countermeasure for frequently performing flushing.
Here, in the first recording mode, since an image is recorded on the medium in one pass, if the number of times of flushing is increased, a delay due to interruption of printing at the time of flushing may be noticed by the user. On the other hand, in the case of the second recording mode, an image is recorded on the medium in a plurality of passes. Therefore, if the number of times of flushing is increased, the delay due to printing interruption at the time of flushing is the case for the first recording mode for the user. I don't care so much.

Therefore, in the first recording mode in which the number of times of flushing cannot be increased, the liquid discharge amount for each nozzle opening in the central nozzle opening group is smaller than the liquid discharge amount for each nozzle opening in the end nozzle opening group. With this control, it is possible to focus on the positional deviation of the joint portion of the ruled line along the transport direction and to cope with the problem of wasting ink. Further, in the second recording mode in which the number of times of flushing can be increased, the liquid discharge amount for each nozzle opening in the end nozzle opening group and the liquid discharge amount for each nozzle opening in the central nozzle opening group are made uniform. In this way, it is possible to control the positional deviation of the entire ruled line and cope with the problem of wasteful consumption of ink.
As described above, by dealing with each of the first recording mode and the second recording mode, it is possible to cope with the problem of wasteful consumption of ink during the flushing operation.

  [Application Example 5] Pressure in which a conveyance mechanism that conveys a medium in a conveyance direction and a nozzle row in which a plurality of nozzle openings arranged in the conveyance direction are arranged are formed and communicated with the nozzle openings by the operation of a pressure generating element A liquid ejecting apparatus comprising: a liquid ejecting head that changes liquid pressure in a room to eject liquid droplets from the nozzle openings; and a moving mechanism that reciprocates the liquid ejecting head in a main scanning direction that intersects the transport direction. A control program for supplying a drive signal to the pressure generating element to control ejection of droplets from the nozzle openings; and recording on the medium by ejecting droplets from the nozzle openings A recording mode determination function for determining a recording mode at the time, and the nozzle row includes an end nozzle opening group including the nozzle openings positioned on the end side in the transport direction, and the end portion nozzle. In the recording mode, an image is recorded on the medium in one pass in the main scanning direction by ejecting liquid droplets from the nozzle openings. A first recording mode; and a second recording mode in which droplets are ejected from the nozzle openings and an image is recorded on the medium in a plurality of passes in the main scanning direction. When a flushing operation for forcibly discharging droplets from the openings is executed, and the recording mode determination function determines that the first recording mode is selected, the liquid discharge amount for each nozzle opening of the end nozzle opening group Rather than controlling the liquid discharge amount for each nozzle opening of the central nozzle opening group to be small, and if the recording mode determination function determines the second recording mode, the end nozzle A liquid ejecting apparatus, characterized by causing a computer to perform control so that a liquid discharge amount for each nozzle opening of a mouth group and a liquid discharge amount for each nozzle opening of the central nozzle opening group are uniform. Control program.

  According to the control program for the liquid ejecting apparatus described above, an image is recorded on the medium in one pass in the main scanning direction in the first recording mode, and a plurality of times in the main scanning direction in the second recording mode. The image is recorded on the medium in the pass. Then, with respect to the liquid discharge amount for each nozzle opening when performing the flushing operation, in the first recording mode, the central nozzle opening group has a smaller amount than the end nozzle opening group in the control function. To control. On the other hand, in the second recording mode, the control is performed so that the end nozzle opening group and the central nozzle opening group are uniform.

In the conventional liquid ejecting apparatus, there is a case where a deviation occurs in the flying direction of the ink droplet due to the thickening of the ink near the nozzle opening. As a result, the landing position of the ink droplet on the medium is shifted, and the recorded ruled line may be shifted in the main scanning direction. In order to suppress this shift, there is a countermeasure for frequently performing flushing.
Here, in the first recording mode, since an image is recorded on the medium in one pass, if the number of times of flushing is increased, a delay due to interruption of printing at the time of flushing may be noticed by the user. On the other hand, in the case of the second recording mode, an image is recorded on the medium in a plurality of passes. Therefore, if the number of times of flushing is increased, the delay due to printing interruption at the time of flushing is the case for the first recording mode for the user. I don't care so much.

Therefore, in the first recording mode in which the number of times of flushing cannot be increased, the liquid discharge amount for each nozzle opening in the central nozzle opening group is smaller than the liquid discharge amount for each nozzle opening in the end nozzle opening group. With this control, it is possible to focus on the positional deviation of the joint portion of the ruled line along the transport direction and to cope with the problem of wasting ink. Further, in the second recording mode in which the number of times of flushing can be increased, the liquid discharge amount for each nozzle opening in the end nozzle opening group and the liquid discharge amount for each nozzle opening in the central nozzle opening group are made uniform. In this way, it is possible to control the positional deviation of the entire ruled line and cope with the problem of wasteful consumption of ink.
As described above, by dealing with each of the first recording mode and the second recording mode, it is possible to cope with the problem of wasteful consumption of ink during the flushing operation.

  Application Example 6 A pressure in which a transport mechanism for transporting a medium in the transport direction and a nozzle array in which a plurality of nozzle openings arranged in the transport direction are arranged are formed and communicated with the nozzle openings by the operation of a pressure generating element. A liquid ejecting head that discharges liquid droplets from the nozzle openings by changing the liquid pressure in the chamber, a moving mechanism that reciprocates the liquid ejecting head in the main scanning direction intersecting the transport direction, and driving the pressure generating element A control unit that supplies a signal to control ejection of droplets from the nozzle opening, and controls fine vibrations of the meniscus in the nozzle opening to the extent that droplets are not ejected from the nozzle opening; And a recording mode determination unit that determines a recording mode when recording on the medium by discharging droplets from the recording medium, and the recording mode discharges droplets from the nozzle openings. A first recording mode for recording an image on the medium in one pass in the main scanning direction, and a first recording mode in which droplets are ejected from the nozzle openings and an image is recorded on the medium in a plurality of passes in the main scanning direction. The recording unit determines that the recording mode determination unit determines that the recording mode is the second recording mode, and the control unit determines that the recording mode determination unit determines that the recording mode is the second recording mode. Is applied to the meniscus at the nozzle opening, and when performing a flushing operation for forcibly discharging droplets from the nozzle opening, compared to the case where the first recording mode is determined. A liquid ejecting apparatus that controls the liquid discharge amount for each nozzle opening to be small.

  According to the above-described liquid ejecting apparatus, an image is recorded on the medium in one pass in the main scanning direction in the first recording mode, and a plurality of passes in the main scanning direction in the second recording mode. An image is recorded on the medium. In the case of the second recording mode, the control unit performs control so as to apply weaker vibration to the meniscus of the nozzle opening than in the case of the first recording mode. Further, when performing the flushing operation, the control unit controls the liquid discharge amount for each nozzle opening to be smaller in the second recording mode than in the first recording mode.

In the conventional liquid ejecting apparatus, there is a case where a deviation occurs in the flying direction of the ink droplet due to the thickening of the ink near the nozzle opening. As a result, the landing position of the ink droplet on the medium is shifted, and the recorded ruled line may be shifted in the main scanning direction. In order to suppress this deviation, there are countermeasures such as frequently performing flushing or applying fine vibration to the meniscus.
Here, in the first recording mode, since an image is recorded on the medium in one pass, if the number of times of flushing is increased, a delay due to interruption of printing at the time of flushing may be noticed by the user. On the other hand, in the case of the second recording mode, an image is recorded on the medium in a plurality of passes. Therefore, if the number of times of flushing is increased, the delay due to printing interruption at the time of flushing is the case for the first recording mode for the user. I don't care so much.

  Therefore, in the second recording mode in which the number of times of flushing can be increased, a weaker vibration is applied to the meniscus than in the first recording mode, and liquid discharge is performed for each nozzle opening during the flushing operation. The amount can be small. In this way, by applying a fine vibration according to each of the first recording mode and the second recording mode to the meniscus and controlling the liquid discharge amount according to the fine vibration, during the flushing operation, It is possible to cope with the problem of wasteful consumption of ink.

  Application Example 7 The nozzle row includes an end nozzle opening group including the nozzle openings located on the end side in the transport direction, and a central nozzle opening group including the nozzle openings other than the end nozzle opening group. And the control unit is weaker than the fine vibration applied to the meniscus in the nozzle openings of the end nozzle opening group when the recording mode determination unit determines that the recording mode is the first recording mode. The fine vibration is controlled so as to be applied to the meniscus in the nozzle openings of the central nozzle opening group, and when performing the flushing operation, the liquid ejection amount for each nozzle opening of the end nozzle opening group is more than The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is controlled so that a liquid discharge amount for each nozzle opening of the central nozzle opening group is small.

  According to the above-described liquid ejecting apparatus, in the first recording mode, the control unit performs control so as to apply a slight vibration weaker than that of the end nozzle opening group to the meniscus in the nozzle opening of the central nozzle opening group. To do. Then, the control unit controls the liquid discharge amount for each nozzle opening when performing the flushing operation so that the central nozzle opening group has a smaller amount than the end nozzle opening group. Thus, for example, when printing a ruled line along the transport direction by ejecting droplets from the nozzle openings, the problem of misalignment that appears prominently at the joint part of the ruled line, As the fine vibration at the nozzle opening is increased, it is possible to cope with the problem that the liquid discharge amount of the entire nozzle row increases. That is, by applying strong fine vibration to the end nozzle opening group that prints the joint portion of the ruled line, the positional deviation of the joint portion of the ruled line can be further suppressed. Further, since a weaker vibration is applied to the central nozzle opening group than to the end nozzle opening group, the liquid discharge amount for each nozzle opening of the central nozzle opening group can be reduced. As a result, it is possible to cope with a problem that the liquid discharge amount of the entire nozzle row becomes large.

FIG. 2 is a perspective view illustrating a configuration of a printer according to the embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a recording head. FIG. 4 is an explanatory diagram of each nozzle opening provided in the recording head. FIG. 3 is a block diagram illustrating an electrical configuration of the printer. (A) The figure which shows the structural example of the drive signal used when discharging an ink drop with respect to a recording paper, and recording an image etc., (b) The figure which expanded the micro vibration pulse. 6 is a flowchart illustrating processing in a printing operation of a printer. The figure which shows the example of the positional offset of the ruled line in band printing and bidirectional | two-way printing. The figure which is a conventional correspondence example and shows the example corresponding to the position shift of a ruled line in band printing and bidirectional printing. The figure which is a correspondence example of this embodiment, and shows the example corresponding to the positional offset of a ruled line in band printing and bidirectional | two-way printing. The figure which shows the example of the positional offset of the ruled line in band printing and unidirectional printing. The figure which shows the example corresponding to the position shift of a ruled line in band printing and unidirectional printing. (A)-(d) The graph which shows the example of the flushing amount required in each nozzle opening, when printing a ruled line. The figure which shows the example of expansion of the ruled line width in interlaced printing and bidirectional | two-way printing. The figure which shows the example corresponding to expansion of a ruled line width in interlaced printing and bidirectional | two-way printing. The figure which shows the example of the positional offset of the ruled line in interlaced printing and unidirectional printing. The figure which shows the example corresponding to the position shift of a ruled line in interlaced printing and unidirectional printing. (A) The graph which shows the relationship between a minute vibration voltage and the positional offset amount of a ruled line, (b) The graph which shows the relationship between a minute vibration voltage and the required flushing amount.

  Hereinafter, the liquid ejecting apparatus according to the present embodiment will be described with reference to the drawings.

<Printer configuration>
First, a configuration of a printer will be described as an example of the liquid ejecting apparatus according to the present embodiment.
FIG. 1 is a perspective view illustrating a configuration of a printer 1 according to the present embodiment. The printer 1 shown in FIG. 1 is an ink jet color printer that prints an image or the like by ejecting ink droplets (droplets) to form ink dots on a medium such as recording paper. The printer 1 includes a carriage 4 to which a recording head 2 (liquid ejecting head) is attached and a cartridge holding unit 3, a platen 5 disposed below the recording head 2, and the carriage 4 in the conveying direction of the recording paper 8. A carriage moving mechanism 6 (moving mechanism) that reciprocates in the paper width direction (main scanning direction) that intersects, a linear encoder 7 that outputs encoder pulses as the carriage 4 moves, and the recording paper 8 in the transport direction. A paper feeding mechanism 9 (conveying mechanism) (refer to FIG. 4) for conveying and a paper feeding mechanism 17 for supplying the recording paper 8 to the paper feeding mechanism 9 side are provided.

  An ink cartridge 10 is detachably held in the cartridge holding unit 3. The ink cartridge 10 is a box-shaped member that stores ink, and is a kind of liquid storage member. In the present embodiment, the ink cartridge 10 includes a black cartridge that stores black ink and a color cartridge that stores cyan ink, magenta ink, and yellow ink color ink. Further, as the color material of each ink, for example, a pigment having excellent weather resistance is used.

  The carriage moving mechanism 6 is connected to a guide shaft 11 installed in the main scanning direction in the printer 1, a carriage moving motor 12 disposed on one side of the main scanning direction, and a rotating shaft of the carriage moving motor 12. A drive pulley 13 that is rotationally driven by the carriage movement motor 12, an idle pulley 14 disposed on the other side in the main scanning direction opposite to the drive pulley 13, and between the drive pulley 13 and the idle pulley 14. The timing belt 15 is stretched and connected to the carriage 4. The carriage movement motor 12 functions as a drive source in the carriage movement mechanism 6, and for example, a pulse motor or a DC motor is used. The carriage moving motor 12 is controlled by the control unit 16 (see FIG. 4) for its rotational speed and direction. When the carriage moving motor 12 rotates, the driving pulley 13 and the timing belt 15 rotate, and the carriage 4 moves along the guide shaft 11 in the paper width direction of the recording paper 8. That is, the carriage 4 is reciprocated in the main scanning direction under the control of the control unit 16.

  The linear encoder 7 is configured to output an encoder pulse corresponding to the scanning position of the recording head 2 as position information in the main scanning direction. The control unit 16 can recognize the scanning position of the recording head 2 based on the received encoder pulse. That is, the position of the recording head 2 can be recognized by counting the received encoder pulses.

  The platen 5 is a plate-like member for guiding the recording paper 8. In the upper surface portion of the platen 5, a portion excluding the peripheral portion is formed as a recess that is one step lower than the peripheral portion. A liquid absorbing member 23 such as a sponge is disposed in the recess. A support protrusion 24 (also called a diamond rib) is raised from the bottom of the recess. The support protrusion 24 is in contact with the back surface of the recording paper 8 to support the recording paper 8, and the tip portion protrudes above the surface of the liquid absorbing member 23. On the platen 5, at a position corresponding to the size of the recording paper 8, specifically, a position slightly outside the end of the recording paper 8 in the paper width direction, ink droplets ejected during a flushing operation described later are placed. A plurality of ink receiving portions 5 'are provided as receiving flushing positions.

  The paper feed mechanism 17 accommodates a plurality of sheets of recording paper 8 and feeds them one by one toward the paper feed mechanism 9 by a paper feed roller (not shown) provided at the bottom. The paper feed mechanism 17 has a fixed support portion 18 that abuts one end of the recording paper 8 in the paper width direction, and the width direction of the recording paper 8 according to the size (width) of the recording paper 8 such as A3, B4, A4, and B5. And a positioning member 19 for defining the position of the recording paper 8 in contact with the other end of the recording paper 8 in the paper width direction.

  The paper feed mechanism 9 includes a paper feed motor 25 as a paper feed drive source and a paper feed roller 26 that is rotationally driven by the paper feed motor 25. The paper feed roller 26 is composed of a pair of upper and lower rollers. That is, it is comprised by the drive roller located in the lower side, and the driven roller (pinch roller / not shown) located in the upper side. The drive roller is disposed in the platen 5 with the upper end portion exposed from the upper surface of the platen 5, and the driven roller is disposed on the exposed portion in a state of being biased toward the drive roller. . Then, the recording paper 8 is brought into contact with the driving roller by the driven roller, and the recording paper 8 is moved in the paper feeding direction by rotating the driving roller in this contact state.

  In addition, a home position serving as a scanning start point of the recording head 2 is set within the moving range of the recording head 2 and outside the platen 5. A capping mechanism 27 is provided at this home position. The capping mechanism 27 seals the nozzle surface of the recording head 2 with a cap member and prevents evaporation of the ink solvent from the nozzle opening 28 (see FIG. 2). Further, the capping mechanism 27 is also used during the flushing operation. Specifically, the cap member is used as a container for receiving ink droplets ejected from the nozzle openings 28 during the flushing operation.

  The recording head 2 ejects liquid ink in the form of ink droplets from the nozzle openings 28 toward the recording paper 8. Various modes have been proposed for the recording head 2, but pressure fluctuations are generated in the ink in the pressure chamber by operating the pressure generating element, and ink droplets are ejected from the nozzle openings 28 using the pressure fluctuations. The method of letting it be common is common.

<Configuration of recording head>
Next, the configuration of the recording head 2 will be described.
FIG. 2 is a cross-sectional view showing the configuration of the recording head 2. As shown in the figure, the recording head 2 includes a case 31, a vibrator unit 32 housed in the case 31, a flow path unit 33 joined to the front end surface of the case 31, and the like. The case 31 is created by molding an epoxy resin, for example, and has a housing empty portion 34 for housing the vibrator unit 32 therein. The vibrator unit 32 is obtained by joining a comb-like piezoelectric vibrator 35 (pressure generating element) to the surface of the fixed plate 36 in a cantilever state. The piezoelectric vibrator 35 is a piezoelectric vibrator in a longitudinal vibration mode, and a free end portion expands and contracts in the element longitudinal direction in accordance with the vibrator potential. That is, it contracts in the longitudinal direction of the element by charging and expands in the longitudinal direction of the element by discharging.

  The flow path unit 33 has a configuration in which a nozzle plate 38 is bonded to one surface of a flow path forming substrate 37 and an elastic plate 39 is bonded to the other surface. The flow path unit 33 is provided with a reservoir 40, an ink supply port 41, a pressure chamber 42, a nozzle communication port 43, and a nozzle opening 28. Each of these portions forms a plurality of ink flow paths from the ink supply port 41 to the nozzle opening 28 via the pressure chamber 42 and the nozzle communication port 43 corresponding to the nozzle opening 28. The nozzle openings 28 are formed in a plurality of rows, and a plurality of nozzle openings 28 belonging to one row constitute a nozzle row.

  FIG. 3 is an explanatory diagram of each nozzle opening 28 provided in the recording head 2. As shown in the figure, each of the nozzle rows K, C, M, and Y is configured by arranging nozzle openings 28 that are ejection ports for ejecting ink of each color at predetermined intervals in the transport direction. In the present embodiment, 180 nozzle openings 28 (# 1 to # 180) are provided in each nozzle row K, C, M, Y. Then, in each nozzle row K, C, M, Y, 40 nozzle openings 28 (# 1 to # 20, # 161 to # 180) located on both end sides in the transport direction are set as end nozzle opening groups, The 140 nozzle openings 28 (# 21 to # 160) other than the end nozzle opening group are defined as a central nozzle opening group.

  Returning to FIG. 2, the elastic plate 39 is provided with a diaphragm portion 44. The diaphragm portion 44 defines a part of the pressure chamber 42, and is provided with an island portion (thick wall portion) to which the distal end surface of the piezoelectric vibrator 35 is joined, and a thin wall having elasticity that is provided around the island portion. Part. When the piezoelectric vibrator 35 expands and contracts in the element longitudinal direction, the island portion is displaced. The pressure chamber volume varies due to the displacement of the island. That is, when the piezoelectric vibrator 35 extends, the pressure chamber volume decreases, and when the piezoelectric vibrator 35 contracts, the pressure chamber volume increases. As the volume of the pressure chamber 42 changes, the pressure in the ink in the pressure chamber 42 varies. Therefore, ink droplets can be ejected from the nozzle openings 28 by controlling this pressure fluctuation. For example, the ink droplets can be ejected by contracting the piezoelectric vibrator 35 in the longitudinal direction of the element and then rapidly expanding the piezoelectric vibrator 35. Further, by changing the pressure fluctuation pattern applied to the ink in the pressure chamber 42, the meniscus in the nozzle opening 28 can be slightly vibrated to the extent that ink droplets are not ejected from the nozzle opening 28. The details of the minute vibration will be described later.

<Electrical configuration of printer>
Next, the electrical configuration of the printer 1 will be described.
FIG. 4 is a block diagram illustrating an electrical configuration of the printer 1. As shown in the figure, the printer 1 includes a printer controller 51 and a print engine 52. The printer controller 51 includes an external I / F (interface) 53 that receives print data and the like from a host computer or the like (not shown), a RAM 54 that stores various data, a program used for controlling each unit, and the like. The stored ROM 55, the control unit 16 that performs electrical control of each unit, the oscillation circuit 56 that generates a clock signal, the timer circuit 57 that can generate a constant timing pulse (PTS: Print Timing Signal), and the recording head 2, a drive signal generation circuit 58 that generates a drive signal to be supplied to 2, and an internal I / F (interface) 59 for transmitting print data, a drive signal, and the like to the print engine 52.

  The control unit 16 supplies a drive signal to the piezoelectric vibrator 35 while reciprocating the recording head 2 in the main scanning direction, thereby causing a printing operation (ejection operation) by the recording head 2 and a slight vibration of the meniscus at the nozzle opening 28. Control. At this time, the control unit 16 develops the print data transmitted from the host computer or the like into print data corresponding to the dot pattern and transmits the print data to the recording head 2. In the recording head 2, the drive pulse in the drive signal is selectively supplied to the piezoelectric vibrator 35 based on the received print data, and ink droplets are ejected and the meniscus is vibrated slightly in the nozzle openings 28. Further, the control unit 16 moves the recording head 2 to the flushing position (either the ink receiving unit 5 ′ or the capping mechanism 27) before starting the printing operation after turning on the printer 1 or at certain time intervals during the printing operation. And a flushing operation for forcibly ejecting ink droplets from the nozzle openings 28 is performed.

  Furthermore, the control unit 16 includes a recording mode determination unit 16a for determining a recording mode when performing a printing operation. The control unit 16 discharges ink droplets from the nozzle openings 28 while reciprocating the recording head 2 in the main scanning direction based on the determination result of the recording mode in the recording mode determination unit 16a. To print.

  The recording mode determination unit 16a determines a recording mode based on a command included in print data transmitted from a host computer or the like. The recording mode includes band printing (first recording mode) and interlaced printing (second recording mode). In each of band printing and interlaced printing, bidirectional printing (bidirectional recording mode) for printing on the recording paper 8 in both forward and backward directions while the recording head 2 reciprocates in the main scanning direction. In addition, both recording modes of unidirectional printing (unidirectional recording mode) for printing on the recording paper 8 in any one direction of the forward path and the backward path are included.

  Here, in band printing, ink is ejected simultaneously from all the nozzle openings 28 (# 1 to # 180) to the recording paper 8 in one pass to form a raster line, and an image or the like along the transport direction. To print. On the other hand, in interlaced printing, in the first pass, ink droplets are ejected from the nozzle openings 28 (a part of # 1 to # 180) at intervals to the recording paper 8 to form a raster line with a dot interval. After the next pass, ink droplets are ejected from the nozzle openings 28 at intervals to the recording paper 8 to form raster lines so as to fill the dot intervals, and images and the like are printed along the transport direction.

The drive signal generation circuit 58 generates a drive signal having a waveform shape determined by the control unit 16. The printer 1 according to the present embodiment can perform multi-gradation recording in which dots having different sizes are formed on the recording paper 8 by ejecting ink droplets having different liquid amounts. Large dots, medium dots, small dots, and A non-ejection four-tone printing operation is possible.
FIG. 5A is a diagram showing a configuration example of a drive signal used when an ink droplet is ejected onto the recording paper 8 to record an image or the like, and FIG. 5B is a microvibration shown in FIG. It is the figure which expanded the pulse VP1, the fine vibration pulse VP2, and the fine vibration pulse VP3. As shown in FIG. 6A, the drive signal generation circuit 58 includes a fine vibration pulse VP1, a fine vibration pulse VP2, a fine vibration pulse VP3, a large dot drive pulse DP1, a small dot drive pulse DP2, A drive signal COM configured by arranging a set with the dot drive pulse DP3 is generated. The drive signal COM is used when an ink droplet is ejected onto the recording paper 8 to print an image or the like. Then, when the recording head 2 is moving at a constant speed in the printing area on the recording paper 8, a driving pulse of the driving signal COM is selectively supplied to the piezoelectric vibrator 35.

Here, the fine vibration pulses VP1, VP2, and VP3 are drive pulses for causing the meniscus of the non-ejection nozzle opening 28 to vibrate. Specifically, the fine vibration pulse VP1 is supplied to each piezoelectric vibrator 35 of all the nozzle openings 28, and the meniscus of each nozzle opening 28 (# 1 to # 180) can be finely vibrated. Further, the fine vibration pulse VP1 is supplied to each piezoelectric vibrator 35 of the central nozzle opening group in each nozzle row K, C, M, Y, and each nozzle opening 28 (# 21 to # 21 to become the central nozzle opening group). It is also possible to slightly vibrate the meniscus of # 160). On the other hand, the fine vibration pulse VP2 is supplied to each piezoelectric vibrator 35 of the end nozzle opening group, and the meniscus of each nozzle opening 28 (# 1 to # 20, # 161 to # 180) which becomes the end nozzle opening group. Can be vibrated slightly. On the other hand, the fine vibration pulse VP3 is supplied to the piezoelectric vibrators 35 of all the nozzle openings 28 to finely vibrate the meniscus of each nozzle opening 28 (# 1 to # 180).
As described above, any one of the fine vibration pulses VP1, VP2, and VP3 is supplied to each piezoelectric vibrator 35 of each nozzle opening 28. Based on the determination result in the recording mode determination unit 16a described above. A fine vibration pulse to be supplied is selected.

  As shown in FIG. 5B, the fine vibration pulse VP1 includes a charging element P11 that increases the potential from the reference potential VB to the first fine vibration potential VH1, and a hold element P12 that maintains the first fine vibration potential VH1 for a short time. And a discharge element P13 that restores the potential from the first slight vibration potential VH1 to the reference potential VB. On the other hand, the fine vibration pulse VP2 includes a charging element P21 that increases the potential from the reference potential VB to the second fine vibration potential VH2, a hold element P22 that maintains the second fine vibration potential VH2 for a short time, and a second fine vibration potential VH2. And a discharge element P23 for restoring the potential from the reference potential VB to the reference potential VB. On the other hand, the fine vibration pulse VP3 includes a charging element P31 that increases the potential from the reference potential VB to the third fine vibration potential VH3, a hold element P32 that maintains the third fine vibration potential VH3 for a short time, and a third fine vibration potential VH3. And a discharge element P33 for restoring the potential from the reference potential VB to the reference potential VB.

  When these fine vibration pulses VP1, VP2, and VP3 are supplied to the piezoelectric vibrator 35, the piezoelectric vibrator 35 is contracted by the respective charging elements P11, P21, and P31, and the pressure chamber 42 is not ejected. Expands slowly. Then, after the expansion state of the pressure chamber 42 is maintained for a short time by the hold elements P12, P22, and P32, the discharge elements P13, P23, and P33 are supplied, whereby the piezoelectric vibrator 35 is expanded. Thus, the pressure chamber 42 returns to the reference volume. A pressure fluctuation occurs in the pressure chamber 42 with a series of volume fluctuations of the pressure chamber 42, and a fine vibration can be applied to the meniscus of the nozzle opening 28 by the pressure fluctuation.

Here, the drive voltage of the micro-vibration pulse VP1, that is, the potential difference from the reference potential VB to the first micro-oscillation potential VH1, is greater than the drive voltage of the micro-vibration pulse VP3, that is, the potential difference from the reference potential VB to the third micro-oscillation potential VH3. Is also set high. Furthermore, the inclination of the charging element P11 of the fine vibration pulse VP1 is steeper than the inclination of the charging element P31 of the fine vibration pulse VP3. For this reason, in the case of the fine vibration pulse VP1, a fine vibration stronger than that in the case of the fine vibration pulse VP3 can be applied to the meniscus of the nozzle opening 28.
Further, the driving voltage of the micro-vibration pulse VP2, that is, the potential difference from the reference potential VB to the second micro-oscillation potential VH2, is larger than the driving voltage of the micro-vibration pulse VP1, that is, the potential difference from the reference potential VB to the first micro-oscillation potential VH1. It is set high. Furthermore, the inclination of the charging element P21 of the fine vibration pulse VP2 is steeper than the inclination of the charging element P11 of the fine vibration pulse VP1. Therefore, in the case of the fine vibration pulse VP2, a fine vibration stronger than that in the case of the fine vibration pulse VP1 can be applied to the meniscus of the nozzle opening 28.
Therefore, the fine vibration applied to the meniscus of the nozzle opening 28 can be strengthened in the order of the fine vibration pulse VP3, the fine vibration pulse VP1, and the fine vibration pulse VP2. (Hereinafter, the micro-vibration by the micro-vibration pulse VP2 is expressed as a strong micro-vibration, the micro-vibration by the micro-vibration pulse VP1 is expressed as a weak micro-vibration, and the micro-vibration by the micro-vibration pulse VP3 is expressed as a weak micro vibration.)

Further, the drive signal generation circuit 58 generates a flushing drive signal used for the flushing operation. This flushing drive signal includes a plurality of types of flushing pulses (not shown), and is appropriately selected according to the flushing amount required during the flushing operation. The flushing amount varies depending on the level of fine vibration applied to the meniscus of the nozzle opening 28, and the flushing amount increases as the fine vibration is increased. Conversely, the flushing amount decreases as the fine vibration is weakened.
Accordingly, the flushing amount for each nozzle opening 28 is the nozzle opening 28 for applying the fine vibration by the fine vibration pulse VP2, the nozzle opening 28 for applying the fine vibration by the fine vibration pulse VP1, and the nozzle for applying the fine vibration by the fine vibration pulse VP3. The amount can be reduced in the order of the opening 28.

<Processing in the printer>
Next, processing in the printing operation of the printer 1 will be described.
FIG. 6 is a flowchart illustrating processing in the printing operation of the printer 1.

  First, the control unit 16 receives print data from the host computer or the like via the external I / F 53 (step S10). This print data includes commands such as recording paper size, recording paper type, resolution, recording mode, and color adjustment.

  Next, the control unit 16 uses the recording mode determination unit 16a to indicate whether to perform band printing or interlaced printing based on the command included in the print data received in step S10. Is determined (step S20).

In the case of band printing (step S20: band printing), the process proceeds to step S30, and the control unit 16 performs bidirectional printing by the recording mode determination unit 16a based on the command included in the print data received in step S10. Or a recording mode indicating whether to perform unidirectional printing.
On the other hand, in the case of interlaced printing (step S20: interlaced printing), the process proceeds to step S80, and the control unit 16 performs bi-directional printing based on the command included in the print data received in step S10 by the recording mode determination unit 16a. The recording mode indicating whether or not to perform unidirectional printing is determined.

  In the case of performing band printing and bidirectional printing (step S30: bidirectional printing), the control unit 16 controls each piezoelectric element in the central nozzle opening group in each nozzle row K, C, M, Y provided in the recording head 2. It is set so that the fine vibration pulse VP1 is supplied to the vibrator 35. Further, the fine vibration pulse VP2 is set to be supplied to each piezoelectric vibrator 35 in the end nozzle opening group (step S40).

  Then, the control unit 16 is necessary when the fine vibration of the meniscus by the fine vibration pulse VP1 is applied to each piezoelectric vibrator 35 of the central nozzle opening group in each nozzle row K, C, M, Y. A setting is made so that a flushing pulse of the flushing amount is supplied. Further, it is set so that the flushing pulse having the flushing amount required when the fine vibration of the meniscus is applied to each piezoelectric vibrator 35 of the end nozzle opening group by the fine vibration pulse VP2 (step S50). ). Then, the process proceeds to step S130.

  On the other hand, when performing band printing and unidirectional printing (step S30: unidirectional printing), the control unit 16 sets all the nozzle openings 28 in the nozzle rows K, C, M, and Y provided in the recording head 2. It is set so that the fine vibration pulse VP1 is supplied to each piezoelectric vibrator 35 (step S60).

  The control unit 16 is necessary when the fine vibrations of the meniscus by the fine vibration pulse VP1 are applied to the piezoelectric vibrators 35 of all the nozzle openings 28 in the nozzle rows K, C, M, and Y. A setting is made so that a flushing pulse of the flushing amount is supplied (step S70). Then, the process proceeds to step S130.

  When performing interlaced printing and bidirectional printing (step S80: bidirectional printing), the control unit 16 uses the piezoelectric elements of all the nozzle openings 28 in the nozzle rows K, C, M, and Y provided in the recording head 2. It is set so that the fine vibration pulse VP1 is supplied to the vibrator 35 (step S90).

  The control unit 16 is necessary when the fine vibrations of the meniscus by the fine vibration pulse VP1 are applied to the piezoelectric vibrators 35 of all the nozzle openings 28 in the nozzle rows K, C, M, and Y. It sets so that the flushing pulse of flushing amount may be supplied (step S100). Then, the process proceeds to step S130.

  On the other hand, when performing interlaced printing and unidirectional printing (step S80: unidirectional printing), the control unit 16 sets all the nozzle openings 28 in the nozzle rows K, C, M, and Y provided in the recording head 2. It sets so that the fine vibration pulse VP3 may be supplied with respect to each piezoelectric vibrator 35 (step S110).

  The control unit 16 is necessary when the fine vibration of the meniscus by the fine vibration pulse VP3 is applied to each piezoelectric vibrator 35 of all the nozzle openings 28 in each nozzle row K, C, M, Y. It sets so that the flushing pulse of the flushing amount may be supplied (step S120). Then, the process proceeds to step S130.

  In step S130, the control unit 16 supplies a drive signal to each piezoelectric vibrator 35 of each nozzle array K, C, M, and Y to perform a printing operation while reciprocating the recording head 2 in the main scanning direction. .

  At this time, in the case of band printing and bi-directional printing, the control unit 16 applies weak micro-vibration by the micro-vibration pulse VP1 to each meniscus of the central nozzle opening in each nozzle row K, C, M, Y. . Further, strong fine vibration by the fine vibration pulse VP2 is applied to each meniscus of the end nozzle opening. On the other hand, in the case of band printing and unidirectional printing, and in the case of interlaced printing and bidirectional printing, the control unit 16 finely controls each meniscus of all the nozzle openings 28 in each nozzle row K, C, M, Y. A weak micro vibration is applied by the vibration pulse VP1. On the other hand, in the case of interlaced printing and unidirectional printing, the control unit 16 gives weaker vibrations by the minute vibration pulse VP3 to each meniscus of all the nozzle openings 28 in each nozzle row K, C, M, Y. To do.

Next, the control unit 16 determines whether or not a condition for executing the flushing operation is satisfied (step S140). Here, for example, when the time measured by the control unit 16 reaches a predetermined time interval, it is determined that the condition for executing the flushing operation is satisfied.
In this embodiment, the time interval of the flushing operation in interlaced printing is set shorter than the time interval in band printing. This is because the user is more interested in interlaced printing, which prints images, etc. in multiple passes than band printing, which prints images, etc. in a single pass, because of the delay in printing due to printing interruption during the flushing operation. By not becoming.

When the condition for executing the flushing operation is satisfied (step S140: Yes), the control unit 16 temporarily interrupts the printing operation and executes the flushing operation (step S150). Then, after completion of the flushing operation, the process returns to step S130 to repeat the printing operation.
Here, in the flushing operation, the control unit 16 moves the recording head 2 to the flushing position of the capping mechanism 27 and the like, forcibly ejects ink droplets from the nozzle openings 28, and the thickened ink is recorded in the recording head 2. Let go outside.

At this time, in the case of band printing and bidirectional printing, the control unit 16 is necessary in the case of the fine vibration pulse VP1 from each nozzle opening 28 of the central nozzle opening group in each nozzle row K, C, M, Y. The flushing amount of ink is discharged. Further, the flushing amount of ink required in the case of the fine vibration pulse VP2 is discharged from each nozzle opening 28 of the end nozzle opening group.
On the other hand, in the case of band printing and unidirectional printing, and in the case of interlaced printing and bidirectional printing, the control unit 16 applies the fine vibration pulse VP1 from all the nozzle openings 28 in each nozzle row K, C, M, Y. The flushing amount of ink necessary for the discharge is discharged. On the other hand, in the case of interlaced printing and unidirectional printing, the control unit 16 discharges the flushing amount of ink necessary for the minute vibration pulse VP3 from all the nozzle openings 28 in each nozzle row K, C, M, Y. Let That is, in the case of band printing, unidirectional printing, and interlace printing, the ink discharge amount for each nozzle opening 28 in the central nozzle opening group and the ink discharge amount for each nozzle opening 28 in the end nozzle opening group are uniform. Control to be.

  On the other hand, when the condition for executing the flushing operation is not satisfied (step S140: No), the process returns to step S130 and the printing operation is repeated.

<Corresponding example of ruled line misalignment>
Next, an example corresponding to the displacement of the ruled line will be described.
FIG. 7 is a diagram illustrating an example of a ruled line position shift in band printing and bidirectional printing. This figure shows an example in which a positional deviation occurs in the ruled line as a result of printing the ruled line on the recording paper 8 by band printing and bidirectional printing. Here, the ruled line L1 is printed in one pass (forward path), and then the recording paper 8 is conveyed by the length of the nozzle row of the nozzle openings 28 (# 1 to # 180), and then in two passes (return path). A ruled line L2 is printed.

  Here, when the regular printing position of the ruled lines L1 and L2 in the main scanning direction is P0, the ruled line L1 is displaced by Ga in the forward direction from P0 as a base point. On the other hand, the ruled line L2 is displaced by Ga in the backward direction from P0 as a base point. As a result, the position shift of the joint portion between the ruled line L1 and the ruled line L2 becomes 2Ga so as to be conspicuous. This is because the ink droplet ejection speed is slowed by increasing the viscosity of the ink in the vicinity of each nozzle opening 28 and the landing position of the ink droplet on the recording paper 8 is shifted in the moving direction of the recording head 2.

FIG. 8 is a diagram showing an example of conventional correspondence, and shows an example corresponding to the displacement of the ruled line in FIG. 7 by applying strong fine vibration to all the nozzle openings 28 in band printing and bidirectional printing. In the figure, strong fine vibration by the fine vibration pulse VP2 is applied to all the nozzle openings 28 (# 1 to # 180), and ruled lines L1 and L2 are printed on the recording paper 8 by band printing and bidirectional printing. is doing.
Here, due to the application of this strong micro vibration, the thickening of the ink in the vicinity of each nozzle opening 28 is kept normal. Then, the ruled lines L1 and L2 that have been displaced in FIG. 7 are printed at the regular printing position P0 as shown in FIG. As a result, the shift of the joint portion between the ruled line L1 and the ruled line L2 is completely eliminated.

  FIG. 12A is a graph showing an example of the flushing amount required at each nozzle opening 28 when the ruled lines L1 and L2 are printed under the conditions of FIG. Here, the value of the flushing amount indicates a coefficient used when calculating the amount of ink ejected from the nozzle opening 28, and the ink amount increases as the value increases. As shown in FIG. 12A, each nozzle opening 28 (# 1 to # 180) requires a flushing value “10”. Therefore, the total value of the flushing amount in the nozzle row (nozzle openings 28 (# 1 to # 180)) is “1,800” (180 × 10).

  FIG. 9 is a correspondence example of the present embodiment. In band printing and bidirectional printing, weak fine vibration is given to the central nozzle opening group and strong fine vibration is given to the end nozzle opening group, and the ruled lines in FIG. It is a figure which shows the example corresponding to position shift. In the same figure, weak fine vibration by the fine vibration pulse VP1 is applied to the central nozzle opening group (nozzle openings 28 (# 21 to # 160)), and the end nozzle opening groups (nozzle openings 28 (# 1 to # 160)). 20, # 161 to # 180)) are applied with strong micro-vibration by the micro-vibration pulse VP2, and ruled lines L1, L2 are printed on the recording paper 8 by band printing and bidirectional printing.

Here, the application of weak micro-vibration to the central nozzle opening group slightly suppresses the thickening of the ink near the central nozzle opening group. Then, as shown in FIG. 9, the ruled lines L1 and L2 that have been displaced in FIG. 7 are the ruled lines L12 and L22 that are printed portions of the central nozzle opening group, and the ruled line L12 is based on P0 as the forward direction. The ruled line L22 is displaced by Gb in the backward direction from P0 as a base point. The positional deviation Gb is smaller than the positional deviation Ga in FIG.
Further, by applying a strong minute vibration to the end nozzle opening group, the viscosity increase of the ink in the vicinity of the end nozzle opening group is maintained normally. Then, as shown in FIG. 9, the ruled lines L1 and L2 that have been displaced in FIG. 7 have the regular print positions P0 for the ruled lines L11, L13, L21, and L23 that are the printing portions of the end nozzle opening groups. It is supposed to be printed. As a result, although a slight misalignment remains between the ruled lines L11 and L13 and the ruled line L12 and between the ruled lines L21 and L23 and the ruled line L22, the misalignment of the joint portion between the ruled line L1 and the ruled line L2 is eliminated. ing.

  FIG. 12B is a graph showing an example of the flushing amount required in each nozzle opening 28 when the ruled lines L1 and L2 are printed under the conditions of FIG. As shown in the figure, in the central nozzle opening group (nozzle openings 28 (# 21 to # 160)), a value “5” of the flushing amount is required. Further, in the end nozzle opening group (nozzle openings 28 (# 1 to # 20, # 161 to # 180)), the value “10” of the flushing amount is required. Therefore, the total value of the flushing amount in the nozzle row (nozzle openings 28 (# 1 to # 180)) is “1,100” (140 × 5 + 40 × 10).

  FIG. 10 is a diagram illustrating an example of a ruled line position shift in band printing and unidirectional printing. This figure shows an example in which a positional deviation occurs in the ruled line as a result of printing the ruled line on the recording paper 8 by band printing and unidirectional printing. Here, when the regular printing positions of the ruled lines L1 and L2 in the main scanning direction are P0, the ruled lines L1 and L2 are both displaced by Ga in the forward direction with P0 as a base point. As a result, the ruled lines L1 and L2 as a whole are misaligned in the forward direction, but the misalignment of the joint portion between the ruled lines L1 and L2 does not occur.

FIG. 11 is a diagram illustrating an example corresponding to the positional deviation of the ruled line in FIG. 10 by applying a slight fine vibration to all the nozzle openings 28 in band printing and unidirectional printing. In the figure, weak fine vibration by the fine vibration pulse VP1 is applied to all the nozzle openings 28 (# 1 to # 180), and ruled lines L1 and L2 are printed on the recording paper 8 by band printing and unidirectional printing. is doing.
Here, the application of weak micro-vibration to all the nozzle openings 28 slightly suppresses the thickening of the ink near each nozzle opening 28. Then, as shown in FIG. 11, the entire ruled lines L1 and L2 that are both displaced in the forward direction in FIG. 10 are displaced by Gb in the forward direction starting from P0. This positional deviation Gb is smaller than the positional deviation Ga in FIG.

  FIG. 12C is a graph showing an example of the flushing amount required at each nozzle opening 28 when the ruled lines L1 and L2 are printed under the conditions of FIG. As shown in the figure, each nozzle opening 28 (# 1 to # 180) requires a flushing amount value “5”. Therefore, the total value of the flushing amount in the nozzle row (nozzle openings 28 (# 1 to # 180)) is “900” (180 × 5).

  FIG. 13 is a diagram illustrating an example of enlarging the ruled line width in interlaced printing and bidirectional printing. This figure shows an example in which the width of the ruled line is increased as a result of printing the ruled line on the recording paper 8 by interlaced printing and bidirectional printing. Here, the ruled line L3 is printed by repeating ejection of ink droplets from a part of the nozzle opening 28 in the forward path (odd number) and the backward path (even number).

  Here, when the regular print position of the ruled line L3 in the main scanning direction is P0 and the regular width of the ruled line L3 in the scan direction is P1, the print position of the ruled line L3 is correct, but the width of the ruled line L3 is larger than P1. It is expanding. This is because the ink droplet ejection speed is slowed by increasing the viscosity of the ink in the vicinity of each nozzle opening 28, and the landing position of the ink droplet on the recording paper 8 is shifted in the forward movement direction in the forward path. This is due to a shift in the moving direction on the return path. Further, since the dot interval of the ink droplets that have landed is wider than the regular dot interval, the ruled line image printed on the recording paper 8 is slightly blurred compared to the normally printed ruled line image.

  FIG. 14 is a diagram illustrating an example corresponding to the enlargement of the ruled line width in FIG. 13 by applying weak micro-vibration to all the nozzle openings 28 in interlaced printing and bidirectional printing. In the figure, weak fine vibration by the fine vibration pulse VP1 is applied to all the nozzle openings 28 (# 1 to # 180), and a ruled line L3 is printed on the recording paper 8 by interlace printing and bidirectional printing. Yes. By applying this weak slight vibration, the thickening of the ink near each nozzle opening 28 is kept normal. As a result, the width of the ruled line L3 that has been enlarged in FIG. 13 and the image of the unclear ruled line L3 become a regular image P1, as shown in FIG. 14, resulting in a clear image.

  When the ruled line L3 is printed under the conditions shown in FIG. 14, the graph showing the example of the flushing amount shown in FIG. Accordingly, each nozzle opening 28 (# 1 to # 180) needs a value “5” of the flushing amount, and the total value of the flushing amount at the nozzle row (nozzle openings 28 (# 1 to # 180)) is “900” (180 × 5).

  FIG. 15 is a diagram illustrating an example of a ruled line misalignment in interlaced printing and unidirectional printing. In the figure, an example is shown in which misregistration occurs in the ruled line as a result of printing the ruled line on the recording paper 8 by interlaced printing and unidirectional printing. Here, the ruled line L3 is printed by repeating ejection of ink droplets from a part of the nozzle opening 28 in a unidirectional pass only in the forward path.

  Here, when the regular printing position of the ruled line L3 in the main scanning direction is P0, the ruled line L3 is displaced by Ga in the forward direction from P0. This is because the ink droplet ejection speed becomes slow due to the increased viscosity of the ink, and the landing position of the ink droplet shifts in the forward movement direction in each pass (outward path).

  FIG. 16 is a diagram showing an example corresponding to the displacement of the ruled line in FIG. 15 by applying even weaker vibrations to all the nozzle openings 28 in interlaced printing and unidirectional printing. In the figure, a weaker vibration is applied to all the nozzle openings 28 (# 1 to # 180) by the vibration pulse VP3, and a ruled line L3 is printed on the recording paper 8 by interlace printing and unidirectional printing. ing. By applying the weaker vibration, the thickening of the ink in the vicinity of each nozzle opening 28 is kept normal. As a result, the ruled line L3 that has been displaced in FIG. 15 is printed at the regular print position P0 as shown in FIG.

  FIG. 12D is a graph showing an example of the flushing amount required at each nozzle opening 28 when the ruled line L3 is printed under the conditions of FIG. As shown in the figure, each nozzle opening 28 (# 1 to # 180) requires a flushing amount value “2.5”. Therefore, the total value of the flushing amount in the nozzle row (nozzle openings 28 (# 1 to # 180)) is “450” (180 × 2.5).

As described above, the conventional correspondence example (see FIG. 8) and the correspondence example of this embodiment (see FIG. 9) are used in order to cope with the positional deviation of the ruled line (see FIG. 7) in band printing and bidirectional printing. Indicated. In the case of the conventional correspondence example, by applying strong fine vibration to all the nozzle openings 28, it is possible to completely eliminate the positional deviation of the joint portion between the ruled line L1 and the ruled line L2. However, the total value of the flushing amount during the flushing operation is “1,800”, which causes a problem that a large amount of ink is consumed.
On the other hand, in the case of the correspondence example of the present embodiment, weak fine vibration is applied to the central nozzle opening group, and strong fine vibration is applied to the end nozzle opening group. Thereby, although a slight misalignment remains between the printing portion of the central nozzle opening group and the printing portion of the end nozzle opening group, the shift of the joint portion between the ruled line L1 and the ruled line L2 can be eliminated. The ruled lines L1 and L2 as a whole can be made ruled lines whose position deviation is not noticeable. Furthermore, the total value of the flushing amount during the flushing operation is “1,100”, and ink consumption can be reduced as compared with the conventional correspondence example.

  Further, in order to cope with the positional deviation of the ruled lines in the band printing and the unidirectional printing (see FIG. 10), a correspondence example in the band printing and the unidirectional printing (see FIG. 11) is shown. In the case of this correspondence example, weak fine vibration is applied to all the nozzle openings 28. Thereby, the positional deviation of the ruled lines L1 and L2 in the forward direction can be reduced. Further, the total value of the flushing amount at the time of the flushing operation is “900”, and the ink consumption can be further reduced as compared with the corresponding example in the bidirectional printing described above.

  Further, in order to cope with the expansion of the ruled line width in interlaced printing and bidirectional printing (see FIG. 13), a correspondence example in interlaced printing and bidirectional printing (see FIG. 14) is shown. In the case of this correspondence example, weak fine vibration is applied to all the nozzle openings 28. Thereby, the width of the ruled line L3 that has been enlarged can be made a normal width. In addition, the total value of the flushing amount during the flushing operation is “900”, and ink consumption can be reduced as compared with the corresponding example in the band printing and bidirectional printing described above.

  Further, in order to cope with the displacement of the ruled line in interlaced printing and unidirectional printing (see FIG. 15), a correspondence example in interlaced printing and unidirectional printing (see FIG. 16) is shown. In the case of this correspondence example, weaker vibrations are applied to all the nozzle openings 28. As a result, the ruled line L3 that has been misaligned can be positioned at the regular printing position. In addition, the total value of the flushing amount in the flushing operation is “450”, and the ink consumption can be further reduced as compared with the corresponding example in the interlaced printing and the bidirectional printing described above.

  As described above, the combination of the recording modes depends on whether the recording mode when performing the printing operation is band printing or interlaced printing, and whether each is bidirectional printing or unidirectional printing. Appropriate fine vibration is applied to each nozzle opening 28. As a result, the amount of flushing during the flushing operation can be reduced to a small amount, and the problem of wasteful consumption of ink during the flushing operation can be addressed.

  In the embodiment described above, the number of nozzle openings 28 in each of the nozzle rows K, C, M, and Y is 180. However, the number of nozzle openings 28 is not limited to this, and may be 90 or 360, for example. Also good.

  In the above-described embodiment, the ink jet color printer has been described as an example of the liquid ejecting apparatus, but is not limited thereto. For example, color filter manufacturing apparatus, dyeing apparatus, fine processing apparatus, semiconductor manufacturing apparatus, surface processing apparatus, three-dimensional molding machine, liquid vaporizer, organic EL manufacturing apparatus (especially polymer EL manufacturing apparatus), display manufacturing apparatus, film formation The present invention may be applied to various liquid ejecting apparatuses to which inkjet technology is applied, such as an apparatus and a DNA chip manufacturing apparatus.

  In the above-described embodiment, an example of printing using four colors of CMYK ink has been described. However, the present invention is not limited to this. For example, printing may be performed using inks of colors other than CMYK, such as light cyan, light magenta, white, and clear.

  In the above-described embodiment, the example of the recording head 2 using the piezoelectric vibrator 35 as a pressure generating element has been described. However, the present invention is not limited to this. For example, as a pressure generating element, a flexural vibration mode piezoelectric vibrator, an electrostatic actuator, a magnetostrictive element, a heating element, or the like may be used.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording head, 3 ... Cartridge holding part, 4 ... Carriage, 5 ... Platen, 5 '... Ink receiving part, 6 ... Carriage moving mechanism, 7 ... Linear encoder, 8 ... Recording paper, 9 ... Paper feed Mechanism, 10 ... ink cartridge, 11 ... guide shaft, 12 ... carriage moving motor, 13 ... driving pulley, 14 ... idle pulley, 15 ... timing belt, 16 ... control unit, 16a ... recording mode determination unit, 17 ... paper feed Mechanism: 18 ... Fixed support part, 19 ... Positioning member, 23 ... Liquid absorbing member, 24 ... Support protrusion, 25 ... Paper feed motor, 26 ... Paper feed roller, 27 ... Capping mechanism, 28 ... Nozzle opening, 31 ... Case, 32 ... Vibrator unit, 33 ... Channel unit, 34 ... Storage space, 35 ... Piezoelectric vibrator, 36 ... Fixed plate, 37 ... Channel forming substrate, 38 ... Nozzle 39, elastic plate, 40 ... reservoir, 41 ... ink supply port, 42 ... pressure chamber, 43 ... nozzle communication port, 44 ... diaphragm part, 51 ... printer controller, 52 ... print engine, 53 ... external I / F, 54 ... RAM, 55 ... ROM, 56 ... oscillation circuit, 57 ... timer circuit, 58 ... drive signal generation circuit, K, C, M, Y ... nozzle row, DP1 ... large dot drive pulse, DP2 ... small dot drive pulse, DP3: Medium dot drive pulse, Ga, Gb: Position shift, L1, L2, L3, L11, L12, L13, L14, L21, L22, L23, L24 ... Ruled line, P0: Normal printing position, P1: Normal width, P11 , P21, P31 ... charging element, P12, P22, P32 ... hold element, VB ... reference potential, VH1 ... first fine vibration potential, VH2 ... second fine vibration potential, VH3: third fine vibration potential, VP1, VP2, VP3 ... fine vibration pulse.

Claims (5)

A transport mechanism for transporting the medium in the transport direction;
A nozzle row in which a plurality of nozzle openings arranged in the transport direction are arranged is formed, and by operating the pressure generating element, the liquid pressure in the pressure chamber communicating with the nozzle opening is changed to discharge droplets from the nozzle opening. A liquid ejecting head,
A moving mechanism for reciprocating the liquid ejecting head in a main scanning direction intersecting the transport direction;
A control unit that supplies a drive signal to the pressure generating element and performs control to discharge droplets from the nozzle opening;
A recording mode determination unit that determines a recording mode when performing recording on the medium by discharging droplets from the nozzle opening,
The nozzle row includes an end nozzle opening group consisting of the nozzle openings located on the end side in the transport direction, and a central nozzle opening group consisting of the nozzle openings other than the end nozzle opening group,
The recording mode includes a first recording mode in which droplets are ejected from the nozzle openings and an image is recorded on the medium in one pass in the main scanning direction, and main scanning is performed by ejecting droplets from the nozzle openings. A second recording mode for recording an image on the medium in a plurality of passes in a direction,
When the controller performs a flushing operation for forcibly discharging droplets from the nozzle opening,
When the recording mode determination unit determines the first recording mode, the liquid discharge amount for each nozzle opening of the central nozzle opening group is larger than the liquid discharge amount for each nozzle opening of the end nozzle opening group. Control to a small amount,
When the recording mode determination unit determines the second recording mode, a liquid discharge amount for each nozzle opening of the end nozzle opening group and a liquid discharge amount for each nozzle opening of the central nozzle opening group A liquid ejecting apparatus that is controlled to be uniform. The control unit supplies a drive signal to the pressure generating element to further control the fine vibration of the meniscus at the nozzle opening to such an extent that a droplet is not discharged from the nozzle opening;
When the recording mode determination unit determines that the recording mode is the first recording mode, the control unit applies a slight vibration that is weaker than the fine vibration applied to the meniscus in the nozzle openings of the end nozzle opening group. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is controlled so as to be applied to the meniscus in the nozzle openings of the part nozzle opening group. The recording mode determination unit records on the medium in a bidirectional recording mode in which recording is performed on the medium in both directions of a forward path and a return path in the main scanning direction and in one direction of either a forward path and a return path in the main scanning direction. Further determine the unidirectional recording mode,
When the recording mode determination unit determines the unidirectional recording mode, the control unit applies weaker vibration to the meniscus at the nozzle opening than when the recording mode determination unit determines the bidirectional recording mode. And performing the flushing operation so that the amount of liquid ejected per nozzle opening is smaller than when the bidirectional recording mode is determined. Item 3. The liquid ejecting apparatus according to Item 1 or 2. A transport mechanism for transporting the medium in the transport direction;
A nozzle row in which a plurality of nozzle openings arranged in the transport direction are arranged is formed, and by operating the pressure generating element, the liquid pressure in the pressure chamber communicating with the nozzle opening is changed to discharge droplets from the nozzle opening. A liquid ejecting head,
A control mechanism of a liquid ejecting apparatus, comprising: a moving mechanism that reciprocates the liquid ejecting head in a main scanning direction intersecting the transport direction,
A control step of supplying a driving signal to the pressure generating element to perform control of discharging a droplet from the nozzle opening;
A recording mode determination step for determining a recording mode when performing recording on the medium by discharging droplets from the nozzle opening,
The nozzle row includes an end nozzle opening group consisting of the nozzle openings located on the end side in the transport direction, and a central nozzle opening group consisting of the nozzle openings other than the end nozzle opening group,
The recording mode includes a first recording mode in which droplets are ejected from the nozzle openings and an image is recorded on the medium in one pass in the main scanning direction, and main scanning is performed by ejecting droplets from the nozzle openings. A second recording mode for recording an image on the medium in a plurality of passes in a direction,
In the control step, when performing a flushing operation for forcibly discharging droplets from the nozzle opening,
When the first recording mode is determined in the recording mode determination step, the liquid discharge amount for each nozzle opening of the central nozzle opening group is larger than the liquid discharge amount for each nozzle opening of the end nozzle opening group. Control to a small amount,
When the second recording mode is determined in the recording mode determination step, a liquid discharge amount for each nozzle opening of the end nozzle opening group and a liquid discharge amount for each nozzle opening of the central nozzle opening group are A method for controlling a liquid ejecting apparatus, wherein the liquid ejecting apparatus is controlled to be uniform. A transport mechanism for transporting the medium in the transport direction;
A nozzle row in which a plurality of nozzle openings arranged in the transport direction are arranged is formed, and by operating the pressure generating element, the liquid pressure in the pressure chamber communicating with the nozzle opening is changed to discharge droplets from the nozzle opening. A liquid ejecting head,
A liquid ejecting apparatus control program comprising: a moving mechanism for reciprocating the liquid ejecting head in a main scanning direction intersecting the transport direction;
A control function for supplying a driving signal to the pressure generating element to perform control of discharging a droplet from the nozzle opening;
A recording mode determination function for determining a recording mode when performing recording on the medium by discharging droplets from the nozzle opening,
The nozzle row includes an end nozzle opening group consisting of the nozzle openings located on the end side in the transport direction, and a central nozzle opening group consisting of the nozzle openings other than the end nozzle opening group,
The recording mode includes a first recording mode in which droplets are ejected from the nozzle openings and an image is recorded on the medium in one pass in the main scanning direction, and main scanning is performed by ejecting droplets from the nozzle openings. A second recording mode for recording an image on the medium in a plurality of passes in a direction,
In the control function, when performing a flushing operation for forcibly discharging droplets from the nozzle opening,
When the recording mode determination function determines the first recording mode, the liquid discharge amount for each nozzle opening of the central nozzle opening group is larger than the liquid discharge amount for each nozzle opening of the end nozzle opening group. Control to a small amount,
When the recording mode determination function determines the second recording mode, a liquid discharge amount for each nozzle opening of the end nozzle opening group and a liquid discharge amount for each nozzle opening of the central nozzle opening group A control program for a liquid ejecting apparatus, which causes a computer to perform control so as to be uniform.

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