JP2018154079A - Method for driving liquid discharge device and liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deterioration in printing image quality while appropriately suppressing air from being entrained.SOLUTION: A method for driving a liquid discharge device comprises a first common liquid chamber that supplies first liquid to a nozzle for discharging the first liquid, a second common liquid chamber that supplies second liquid to a nozzle for discharging the second liquid whose color is different from the color of the first liquid and a detecting part that detects a dot pattern satisfying a specific condition on the basis of a dot pattern of the first liquid which is expanded by printing data; and when the detecting part detects the dot pattern, reduces discharge amounts of the first liquid and discharges the second liquid to supplement the first liquid, so as to print the dot pattern.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a technique for discharging a liquid such as ink.

  In the liquid ejecting apparatus, a liquid such as ink supplied from a liquid container via a common liquid chamber (reservoir) is ejected from a nozzle based on a dot pattern developed from print data. Depending on the dot pattern, the supply of liquid is not in time, the supply is insufficient, the meniscus in the nozzle (the surface of the liquid formed in the nozzle) is destroyed, and air is drawn from the nozzle into the common liquid chamber. there is a possibility. When air is drawn from the nozzle, there is a possibility that a defective ejection of the nozzle may occur. Patent Document 1 exemplifies a dot pattern in which two or more discharges are continued as a case where liquid supply is likely to be insufficient. Then, for example, according to the liquid discharge amount (duty value) in the two or more continuous discharges immediately before, a waiting time is provided after each discharge, thereby eliminating the shortage of liquid supply.

JP 2010-228349 A

  However, if a standby time is provided after each discharge as in Patent Document 1, the overall printing speed is reduced. In addition, the dot pattern in which air is actually likely to be drawn is not limited to a dot pattern that is continuously ejected twice or more as exemplified in Patent Document 1. For example, air is likely to be drawn even in a dot pattern in which a non-ejection or ejection period with a small ejection volume is interposed between ejection with a large ejection volume and ejection with a large ejection volume. In such a dot pattern, there is a high possibility that the supply of liquid will not be in time because of a rapid change in flow velocity in the common liquid chamber. If there is a non-ejection nozzle, even if liquid is ejected from many nozzles, an excessive negative pressure is generated in the common liquid chamber so that even the ink in the vicinity of the non-ejection nozzle is taken away, and the non-ejection nozzle Even air is easily drawn in. The air drawing by such a dot pattern is not assumed in Patent Document 1, and cannot be handled by the technology of Patent Document 1. Further, in order to keep the supply of the liquid in time, it is only necessary to reduce the amount of liquid discharged from the nozzles. However, if only the amount of liquid discharged is reduced, the print image quality is deteriorated. In view of the above circumstances, an object of the present invention is to suppress deterioration in print image quality while accurately suppressing air entrainment.

  In order to solve the above-described problems, a driving method of a liquid discharge apparatus according to the present invention is a driving method of a liquid discharge apparatus, and the liquid discharge apparatus supplies a first liquid to a nozzle that discharges the first liquid. The first common liquid chamber, the nozzle that discharges the second liquid of a color different from the first liquid, the second common liquid chamber that supplies the second liquid, and the dot pattern of the first liquid developed from the print data And a detection unit that detects a dot pattern that satisfies a specific condition. When the detection unit detects a dot pattern, the discharge amount of the first liquid is reduced and the second liquid is supplemented to supplement the first liquid. A dot pattern is printed by discharging liquid. According to the above aspect, since the discharge amount of the first liquid is reduced when the detection unit detects the dot pattern of the first liquid that satisfies the specific condition, for example, the flow rate of the first liquid in the first common liquid chamber It is possible to reduce the discharge amount of the first liquid with a dot pattern that tends to cause insufficient supply of the first liquid due to an abrupt change. Thereby, since the rapid change of the flow velocity of the liquid in a 1st common liquid chamber can be suppressed, supply of a 1st liquid comes in time and the supply shortage of a 1st liquid can be suppressed. Therefore, it is possible to suppress air from being drawn not only from the nozzles that discharge the first liquid, but also from the non-discharge nozzles that do not discharge the first liquid, among the nozzles of the first common liquid chamber. Further, according to this aspect, the standby time is not provided after each discharge, but the discharge amount of the first liquid is reduced, so that a decrease in the overall printing speed can be suppressed as compared with the case where the standby time is provided. . Further, since the second liquid having a color different from that of the first liquid is ejected so as to supplement the first liquid, for example, a liquid having a color different from that of the first liquid but having a color close to the first liquid, the first liquid is used. The first liquid can be supplemented by using a liquid having a different color material concentration (darkness) from one liquid, a plurality of liquids that have colors close to the first liquid when combined, and the like as the second liquid. Thereby, it is possible to suppress a decrease in print image quality. In addition, since the first liquid is supplemented by the second liquid supplied from the second common liquid chamber different from the first common liquid chamber, the first liquid in the first common liquid chamber is further discharged and supplemented. Thus, the first liquid can be supplemented so as not to be insufficiently supplied. Thus, according to this aspect, it is possible to suppress a decrease in print image quality while suppressing air entrainment due to a rapid change in the velocity of the liquid in the common liquid chamber.

  In a preferred aspect of the present invention, when the first liquid is discharged from the nozzle by changing the pressure in the pressure chamber by driving the driving element, the shape or number of driving waveforms for driving the driving element is changed. The discharge amount of the first liquid is reduced. According to the above aspect, since the discharge amount of the first liquid is reduced by changing the shape or number of drive waveforms for driving the drive elements, the discharge amount can be easily adjusted.

  In a preferred aspect of the present invention, the second liquid supplemented with the first liquid is a plurality of different color liquids. According to the above aspect, by supplementing the first liquid with a plurality of second liquids of different colors, it is possible to suppress a decrease in print image quality. According to this aspect, for example, when the first liquid is black, cyan, magenta, and yellow, which become colors close to black by being combined, can be used as the second liquid.

  In a preferred aspect of the present invention, the detection unit has a dot pattern that satisfies a specific condition from the dot pattern developed from the print data based on the discharge duty of the first liquid and the discharge or non-discharge time of the first liquid. Is detected. According to the above aspect, since the dot pattern satisfying the specific condition is detected based on the discharge duty of the first liquid and the discharge or non-discharge time, it is compared with the case where the dot pattern is detected only by the discharge duty. Thus, it is possible to accurately detect a dot pattern in which the first liquid is likely to be insufficiently supplied.

  In a preferred aspect of the present invention, the range of the discharge duty satisfying the specific condition varies depending on the color of the first liquid. According to the above aspect, since the range of the discharge duty satisfying the specific condition varies depending on the color of the first liquid, even if the viscosity or weight of the first liquid changes depending on the color of the first liquid, the first liquid accordingly It is possible to make the ranges detected as dot patterns that are likely to be insufficient to supply differ. Therefore, according to this aspect, it is possible to accurately detect a dot pattern that tends to be insufficiently supplied with the first liquid according to the color of the first liquid.

  In order to solve the above problems, a driving method of a liquid discharge apparatus according to the present invention includes a first common liquid chamber that supplies a first liquid to a nozzle that discharges the first liquid, and a color different from that of the first liquid. A second common liquid chamber that supplies the second liquid to the nozzle that discharges the second liquid, and a detection unit that detects a dot pattern that satisfies a specific condition based on the dot pattern of the first liquid developed from the print data; When the detection unit detects a dot pattern, the discharge amount of the first liquid is reduced, and the second liquid is discharged so as to supplement the first liquid, thereby printing the dot pattern. According to the above aspect, since the discharge amount of the first liquid is reduced when the detection unit detects the dot pattern of the first liquid that satisfies the specific condition, for example, the flow rate of the first liquid in the first common liquid chamber It is possible to reduce the discharge amount of the first liquid with a dot pattern that tends to cause insufficient supply of the first liquid due to an abrupt change. Thereby, since the rapid change of the flow velocity of the liquid in a 1st common liquid chamber can be suppressed, supply of a 1st liquid comes in time and the supply shortage of a 1st liquid can be suppressed. Therefore, it is possible to suppress air from being drawn not only from the nozzles that discharge the first liquid, but also from the non-discharge nozzles that do not discharge the first liquid, among the nozzles of the first common liquid chamber. Further, according to this aspect, the standby time is not provided after each discharge, but the discharge amount of the first liquid is reduced, so that a decrease in the overall printing speed can be suppressed as compared with the case where the standby time is provided. . Furthermore, since the second liquid having a color different from that of the first liquid is ejected so as to supplement the first liquid, for example, the second liquid may be a liquid having the same color material type and a different concentration from the first liquid. The first liquid can be supplemented as the liquid. Thereby, it is possible to suppress a decrease in print image quality. In addition, since the first liquid is supplemented by the second liquid supplied from the second common liquid chamber different from the first common liquid chamber, the first liquid in the first common liquid chamber is further discharged and supplemented. Thus, the first liquid can be supplemented so as not to be insufficiently supplied. Thus, according to this aspect, it is possible to suppress a decrease in print image quality while suppressing air entrainment due to a rapid change in the velocity of the liquid in the common liquid chamber.

1 is a configuration diagram of a liquid ejection apparatus according to a first embodiment of the present invention. It is a disassembled perspective view of a liquid discharge part. It is III-III sectional drawing shown in FIG. It is a partial section perspective view of a communication board. It is the partial top view which looked at the flow-path board | substrate from the downward direction. It is a functional block diagram of a liquid discharge apparatus. It is a figure which shows the drive waveform of the drive signal which drives a piezoelectric element. 6 is a flowchart illustrating an operation during printing of the liquid ejection apparatus. It is a figure which shows the relationship between the time of discharge or non-discharge, and meniscus pressure | voltage resistance. It is a figure which shows the modification of the drive waveform of the dot pattern which satisfy | fills specific conditions. It is a figure which shows the relationship between the number of the drive waveforms in a drive signal, and dot size.

<First Embodiment>
FIG. 1 is a partial configuration diagram of a liquid ejection apparatus 10 according to the first embodiment of the present invention. The liquid ejection apparatus 10 according to the first embodiment is an ink jet printing apparatus that ejects ink, which is an example of a liquid, onto a medium 12 such as printing paper. A liquid ejection apparatus 10 shown in FIG. 1 includes a control unit 20, a transport mechanism 22, a carriage 24, and a liquid ejection head 26. A liquid container (cartridge) 14 for storing ink is attached to the liquid ejection apparatus 10.

  The liquid container 14 is an ink tank type cartridge composed of a box-shaped container that can be attached to and detached from the main body of the liquid ejection apparatus 10. The liquid container 14 is not limited to a box-shaped container, and may be an ink pack type cartridge including a bag-shaped container. In this embodiment, eight colors of cyan (C), magenta (M), yellow (Y), black (K), light cyan (LC), light magenta (LM), dark yellow (DY), and light black (LK) are used. The ink is stored in the liquid container 14. Cyan (C), magenta (M), yellow (Y), and black (K) have different color materials (pigments, dyes, etc.). In addition, cyan (C), magenta (M), yellow (Y), and black (K) are light cyan (LC), light magenta (LM), dark yellow (DY), light black (LK), and color materials (respectively). Ink of different colors (pigments, dyes, etc.). The ink stored in the liquid container 14 is not limited to the illustrated eight colors of ink. The ink stored in the liquid container 14 is supplied (pressure fed) to the liquid ejection head 26 by a pump (not shown).

  The control unit 20 includes, for example, a control device 202 such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array) and a storage device 203 such as a semiconductor memory, and stores a control program stored in the storage device 203. When executed by the control device 202, each element of the liquid ejection device 10 is comprehensively controlled. As shown in FIG. 1, print data G representing an image to be formed on the medium 12 is supplied to the control unit 20 from an external device (not shown) such as a host computer. The control unit 20 controls each element of the liquid ejection device 10 so that an image designated by the print data G is formed on the medium 12.

  The liquid discharge head 26 is mounted on the carriage 24. The liquid discharge head 26 includes a plurality of liquid discharge units 70. In the present embodiment, a case where four liquid ejection units 70 are arranged so as to be aligned along a direction X orthogonal to the Y direction that is the conveyance direction of the medium 12 is illustrated. However, the arrangement of the four liquid ejecting units 70 is not limited to the illustrated one, and may be arranged along the Y direction, for example, or may be arranged in a staggered shape or a staggered shape. Moreover, the number of the liquid discharge parts 70 is not restricted to what was illustrated. Each liquid ejection unit 70 is provided with two nozzle rows, and the liquid ejection head 26 includes a total of eight nozzle rows. Each nozzle row is a set of a plurality of nozzles N arranged linearly along the Y direction. Eight colors of ink are separately supplied to the eight nozzle rows, and different colors of ink are ejected from the nozzles N of the eight nozzle rows for each nozzle row.

  The carriage 24 is a structure that accommodates and supports the liquid ejection head 26, and is controlled in the X direction orthogonal to the Y direction by a moving mechanism (not shown) including a conveyance belt and a motor under the control of the control unit 20. Iteratively reciprocates along In parallel with the transport of the medium 12 by the transport mechanism 22 and the reciprocating reciprocation of the carriage 24, the liquid discharge head 26 discharges ink onto the medium 12, thereby forming a desired image on the surface of the medium 12. However, the configurations of the transport mechanism 22 and the carriage 24 are not limited to the above examples. A direction perpendicular to the XY plane (a plane parallel to the surface of the medium 12) is hereinafter referred to as a Z direction. The ink discharge direction by the liquid discharge head 26 corresponds to the Z direction.

  FIG. 2 is an exploded perspective view of any one liquid ejection unit 70. 3 is a cross-sectional view of the liquid ejection unit 70 shown in FIG. 2 taken along the line III-III. As shown in FIGS. 2 and 3, the liquid ejection unit 70 is configured by fixing (joining) the case member 40 to the head body 30. The head main body 30 includes a communication substrate 32, and a nozzle plate 52 on which a plurality of nozzles N are formed and a compliance substrate (sealing plate) 54 are installed on one side (a positive side surface in the Z direction). This is a structure in which the laminated portion 38 including the pressure chamber substrate 382 is laminated on the side (the negative side surface in the Z direction). The elements of the head body 30 are fixed to each other with an adhesive, for example.

  The nozzle plate 52 is a flat plate material that constitutes an ejection surface (a surface facing the medium 12) on which a plurality of nozzles N arranged in the Y direction are formed. The nozzle plate 52 is made of, for example, a silicon material. The plurality of nozzles N includes two nozzle rows. The arrangement of the nozzle rows is not limited to that illustrated in the present embodiment. For example, the nozzle rows may be shifted in the Y direction. Further, the nozzle rows formed on the nozzle plate 52 are not limited to two rows, and may be one row.

  As shown in FIG. 3 (III-III cross-sectional view of the liquid ejection unit 70 shown in FIG. 1 taken along the XZ plane perpendicular to the XY plane), the liquid ejection unit 70 according to the present embodiment is as shown in FIG. A structure corresponding to each nozzle row is formed substantially line-symmetric with respect to an imaginary line OO parallel to the Z direction, and both structures divided at the imaginary line OO are substantially the same. Therefore, in the following description, attention is paid to the structure corresponding to one nozzle row (the left side of the imaginary line OO in FIG. 3), and the structure corresponding to the other nozzle row (the imaginary line OO in FIG. 3). The description of the elements on the right side) is omitted for the sake of convenience. FIG. 4 is a partial cross-sectional perspective view of the communication substrate 32 in the structure corresponding to one nozzle row (the left side of the imaginary line OO in FIG. 3). In FIG. 4, the plurality of pressure chambers SC are indicated by broken lines.

  The communication substrate 32 shown in FIGS. 2 to 4 is a flat channel substrate that constitutes the ink channel. The communication substrate 32 is made of, for example, a silicon material. A common liquid chamber 34 and a plurality of nozzle side communication channels 326 are formed in the communication substrate 32. The common liquid chamber 34 includes an inlet 342 through which ink flows and a plurality of supply-side communication channels 344. The plurality of supply side communication channels 344 and the plurality of nozzle side communication channels 326 are through holes formed for each nozzle N, and the common liquid chamber 34 is an opening common to the plurality of nozzles N.

  The compliance substrate 54 is a flexible film and functions as a vibration absorber that absorbs pressure fluctuations of ink in the common liquid chamber 34. As shown in FIG. 3, the compliance substrate 54 seals the common liquid chamber 34 and constitutes the bottom surface of the common liquid chamber 34. In FIG. 3, the case where the common liquid chambers 34 corresponding to the respective nozzle rows are sealed with the separate compliance substrates 54 has been described. However, the present invention is not limited to this, and one compliance is provided for both common liquid chambers 34. The substrate 54 may be continuous.

  The stacking unit 38 is configured by stacking a pressure chamber substrate 382 that forms a pressure chamber SC (cavity) communicating with the nozzle N, a vibration plate 384, and a protection plate 386 in this order. However, the configuration is not limited to this, and the stacked portion 38 may have a configuration without the protective plate 386. In the pressure chamber substrate 382, a plurality of openings 383 that form a pressure chamber SC communicating with each nozzle N are formed. The pressure chamber substrate 382 is made of, for example, a silicon material like the communication substrate 32.

  A diaphragm 384 is installed on the surface of the pressure chamber substrate 382 opposite to the communication substrate 32. The diaphragm 384 is a flat plate that can vibrate elastically. The vibration plate 384 and the communication substrate 32 face each other with an interval inside each opening 383 formed in the pressure chamber substrate 382. A space sandwiched between the communication substrate 32 and the diaphragm 384 inside the opening 383 of the pressure chamber substrate 382 constitutes a pressure chamber SC that generates pressure for ejecting ink from each nozzle N. Each supply-side communication channel 344 of the communication substrate 32 communicates a common liquid chamber 34 and a pressure chamber SC, which will be described later, and each nozzle-side communication channel 326 of the communication substrate 32 communicates the pressure chamber SC and the nozzle N. .

  A plurality of piezoelectric elements 385 corresponding to different nozzles N (pressure chambers SC) are formed on the surface of the vibration plate 384 opposite to the pressure chamber substrate 382. Each piezoelectric element 385 is a drive element in which a piezoelectric body is interposed between electrodes facing each other. Each piezoelectric element 385 vibrates individually by a drive signal V supplied from a drive unit 262 of FIG. The protective plate 386 is an element that protects each piezoelectric element 385, and is fixed to the surface of the pressure chamber substrate 382 (vibrating plate 384) with an adhesive, for example. Each piezoelectric element 385 is accommodated in a recess 387 formed on the surface of the protective plate 386 on the vibration plate 384 side. When each piezoelectric element 385 vibrates according to the drive signal V, the diaphragm 384 vibrates in conjunction with the piezoelectric element 385. As a result, the pressure of the ink in the pressure chamber SC varies and ink is ejected from the nozzle N. As described above, the piezoelectric element 385 functions as a pressure generating element that varies the pressure in the pressure chamber SC and discharges the ink in the pressure chamber SC from the nozzle N. The piezoelectric element 385 is connected to the control unit 20 via a flexible printed cable (FPC: Flexible Printed Circuit), a chip-on film (COF: Chip On Film), or the like (not shown).

  The surface on the positive side in the Z direction of the case member 40 (hereinafter referred to as “joining surface”) is fixed to the surface on the negative side in the Z direction of the communication substrate 32 with an adhesive, for example. The case member 40 is made of a molded resin material such as a plastic material. When the case member 40 is made of a molded resin material, it can be integrally formed by injection molding of the molded resin material. The case member 40 is a structure in which ink supplied to the plurality of pressure chambers SC is stored, and a liquid storage chamber 42 that communicates with the common liquid chamber 34 by the inflow port 342 is formed. The liquid storage chamber 42 communicates with an introduction port 43 for introducing ink.

  The common liquid chamber 34 and the liquid storage chamber 42 are a common space extending over the plurality of nozzles N, and store the ink supplied from the liquid container 14 to the introduction port 43. The common liquid chamber 34 is formed of a long space in the Y direction. The common liquid chamber 34 of the present embodiment has a shape in which the flow path expands from the inlet 342 side toward the supply side communication flow path (outlet) 344 side. The plurality of pressure chambers SC are arranged in one direction (Y direction), and the plurality of supply side communication channels 344 are arranged in the Y direction along the arrangement of the plurality of pressure chambers SC.

  As shown in FIG. 4, the ink that has flowed into the common liquid chamber 34 from the liquid storage chamber 42 is branched into a plurality of supply-side communication channels 344, and supplied and filled in parallel to the pressure chambers SC. Then, due to the pressure fluctuation corresponding to the vibration of the vibration plate 384, the pressure chamber SC passes through the nozzle side communication channel 326 and the nozzle N and is discharged to the outside. That is, the pressure chamber SC functions as a space for generating pressure for ejecting ink from the nozzles N, and the common liquid chamber 34 and the liquid storage chamber 42 store ink supplied to the plurality of pressure chambers SC. Functions as a space (reservoir).

  5 is a partial plan view of the communication board 32 of FIG. 2 as viewed from the negative side (downward) in the Z direction, and is a structure on the negative side in the X direction with respect to the imaginary line yy in the Y direction in FIG. Indicates. In the communication substrate 32, the negative structure in the X direction and the positive structure in the X direction are substantially symmetrical with respect to the imaginary line yy in the Y direction in FIG. Common. For this reason, the following description will focus on the structure on the negative side in the X direction with respect to the virtual line yy.

  As shown in FIG. 5, the common liquid chamber 34 is a long space in the Y direction. In the common liquid chamber 34, in the arrangement direction (Y direction) of the supply-side communication channel 344, the first region A including the central portion O ′ and the end portions on the positive and negative end portions E side in the X direction When divided into the second region B including the region Q, the inflow port 342 is arranged on one side in the X direction of the first region A, and the supply side communication channel 344 extends over the first region A and the second regions B on both sides. And arranged on the other side in the X direction. The introduction port 43 is arranged at a position overlapping the central portion O ′ in plan view. In addition, the inflow port 342 is not necessarily arranged only in the first region A. For example, both ends of the inflow port 342 in the Y direction may protrude to the second region B. In the present embodiment, the case where one inflow port 342 that is long in the Y direction of the first region A is illustrated, but the present invention is not limited to this, and a plurality of flows arranged in the Y direction of the first region A are illustrated. An inlet 342 may be formed. As shown in FIG. 4, the plurality of pressure chambers SC are arranged in one direction (Y direction), and the plurality of supply side communication channels 344 are arranged in the Y direction along the arrangement of the plurality of pressure chambers SC. It is out.

  The common liquid chamber 34 of the present embodiment has a shape in which the flow path expands from the inlet 342 side toward the supply side communication flow path (outlet) 344 side. The common liquid chamber 34 is inclined from the first region A toward the end E of the second region B on both sides so as to gradually expand from the inlet 342 side toward the supply side communication channel 344 side. . The common liquid chamber 34 is not limited to the shape exemplified in the present embodiment, and the second region B may not be inclined toward the end E.

  In such a common liquid chamber 34, the ink flowing in from the inlet 342 spreads over a wide range from the first area A to the second areas B on both sides as shown by the thin line arrows in FIG. It flows into the communication channel 344. The ink that has flowed into the plurality of supply side communication channels 344 is supplied to the pressure chamber SC, and from the nozzle N to the outside via the nozzle side communication channel 326 due to the pressure fluctuation of the pressure chamber SC according to the vibration of the vibration plate 384. Discharged. In the case of forming an image based on the print data G, a plurality of nozzles N to which ink is supplied from the common liquid chamber 34 based on the dot pattern developed from the print data G is used to determine whether the nozzle N is to be ejected or not ejected. The ink selected and supplied from the common liquid chamber 34 is ejected from the nozzle N selected for ejection.

  By the way, the amount of ink discharged from the common liquid chamber 34 from the nozzles N varies depending on the dot pattern, so that there may be a sudden change in the ink flow velocity in the common liquid chamber 34 depending on the dot pattern. For example, in a dot pattern in which a non-discharge period or a discharge period with a small discharge amount is interposed between discharge periods with a large discharge amount, a rapid change in flow velocity occurs in the common liquid chamber 34 that supplies ink to the nozzle N. There is a high possibility that the supply of ink will not be in time. If there is a non-ejection nozzle N even though liquid is ejected from many nozzles, an excessive negative pressure is generated in the common liquid chamber 34 so that even ink near the non-ejection nozzle N is taken away. Air is easily drawn from the discharge nozzle. Thus, when a rapid change in the flow velocity occurs in the common liquid chamber 34, air is likely to be drawn not only from the nozzle N that ejects ink but also from the non-ejection nozzles.

  For example, FIG. 5 assumes a case where the nozzles N in the negative end region Q in the Y direction are not ejected and ink is ejected from the other nozzles N. When a rapid change in the ink flow velocity occurs in the common liquid chamber 34, air (bubbles Bu) is likely to be drawn into the common liquid chamber 34 from the non-ejection nozzle N, as indicated by a thick arrow in FIG.

  Since the compliance substrate 54 as shown in FIGS. 3 and 4 is provided in the common liquid chamber 34, even if a change in the flow velocity occurs in the common liquid chamber 43 due to the ink ejection cycle, vibration due to the change in the flow velocity. The ink can be stably supplied to each pressure chamber SC. However, when the ink flow rate suddenly changes in the common liquid chamber 34 as in the dot pattern described above, the compliance substrate 54 vibrates greatly with a specific vibration period. Depending on the change timing of the flow velocity, the compliance substrate 54 resonates and the vibration further increases. When the vibration of the compliance substrate 54 is large, the ink supply is not instantaneously met, and the ink supply is insufficient.

  When the supply of ink is insufficient due to such excessive vibration of the compliance substrate 54, the meniscus pressure resistance is lowered. Therefore, the meniscus in the nozzle N from which ink is ejected is destroyed and air is drawn from the nozzle N. . In addition, air is easily drawn from the non-ejection nozzles N by drawing ink into the common liquid chamber 34 side. Insufficient supply of ink due to excessive vibration of the compliance substrate 54 occurs even when printing is performed at a flow rate lower than the flow rate of solid ink (discharge duty is 100%) with the largest ink discharge amount. Even if it is not solid discharge, there is a possibility that air is drawn from the nozzle N. The ejection duty here is the ratio of the ink amount to be ejected to the maximum possible ink ejection amount per unit time. It should be noted that the nozzle N in the end region Q may not be discharged even in the solid discharge, and in such a case, air may be drawn from the non-discharge nozzle N in the solid discharge. Further, the non-ejection nozzles N that are likely to draw air are not limited to the nozzles N in the end region Q. For example, if there is a non-ejection nozzle N between the ejection nozzle N and the ejection nozzle N, air is easily drawn from the non-ejection nozzle.

  As described above, depending on the dot pattern, the supply of ink may not be in time due to excessive vibration of the compliance substrate 54 due to a rapid change in the flow rate of ink in the common liquid chamber 34, causing an insufficient supply of ink. There is a risk of air being easily drawn. When air is drawn from the nozzle N, defective dots occur due to ejection failure of the nozzle N, and the print image quality deteriorates. Further, in order to keep the ink supply in time, the ink discharge amount from the nozzle N may be reduced. However, if the ink discharge amount is reduced, the color reproducibility on the medium 12 is reduced. There is a risk that the image quality will deteriorate.

  Therefore, when the liquid ejection apparatus 10 of the present embodiment detects a dot pattern that satisfies the specific condition for each common liquid chamber 34, the liquid ejection apparatus 10 reduces the ink ejection amount corresponding to the detected common liquid chamber 34, A function of printing a dot pattern is provided by ejecting ink in the common liquid chamber 34 corresponding to ink of other colors so as to supplement the ink. When a dot pattern satisfying a specific condition is detected for each common liquid chamber 34, for example, a dot pattern that is likely to be short of ink supply due to a sudden change in the detected ink flow velocity in the common liquid chamber 34 is detected. The dot pattern can be changed to a reduced discharge amount. Thereby, since the rapid change of the ink flow velocity in the common liquid chamber 34 can be suppressed, the supply of ink can be made in time, and the shortage of supply of ink can be suppressed. Therefore, it is possible to suppress air from being drawn not only from the nozzles that eject ink among the nozzles N of the common liquid chamber 34 but also from non-ejection nozzles that do not eject ink. In addition, since the waiting time is not provided after each ejection but the ink ejection amount is reduced, a decrease in the overall printing speed can be suppressed as compared with the case where the waiting time is provided. Furthermore, since the ink from the common liquid chamber 34 corresponding to other different color inks for which the specific condition has not been detected is ejected so as to supplement the ink whose ejection amount has been reduced, it is possible to suppress a decrease in print image quality. Different color inks are inks that differ in at least one of the color material type and the color material density. In the present embodiment, for example, by supplementing one of cyan (C) and light cyan (LC) with the other, a decrease in color reproducibility on the medium 12 can be suppressed, so that a decrease in print image quality can be suppressed. As described above, according to the present embodiment, it is possible to suppress the deterioration of the print image quality while suppressing the air drawing due to the rapid change in the ink speed in the common liquid chamber 34.

  FIG. 6 is a functional configuration diagram of the liquid ejection apparatus 10 for explaining the above-described functions. In FIG. 6, illustration of the transport mechanism 22, the carriage 24, and the like is omitted for convenience. When the control device 202 described above executes the control program, the control device 202 functions as the drive signal generation unit 64, the control unit 60, and the detection unit 62. The control unit 60 controls the drive signal generation unit 64. The data table C is stored in the storage device 203 described above. The drive signal generator 64 generates a drive signal COM. The drive signal COM is a drive waveform of a voltage signal including a plurality of potentials (VL1, VH1, VH1 ') having a potential difference with respect to the intermediate potential VM, for example, as in the drive waveforms W1 and W2 of FIG. The drive waveforms W1 and W2 of the drive signal COM shown in FIG. 7 are generated every predetermined period.

  As shown in FIG. 6, the liquid discharge head 26 includes a drive unit 262 and a liquid discharge unit 264. The drive unit 262 drives the liquid discharge unit 264 under the control of the control unit 20. The liquid ejection unit 264 ejects ink supplied from the liquid container 14 from the plurality of nozzles N to the medium 12. The liquid ejection unit 264 includes a plurality of ejection units 266 corresponding to the plurality of nozzles N. Each ejection unit 266 ejects ink according to the drive signal V supplied from the drive unit 262.

  A drive signal COM generated by the drive signal generation unit 64 and a print signal SI instructing whether or not to eject ink in accordance with the print data G are supplied from the control unit 20 to the drive unit 262. The drive unit 262 generates a drive signal V corresponding to the drive signal COM and the print signal SI for each discharge unit 266 and outputs the drive signal V to the plurality of discharge units 266 in parallel. Specifically, the drive unit 262 supplies the drive signal COM as the drive signal V to the discharge unit 266 in which the print signal SI instructs the discharge of the ink among the plurality of discharge units 266, and the print signal SI is not ink. An intermediate potential VM is supplied as a drive signal V to the ejection unit 266 that instructs ejection.

  A drive signal V is supplied to one electrode of each piezoelectric element 385, and a predetermined intermediate potential VM is supplied to the other electrode. When the vibration plate 384 is vibrated by the deformation of the piezoelectric element 385 due to the supply of the drive signal V, the pressure in the pressure chamber SC varies and the ink in the pressure chamber SC is ejected from the nozzle N. Specifically, ink of an ejection amount corresponding to the amplitude of the drive signal V is ejected from the nozzle N. One discharge portion 266 illustrated in FIG. 6 is a portion including the piezoelectric element 385, the vibration plate 384, the pressure chamber SC, and the nozzle N.

  FIG. 7 is a diagram illustrating a specific example of the drive waveform of the drive signal COM that drives the piezoelectric element 385. As shown in FIG. 7, in this embodiment, a drive signal COM having a different drive waveform is applied to the piezoelectric element 385 depending on whether or not the dot pattern satisfies a specific condition. FIG. 7 illustrates a drive waveform W1 when the dot pattern does not satisfy the specific condition and a drive waveform W2 when the dot pattern satisfies the specific condition. A drive waveform W2 in FIG. 7 is a specific example of a drive waveform in which the ink discharge amount is smaller than that of the drive waveform W1. By driving the piezoelectric element 385 with the drive waveform W2 in the case of a dot pattern that satisfies a specific condition, the ink ejection amount can be reduced. Data (eg, voltage data) for generating the drive waveform W1 and the drive waveform W2 is stored in the data table C. The control unit 60 reads data from the data table C, and the drive signal generation unit 64 generates the drive waveform W1 or the drive waveform W2 of the drive signal COM.

  The drive waveform W1 is indicated by a solid line on the left side of FIG. 7, and the drive waveform W2 is indicated by a solid line on the right side of FIG. The right side of FIG. 7 makes it easy to understand the difference in waveform by superimposing the dotted drive waveform W1 on the solid drive waveform W2. The driving waveforms W1 and W2 are the first waveform Wm for drawing the meniscus in the nozzle N toward the pressure chamber SC and then pushing out the ink to the opening side of the nozzle N, and the ink is pulled into the nozzle N to tear off the ink. A second waveform Wd for forming droplets.

  In the drive waveform W1, the first waveform Wm changes from the intermediate potential VM to the potential VL1, and after the potential VL1 is held for a certain time, the first waveform Wm changes from the potential VL1 to the potential VH1, and the potential VH1 is held for a certain time. . According to such a first waveform Wm, a transition from the intermediate potential VM to the potential VL1 causes the meniscus in the nozzle N to be once drawn into the pressure chamber SC. After that, the transition from the potential VL1 to the potential VH1 causes the meniscus in the nozzle N to move at a stroke toward the opening of the nozzle N (the opening of the nozzle N from which ink is ejected), and the ink from the opening of the nozzle N Is pushed out.

  By tearing the ink pushed out from the opening of the nozzle N by the second waveform Wd, the ink is ejected as a droplet from the opening of the nozzle N. Specifically, the second waveform Wd of the drive waveform W1 transitions from the potential VH1 to the intermediate potential VM, so that the meniscus in the nozzle N is drawn to the pressure chamber SC side and pushed out from the opening of the nozzle N. Can tear off the ink.

  The drive waveform W2 is obtained by reducing the drive voltage by making the potential of the entire waveform of the drive waveform W2 smaller than the drive waveform W1 with reference to VL1. In such a drive waveform W2, for example, the potential VH1 'is smaller than the potential VH1 of the drive waveform W1. For this reason, in the first waveform Wm of the drive waveform W2, the force for pushing out the meniscus in the nozzle N is weaker than that of the drive waveform W1, so that the ink discharge amount can be reduced more than the drive waveform W1. Therefore, when the dot pattern does not satisfy the specific condition, the piezoelectric element 385 is driven using the drive waveform W1, and when the dot pattern satisfies the specific condition, the piezoelectric element 385 is driven using the drive waveform W2. As a result, the drive waveform W2 can reduce the ink ejection amount as compared with the drive waveform W1. Further, since the ink discharge amount is reduced by changing the shape of the drive waveform, it is easy to adjust the discharge amount.

  Next, an operation method of the liquid ejection apparatus 10 of the present embodiment will be described with reference to the drawings. FIG. 8 is a flowchart illustrating the operation of the liquid ejection apparatus 10 during printing. As shown in FIG. 8, in step S <b> 11, the detection unit 62 detects a dot pattern that satisfies a specific condition from the dot pattern developed by the print data G. Specifically, the detection unit 62 detects a dot pattern that satisfies a specific condition based on the above-described ejection duty and ejection or non-ejection time. For example, in the case of a dot pattern in which a non-discharge period or a discharge period with a small discharge amount is interposed between a discharge period with a large discharge amount and a discharge period with a large discharge amount, Detect dot patterns that are prone to insufficient supply. For example, discharge with a discharge duty of approximately 70% or more and discharge time of 1.5 msec or more, discharge with a discharge duty of approximately 30% or less and discharge time of 1.5 msec to 3 msec, or discharge duty with discharge duty of approximately 70% or more However, the specific condition can be satisfied when the discharge continues for 1.5 msec or more. In addition, there are discharges with a discharge duty of about 70% or more and discharge time of 1.5 msec or more, non-discharge of 1.5 msec to 3 msec, and discharges with a discharge duty of about 70% or more and discharge time of 1.5 msec or more. A specific condition may be satisfied when consecutive. This is because a dot pattern that satisfies such a specific condition is likely to cause insufficient ink supply due to a rapid change in the ink flow velocity.

  The reason why such a discharge duty is used as a criterion for determining whether or not the specific condition is satisfied is that as the discharge duty before and after the discharge or non-discharge time increases, the difference in the ink discharge amount also increases. This is because an abrupt change in the ink flow rate is likely to occur in the chamber 34. Note that the range of the ejection duty that satisfies the specific condition may be different depending on the color of the ink. Since the viscosity and weight of the ink change depending on the color of the ink, the flow rate of the ink in the common liquid chamber 34 changes accordingly, so that there is a possibility that the dot pattern that tends to be insufficiently supplied with the ink also changes. By making the discharge duty range satisfying the specific conditions different depending on the color of the ink, it is possible to accurately detect a dot pattern that tends to cause insufficient ink supply according to the color of the ink.

  Further, not only the discharge duty but also the discharge or non-discharge time, the criterion for determining whether or not the specific condition is satisfied is that air due to excessive vibration of the compliance substrate 54 depends on the discharge or non-discharge time. This is because there may or may not be a pull-in. Therefore, by using the ejection duty and the ejection or non-ejection time as a criterion, it is possible to accurately detect a dot pattern that is likely to cause air drawing compared to a case where a dot pattern is detected only by the ejection duty. .

  FIG. 9 is a diagram illustrating the relationship between the non-ejection time and the meniscus breakdown voltage. Here, a description will be given of a specific condition in which air is drawn in a dot pattern in which non-ejection time is interposed between solid ejection and solid ejection with a ejection duty of 100%. FIG. 9 is a specific example in the case where the ink supplied from any one common liquid chamber 34 is ejected from the nozzle N. In FIG. 9, the vertical axis represents the meniscus pressure resistance [Pa], and the horizontal axis represents the non-ejection time [msec]. The meniscus pressure resistance is the maximum pressure at which the meniscus in the nozzle N is not destroyed. The non-ejection time is a non-ejection time (intermittent time) between solid ejections.

  The solid line graph in FIG. 9 is a case where the meniscus pressure resistance is reduced due to excessive vibration of the compliance substrate 54. The dotted line graph of FIG. 9 is a case where the meniscus pressure resistance does not decrease. P in FIG. 9 is the pressure loss in the ink flow path. When the meniscus pressure resistance decreases, when the meniscus pressure resistance falls below the pressure loss P of the flow path, the meniscus is destroyed and air easily enters.

  According to the solid line graph of FIG. 9, even with a dot pattern in which a non-ejection time is interposed between solid ejections, the meniscus withstand pressure does not fall below the pressure loss P of the flow path depending on the non-ejection time. It can be seen that there are cases. Specifically, when the non-ejection time is approximately 1.5 msec to 2.5 msec, the meniscus pressure resistance is lower than the pressure loss P of the flow path, and the non-ejection time is shorter than the time T. When the non-ejection time is longer than the time T, the meniscus pressure resistance exceeds the pressure loss of the flow path. Therefore, in the dot pattern illustrated in FIG. 9, when the non-ejection time is in the range of time T, the meniscus is easily broken and air is easily drawn from the nozzle N, and the non-ejection time is shorter than the time T. When the non-ejection time is in a range other than the time T range, such as when it is longer than T, air is not drawn from the nozzle N because the meniscus is not destroyed.

  As described above, depending on the non-ejection time between the solid ejection and the solid ejection, there are cases where air is likely to be drawn in and air may not be drawn. Therefore, by using not only the ejection duty but also the non-ejection time as a criterion for determining whether or not the specific condition is satisfied, it is possible to accurately detect a dot pattern in which air is likely to be drawn. Note that the non-ejection time range in which the meniscus pressure resistance falls below the pressure loss P of the flow path varies depending on, for example, the type and viscosity of the ink. Therefore, the non-ejection time range that satisfies the specific condition can be set to approximately 1.5 msec to 3 msec, for example, as described above in consideration of the margin.

  Next, in step S <b> 12, the control unit 60 determines whether a dot pattern that satisfies the specific condition is detected by the detection unit 62. If the control unit 60 determines that a dot pattern that satisfies the specific condition is not detected, it is not necessary to reduce the ink ejection amount, and thus the ink is ejected without reducing the ejection amount in step S13. Specifically, the control unit 60 generates the drive signal COM having the drive waveform W <b> 1 by the drive signal generation unit 64 and outputs the drive signal COM to the drive unit 262. Thus, when the dot pattern does not satisfy the specific condition, the piezoelectric element 385 is driven by the drive waveform W1 and ink is ejected, so printing is performed without reducing the ink ejection amount.

  On the other hand, when the control unit 60 determines that a dot pattern satisfying the specific condition is detected, in order to reduce the ink ejection amount, the ink ejection is performed with the ejection amount reduced in step S14. Specifically, the control unit 60 generates the drive signal COM having the drive waveform W <b> 2 by the drive signal generation unit 64 and outputs the drive signal COM to the drive unit 262. Thereby, in the case of a dot pattern that satisfies the specific condition, the piezoelectric element 385 is driven by the drive waveform W2 and ink is ejected, so that the ink ejection amount is reduced. Accordingly, when the piezoelectric element 385 is driven with the drive waveform W1 of FIG. 7 in a dot pattern that satisfies the specific condition, even if the meniscus breakdown voltage decreases as shown by the solid line graph of FIG. 9, the piezoelectric element 385 with the drive waveform W2 of FIG. Is driven, the meniscus breakdown voltage does not decrease as shown by the dotted line graph in FIG. Thereby, the entrainment of air from the nozzle N can be suppressed.

  Subsequently, in step S15, the control unit 60 ejects ink of other colors so as to supplement the ink whose ejection amount has been reduced. If the ink discharge amount is reduced, the image quality may be deteriorated. Therefore, in this embodiment, the deterioration of the image quality can be suppressed by supplementing the ink with the reduced discharge amount with ink of other colors. . In the following description, the ink whose discharge amount is reduced is referred to as a first liquid, and the ink of another color that supplements the first liquid is referred to as a second liquid. The common liquid chamber 34 for supplying the first liquid is referred to as a first common liquid chamber, and the common liquid chamber 34 for supplying the second liquid is referred to as a second common liquid chamber.

  The second liquid is a liquid having a different color from the first liquid. The “different color liquids” are liquids in which at least one of the type and concentration of the color material (pigment, dye, etc.) is different. “Supplementing the first liquid” is to supplement the discharge amount and the color by printing the second liquid so as to overlap the first liquid in order to suppress the deterioration of the image quality due to the reduction of the discharge amount of the first liquid. is there. Therefore, the second liquid is a color that does not stand out even when supplemented with the first liquid. For example, a color that can improve an index representing an image quality such as gamut (Gamut: color reproduction region) or OD value (Optical Density: optical density). It is preferable that It should be noted that the first liquid and the second liquid may be ejected so as to overlap each other by the forward movement or the backward movement of the carriage 24, and the first liquid is ejected by one of the forward movement and the backward movement of the carriage. The second liquid may be discharged so as to overlap the first liquid.

  The liquid ejection apparatus 10 according to this embodiment includes cyan (C) and light cyan (LC), magenta (M) and light magenta (LM), yellow (Y), dark yellow (DY), and black K) and light black (LK) inks of all eight colors are provided. Light cyan (LC) has a lower colorant density than cyan (C). Light magenta (LM) has a lower colorant density than magenta (M). Light black (LK) has a lower colorant concentration than black (K). Dark yellow (DY) has a higher color material concentration than yellow (Y).

  Therefore, in this embodiment, one of cyan (C) and light cyan (LC) can be the first liquid and the other can be the second liquid, and one of magenta (M) and light magenta (LM) can be the first liquid. The liquid can be the second liquid. Similarly, one of yellow (Y) and dark yellow (DY) can be the first liquid and the other can be the second liquid, one of black (K) and light black (LK) can be the first liquid and the other The second liquid can be used. Instead of using dark yellow (DY) as the second liquid, light yellow having a lower density than yellow (Y) may be used as the second liquid. Here, the case where the second liquid is a liquid having the same color material type and different concentration as the first liquid is illustrated, but the first liquid is different in color type (for example, black and black purple). The second liquid may be a mixture of other color materials based on the first liquid.

  The second liquid supplemented by the first liquid may be a plurality of different color liquids. For example, cyan (C), magenta (M), and yellow (Y) are combined into black (K) or black (K). Therefore, black (K) may be used as the first liquid, cyan (C), magenta (M), and yellow (Y) may be used as the second liquid, and these may be ejected so as to overlap the first liquid.

  By supplementing the first liquid with such a second liquid, even if the discharge amount of the first liquid is reduced, an index representing the image quality such as the gamut and the OD value can be improved. it can. In addition, since the first liquid is supplemented with the second liquid supplied from the second common liquid chamber different from the first common liquid chamber, the first liquid in the first common liquid chamber is further discharged and supplemented. Thus, the first liquid can be supplemented so as not to be insufficiently supplied. Thus, according to this aspect, it is possible to suppress a decrease in print image quality while suppressing air entrainment due to a rapid change in the velocity of the liquid in the common liquid chamber. The first liquid and the second liquid do not necessarily have the same color. Even if the type of the color material is different from that of the first liquid, it may be a single-color liquid or a multi-color liquid that is inconspicuous when superimposed on the first liquid.

  In the present embodiment, the drive waveform W2 for reducing the ink discharge amount is exemplified by the case where the drive voltage is made smaller than the drive waveform W1 as shown in FIG. 4, but the present invention is not limited to this. You may make it change the electric potential of another part, a voltage change gradient, the holding time of an electric potential, etc.

  FIG. 10 is a table showing modifications 1 to 4 of the drive waveform W2 of the drive signal COM when the specific condition is satisfied. In the first modification, the intermediate potential VM ′ of the drive waveform W2 is smaller than the intermediate potential VM of the drive waveform W1. According to the driving waveform W2 of the first modified example, since the force for drawing the meniscus in the nozzle N toward the pressure chamber SC can be reduced, the ink discharge amount can be reduced as compared with the driving waveform W1. In the second modification, the transition time from the intermediate potential VM to VL1 in the first waveform Wm of the drive waveform W2 is longer than that in the drive waveform W1. According to the driving waveform W2 of the second modification example, the speed of drawing the meniscus in the nozzle N toward the pressure chamber SC can be made moderate, so that the ink discharge amount can be reduced as compared with the driving waveform W1.

  In the third modification, the transition time from VL1 to VH1 in the first waveform Wm of the drive waveform W2 is longer than that in the drive waveform W1. According to the driving waveform W2 of the third modification example, since the force for pushing the meniscus toward the opening side of the nozzle N can be moderated, the ink discharge amount can be reduced as compared with the driving waveform W1. In the fourth modification, in the first waveform Wm of the drive waveform W2, the time for holding VL1 is made longer than that of the drive waveform W1. According to the drive waveform W2 of Modification 4 as described above, since the vibration is difficult to be transmitted by shifting the timing from the vibration generated when the meniscus in the nozzle N is drawn, the ink discharge amount is higher than that of the drive waveform W1. Can be reduced.

Second Embodiment
A second embodiment of the present invention will be described. In the following exemplary embodiments, elements having the same functions and functions as those of the first embodiment are diverted using the same reference numerals used in the description of the first embodiment, and detailed descriptions thereof are appropriately omitted. In the first embodiment, in the case of a dot pattern that satisfies a specific condition, the case where the ink ejection amount is reduced by changing the shape of the drive waveform that drives the piezoelectric element 385 is illustrated, but in the second embodiment, An example in which the ink discharge amount is reduced by changing the dot size (the size of the ink dots landed on the medium 12) will be described.

  FIG. 11 is a diagram illustrating the relationship between the number of drive waveforms W3 in the drive signal COM and the dot size. The drive signal COM in FIG. 11 includes three drive waveforms W3 in one cycle. The shape of the drive waveform W3 may be the same as or different from the drive waveform W1. In the second embodiment, the dot size can be changed according to the number of drive waveforms W3 selected from such a drive signal COM. Specifically, by supplying three drive waveforms W3 selected from the drive signal COM to the piezoelectric element 385 as the drive signal V, a droplet having a large dot size can be ejected from the nozzle N. By supplying two drive waveforms W3 selected from the drive signal COM as the drive signal V to the piezoelectric element 385, a droplet having a medium dot size can be ejected from the nozzle N. By supplying one drive waveform W3 selected from the drive signal COM to the piezoelectric element 385 as the drive signal V, a droplet having a small dot size can be ejected from the nozzle N.

  The ink discharge amount decreases in the order of dot size “large”, “medium”, and “small”. Therefore, in the case of a dot pattern that satisfies a specific condition, the amount of ink discharged can be reduced by setting the dot size to “medium” or “small” in the portion where the dot size is “large”. It should be noted that the dot size may be set to “small” in the portion where the dot size is “medium”. Further, according to the second embodiment, since the ink discharge amount is reduced by changing the number of drive waveforms W1, the discharge amount can be easily adjusted.

<Modification>
The aspects and embodiments exemplified above can be variously modified. Specific modifications are exemplified below. Two or more aspects arbitrarily selected from the following exemplifications and the above-described aspects can be appropriately combined as long as they do not contradict each other.

(1) In the above-described embodiment, the serial head that reciprocally reciprocates the carriage 24 on which the liquid discharge head 26 is mounted along the X direction is exemplified. The present invention can also be applied to.

(2) In the above-described embodiment, the piezoelectric liquid discharge head 26 using the piezoelectric element that imparts mechanical vibration to the pressure chamber is exemplified. However, a heating element that generates bubbles in the pressure chamber by heating is used. It is also possible to employ a heat-type liquid discharge head that is used.

(3) The liquid ejecting apparatus 10 exemplified in the above-described embodiment can be employed in various apparatuses such as a facsimile apparatus and a copying machine, in addition to an apparatus dedicated to printing. However, the use of the liquid ejection apparatus 10 of the present invention is not limited to printing. For example, a liquid ejection device that ejects a color material solution is used as a manufacturing device for forming a color filter of a liquid crystal display device, an organic EL (Electro Luminescence) display, an FED (surface emitting display), or the like. In addition, a liquid discharge apparatus that discharges a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes of a wiring board. Further, it is also used as a chip manufacturing apparatus that discharges a bioorganic solution as a kind of liquid.

DESCRIPTION OF SYMBOLS 10 ... Liquid discharge apparatus, 12 ... Medium, 14 ... Liquid container, 20 ... Control unit, 202 ... Control apparatus, 203 ... Memory | storage device, 22 ... Conveyance mechanism, 24 ... Carriage, 26 ... Liquid discharge head, 262 ... Drive part, 264 ... Liquid discharge section, 266 ... Discharge section, 30 ... Head body, 32 ... Communication substrate, 326 ... Nozzle side communication flow path, 34 ... Common liquid chamber, 342 ... Inlet, 344 ... Supply side communication flow path, 38 ... Laminated portion, 382 ... pressure chamber substrate, 383 ... opening, 384 ... diaphragm, 385 ... piezoelectric element, 386 ... protective plate, 387 ... recess, 40 ... case member, 42 ... liquid reservoir, 43 ... inlet, 52 ... Nozzle plate, 54 ... Compliance substrate, 60 ... Control unit, 62 ... Detection unit, 64 ... Drive signal generation unit, 70 ... Liquid ejection unit, A ... First region, B ... Second region, C ... Data table, COM ... Drive signal , G ... print data, N ... nozzle, P ... pressure loss, Q ... edge region, SC ... pressure chamber, SI ... print signal, V ... drive signal, Wm ... first waveform, Wd ... second waveform, W1, W2, W3 ... drive waveform, Bu ... bubble.

Claims (6)

A method for driving a liquid ejection device, comprising:
The liquid ejection device includes:
A first common liquid chamber for supplying the first liquid to a nozzle for discharging the first liquid;
A second common liquid chamber for supplying the second liquid to a nozzle for discharging a second liquid having a color different from that of the first liquid;
A detection unit that detects a dot pattern that satisfies a specific condition based on the dot pattern of the first liquid developed from print data; and
When the detection unit detects the dot pattern, a liquid that prints the dot pattern by reducing the discharge amount of the first liquid and discharging the second liquid so as to supplement the first liquid. A method for driving the discharge device. When the first liquid is ejected from the nozzle by changing the pressure in the pressure chamber by driving the driving element, the shape or number of driving waveforms for driving the driving element is changed to change the pressure of the first liquid. The method for driving a liquid ejection apparatus according to claim 1, wherein the ejection amount is reduced. The method for driving a liquid ejection apparatus according to claim 1, wherein the second liquid supplemented by the first liquid is a plurality of different color liquids. The detection unit detects a dot pattern satisfying the specific condition from a dot pattern developed from the print data based on a discharge duty of the first liquid and a discharge or non-discharge time of the first liquid. The method for driving a liquid ejection device according to claim 1. The method of driving a liquid ejection apparatus according to claim 4, wherein a range of the ejection duty satisfying the specific condition varies depending on a color of the first liquid. A first common liquid chamber for supplying the first liquid to a nozzle for discharging the first liquid;
A second common liquid chamber for supplying the second liquid to a nozzle for discharging a second liquid having a color different from that of the first liquid;
A detection unit that detects a dot pattern that satisfies a specific condition based on the dot pattern of the first liquid developed from print data; and
When the detection unit detects the dot pattern, a liquid that prints the dot pattern by reducing the discharge amount of the first liquid and discharging the second liquid so as to supplement the first liquid. Discharge device.

Images