JP2007216495A - Liquid droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize cost reductions and size reductions and image quality improvements by making a nozzle arrangement and a driving circuit for an ink head and a processing liquid head differ. <P>SOLUTION: The ink head 34Y discharges ink droplets from a plurality of nozzles 35A, and the processing liquid head 34L discharges processing liquid droplets from a plurality of nozzles 35B. The ink and the processing liquid are mixed and react with each other on papers. For the processing liquid head 34L, a defective head which cannot be used as the ink head 34Y in a defective nozzle inspection process is used under prescribed conditions. On that occasion, a defective head including defective nozzles capable of discharge 25% or higher with respect to the ink head 34Y is permitted for the processing liquid head 34L. A binary driving circuit is used for the driving circuit of the processing liquid head 34L. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to, for example, a droplet discharge apparatus that discharges droplets as typified by an ink jet recording method and performs image recording, and more particularly, a first liquid and a second liquid discharged from a first liquid head. The present invention relates to a droplet discharge device that reacts with a second liquid discharged from a head for use.

  2. Description of the Related Art Conventionally, there is an ink jet recording apparatus as a liquid droplet ejecting apparatus that ejects liquid droplets from a plurality of nozzles and prints on a recording medium such as paper. The ink jet recording apparatus is small, inexpensive, and quiet. It has advantages and is widely available commercially. In particular, piezo inkjet systems that eject ink droplets by changing the pressure in the pressure chamber using piezoelectric elements and thermal inkjet recording devices that eject ink droplets by expanding the ink by the action of thermal energy are high-speed printing. It has many advantages such as high resolution.

  In such an ink jet recording apparatus, ink and a treatment liquid that reacts with the ink (for example, a liquid for promoting ink fixing and improving image density and water resistance, and spreading of a coloring material) There is a type that performs image recording using a liquid for suppressing bleeding and suppressing bleeding.

  The recording apparatus ejects ink from the nozzles of the ink head and simultaneously ejects the processing liquid from the nozzles of the processing liquid head. In general, the processing liquid head and the ink head have the same configuration. For example, when the ink head can hit a plurality of sizes of dots by droplet diameter modulation, such as large droplets and small droplets, the processing liquid head can also hit a plurality of sizes.

However, in many cases, the treatment liquid and ink are not always used in the same manner. For example, a recording apparatus is disclosed in which processing liquid dots are made larger than ink dots by controlling a drive unit, and the processing liquid has a lower resolution than ink (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-010858

  However, because the specifications and specifications required for the processing liquid head and the ink head differ depending on the purpose such as cost reduction and high image quality, the recording liquid head and the ink head have the same configuration. In the case of or the configuration described in Patent Document 1, these specifications and specifications cannot be satisfied.

  For example, when cost reduction is intended, the treatment liquid is easier to spread than the ink, and the treatment liquid does not require a plurality of sizes of dots. . In addition, the duty of the treatment liquid dot is hardly hit at 100% and may be about 10% to 30%.

  Further, in order to obtain high image quality (an image with little density unevenness), it is desirable that small processing liquid dots can be printed at high density. However, in the case where the ink head and the processing liquid head have the same configuration, Patent Document 1 discloses that With the described configuration, it is not possible to strike the treatment liquid dots with high density.

  The present invention has been made in view of the above-described problems, and the liquid droplet ejection that enables low cost and high image quality by using different configurations for the first liquid head and the second liquid head. An object is to provide an apparatus.

  In order to achieve the above object, the invention according to claim 1 includes a first liquid head that discharges the first liquid and a second liquid head that discharges the second liquid, and the first liquid, A droplet discharge device for mixing and reacting the second liquid on a recording medium, wherein the second liquid head has a nozzle configuration of the second liquid head and the first liquid head. At least one of the drive circuits that drive the second liquid head is different.

  In the first aspect of the present invention, the first liquid head can be obtained by changing at least one of the nozzle structure of the second liquid head and the drive circuit for driving the second liquid head with the first liquid head. The specifications and specifications required for the second liquid head can be set differently. For this reason, it can respond to the objectives, such as cost reduction, size reduction, and high image quality.

  According to a second aspect of the present invention, in the droplet discharge device according to the first aspect, the second liquid head is a binary circuit in which the driving circuit controls only ON / OFF of the discharge of the second liquid. It is characterized by being.

  In the second aspect of the invention, the second liquid head is a binary circuit in which the drive circuit controls only ON / OFF of the discharge of the second liquid, and therefore the first liquid head is the same as the first liquid head. There is no need to switch the drive circuit to change the size of the dots, and the cost is low. For this reason, cost reduction and size reduction are attained.

  According to a third aspect of the present invention, in the droplet discharge device according to the first or second aspect, the second liquid head is characterized in that the drive circuit is a rectangular wave drive circuit.

  In the third aspect of the invention, since the driving circuit of the second liquid head is a rectangular wave driving circuit, it can be inexpensive and can be driven at a high speed, and can be reduced in cost and size.

  According to a fourth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first to third aspects, the first liquid is ink and the second liquid reacts with the ink. The second liquid head is a defective head having a defective nozzle that cannot be used as the first liquid head.

  In the invention according to claim 4, the second liquid head is a defective head having a defective nozzle that cannot be used as the first liquid head. Can be used effectively. For this reason, a manufacturing loss is reduced, it leads to the improvement of a yield, and cost reduction is attained.

  According to a fifth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the second to fourth aspects, the second liquid head ejects the second liquid. Is larger than the first liquid dot that discharges the first liquid.

  According to the fifth aspect of the present invention, since the second liquid dot for discharging the second liquid is larger than the first liquid dot for discharging the first liquid, the resolution of the second liquid can be lowered and the cost can be reduced. Is possible.

  According to a sixth aspect of the present invention, in the liquid droplet ejection device according to any one of the second to fifth aspects, the second liquid head has a lower density of nozzles than the first liquid head. It is characterized by being a low-density head arranged in the head.

  In the invention described in claim 6, since the second liquid head is a low density head in which nozzles are arranged at low density, manufacturing is simple, data processing is small, cost reduction, and miniaturization. Is possible.

  According to a seventh aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first to third aspects, the first liquid is ink and the second liquid reacts with the ink. The second liquid head is a high-density head in which nozzles are arranged at a higher density than the first liquid head.

  In the seventh aspect of the invention, the second liquid head for discharging the processing liquid is a high density head in which the nozzles are arranged at high density, so that the processing liquid is discharged at high density. Thereby, density unevenness is reduced, and high image quality is possible.

  According to an eighth aspect of the present invention, in the liquid droplet ejection device according to the seventh aspect, the second liquid head ejects the first liquid from the second liquid dot that ejects the second liquid. It is characterized by being smaller than one liquid dot.

  In the invention according to claim 8, since the second liquid dot for discharging the second liquid (processing liquid) is smaller than the first liquid dot for discharging the first liquid (ink), a large amount of processing liquid with small dots is discharged. It becomes possible to do. Thereby, density unevenness is reduced, and high image quality is possible.

  According to a ninth aspect of the present invention, in the liquid droplet ejection apparatus according to any one of the first to third aspects, the first liquid is ink and the second liquid reacts with the ink. It is characterized by being a liquid.

  According to the ninth aspect of the present invention, the specifications and specifications required for the ink head and the processing liquid head can be set differently, and it is possible to meet the objectives such as cost reduction, downsizing, and high image quality. .

  According to the present invention, the specifications and specifications required for the first liquid head and the second liquid head can be made different depending on purposes such as cost reduction, size reduction, and image quality improvement.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, an overall configuration of an ink jet printer which is a droplet discharge device of the present invention will be outlined. FIG. 1 shows a schematic configuration of an inkjet printer 10 according to the first embodiment of the present invention.

  As shown in FIG. 1, the inkjet printer 10 includes a paper feed cassette 12 in which paper (recording medium) P is accommodated. A feed roll 14 that takes out the paper P from the inside of the paper feed cassette 12 is disposed at the top of the paper feed cassette 12 on the front end side (left end side in FIG. 1).

  Further, a first transport path 18 is provided that extends from the leading end of the paper feed cassette 12 and reaches the recording unit 16 that records an image on the paper P. The first transport path 18 is provided with a plurality of first transport roll pairs 20 that sandwich and transport the paper P to the recording unit 16.

  Furthermore, a second transport path 24 is provided that extends upward from the recording unit 16 and reaches the discharge tray 22 that stores the paper P on which an image is recorded. A plurality of second transport roll pairs 26 that transport the paper P to the discharge tray 22 are provided in the second transport path 24. A reverse conveyance path 36 for duplex printing is connected from the second conveyance path 24 to the first conveyance path 18.

  With the above configuration, the paper P taken out from the paper feed cassette 12 by the feed roll 14 is transported through the first transport path 18 by the plurality of transport roll pairs 20 and sent to the recording unit 16 for image recording. The paper on which the image has been recorded is transported through the second transport path 24 by a plurality of transport roll pairs 26 and is discharged to the discharge tray 22. When performing double-sided printing, the paper on which single-sided printing has been performed is transported from the second transport path 24 to the first transport path 18 via the reverse transport path 36 and sent again to the recording unit 16 to perform image recording. Is called. As described above, a series of image recording is performed.

  Next, the configuration of the recording unit 16 will be described.

  The recording unit 16 includes a drive roll 28 disposed on the upstream side in the sheet conveyance direction and an endless conveyance belt 32 wound around a driven roll 30 disposed on the downstream side. 1 is configured to circulate (rotate) in the direction of arrow A (clockwise). Further, a nip roll 38 that is in sliding contact with the transport belt 32 from the front side is disposed on the drive roll 28.

  An ink jet recording head 34 is disposed above the transport belt 32. The inkjet recording head 34 has a long shape in which the effective recording area is equal to or larger than the width of the paper P (the length in the direction orthogonal to the transport direction), promotes ink fixing, and improves image density and water resistance. Processing liquid head 34L for discharging the processing liquid for the purpose of, and four ink heads for discharging yellow (Y), magenta (M), cyan (C), and black (K) inks, respectively. 34Y, 34M, 34C, and 34K are arranged along the transport direction, and can record full-color images.

  The ink jet recording head 34 faces the flat portion 32F of the transport belt 32, and the facing region is an ejection region where ink droplets and processing liquid are ejected from the ink jet recording head 34. The paper P transported through the first transport path 18 is held by the transport belt 32, reaches the discharge region, and faces the ink jet recording head 34. Treatment liquid is attached.

  Further, above the ink jet recording head 34, the ink tanks 40Y, 40M, 40C, and 40K that supply ink to the ink heads 34Y, 34M, 34C, and 34K, and the processing liquid that supplies the processing liquid to the processing liquid head 34L. A tank 40L is provided.

  The ink heads 34Y, 34M, 34C, 34K and the treatment liquid head 34L are connected to the recording head controller 50. The recording head control unit 50 determines, for example, the ejection timing of ink droplets and processing liquid and the ink ejection port (nozzle) to be used according to the image information, and sends drive signals to the ink heads 34Y, 34M, 34C, 34K and The ink jet recording head 34 is controlled by inputting to the treatment liquid head 34L.

  The recording head control unit 50 also sets the ejection timing of the inkjet recording head 34 and the ink ejection port (nozzle) to be used even when a dummy jet (preliminary ejection performed to suppress nozzle clogging due to ink coagulation or the like) is performed. Control.

  In addition, a cleaning device 42 for cleaning the ink and the processing liquid adhering to the transport belt 32 when the dummy jet is performed on the transport belt 32 is provided in the vicinity of the driven roll 30. The cleaning device 42 cleans the ink and processing liquid adhering to the transport belt 32 immediately after the transport belt 32 rotates and passes through the driven roll 30.

  Next, the treatment liquid head 34L and the ink heads 34Y, 34M, 34C, and 34K that can be used in the inkjet printer 10 having the above-described configuration will be described in detail.

  Each of the ink heads 34Y, 34M, 34C, 34K is analog-driven by a multi-value (large dot, medium dot, small dot, no dot) by an analog drive circuit provided in the recording head controller 50. By making the ink heads 34Y, 34M, 34C, and 34K multi-valued, high speed and high image quality can be achieved. That is, by ejecting large droplets, ink can be placed on a large area, so that it can be output at high speed, and by ejecting small droplets, the graininess can be improved and output with high image quality. In order to eject dots of different sizes from one nozzle, for example, when ejecting large droplets (large dots) and small droplets (small dots) as shown in FIGS. The voltages having different analog waveforms are applied to the ink heads 34Y, 34M, 34C, and 34K.

  On the other hand, the treatment liquid head 34L is driven and controlled in a binary manner (only dot ON and dot OFF) by a drive circuit provided in the recording head controller 50. When only one type of the analog waveforms shown in FIG. 2 is applied or when the processing liquid is ejected as shown in FIG. 3, a rectangular wave voltage is applied to the processing liquid head 34L. The rectangular wave drive circuit is difficult to perform fine dot control compared to the analog drive circuit, but is inexpensive and can be driven at high speed.

  In such an ink jet recording head 34, by setting the treatment liquid head 34L to a binary value, switching between large dots, medium dots, and small dots becomes unnecessary, and the drive circuit is simplified. Furthermore, treatment liquid dots can be generated by simple drive control using a rectangular wave, and the cost can be reduced. Also, by setting the binary value, the increase in the total number of dots can be suppressed, and the power consumed by the drive control can be suppressed.

  Next, the treatment liquid head 34L and the ink heads 34Y, 34M, 34C, and 34K that can be used in the ink jet printer according to the second embodiment of the present invention will be described.

  As shown in FIG. 4A, each of the ink heads 34Y, 34M, 34C, 34K ejects ink droplets from a plurality of nozzles 35A (FIG. 4A shows only the ink head 34Y. ). The ink heads 34Y, 34M, 34C, and 34K are not used if they become defective heads in the defective nozzle inspection process. As shown in FIG. 4B, each of the ink heads 34Y, 34M, 34C, and 34K controls the dot ON so that the ink dot is generated in the pixel through which each nozzle 35A passes.

  On the other hand, as shown in FIG. 4A, the treatment liquid head 34L ejects treatment droplets from a plurality of nozzles 35B. The treatment liquid head 34L uses a defective head having defective nozzles that cannot be used as the ink heads 34Y, 34M, 34C, and 34K in the defective nozzle inspection process. That is, a defective head including a defective nozzle is recognized under a predetermined condition, and for example, a defective nozzle that can discharge a processing liquid with a duty of 25% or more is allowed.

  The treatment liquid head 34L sets the amount of treatment liquid ejected from the nozzle 35B to 25% with respect to the amount of ink ejected from the nozzles 35A of the ink heads 34Y, 34M, 34C, and 34K. The driving circuit is an inexpensive circuit such as a binary circuit or a rectangular wave driving circuit. As shown in FIGS. 4A and 4B, in the treatment liquid head 34L, dots are not generated so that treatment liquid dots are not generated in the pixels through which the defective nozzle passes, and treatment liquid dots are generated from the adjacent nozzle 35B. , OFF is controlled. By using such a defective head, the arrangement of the nozzles 35B may result in a lower density than the arrangement of the nozzles 35A for ink.

  In the example of FIG. 4A, the number of defective nozzles in the processing liquid head 34L is one, so that there is no need to change the drive circuit. However, when a plurality of defective nozzles are continuous, the processing liquid head 34L changes the drive circuit so that a processing liquid dot larger than the ink dot can be shot. For example, a medium dot drive waveform is changed to a large dot drive waveform, and a large dot drive waveform is changed to a continuous wave waveform. The size of the treatment liquid dot after the change may be a size that can cover the pixel through which the defective nozzle passes.

  In such an ink jet printer, since a defective head including defective nozzles that cannot be used for the ink heads 34Y, 34M, 34C, and 34K is used as the processing liquid head 34L, manufacturing loss can be reduced. For this reason, it leads to the improvement of a yield and cost reduction is possible.

  Next, the treatment liquid head 134L and the ink heads 134Y, 134M, 134C, and 134K that can be used in the ink jet printer according to the third embodiment of the present invention will be described.

  As shown in FIG. 5A, each of the ink heads 134Y, 134M, 134C, and 134K ejects ink droplets from a plurality of nozzles 135A arranged at a high density (in FIG. 5A, ink is used). Only the head 134Y is shown). Each of the ink heads 134Y, 134M, 134C, and 134K has an output of high resolution (for example, 600 dpi), and ink dots are generated in pixels through which all the nozzles 135A pass, as shown in FIG. 5B. In this way, dot ON is controlled.

  On the other hand, as shown in FIG. 5A, the treatment liquid head 134L ejects treatment droplets from a plurality of nozzles 135B having a lower density than the ink head 134Y. The driving circuit is an inexpensive circuit such as a binary circuit or a rectangular wave driving circuit. The processing liquid head 134L has a low resolution (eg, 300 dpi) output, and as shown in FIG. 5B, the dot ON is set so that the processing liquid dots are generated in the pixels through which all the nozzles 135B pass. Control. If it is known from the beginning that the density of the nozzles 135B is low, the nozzles 135B are ejected at a low resolution, so control is performed so as to generate large treatment liquid dots. Further, since the resolution in the paper transport direction may be low in accordance with the density of the nozzles 135B, the data processing amount of the entire image is reduced.

  In such an ink jet printer, the nozzles 135B of the treatment liquid head 134L have a low density, so that the manufacture is simple and the data processing amount is small. For this reason, cost reduction and size reduction are possible.

  Alternatively, when a high-density head is realized by connecting a plurality of low-density heads while shifting, a low-density processing liquid head 134L requires fewer heads than a high-density ink head 134Y. . Therefore, manufacture is easy, and cost reduction and size reduction are possible.

  Next, the treatment liquid head 234L and the ink heads 234Y, 234M, 234C, and 234K that can be used in the ink jet printer according to the fourth embodiment of the present invention will be described.

  Each of the ink heads 234Y, 234M, 234C, and 234K ejects ink droplets from a plurality of nozzles 235A as shown in FIG. 6A (FIG. 6A shows only the ink head 234Y. ). As shown in FIG. 6B, each of the ink heads 234Y, 234M, 234C, and 234K is controlled so as to generate a large ink dot from the nozzle 235A.

  On the other hand, as shown in FIG. 6A, the treatment liquid head 234L ejects treatment droplets from a plurality of nozzles 235B arranged at a higher density than the ink head 234Y. That is, the resolution of the treatment liquid head 234L is set higher than the resolution of the ink heads 234Y, 234M, 234C, and 234K. The drive circuit for the treatment liquid head 234L uses an inexpensive circuit such as a binary rectangular wave drive circuit. As shown in FIG. 6B, the processing liquid head 234L is controlled to generate smaller processing liquid dots from the nozzles 235B than the ink head 234Y, and processing is performed on the pixels through which all the nozzles 235B pass. The dot ON is controlled so that a liquid dot is generated.

  Further, by using a drive circuit capable of high-speed ejection, it is possible to form treatment liquid dots not only in a high density only in the direction in which the nozzles 235B are arranged but also in a high density in the paper transport direction.

  As shown in FIG. 7, when the treatment liquid amount is 25%, which is the same as the ink amount, the ink dots and the treatment liquid dots are ejected more than the same size (FIG. 7A). The image in FIG. 7B has less density unevenness and better image quality. In FIG. 7, the ink dots are densely distributed. However, when the ink dots are sparsely distributed in a highlight portion or the like, it is better that there is a processing liquid dot for each ink dot. If small processing liquid dots can be ejected, the amount of processing liquid can be reduced, and sheet deformation caused by a large amount of water can be suppressed.

  In the present embodiment, the density of the nozzle 235B of the processing liquid head 234L is set to be larger than the density of the nozzles 235A of the ink heads 234Y, 234M, 234C, and 234K, but the driving circuit of the processing liquid head 234L is binary. By using the rectangular wave driving circuit, it is possible to suppress the increase in cost and achieve high image quality.

  On the other hand, the treatment liquid has an effect of aggregating ink and suppressing bleeding. Therefore, in order to improve feathering and bleeding, a large amount of processing liquid may be discharged to the image boundary portion. As shown in FIG. 9, when the nozzle density of the treatment liquid head is made higher than that of the ink head and the ink dots and the treatment liquid dots have the same size, the treatment liquid amount becomes four times the ink amount. Consumption is high. On the other hand, in this embodiment, since many small process liquid dots are discharged, it can prevent that the consumption of a process liquid increases.

  Similarly to FIG. 9, in order to achieve the effect of suppressing the bleeding at the image boundary with a smaller amount of processing liquid, as shown in FIG. You may control so that a process liquid dot is not discharged to the center part of a dot. Even if the treatment liquid dots are not ejected to the center of the ink dots (the center of the image), bleeding at the image boundary can be prevented, and the influence on the image quality is small. As a result, the consumption of the processing liquid can be reduced and high image quality can be realized.

  In the example shown in FIG. 1 and the like, an example of FWA corresponding to the paper width has been described. However, the inkjet recording head of the present invention is not limited to this, and a partial width array (PWA) having a main scanning mechanism and a sub-scanning mechanism. It can also be applied to the apparatus of

  In the example shown in FIG. 1 and the like, an image (including characters) is recorded on the paper P as a recording medium. However, the liquid droplet ejection head and the liquid droplet ejection apparatus of the present invention are not limited to this. Is not to be done. That is, the recording medium is not limited to paper, and the liquid to be ejected is not limited to ink. For example, it is industrially useful to create color filters for displays by discharging ink onto polymer films or glass, or to form bumps for component mounting by discharging solder in a welded state onto a substrate. The present invention can be applied to all droplet discharge heads and droplet discharge apparatuses used.

1 is a schematic configuration diagram illustrating an ink jet printer (droplet discharge device) according to a first embodiment of the present invention. (A) is a figure which shows the voltage waveform at the time of discharging a large drop of ink from the ink head in the inkjet printer shown in FIG. 1, (B) is the voltage waveform at the time of discharging a small drop of ink. FIG. It is a figure which shows the voltage waveform at the time of discharging a process droplet from the process liquid head in the inkjet printer shown in FIG. (A) is a partially enlarged view showing the nozzle arrangement of the processing liquid head and ink head used in the ink jet printer according to the second embodiment of the present invention, and (B) shows the processing liquid dots and ink dots. It is a figure which shows distribution. (A) is a partially enlarged view showing a nozzle arrangement of a processing liquid head and an ink head used in an ink jet printer according to a third embodiment of the present invention, and (B) shows processing liquid dots and ink dots. It is a figure which shows distribution. (A) is a partially enlarged view showing a nozzle arrangement of an ink head and a processing liquid head used in an ink jet printer according to a fourth embodiment of the present invention, and (B) shows ink dots and processing liquid dots. FIG. It is the figure which compared the relationship between the ink dot discharged from the head for ink, and the head for process liquid, and a process liquid dot. It is a figure which shows the modification of the ink dot and the process liquid dot which are discharged from the head for an ink shown in FIG. 6, and the process liquid head. It is a figure which shows the comparative example of the ink dot discharged from the head for ink, and the head for process liquid, and a process liquid dot.

Explanation of symbols

10 Inkjet printer (droplet discharge device)
34 Inkjet recording head (droplet ejection head)
34Y, 34M, 34C, 34K Ink head 34L Processing liquid head 35A Nozzle 35B Nozzle 50 Recording head controller 134Y Ink head 134L Processing liquid head 135A Nozzle 135B Nozzle 234Y Ink head 234L Processing liquid head 235A Nozzle 235B Nozzle

Claims (9)

Droplet discharge comprising a first liquid head for discharging the first liquid and a second liquid head for discharging the second liquid, and mixing and reacting the first liquid and the second liquid on a recording medium A device,
The second liquid head is different from the first liquid head in that at least one of a nozzle configuration of the second liquid head and a drive circuit for driving the second liquid head is different. Droplet discharge device.   2. The droplet discharge device according to claim 1, wherein the second liquid head is a binary circuit in which the driving circuit controls only ON / OFF of discharge of the second liquid.   The liquid droplet ejection apparatus according to claim 1, wherein the second liquid head has a rectangular wave drive circuit as the drive circuit. The first liquid is an ink and the second liquid is a treatment liquid that reacts with the ink;
4. The droplet discharge device according to claim 1, wherein the second liquid head is a defective head having a defective nozzle that cannot be used as the first liquid head. 5. .   5. The second liquid head according to claim 2, wherein the second liquid dot that discharges the second liquid is larger than the first liquid dot that discharges the first liquid. 2. A droplet discharge device according to item 1.   6. The liquid according to claim 2, wherein the second liquid head is a low density head in which nozzles are arranged at a lower density than the first liquid head. Drop ejection device. The first liquid is an ink and the second liquid is a treatment liquid that reacts with the ink;
The liquid according to any one of claims 1 to 3, wherein the second liquid head is a high-density head in which nozzles are arranged at a higher density than the first liquid head. Drop ejection device.   The liquid droplet ejection apparatus according to claim 7, wherein the second liquid head has a second liquid dot that discharges the second liquid smaller than a first liquid dot that discharges the first liquid.   4. The liquid droplet ejection apparatus according to claim 1, wherein the first liquid is ink and the second liquid is a processing liquid that reacts with the ink. 5.

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