JP2012051323A - Liquid ejector, and control method and control program of liquid ejector - Google Patents

Abstract

[PROBLEMS] To reduce the position deviation of a ruled line by strengthening slight meniscus vibration during regular flushing, and the amount of flushing required increases as the amount of deviation of the ruled line decreases. This causes a problem of wasteful consumption.
A drive signal generation circuit 58 includes a drive signal including a first micro-vibration pulse for applying micro-vibration to a meniscus in a nozzle opening of a central nozzle opening group, and micro-vibration stronger than the first micro-vibration pulse. And a drive signal including a second micro-vibration pulse that is applied to the meniscus at the nozzle openings of the end nozzle opening group. When executing the flushing operation for forcibly discharging the liquid droplets from the nozzle openings, the control unit 16 uses the liquid discharge amount for each nozzle opening in the end nozzle opening group for each nozzle opening in the central nozzle opening group. Control the liquid discharge amount to be small.
[Selection] Figure 4

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 performs recording by ejecting ink droplets (droplets) from the nozzle openings of the liquid ejecting head while reciprocating the liquid ejecting head in a direction intersecting the recording paper (medium) conveyance direction. Print on 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 for suppressing the increase in the viscosity of the ink near the nozzle opening, there is a method of stirring the ink by slightly vibrating the meniscus. 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. By causing the meniscus to vibrate slightly, the ink in the vicinity of the nozzle opening is agitated and the increase in the viscosity of the ink is suppressed.
In addition, every time a certain period of time elapses during the printing operation, flushing that forcibly ejects ink droplets out of the liquid ejecting head is performed, and measures for discharging the thickened ink near the nozzle openings are widely performed. 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 above-described deviation in the flying direction of the ink droplets appears remarkably at the joint portion of the ruled line, for example, when the ruled line along the transport direction is printed by bidirectional printing and band printing. In particular, the positional deviation of the ruled lines on the forward path and the return path in bidirectional printing is conspicuous. In band printing, a band-shaped image piece corresponding to the length of the nozzle row is formed in one pass. Then, each pass and the recording paper conveyance operation are alternately repeated, whereby the band-shaped image pieces are joined in the conveyance direction to form an image.

  In order to cope with this problem, there is a method of making the position deviation of the ruled lines inconspicuous by frequently performing regular flushing. However, in this case, since printing must be interrupted during the flushing operation, the total output time of the liquid ejecting apparatus is delayed. In view of this, it is conceivable to reduce the ruled line position deviation by reducing the number of periodic flushing as much as possible and increasing the fine vibration of the meniscus between the regular flushing.

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, as the amount of ruled line displacement is reduced, the required flushing amount increases, resulting in a problem of wasteful consumption of ink.

  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 for discharging liquid droplets from the nozzle openings by changing the liquid pressure in the chamber, a moving mechanism for reciprocating the liquid ejecting head in the direction intersecting the transport direction with respect to the medium, and the pressure generation A drive signal generator for generating a drive signal for driving the element, and supplying the drive signal to the pressure generating element to control discharge of the droplet from the nozzle opening, and discharging the droplet from the nozzle opening A control unit for controlling the slight vibration of the meniscus in the nozzle opening, and the nozzle row includes the nozzle opening located on the end side in the transport direction. An end nozzle opening group and a central nozzle opening group composed of the nozzle openings other than the end nozzle opening group, and the drive signal generator is configured to prevent a meniscus in the nozzle openings of the central nozzle opening group. A drive signal including a first micro-vibration pulse for applying micro-vibration, and a second micro-vibration pulse for applying a micro-vibration stronger than the first micro-vibration pulse to the meniscus in the nozzle openings of the end nozzle opening group. And the control unit performs a flushing operation for forcibly ejecting liquid droplets from the nozzle openings, than the liquid discharge amount for each nozzle opening of the end nozzle opening group. 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, the drive signal generation unit causes the drive signal including the first fine vibration pulse that gives the fine vibration to the central nozzle opening group and the fine vibration to the end nozzle opening group. A drive signal including a second fine vibration pulse to be applied is generated. And a control part supplies these drive signals to each pressure generation element of a center part nozzle opening group and an end part nozzle opening group, and controls the fine vibration of the meniscus in each nozzle opening. Thereby, the thickening of the droplets in the vicinity of the nozzle openings of the central nozzle opening group and the end nozzle opening group is suppressed, and it is possible to cope with the occurrence of a deviation in the flight direction due to the thickening of the droplets.

Further, the second fine vibration pulse for the end nozzle opening group gives a fine vibration stronger than the first fine vibration pulse for the central nozzle opening group. The control unit controls the liquid discharge amount for each nozzle opening in the central nozzle opening group to be smaller than the liquid discharge amount for each nozzle opening in the end nozzle opening group when performing the flushing operation. To do.
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.

  Application Example 2 Droplet Discharge for Printing Raster Lines on the Medium by Discharging Droplets from the Nozzle Openings of the Nozzle Rows While the Liquid Ejecting Head is Moving in the Direction Crossing the Transport Direction by the Moving Mechanism The operation and the transport operation of transporting the medium by the transport mechanism and positioning the nozzle openings of the nozzle rows in a region that does not overlap the printed raster line region are alternately repeated. Liquid ejector.

  According to the above-described liquid ejecting apparatus, the liquid droplet ejection operation for ejecting the liquid droplets from the nozzle opening to print the raster line, and the nozzle opening in the area where the medium is transported and does not overlap with the printed raster line area. For example, when printing ruled lines by alternately repeating the transport operation for positioning the position, the problem of misalignment of the joints of the ruled lines and the problem that the liquid discharge amount of the entire nozzle array becomes large are dealt with. Can do.

  Application Example 3 The liquid ejecting apparatus according to the application example, wherein the nozzle openings of the end nozzle opening group are located on both end sides or one end side in the transport direction in the nozzle row.

  According to the above-described liquid ejecting apparatus, the nozzle openings of the end nozzle opening group are located on both end sides or one end portion side of the nozzle row. As a result, when the nozzle openings of the end nozzle opening group are located on both end sides of the nozzle row, for example, it is possible to cope with the problem of the positional deviation of the joint portion of the ruled line so that the positional deviation is not more conspicuous. it can. Further, when the nozzle opening of the end nozzle opening group is located on one end side of the nozzle row, it is possible to more effectively cope with the problem that the liquid discharge amount of the entire nozzle row becomes large. it can.

  Application Example 4 The second micro-vibration pulse is stronger with respect to the meniscus at the nozzle opening of the end nozzle opening group as the nozzle opening of the end nozzle opening group is positioned on the end side in the transport direction. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus imparts slight vibration.

  According to the above-described liquid ejecting apparatus, strong vibration is applied as the nozzle openings of the end nozzle opening group are positioned on the end side. As a result, a fine vibration close to the fine vibration of the central nozzle opening group is given to the nozzle openings located on the side of the central nozzle opening group among the nozzle openings of the end nozzle opening group. Strong vibrations can be applied in a step-wise manner toward the end side. As a result, the connection between the printed portion formed by the central nozzle opening group and the printed portion formed by the end nozzle opening group can be made inconspicuous and natural.

  Application Example 5 In the number of nozzle openings in the nozzle row, the end nozzle opening group increases as the amount of landing position deviation in the direction intersecting the transport direction of droplets discharged from the nozzle openings onto the medium increases. The liquid ejecting apparatus according to claim 1, wherein a ratio of the number of the nozzle openings is increased.

  According to the above-described liquid ejecting apparatus, as the amount of landing position deviation of the droplet increases, the ratio of the number of nozzle openings serving as the end nozzle opening group increases. As a result, when the landing position deviation amount is large, the number of nozzle openings that form the end nozzle opening group is increased, so that a ruled line in which, for example, the entire ruled line is not conspicuous can be obtained.

  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 changes liquid pressure in the chamber to eject liquid droplets from the nozzle openings, and a moving mechanism that reciprocates the liquid ejecting head in the direction intersecting the transport direction with respect to the medium. A control method for an ejection device, comprising: a drive signal generating step for generating a drive signal for driving the pressure generating element; and a control for supplying the drive signal to the pressure generating element and discharging a droplet from the nozzle opening And a control step for controlling a slight vibration of the meniscus at the nozzle opening to such an extent that no liquid droplets are discharged from the nozzle opening. An end nozzle opening group consisting of the nozzle openings located on the end side in the direction, and a central nozzle opening group consisting of the nozzle openings other than the end nozzle opening group, and in the drive signal generating step, A drive signal including a first micro-vibration pulse that imparts micro-vibration to the meniscus in the nozzle openings of the central nozzle opening group and a fine vibration stronger than the first micro-vibration pulse are applied to the nozzle openings of the end nozzle opening group. And generating a driving signal including a second micro-vibration pulse to be applied to the meniscus at the end, and performing a flushing operation for forcibly discharging a droplet from the nozzle opening in the control step. Control is performed so that the liquid discharge amount for each nozzle opening of the central nozzle opening group is smaller than the liquid discharge amount for each nozzle opening of the nozzle opening group. Control method for a liquid ejecting apparatus that.

  According to the control method of the liquid ejecting apparatus described above, in the drive signal generation step, the drive signal including the first fine vibration pulse for applying the fine vibration to the central nozzle opening group and the end nozzle opening group And a drive signal including a second micro-vibration pulse for applying micro-vibration. In the control step, these drive signals are supplied to the pressure generating elements of the central nozzle opening group and the end nozzle opening group to control the fine vibration of the meniscus at each nozzle opening. Thereby, the thickening of the droplets in the vicinity of the nozzle openings of the central nozzle opening group and the end nozzle opening group is suppressed, and it is possible to cope with the occurrence of a deviation in the flight direction due to the thickening of the droplets.

Further, the second fine vibration pulse for the end nozzle opening group gives a fine vibration stronger than the first fine vibration pulse for the central nozzle opening group. In the control process, when the flushing operation is executed, the liquid discharge amount for each nozzle opening in the central nozzle opening group is controlled to be smaller than the liquid discharge amount for each nozzle opening in the end nozzle opening group. To do.
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.

  Application Example 7 A pressure in which a transport mechanism that transports a medium in the transport direction and a nozzle array in which a plurality of nozzle openings arranged in the transport direction are arranged is formed and communicated with the nozzle openings by the operation of a pressure generating element A liquid ejecting head that changes liquid pressure in the chamber to eject liquid droplets from the nozzle openings, and a moving mechanism that reciprocates the liquid ejecting head in the direction intersecting the transport direction with respect to the medium. A control program for an ejection device, a drive signal generating function for generating a drive signal for driving the pressure generating element, and a control for supplying the drive signal to the pressure generating element and discharging droplets from the nozzle opening And a control function for controlling fine vibrations of the meniscus in the nozzle opening to such an extent that droplets are not discharged from the nozzle opening, In the drive signal generating function, including an end nozzle opening group consisting of the nozzle openings located on the end side in the conveyance direction and a central nozzle opening group consisting of the nozzle openings other than the end nozzle opening group , A drive signal including a first micro-vibration pulse that imparts micro-vibration to the meniscus in the nozzle openings of the central nozzle opening group, and a micro-vibration stronger than the first micro-vibration pulse is transmitted to the end nozzle opening group. Generating a drive signal including a second micro-vibration pulse to be applied to the meniscus at the nozzle opening, and performing the flushing operation for forcibly discharging the droplet from the nozzle opening in the control function, Control so that the liquid discharge amount for each nozzle opening of the central nozzle opening group is smaller than the liquid discharge amount for each nozzle opening of the end nozzle opening group. The control program of the liquid-jet apparatus characterized by to be executed by the computer.

  According to the control program for the liquid ejecting apparatus described above, the drive signal generation function causes the drive signal including the first fine vibration pulse to apply the fine vibration to the central nozzle opening group and the end nozzle opening group. And a drive signal including a second micro-vibration pulse for applying micro-vibration. Then, these drive signals are supplied to the pressure generating elements of the central nozzle opening group and the end nozzle opening group by the control function to control the slight vibration of the meniscus at each nozzle opening. Thereby, the thickening of the droplets in the vicinity of the nozzle openings of the central nozzle opening group and the end nozzle opening group is suppressed, and it is possible to cope with the occurrence of a deviation in the flight direction due to the thickening of the droplets.

Further, the second fine vibration pulse for the end nozzle opening group gives a fine vibration stronger than the first fine vibration pulse for the central nozzle opening group. Then, when performing the flushing operation by the control function, the liquid discharge amount for each nozzle opening of the central nozzle opening group is controlled to be smaller than the liquid discharge amount for each nozzle opening of the end nozzle opening group. To do.
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 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 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 bidirectional printing. The figure which shows the example of the positional offset of the ruled line in unidirectional printing. The figure which shows the example corresponding to the positional offset of a ruled line in unidirectional printing. (A)-(c) The graph which shows the example of the flushing amount required in each nozzle opening, when printing a ruled line. Explanatory drawing of each nozzle opening provided in the recording head of the printer which concerns on 2nd Embodiment. The figure which shows the example corresponding to the positional offset of the ruled line in bidirectional | two-way printing in 2nd Embodiment. The graph which shows the example of the flushing amount required in each nozzle opening, when printing a ruled line in 2nd Embodiment. The figure which shows the example corresponding to the positional offset of the ruled line in bidirectional | two-way printing in 3rd Embodiment. (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.

(First embodiment)
Hereinafter, the liquid ejecting apparatus according to the first 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) (see FIG. 4) for conveying is provided, and a paper feeding mechanism 17 for supplying the recording paper 8 to the paper feeding mechanism 9 side.

  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 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 to support the recording paper 8, and the tip portion projects upward from 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, at a position slightly outside the end in the width direction of the recording paper 8, ejected ink droplets at the time of 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 controls each part electrically, 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 A drive signal generation circuit 58 (drive signal generation unit) that generates a drive signal to be supplied to 2, and an internal I / F (interface) 59 for transmitting print data and drive signals to the print engine 52. I have.

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.

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 and the fine vibration pulse VP2. As shown in FIG. 6A, the drive signal generation circuit 58 includes a fine vibration pulse VP1 (first fine vibration pulse), a fine vibration pulse VP2 (second fine vibration pulse), a large dot drive pulse DP1, A drive signal COM configured by arranging a set of a small dot drive pulse DP2 and a medium 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 and VP2 are drive pulses for finely vibrating the meniscus of the non-ejection nozzle opening 28. Specifically, 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 ( The meniscus of # 21 to # 160) is slightly vibrated. 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. Is vibrated slightly.

  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.

  When these fine vibration pulses VP1 and VP2 are supplied to the piezoelectric vibrator 35, the piezoelectric vibrator 35 contracts by the respective charging elements P11 and P21, and the pressure chamber 42 expands gently to the extent that ink droplets are not ejected. To do. Then, after the expansion state of the pressure chamber 42 is maintained for a short time by the respective hold elements P12 and P22, the discharge elements P13 and P23 are supplied, whereby the piezoelectric vibrator 35 is expanded and the pressure chamber 42 is expanded. 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 VP2, that is, the potential difference from the reference potential VB to the second micro-oscillation potential VH2, is greater than 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 also set high. Further, 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. (Hereinafter, the micro-vibration caused by the micro-vibration pulse VP1 is expressed as weak micro-vibration and the micro-vibration caused by the micro-vibration pulse VP2 is expressed as strong micro-vibration.)
Accordingly, weak fine vibration is applied to each nozzle opening 28 (# 21 to # 160) of the central nozzle opening group, and each nozzle opening 28 (# 1 to # 20, # 161 to # 180) of the end nozzle opening group. Then, strong slight vibration is applied.

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, and conversely, the flushing amount decreases as the fine vibration is weakened.
Accordingly, the flushing amount for each nozzle opening 28 (# 21 to # 160) of the central nozzle opening group that imparts a slight fine vibration is the nozzle opening 28 (# 1 to ##) of the end nozzle opening group that imparts a strong fine vibration. 20, # 161 to # 180), and the amount is less than the flushing amount.

<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, printing mode, bidirectional printing or unidirectional printing, and color adjustment.

Next, the control unit 16 determines whether or not to perform bidirectional printing based on the command included in the print data received in step S10 (step S20).
Here, in bidirectional printing, when the recording head 2 reciprocates in the main scanning direction, a printing operation is performed in both forward movement and backward movement. On the other hand, in unidirectional printing, when the recording head 2 reciprocates in the main scanning direction, the printing operation is performed only in the forward movement.

  When bidirectional printing is performed (step S20: Yes), the control unit 16 is weak against each piezoelectric vibrator 35 of the central nozzle opening group in each nozzle row K, C, M, Y of the recording head 2. It is set so that a fine vibration pulse VP1 for applying fine vibration is supplied. Further, it is set so that the fine vibration pulse VP2 that gives strong fine vibration is supplied to each piezoelectric vibrator 35 of the end nozzle opening group (step S30).

  Then, the control unit 16 applies a flushing pulse having a flushing amount corresponding to weak microvibration by the microvibration pulse VP1 to each piezoelectric vibrator 35 of the central nozzle opening group in each nozzle row K, C, M, Y. Set to be supplied. In addition, a setting is made so that a flushing pulse having a flushing amount corresponding to the strong micro-vibration generated by the micro-vibration pulse VP2 is supplied to each piezoelectric vibrator 35 in the end nozzle opening group (step S40). Then, the process proceeds to step S70.

  On the other hand, when unidirectional printing is performed instead of bidirectional printing (step S20: No), the control unit 16 uses the piezoelectric elements of all the nozzle openings 28 in the nozzle rows K, C, M, and Y of the recording head 2. Similarly to the central nozzle opening group in bidirectional printing, the vibrator 35 is set so as to be supplied with a fine vibration pulse VP1 that gives a weak fine vibration (step S50).

  Then, the control unit 16 applies a flushing pulse with a flushing amount corresponding to weak microvibration by the microvibration pulse VP1 to each piezoelectric vibrator 35 of all the nozzle openings 28 in each nozzle row K, C, M, Y. It sets so that it may be supplied (step S60). Then, the process proceeds to step S70.

In step S70, the control unit 16 supplies a drive signal to each piezoelectric vibrator 35 of each nozzle row K, C, M, Y while causing the recording head 2 to reciprocate in the main scanning direction to execute a printing operation. .
At this time, in the case of bi-directional printing, the control unit 16 applies weak micro-vibration by the micro-vibration pulse VP1 to the central nozzle opening group in each nozzle row K, C, M, Y. Further, strong fine vibration by the fine vibration pulse VP2 is applied to the end nozzle opening group. On the other hand, in the case of unidirectional printing, the control unit 16 applies weak microvibration by the microvibration pulse VP1 to all the nozzle openings 28 in the nozzle rows K, C, M, and Y.

  Next, the control unit 16 determines whether or not a condition for executing the flushing operation is satisfied (step S80). 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.

When the condition for executing the flushing operation is satisfied (step S80: Yes), the control unit 16 temporarily interrupts the printing operation and executes the flushing operation (step S90). Then, after the flushing operation is completed, the process returns to step S70 to continue the printing operation.
On the other hand, when the condition for executing the flushing operation is not satisfied (step S80: No), the process returns to step S70 to continue the printing operation.

In this 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 discharges the thickened ink to the outside of the recording head 2. To discharge.
At this time, in the case of bidirectional printing, the control unit 16 discharges the flushing amount of ink set in step S40 from each nozzle opening 28 of the central nozzle opening group and the end nozzle opening group. That is, a smaller amount of ink is discharged from each nozzle opening 28 in the central nozzle opening group than in each nozzle opening 28 in the end nozzle opening group.
On the other hand, in the case of unidirectional printing, the control unit 16 discharges the flushing amount of ink set in step S <b> 60 from all the nozzle openings 28. That is, a smaller amount of ink is discharged from all the nozzle openings 28 than the nozzle openings 28 of the end nozzle opening group in bidirectional printing.

<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 showing an example of ruled line positional deviation in 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 bidirectional printing and band printing. In the case of 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 (dot row composed of a plurality of dots along the transport direction). ) And ruled lines are printed along the transport direction. In FIG. 7, the ruled line L1 is printed in one pass (outward 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 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 conventional correspondence example, and shows an example corresponding to the positional deviation of the ruled lines in FIG. 7 by applying strong fine vibrations to all the nozzle openings 28 in 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 bidirectional printing and band 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 this embodiment, and in bi-directional printing, weak fine vibration is applied to the central nozzle opening group and strong fine vibration is applied to the end nozzle opening group, thereby shifting the ruled line position in FIG. It is a figure which shows the corresponding example. 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 provided with strong micro-vibration by micro-vibration pulse VP2, and ruled lines L1 and L2 are printed on recording paper 8 by bidirectional printing and band 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 ruled line positional deviation in 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 unidirectional printing and band 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 showing an example corresponding to the displacement of the ruled line in FIG. 10 by applying a slight slight vibration to all the nozzle openings 28 in the unidirectional printing. In the figure, weak fine vibration by the fine vibration pulse VP1 is applied to all nozzle openings 28 (# 1 to # 180), and ruled lines L1 and L2 are printed on the recording paper 8 by unidirectional printing and band 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).

As described above, the conventional correspondence example (see FIG. 8) and the correspondence example of this embodiment (see FIG. 9) are shown in order to cope with the displacement of the ruled line (see FIG. 7) in bidirectional printing. 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.

  In addition, in order to cope with the positional deviation of the ruled lines in the unidirectional printing (see FIG. 10), a correspondence example in 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.

(Second Embodiment)
Next, a liquid ejecting apparatus according to a second embodiment will be described with reference to the drawings.

  The configuration of the printer as an example of the liquid ejecting apparatus according to the second embodiment is different from the configuration of the printer 1 according to the first embodiment in the configuration of each nozzle opening 28 provided in the recording head 2. FIG. 13 is an explanatory diagram of each nozzle opening 28 provided in the recording head 2 of the printer according to the second embodiment. As shown in the figure, in the recording head 2 in the second embodiment, 180 nozzle openings 28 (# 1 to # 1) are arranged in each nozzle row K, C, M, Y as in the recording head 2 in the first embodiment. # 180). However, in the recording head 2 in the second embodiment, unlike the recording head 2 in the first embodiment, 20 nozzle openings 28 (# 161 to # 180) positioned on one end side in the transport direction are end portions. A nozzle opening group is used, and 160 nozzle openings 28 (# 1 to # 160) other than the end nozzle opening group are used as a central nozzle opening group.

  Further, in the drive signal generation circuit 58 of the printer according to the second embodiment, 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, Weak weak vibration is applied to the nozzle openings 28 (# 1 to # 160) of the central nozzle opening group. Then, the fine vibration pulse VP2 is supplied to each piezoelectric vibrator 35 of the end nozzle opening group to give strong fine vibration to the nozzle openings 28 (# 161 to # 180) of the end nozzle opening group.

  FIG. 14 shows the configuration of each nozzle opening 28 according to the second embodiment. In 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. It is a figure which shows the example corresponding to the position shift of the ruled line in. In the same figure, weak fine vibration by the fine vibration pulse VP1 is applied to the central nozzle opening group (nozzle openings 28 (# 1 to # 160)), and the end nozzle opening group (nozzle openings 28 (# 161 to # 160) is applied. 180)), a strong fine vibration is applied by the fine vibration pulse VP2, and the ruled lines L1 and L2 are printed on the recording paper 8 by bidirectional printing and band 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. 14, the ruled lines L1 and L2 that have been displaced in FIG. 7 are displaced by Gb in the forward direction from the ruled line L14 that is the printing portion of the central nozzle opening group, starting from P0. The ruled line L24 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, the ruled lines L1 and L2 that have been displaced in FIG. 7 are printed at the regular print position P0, as shown in FIG. 14, the ruled lines L13 and L23 that are the printing portions of the end nozzle opening group. ing. As a result, although a slight misalignment remains between the ruled lines L14, L13, L24, and L23, the misalignment is not conspicuous for the entire ruled lines L1 and L2.

  FIG. 15 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, the central nozzle opening group (nozzle openings 28 (# 1 to # 160)) requires a flushing value “5”. Further, in the end nozzle opening group (nozzle openings 28 (# 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 “1,000” (160 × 5 + 20 × 10).

As described above, in the present embodiment, in order to cope with the positional deviation of the ruled line in bidirectional printing (see FIG. 7), a weak slight vibration is applied to the central nozzle opening group, and one end portion side in the transport direction. A strong microvibration is applied to the end nozzle opening group located in the position. As a result, although there is a slight misalignment between the printing portion of the central nozzle opening group and the printing portion of the end nozzle opening group and at the joint portion of the ruled line L1 and the ruled line L2, the entire ruled lines L1 and L2 remain. Can be a ruled line that does not stand out.
Further, by setting the 20 nozzle openings 28 (# 161 to # 180) positioned on one end side in the transport direction as the end nozzle opening group, the total value of the flushing amount in the flushing operation is “1,000. " As a result, in the first embodiment, the 40 nozzle openings 28 (# 1 to # 20, # 161 to # 180) positioned on both end sides are used as an end nozzle opening group. Consumption can be further reduced.

(Third embodiment)
Next, a liquid ejecting apparatus according to a third embodiment will be described with reference to the drawings.

  The configuration of the printer as an example of the liquid ejecting apparatus according to the third embodiment is the same as the configuration of the printer 1 according to the first embodiment, but the drive signal generation circuit 58 includes nozzle arrays K, C, The contents of the fine vibration pulse VP supplied to the piezoelectric vibrators 35 in the end nozzle opening groups in M and Y are different. Note that the micro-vibration pulse VP1 is supplied to each piezoelectric vibrator 35 of the central nozzle opening group as in the first embodiment.

  In the drive signal generation circuit 58 in the third embodiment, the nozzle openings 28 are stronger against the piezoelectric vibrators 35 in the end nozzle opening groups in the nozzle rows K, C, M, and Y as the nozzle openings 28 are positioned on the end side. A fine vibration pulse (second fine vibration pulse) is supplied so as to apply the fine vibration. Specifically, the piezoelectric vibrator 35 of the nozzle opening 28 (# 20, # 161) located on the central nozzle opening group side is subjected to fine vibration by the fine vibration pulse VP1 applied to the central nozzle opening group. A micro-vibration pulse that gives a slightly strong micro-vibration is also supplied. Then, as the position of the nozzle opening 28 becomes closer to the end side, stronger fine vibration is applied in a stepwise manner, and the nozzle opening 28 (# 1, # 180) positioned closest to the end side is slightly vibrated. The fine vibration pulse is supplied so that the same fine vibration as that of the pulse VP2 is applied.

  FIG. 16 shows the positional deviation of the ruled line in FIG. 7 by applying weak micro-vibration to the central nozzle opening group and strong micro-vibration to the end nozzle opening group toward the end side in bi-directional printing. It is a figure which shows the example corresponding to. 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 fine vibrations that are stronger toward the end, and ruled lines L1 and L2 are printed on the recording paper 8 by bidirectional printing and band 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. 16, 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. 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 fine vibration that is stronger as the position is closer to the end with respect to the end nozzle opening group, the thickening of the ink is suppressed toward the end side nozzle opening 28. Then, the ruled lines L1 and L2 that have been displaced in FIG. 7 are the end parts of the ruled lines L11 ′, L13 ′, L21 ′, and L23 ′ that are the printing portions of the end nozzle opening groups as shown in FIG. It is printed so that it is closer to the regular printing position P0 as it is closer.

  As described above, in the present embodiment, in order to cope with the positional deviation of the ruled line in bidirectional printing (see FIG. 7), weak vibration is given to the central nozzle opening group, and the end nozzle opening group is given. On the other hand, the stronger the fine vibration is given to the end portion side. Thereby, the positional deviation of the joint portion between the printing portion of the central nozzle opening group and the printing portion of the end nozzle opening group becomes inconspicuous, and the positional deviation of the joint portion between the ruled line L1 and the ruled line L2 is eliminated. Thus, the ruled lines L1 and L2 as a whole can be made into natural ruled lines whose positional deviation is not more noticeable.

  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.

The number of nozzle openings 28 in the end nozzle opening group and the central nozzle opening group is 40 and 160, respectively. However, the number is not limited to this, and the number of the nozzle openings 28 is not limited to this. May be set.
For example, when the positional deviation is large, the number of nozzle openings 28 in the end nozzle opening group is increased, and the number of nozzle openings 28 in the central nozzle opening group is decreased. Conversely, when the positional deviation is small, the number of nozzle openings 28 in the end nozzle opening group is decreased, and the number of nozzle openings 28 in the central nozzle opening group is increased. Thereby, when the positional deviation is large, the printing portion of the end nozzle opening group is enlarged, so that the positional deviation is not conspicuous for the entire ruled lines L1 and L2. On the other hand, when the positional deviation is small, the printing portion of the central nozzle opening group becomes large, so that ink consumption can be reduced.

  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 movement motor, 13 ... driving pulley, 14 ... idle pulley, 15 ... timing belt, 16 ... control unit, 17 ... paper feed mechanism, 18 ... fixed support unit , 19 ... Positioning member, 23 ... Liquid absorbing member, 24 ... Support protrusion, 25 ... Motor, 26 ... Roller, 27 ... Capping mechanism, 28 ... Nozzle opening, 31 ... Case, 32 ... Vibrator unit, 33 ... Channel unit 34 ... Storage empty space, 35 ... Piezoelectric vibrator, 36 ... Fixed plate, 37 ... Flow path forming substrate, 38 ... Nozzle plate, 39 ... Elastic plate, 40 ... Reservoir DESCRIPTION OF SYMBOLS 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 array, DP1 ... Large dot drive pulse, DP2 ... Small dot drive pulse, DP3 ... Medium dot drive pulse, Ga, Gb ... Misalignment, L1, L2, L11, L11 ′, L12, L13, L13 ′, L14, L21, L21 ′, L22, L23, L23 ′, L24... Ruled line, P0. P12, P22: Hold element, VB: Reference potential, VH1: First fine vibration potential, VH2: Second fine vibration potential, VP1, VP2: Fine vibration pulse.

Claims (7)

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 with respect to the medium in a direction intersecting the transport direction;
A drive signal generator for generating a drive signal for driving the pressure generating element;
The drive signal is supplied to the pressure generating element to control the ejection of droplets from the nozzle opening, and the fine vibration of the meniscus at the nozzle opening is controlled to the extent that no droplet is ejected from the nozzle opening. A control unit,
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 drive signal generator includes a drive signal including a first micro-vibration pulse that applies micro-vibration to a meniscus in a nozzle opening of the central nozzle opening group, and a micro-vibration stronger than the first micro-vibration pulse. A drive signal including a second micro-vibration pulse applied to the meniscus at the nozzle openings of the end nozzle opening group,
When the controller performs a flushing operation for forcibly discharging droplets from the nozzle openings, the nozzles of the central nozzle opening group are more than the liquid discharge amount for each nozzle opening of the end nozzle opening group. A liquid ejecting apparatus that controls a liquid discharge amount per opening to be small. A droplet ejection operation for ejecting droplets from the nozzle openings of the nozzle row and printing a raster line on the medium while the liquid ejecting head is moved in a direction intersecting the transport direction by the moving mechanism;
The conveyance operation of conveying the medium by the conveyance mechanism and positioning the nozzle openings of the nozzle rows in an area that does not overlap the area of the printed raster line is alternately repeated. The liquid ejecting apparatus described.   3. The liquid ejecting apparatus according to claim 1, wherein the nozzle openings of the end nozzle opening group are located on both end sides or one one end side in the transport direction in the nozzle row.   The second fine vibration pulse gives a strong fine vibration to the meniscus at the nozzle openings of the end nozzle opening group as the nozzle openings of the end nozzle opening group are positioned on the end side in the transport direction. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.   As the amount of landing position deviation in the direction intersecting the transport direction of the droplets discharged from the nozzle openings to the medium increases, the nozzle openings that form the end nozzle opening group in the number of the nozzle openings in the nozzle row 5. The liquid ejecting apparatus according to claim 1, wherein a ratio of the number of the liquid jets increases. 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 method comprising: a moving mechanism that reciprocates the liquid ejecting head in a direction intersecting the transport direction with respect to the medium;
A drive signal generating step for generating a drive signal for driving the pressure generating element;
The drive signal is supplied to the pressure generating element to control the ejection of droplets from the nozzle opening, and the fine vibration of the meniscus at the nozzle opening is controlled to the extent that no droplet is ejected from the nozzle opening. A control process,
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,
In the drive signal generation step, a drive signal including a first fine vibration pulse for giving a fine vibration to a meniscus in a nozzle opening of the central nozzle opening group and a fine vibration stronger than the first fine vibration pulse are A drive signal including a second micro-vibration pulse applied to the meniscus at the nozzle openings of the end nozzle opening group,
In the control step, when performing a flushing operation for forcibly discharging droplets from the nozzle openings, the nozzles of the central nozzle opening group are more than the liquid discharge amount for each nozzle opening of the end nozzle opening group. A control method for a liquid ejecting apparatus, wherein the liquid ejection amount for each opening is controlled to be small. 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 direction intersecting the transport direction with respect to the medium;
A drive signal generating function for generating a drive signal for driving the pressure generating element;
The drive signal is supplied to the pressure generating element to control the ejection of droplets from the nozzle opening, and the fine vibration of the meniscus at the nozzle opening is controlled to the extent that no droplet is ejected from the nozzle opening. A control function;
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,
In the drive signal generating function, the drive signal including a first fine vibration pulse for giving a fine vibration to the meniscus in the nozzle openings of the central nozzle opening group, and a fine vibration stronger than the first fine vibration pulse A drive signal including a second micro-vibration pulse applied to the meniscus at the nozzle openings of the end nozzle opening group,
In the control function, when performing a flushing operation for forcibly discharging droplets from the nozzle openings, the nozzles of the central nozzle opening group are more than the liquid discharge amount for each nozzle opening of the end nozzle opening group. A control program for a liquid ejecting apparatus, which causes a computer to execute control so that a liquid discharge amount per opening is small.

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