JP2017094672A - Liquid injection device and liquid injection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection device improving printing image quality by enhancing wetting spreadability of pretreatment liquid while enhancing reactivity between the pretreatment liquid and ink irrespective of a type of a medium.SOLUTION: A liquid injection device 10 comprises: a pretreatment liquid coating mechanism 36 coating a medium 22 with a plurality of types of pretreatment liquid 40 having different permeability; a liquid injection section 36 injecting ink 41 onto the medium 22; a determination section 303 determining a type of the medium 22; and a control section 30 controlling the pretreatment liquid coating mechanism and the liquid injection section with respect to the medium 22. The control section 30 controls the order for coating of the plurality of types of pretreatment liquid 40 and changes the order for overlapping of the plurality of types of pretreatment liquid 40 on the medium 22 according to the type of the medium 22 determined by the determination section 303.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for ejecting a liquid such as ink onto a medium.

  In an ink jet type liquid ejecting apparatus, in order to improve the fixability of ink to a medium, a pretreatment liquid containing a reaction component such as an aggregating agent and ink are ejected by a liquid ejecting head to land the pretreatment liquid on the medium. Then, a technique has been developed in which the ink is landed and then both are reacted on the surface of the medium. In this technique, the larger the landing time difference between the pretreatment liquid and the ink, the more pretreatment liquid that has landed earlier penetrates the medium and the remaining amount of reaction components on the medium surface decreases. The amount of reaction falls. For this reason, there is a problem that the print image quality is likely to deteriorate as the landing time difference increases in each part of the medium surface. In this regard, for example, in Patent Document 1, when one kind of pretreatment liquid is used and the difference in landing time between the pretreatment liquid and the ink is longer, the amount of droplets of the pretreatment liquid (the ejection amount per unit time) is larger. On the contrary, the amount of droplets of the pretreatment liquid is reduced as the landing time difference is shorter, and the size of the dots that land on the medium is changed to adjust the reaction amount of the pretreatment liquid and the ink. ing.

JP 2005-119115 A

  However, in Patent Document 1, one kind of pretreatment liquid is landed on the medium by one ejection, and then ink is landed. For this reason, as the amount of droplets of the pretreatment liquid is reduced, the amount of the reaction component to be landed on the medium is spread while being small, and the ink is landed in that state. In addition, the higher the liquid absorbency type medium, the more easily the pretreatment liquid penetrates into the medium, and the amount of the reaction component of the pretreatment liquid remaining on the medium becomes smaller. In this case, the variation in reactivity between the pretreatment liquid and the ink becomes large, and on the contrary, the print image quality is deteriorated. In consideration of the above circumstances, the present invention improves the print image quality by increasing the wettability of the pretreatment liquid while increasing the reactivity between the pretreatment liquid and the ink regardless of the type of the medium. For the purpose.

  In order to solve the above problems, a liquid ejecting apparatus of the present invention includes a pretreatment liquid coating mechanism that coats a plurality of pretreatment liquids having different penetrability onto a medium, a liquid ejecting unit that ejects ink onto the medium, and a medium A control unit that controls the pretreatment liquid coating mechanism and the liquid ejecting unit with respect to the medium, and the control unit is configured according to the type of the medium determined by the determination unit. The order in which the plurality of pretreatment liquids are stacked on the medium is changed by controlling the order of coating the plurality of pretreatment liquids. In the above configuration, the permeability and wettability of the pretreatment liquid are changed by changing the order of stacking the plurality of pretreatment liquids on the medium by controlling the ejection order of the plurality of pretreatment liquids according to the type of the medium. Can be stabilized regardless of the characteristics of the medium. Accordingly, the wettability of the pretreatment liquid can be improved while improving the reactivity between the pretreatment liquid and the ink regardless of the type of the medium, and the print image quality can be improved.

  In a preferred aspect of the present invention, the control unit adjusts the amount of the plurality of pretreatment liquids so that the coverage area and the surface residual amount on the medium of the plurality of pretreatment liquids are uniform. According to the above aspect, the spreadability of the plurality of pretreatment liquids can be controlled, and the dot size immediately before ink landing can be made uniform, so that the effect of improving the print image quality can be enhanced.

  In a preferred aspect of the present invention, the discriminating unit discriminates between a medium having a high liquid absorbency and a medium having a low liquid absorbency. Since the medium having high absorbency has a characteristic that the pretreatment liquid easily permeates, the amount of the pretreatment liquid remaining on the surface decreases, and the reactivity with the ink may decrease. On the other hand, a medium with low absorbability has a characteristic that the pretreatment liquid is difficult to permeate, so that it is difficult to control the wet spreading property of the pretreatment liquid. In this regard, according to the aspect of the present invention, since it is determined whether the medium is a type having a high liquid absorbency or a type having a low liquid absorbency, a plurality of types are determined on the medium according to the type of the determined medium. By changing the order in which the pretreatment liquids are stacked, the permeability and wetting and spreading of the pretreatment liquid can be stabilized regardless of the characteristics of such a medium.

  In a preferred aspect of the present invention, the plurality of pretreatment liquids are a first pretreatment liquid and a second pretreatment liquid having a higher permeability to the medium than the first pretreatment liquid, and the control unit is a determination unit. If the medium is determined to be a medium having a high liquid absorbency, the second pretreatment liquid is coated so that the first pretreatment liquid overlaps the second pretreatment liquid on the medium. When the first pretreatment liquid is coated and the discriminating unit determines that the medium has a low liquid absorbency, the second pretreatment liquid is superimposed on the first pretreatment liquid on the medium. First, after coating the first pretreatment liquid, the second pretreatment liquid is coated. According to the above aspect, by changing the order of stacking the first pretreatment liquid and the second pretreatment liquid having different permeability according to the type of the medium, the permeability and wet spread of the pretreatment liquid can be reduced. It can be stabilized regardless of the nature of the.

  In a preferred aspect of the present invention, a liquid ejecting head including a transport mechanism for transporting a medium in the first direction, a pretreatment liquid coating mechanism, and a liquid ejecting unit, and a liquid ejecting head in a second direction intersecting the first direction. The pretreatment liquid coating mechanism includes a nozzle that ejects the first pretreatment liquid and a nozzle that ejects the second pretreatment liquid, and the liquid ejecting section ejects ink. The nozzle that ejects the first pretreatment liquid and the nozzle that ejects the second pretreatment liquid are disposed upstream of the nozzle that ejects ink in the first direction. According to the above aspect, the first pretreatment liquid and the second pretreatment liquid can be ejected onto the medium while the liquid ejecting head reciprocates. Can be changed, and the ink can be landed after the first pretreatment liquid and the second pretreatment liquid are landed on the medium.

  In a preferred aspect of the present invention, the control unit changes the ejection order of the first pretreatment liquid and the second pretreatment liquid between the forward movement and the backward movement of the liquid ejection head. According to the above aspect, the order of ejecting the first pretreatment liquid and the second pretreatment liquid can be changed according to the type of the medium by reciprocating the liquid ejecting head. According to this, it is not necessary to return the carriage as compared with the case where the first pretreatment liquid and the second pretreatment liquid are ejected only when the liquid ejecting head moves forward (or only when the liquid ejecting head moves backward). Accordingly, the time for stacking the first pretreatment liquid and the second pretreatment liquid on the medium can be shortened.

  In a preferred aspect of the present invention, the apparatus includes a transport mechanism that transports the medium in the first direction, and a liquid ejecting head that includes a pretreatment liquid coating mechanism and a liquid ejecting unit. A nozzle that ejects the pretreatment liquid and a nozzle that ejects the second pretreatment liquid, the liquid ejecting section includes a nozzle that ejects the ink, and the liquid ejecting head extends in a second direction that intersects the first direction. A long line head, a nozzle for ejecting the first pretreatment liquid, a nozzle for ejecting the second pretreatment liquid, and a nozzle for ejecting ink are arranged along the second direction, and The nozzle that ejects the first pretreatment liquid and the nozzle that ejects the second pretreatment liquid are arranged on the upstream side in the first direction with respect to the nozzle that ejects the ink. According to the above aspect, even if the liquid ejecting head is a line head, the order of stacking the first pretreatment liquid and the second pretreatment liquid can be changed, and the first pretreatment liquid and the second pretreatment liquid can be changed. The ink can be landed after landing on the medium.

  In a preferred aspect of the present invention, the plurality of pretreatment liquid nozzles includes two nozzle rows, and each of the two nozzle rows includes a nozzle for ejecting the first pretreatment liquid and a second front nozzle along the second direction. Nozzles for injecting treatment liquid are arranged, and nozzles for injecting the first pretreatment liquid in one of the two nozzle arrays and nozzles for injecting the second pretreatment liquid in the other nozzle array Overlap in the first direction in plan view. According to the above aspect, since the first pretreatment liquid and the second pretreatment liquid can be ejected by selecting the nozzle according to the type of the medium, even if the liquid ejection head is a line head, The order of stacking the first pretreatment liquid and the second pretreatment liquid can be easily changed.

  A liquid ejecting method according to a preferred aspect of the present invention is a liquid ejecting method in which a medium is coated with a pretreatment liquid and then ink is ejected onto the medium. The type of the medium is determined and the determined type of the medium is determined. Accordingly, the order in which the plurality of pretreatment liquids are stacked on the medium is changed by controlling the order of coating the plurality of pretreatment liquids. According to the above configuration, it is possible to stabilize the penetrability and wettability of the pretreatment liquid regardless of the characteristics of the medium. Accordingly, the wettability of the pretreatment liquid can be improved while improving the reactivity between the pretreatment liquid and the ink regardless of the type of the medium, and the print image quality can be improved.

1 is a configuration diagram of a liquid ejecting apparatus according to a first embodiment. FIG. 6 is a plan view of an ejection surface of the liquid ejection head. FIG. 3 is a cross-sectional view of a liquid ejecting head. As a comparative example, it is a figure for demonstrating the state of the pre-processing liquid at the time of making one type of pre-processing liquid with which permeability differs on the medium of a different kind. In FIG. 4, it is a figure for demonstrating the state of the ink in the case where the permeability of a pretreatment liquid is excessive, and the spreading property of a pretreatment liquid is insufficient. It is a figure for demonstrating the state of the pre-processing liquid in the case where the order which accumulates the pre-processing liquid is changed according to the kind of medium with the liquid jet head which concerns on 1st Embodiment. FIG. 7 is a diagram for explaining the state of ink immediately after ink landing and after a lapse of a predetermined time in the case of FIG. 6. 6 is a flowchart illustrating control of a liquid ejecting head in print control. It is a figure for demonstrating the case where the magnitude | size of the dot of the pretreatment liquid to land is adjusted. FIG. 10 is a plan view of an ejection surface of a liquid ejection head according to a modification of the first embodiment. It is a block diagram of the liquid ejecting apparatus according to the second embodiment. FIG. 10 is a configuration diagram of a liquid ejecting apparatus according to a modification of the second embodiment.

<First Embodiment>
FIG. 1 is a configuration diagram of a liquid ejecting apparatus 10 according to the first embodiment of the present invention. The liquid ejecting apparatus 10 is a printing apparatus (inkjet apparatus) that prints an image on the surface of the medium 22 by ejecting ink, which is an example of a liquid, onto the medium 22. The medium 22 is a recording medium such as a printing paper or a film to be ejected with ink. Details of the type of medium used in the first embodiment will be described later.

  The liquid ejecting apparatus 10 is equipped with a liquid container 24 that stores liquid, and the liquid container 24 stores pretreatment liquid 40 and ink 41. The ink 41 is a liquid (color ink) containing a color material such as a pigment or a dye. For example, a total of four inks 41 of cyan (C), magenta (M), yellow (Y), and black (K) are stored in the liquid container 24. Note that a resin material may be included in the ink 41.

  As the pretreatment liquid 40, a plurality of pretreatment liquids 40 having different permeability to the medium 22 are used. In the first embodiment, two types of pretreatment liquids 40 are used: a first pretreatment liquid 40a having a low permeability to the medium 22 and a second pretreatment liquid 40b having a higher permeability than the first pretreatment liquid 40a. Take the case as an example. Each of the first pretreatment liquid 40a and the second pretreatment liquid 40b is a liquid (optimizer ink) for improving the fixability of the ink 41 landing on the surface of the medium 22, and for example, an aggregating agent that reacts with the ink 41 And a reaction component such as water or a solvent. Color materials and resin materials contained in the ink 41 are not contained in the pretreatment liquid 40. Note that the pretreatment liquid 40 may contain a surfactant.

  The reaction components of the first pretreatment liquid 40a and the second pretreatment liquid 40b are the same, and the permeability to the medium 22 is different. As a specific example of the first pretreatment liquid 40a, there is a slow penetration pretreatment liquid that has low permeability to the medium 22 and slowly permeates. As a specific example of the second pretreatment liquid 40b, there is a super-penetration pretreatment liquid that has higher permeability to the medium 22 than the slow penetration pretreatment liquid and penetrates quickly. The terms “superosmosis” and “slow penetration” herein refer to their relative properties.

  The liquid container 24 stores the first pretreatment liquid 40a and the second pretreatment liquid 40b separately. In FIG. 1, the liquid container 24 is illustrated as one element for convenience, but a configuration in which a plurality of pretreatment liquids 40 and a plurality of types of inks 41 are stored in separate liquid containers 24 or a plurality of types of inks 41 are illustrated. For each of these, a configuration stored in a separate liquid container 24 may be employed.

  The liquid ejecting apparatus 10 includes a control unit 30, a transport mechanism 32, a moving mechanism 34, and a liquid ejecting head 36. The control unit 30 is, for example, a control unit such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), a ROM (Read Only Memory) 301, a RAM (Random Access Memory) 302, and a determination unit that determines the type of the medium 22. 303. The ROM 301 is a rewritable flash ROM, for example. The ROM 301 stores a program executed by the control unit 30 and various data (such as a medium data table described later) necessary for executing the program. The RAM 302 stores data temporarily used when the control unit 30 executes the program. A management device (not shown) such as a personal computer is connected to the control unit 30. The control unit 30 comprehensively controls each element of the liquid ejecting apparatus 10 according to an instruction from the management apparatus. The determination unit 303 determines the type of the medium 22 based on the medium data table. Details of the type determination of the medium 22 will be described later.

  The transport mechanism 32 transports the medium 22 in the Y direction (example of the first direction) under the control of the control unit 30. The transport mechanism 32 of the first embodiment includes a supply roller 322 and a discharge roller 324. The supply roller 322 is installed on the upstream side (negative side in the Y direction) of the discharge roller 324 and conveys the medium 22 to the discharge roller 324 side. The discharge roller 324 downstream of the medium 22 supplied from the supply roller 322 Transport to (positive side in Y direction). In addition, the structure of the conveyance mechanism 32 is not limited to the above illustration.

  The moving mechanism 34 is a mechanism that reciprocates the liquid ejecting head 36 in the X direction under the control of the control unit 30. The X direction in which the liquid ejecting head 36 reciprocates is a direction that intersects (typically orthogonal) the Y direction in which the medium 22 is conveyed. The moving mechanism 34 includes a carriage 342 and a conveyance belt 344. The carriage 342 is a substantially box-shaped structure that supports the liquid ejecting head 36, and is fixed to the transport belt 344. The conveyor belt 344 is an endless belt constructed in the X direction. The liquid ejecting head 36 reciprocates in the X direction together with the carriage 342 by rotating the transport belt 344 under the control of the control unit 30. In addition, the structure of the moving mechanism 34 is not limited to the above illustration. For example, the liquid container 24 can be mounted on the carriage 342 together with the liquid ejecting head 36.

  The liquid ejecting head 36 ejects each pretreatment liquid 40 and ink 41 supplied from the liquid container 24 onto the medium 22 under the control of the control unit 30. In parallel with the conveyance of the medium 22 by the conveyance mechanism 32 and the reciprocation by the movement mechanism 34, the liquid ejecting head 36 ejects the pretreatment liquid 40 and the ink 41 onto the medium 22, whereby a desired image is formed on the surface of the medium 22. Is formed. That is, the liquid ejecting head 36 functions as a pretreatment liquid coating mechanism that coats the medium 22 with the pretreatment liquid 40.

(Configuration example of liquid jet head)
The liquid ejecting head 36 according to the first embodiment is configured such that the ink 41 can be landed after the first pretreatment liquid 40 a and the second pretreatment liquid 40 b are landed and stacked on the medium 22. A specific configuration example of such a liquid jet head 36 is shown in FIG. FIG. 2 is a plan view of a surface (hereinafter referred to as “ejection surface”) 360 facing the medium 22 in the liquid ejection head 36. Two pretreatment nozzle rows LP1 to LP2 and four ink nozzle rows LI1 to LI4 are arranged on the ejection surface 360 of the liquid ejection head 36 shown in FIG. Each of the pretreatment nozzle rows LP1 to LP2 and each of the ink nozzle rows LI1 to LI4 is a set of a plurality of nozzles N arranged linearly along the Y direction. Each of the pretreatment nozzle rows LP1 to LP2 and each of the ink nozzle rows LI1 to LI4 may be a plurality of rows (for example, a staggered arrangement or a staggered arrangement).

  The first pretreatment liquid 40a supplied from the liquid container 24 is ejected from the nozzle N [S] of the pretreatment nozzle row LP1, and supplied from the liquid container 24 from the nozzle N [U] of the pretreatment nozzle row LP2. The second pretreatment liquid 40b is ejected. The preprocessing nozzle rows LP1 to LP2 are arranged in the X direction with a space therebetween. On the other hand, from the nozzles N [C], N [M], N [Y], and N [K] of the ink nozzle rows LI1 to LI4, inks 41 of different colors, that is, cyan (C) and magenta (M), respectively. , Yellow (Y) and black (K) inks 41 are ejected. The ink nozzle rows LI1 to LI4 are arranged in the X direction with a space therebetween.

  In the liquid ejecting head 36 shown in FIG. 2, the pre-processing nozzle rows LP1 to LP2 are arranged on the negative side in the Y direction (that is, upstream in the transport direction of the medium 22) as viewed from the ink nozzle rows LI1 to LI4. For example, assuming a straight line G parallel to the X direction on the ejection surface 360, each pretreatment nozzle row LP1 to LP2 is positioned on the negative side in the Y direction (upstream side in the transport direction of the medium 22) as viewed from the straight line G. The nozzle rows LI1 to LI4 are located on the positive side in the Y direction when viewed from the straight line G (downstream in the transport direction of the medium 22). According to such a configuration, after the landing of the first pretreatment liquid 40a and the second pretreatment liquid 40b ejected from the nozzles N of the pretreatment nozzle rows LP1 to LP2 on the surface of the medium 22, each ink nozzle The ink 41 ejected from the nozzles N in the rows LI1 to LI4 can be landed. At this time, since the pretreatment nozzle rows LP1 to LP2 are arranged in the X direction with a space between each other, one of the first pretreatment liquid 40a and the second pretreatment liquid 40b is landed. Therefore, the other can be landed and stacked on the medium 22. That is, after the first pretreatment liquid 40a and the second pretreatment liquid 40b are adhered to the surface of the medium 22 so as to overlap, the ink 41 can be landed.

  FIG. 3 is a cross-sectional view focusing on any one nozzle N in the liquid jet head 36. As illustrated in FIG. 3, in the liquid jet head 36, the pressure chamber substrate 72, the vibration plate 73, the piezoelectric element 74, and the support body 75 are disposed on one side of the flow path substrate 71 and the nozzle plate 76 is disposed on the other side. Is a structure in which is arranged. The flow path substrate 71, the pressure chamber substrate 72, and the nozzle plate 76 are formed of, for example, a silicon flat plate material, and the support body 75 is formed of, for example, an injection molding of a resin material. The plurality of nozzles N are formed on the nozzle plate 76.

  In the flow path substrate 71, an opening 712, a branch flow path (restricted flow path) 714, and a communication flow path 716 are formed. The branch flow path 714 and the communication flow path 716 are through holes formed for each nozzle N, and the opening 712 is an opening continuous over a plurality of nozzles N. A space in which the accommodating portion (concave portion) 752 formed in the support body 752 and the opening 712 of the flow path substrate 71 communicate with each other is supplied from the liquid container 24 through the introduction flow path 754 of the support body 75. It functions as a common liquid chamber (reservoir) SR for storing the pretreatment liquid 40 or the ink 41.

  An opening 722 is formed for each nozzle N in the pressure chamber substrate 72. The vibration plate 73 is an elastically deformable flat plate that is installed on the surface of the pressure chamber substrate 72 opposite to the flow path substrate 71. The space sandwiched between the diaphragm 73 and the flow path substrate 71 inside each opening 722 of the pressure chamber substrate 72 is the pretreatment liquid 40 or ink 41 supplied from the common liquid chamber SR via the branch flow path 714. Functions as a pressure chamber (cavity) SC in which is filled. Each pressure chamber SC communicates with the nozzle N via the communication channel 716 of the channel substrate 71.

  A piezoelectric element 74 is formed for each nozzle N on the surface of the diaphragm 73 opposite to the pressure chamber substrate 72. Each piezoelectric element 74 is a drive element in which a piezoelectric body is interposed between electrodes facing each other. When the diaphragm 73 is vibrated by the deformation of the piezoelectric element 74 due to the supply of the drive signal, the pressure in the pressure chamber SC varies and the ink 41 in the pressure chamber SC is ejected from the nozzle N.

(Determination of media type)
The determination unit 303 of the control unit 30 according to the first embodiment determines the type of the medium 22. Specifically, the determination unit 303 determines the medium 22a having a high liquid absorbency and the medium 22b having a low liquid absorbency. Examples of the medium 22a having a high liquid absorbency include plain paper, inkjet paper, and coating media. Examples of the medium 22b having low liquid absorbency include plastic films such as polyvinyl chloride (polyvinyl chloride), polyethylene terephthalate (PET), and polycarbonate (PC), films in which a base material is coated with a plastic or a receiving layer, metal, and printed wiring. Examples include substrates and fabrics. In addition, the absorptivity of a fabric may differ with the fibers which comprise a fabric. The cloth here is assumed to be composed of fibers having low absorbency, and is included in the medium 22b having low liquid absorbency, but is not limited to this, and is composed of fibers having high absorbency. The cloth to be used may be included in the medium 22a having a high liquid absorbency.

  For example, the ROM 301 stores in advance a medium data table including a group listing the medium 22a having high liquid absorbency and a group listing the medium 22b having low liquid absorbency. The type of the medium 22 can be selected by the user from an operation unit (not shown) connected to the control unit 30. The discriminating unit 303 discriminates the medium 22a having a high liquid absorbency and the medium 22b having a low liquid absorbency according to which group in the medium data table the medium 22 selected by the user is included.

  Note that the method of determining the type of the medium 22 is not limited to the case described above. The determination unit 303 may determine the type of the medium 22 based on, for example, a detection signal from the medium sensor 37 illustrated in FIG. The medium sensor 37 is connected to the control unit 30. The medium sensor 37 is composed of, for example, an optical sensor, and irradiates the medium 22 with light and detects the reflected light. The discriminating unit 303 discriminates between the medium 22a having high liquid absorbency and the medium 22b having low liquid absorbency depending on whether or not the detection signal from the medium sensor 37 exceeds a predetermined threshold.

  For example, since the light reflection intensity varies depending on the type of the medium 22, the medium 22 that can determine whether the liquid absorbency is high or low can be set as the threshold value of the light reflection intensity. Specifically, in the case of a plurality of media 22 in which the higher the light reflection intensity, the lower the liquid absorbency, if the detection signal from the media sensor 37 does not exceed a predetermined threshold value, It is determined that the medium 22a has high absorbency, and if it exceeds the threshold, it is determined that the medium 22b has low liquid absorbency. The medium sensor 37 may not be provided when the type of the medium 22 is determined by the user selecting the medium 22 as described above.

  In the first embodiment, the type of the medium 22 is determined as described above, and the first pretreatment liquid 40a and the second pretreatment liquid 40b having different penetrability on the medium 22 according to the determined type of the medium 22 are used. Change the stacking order. According to this, the surface residual amount (penetration into the inside of the medium 22) and the covering area (wetting and spreading property) of the medium 22 on the surface of the medium 22 of the stacked pretreatment liquid 40 are determined. It can be stabilized regardless of the characteristics (liquid absorbency). Therefore, the wettability of the pretreatment liquid 40 can be improved while improving the reactivity between the pretreatment liquid 40 and the ink 41 regardless of the type of the medium 22, and the print image quality can be improved.

  On the other hand, if only one type of pretreatment liquid 40 is used, depending on the type of medium 22 described above, the amount of the reaction component of the pretreatment liquid 40 remaining on the surface may change depending on the portion of the medium 22 or the pretreatment liquid 40 may be pretreated. The liquid 40 may become too wet and spread, or conversely, the wet spread may be insufficient, and the remaining amount of the surface and the covered area may not be stable, leading to a decrease in print image quality.

(Media type and one kind of pretreatment liquid)
Here, the relationship between the type of the medium 22 and one type of pretreatment liquid 40 will be described in more detail as a comparative example of the first embodiment. FIG. 4 is a comparative example of the first embodiment, and illustrates the state of the pretreatment liquid 40 in four cases 1 to 4 in which one kind of pretreatment liquid 40 having different permeability is landed on different types of media 22. It is a figure for doing. Here, one type of pretreatment liquid 40 having different permeability is either a pretreatment liquid 40a ′ having low permeability or a pretreatment liquid 40b ′ having high permeability. A slow penetration pretreatment liquid is used as the low-penetration pretreatment liquid 40a ', and a super-penetration pretreatment liquid is used as the high-penetration pretreatment liquid 40b'. The medium 22 having a different type is either a medium 22a having a high liquid absorbency (for example, coated paper having an ink absorption layer) or a medium 22b having a low liquid absorbency (for example, a plastic film such as vinyl chloride). It is.

  In FIG. 4, Case 1 is a case where a highly permeable pretreatment liquid 40 b ′ is landed on a highly absorbent medium 22 a, and Case 2 is a case where a highly permeable medium 22 a has a low permeability. This is a case where the treatment liquid 40a ′ is landed. Case 3 is a case where the pretreatment liquid 40b ′ having high permeability is landed on the medium 22b having low absorbency, and the case 4 is that of the pretreatment liquid 40a ′ having low permeability on the medium 22b having low absorbency. This is the case where

  In the case 1 of FIG. 5, the ink 41 is landed after the highly permeable pretreatment liquid 40b ′ is landed on the highly absorbent medium 22a in the case 1 of FIG. 4 (the pretreatment liquid 40b ′). It is a figure for demonstrating the state of the ink 41 in the case of excessive permeability. In the case 4 of FIG. 5, the ink 41 is landed after the highly permeable pretreatment liquid 40b ′ is landed on the medium 22b having low absorbability in the case 4 of FIG. 4 (wetting of the pretreatment liquid 40a ′). It is a figure for demonstrating the state of the ink 41 of the case where spread property is too small. In FIG. 5, the black portion is the ink 41.

  The surface remaining amount in FIG. 4 is the remaining amount of the pretreatment liquid 40a 'or 40b' remaining on the surface of the medium 22a or 22b immediately before ink landing. As the degree of penetration (permeability) of the pretreatment liquid 40a 'or 40b' from the surface of the medium 22a or 22b increases, the surface residual amount of the pretreatment liquid 40a 'or 40b' decreases. The covered area in FIG. 4 is an area where the pretreatment liquid 40a 'or 40b' remaining on the surface of the medium 22a or 22b immediately before ink landing covers the medium 22a or 22b. As the degree of wet spreading of the pretreatment liquid 40a 'or 40b' on the surface of the medium 22a or 22b (wetting spreadability) increases, the coverage area of the pretreatment liquid 40a 'or 40b' also increases. In FIG. 4, when the surface residual amount is large, it is expressed as “large”, when it is small, it is expressed as “low”, when the covering area is large, it is expressed as “large”, when it is small, it is expressed as “small”. When the covering area is medium, it is described as “medium”.

  In addition, the ultra-slow osmotic solution, which is the pretreatment solution 40b 'having high permeability, penetrates quickly into the medium 22a or 22b, and easily spreads on the surface of the medium 22a or 22b. On the other hand, the slow osmotic solution that is the low-permeability pretreatment liquid 40a ′ is less permeable to the inside of the medium 22a or 22b than the ultra-low osmosis liquid that is the high-penetration pretreatment liquid 40b ′. Difficult to spread on the surface of the medium 22a or 22b. For this reason, the remaining amount of the surface of the pretreatment liquid 40b 'or 40a' and the coating area differ depending on the combination of the pretreatment liquid 40a 'or 40b' and the medium 22a or 22b as in the cases 1 to 4 in FIG. Hereinafter, each case 1-4 is demonstrated concretely.

  First, the highly absorbent medium 22a in case 1 and case 2 of FIG. 4 will be described. As shown in Case 1 of FIG. 4, when the highly permeable pretreatment liquid 40b ′ is landed on the highly absorbent medium 22a, the surface remaining amount of the pretreatment liquid 40b ′ is “low”. The covering area is also “small”. That is, in this case, since the medium 22a has high absorbability, in the pretreatment liquid 40b ′ having high permeability, the pretreatment liquid 40b ′ is immediately after the landing of the pretreatment liquid 40b ′ to immediately before the ink 41 is landed. Since it permeates too much, the amount of the remaining surface of the pretreatment liquid 40b ′ remaining on the surface of the medium 22a becomes too small immediately before ink landing, and the covering area also becomes small. In addition, since the pretreatment liquid 40b 'having higher permeability is more easily spread and wet, the wet spread is increased. In this case, when the ink 41 is landed as shown in Case 1 of FIG. 5, since the remaining amount of the surface of the pretreatment liquid 40b ′ is too small and the covering area is small, the reaction between the pretreatment liquid 40b ′ and the ink 41 occurs. Low. For this reason, since the dots that have landed on the surface of the medium 22a spread and easily aggregate, the image quality may be degraded.

  On the other hand, as shown in Case 2 of FIG. 4, when the pretreatment liquid 40a ′ having low permeability is landed on the highly absorbent medium 22a, the surface residual amount and the coating area of the pretreatment liquid 40a ′ are as follows. Both are “medium”. In this case, since the permeability of the pretreatment liquid 40a ′ is low even with the medium 22a having high absorbency, the pretreatment is performed immediately after the pretreatment liquid 40a ′ has landed on the medium 22a and immediately before the ink 41 has landed. The liquid 40a ′ does not penetrate too much. For this reason, the remaining amount of the surface of the pretreatment liquid 40a 'does not become too small immediately before ink landing and the covering area is medium, so that the dots that have landed on the surface of the medium 22a are less likely to aggregate. On the other hand, in the pretreatment liquid 40a 'having low permeability, the penetration is slow and the wet spread is weak.

  As described above, the state of the pretreatment liquid 40a ′ in the case 2 of FIG. 4 is not bad, but the state of the pretreatment liquid 40a ′ changes depending on the time difference from the landing of the pretreatment liquid 40a ′ to the landing of the ink 41. Therefore, it is not always possible to provide a stable and favorable environment for the pretreatment liquid 40a ′ in all the print areas of the medium 22a.

  Next, the medium 22b having low absorbency in the case 3 and the case 4 of FIG. 4 will be described. As shown in Case 3 of FIG. 4, when the pretreatment liquid 40b ′ having high permeability is landed on the medium 22b having low absorbency, the surface residual amount of the pretreatment liquid 40b ′ becomes “medium”. The covering area is “large”. That is, in this case, since the medium 22b has low absorbability, in the pretreatment liquid 40b ′ having high permeability, the pretreatment liquid 40b ′ is formed immediately after the pretreatment liquid 40b ′ has landed and immediately before the ink 41 has landed. Does not penetrate too much, has good fixing properties and is good. For this reason, the remaining amount of the surface of the pretreatment liquid 40 b ′ does not decrease too much, the dots of the ink 41 that land on the surface of the medium 22 b hardly aggregate, and the color developability of the ink 41 is good. On the other hand, the pretreatment liquid 40b 'having higher penetrability is more likely to spread and wet, so that the pretreatment liquid 40b' that has landed tends to vary.

  As described above, although the state of the pretreatment liquid 40b ′ in the case 3 of FIG. 4 is not bad, the state of the pretreatment liquid 40b ′ changes due to the time difference from the landing of the pretreatment liquid 40a ′ to the landing of the ink 41. Therefore, it is not always possible to provide a stable and favorable environment for the pretreatment liquid 40b ′ in the entire printing region of the medium 22b.

  On the other hand, as shown in Case 4 of FIG. 4, when the pretreatment liquid 40a ′ having low permeability is landed on the medium 22b having low absorbency, the surface residual amount of the pretreatment liquid 40a ′ is “large”. Thus, the covering area becomes “medium”. That is, in this case, since the medium 22b has low absorbability, in the pretreatment liquid 40a ′ having low permeability, the pretreatment liquid 40a ′ immediately after the pretreatment liquid 40a ′ has landed and immediately before the ink 41 has landed. The remaining amount of the surface does not become too small. In this case, as shown in the case 4 of FIG. 5, when the ink 41 is landed, the dots that have landed on the surface of the medium 22b are less likely to aggregate. However, on the other hand, the pretreatment liquid 40a 'is more difficult to permeate and the fixability is poor, so the color developability of the ink 41 is lowered. In addition, since the permeability of the pretreatment liquid 40a 'is low, it is difficult for the pretreatment liquid 40a' to spread and the contact area between the pretreatment liquid 40a 'and the ink 41 is reduced, the reactivity is lowered, and the image quality may be lowered.

  According to the above, in order to improve the print image quality, from the viewpoint of the surface residual amount (penetration) of the pretreatment liquid, the medium 22a having high absorbability like the case 2 in FIG. 4 has high permeability. The pretreatment liquid 40a ′ having a lower permeability than the pretreatment liquid 40b ′ is better, and the medium 22a having a high absorbency as in the case 3 of FIG. 4 is more permeable than the pretreatment liquid 40a ′ having a low permeability. It can be seen that a higher pretreatment liquid 40b 'is better. On the other hand, from the viewpoint of the coating area (wetting and spreading property) of the pretreatment liquid, there is much room for improvement in that the pretreatment liquid is excessively spread, insufficient, or tends to vary. In addition, the smaller the amount of droplets of pretreatment liquid (the amount of jetting per unit time), the less the landing dots will get wet and spread, so the amount of droplets of pretreatment liquid is reduced. The liquid becomes easy to control the wetting and spreading property. However, the smaller the amount of droplets of the pretreatment liquid, the smaller the remaining amount of the surface of the pretreatment liquid, so that the reactivity between the pretreatment liquid and the ink decreases. Thus, it can be seen that it is very difficult to improve wettability while increasing reactivity with ink with only one kind of pretreatment liquid.

(Media type and multiple pretreatment liquids)
Therefore, in the first embodiment, a plurality of pretreatment liquids 40 are stacked on the medium 22, and the stacking order is changed according to the type of the medium 22, thereby improving the reactivity with the ink 41 and improving the wetting and spreading properties. It is intended to improve. Hereinafter, the state of the pretreatment liquid 40 and the state of the ink 41 in which the plurality of pretreatment liquids 40 are stacked in this way will be described. FIG. 6 illustrates the state of the pretreatment liquid 40 in the two cases 5 and 6 in which the order in which the pretreatment liquids 40 are stacked according to the type of the medium 22 is changed by the liquid jet head 36 according to the first embodiment. FIG.

  In FIG. 6, as the plurality of pretreatment liquids 40, two types of a first pretreatment liquid 40 a having low permeability and a pretreatment liquid 40 b having high permeability are used. A slow penetration pretreatment liquid is used as the first pretreatment liquid 40a having low permeability, and a super-penetration pretreatment liquid is used as the second pretreatment liquid 40b having high permeability. The medium 22 having a different type is either a medium 22a having a high liquid absorbency (for example, coated paper having an ink absorption layer) or a medium 22b having a low liquid absorbency (for example, a plastic film such as vinyl chloride). It is.

  Case 5 in FIG. 6 is a case where the second pretreatment liquid 40b having high permeability is landed on the medium 22a having high absorbability, and then the first pretreatment liquid 40a having low permeability is landed and stacked. . Case 6 in FIG. 5 is a case where the first pretreatment liquid 40a with low permeability is landed on the medium 22b with low absorbability, and then the second pretreatment liquid 40b with high permeability is landed and stacked. . FIG. 7 is a diagram for explaining the state of the ink 41 immediately after the landing of the ink 41 and after a lapse of a predetermined time in the case 5 and the case 6 of FIG. 6 and 7 are the second pretreatment liquid 40b and the first pretreatment liquid 40a after being overlaid.

  As shown in case 5 in FIG. 6, after the second pretreatment liquid 40b having high permeability is landed on the medium 22a having high absorbency, the first pretreatment liquid 40a having low permeability is landed and stacked. . In Case 5, the surface remaining amount of the pretreatment liquid 40b 'is "medium", and the covering area is also "medium". According to the case 5, by allowing the second pretreatment liquid 40b having high permeability to land first, it is possible to suppress the penetration of the first pretreatment liquid 40a having low permeability that will land later. Therefore, it becomes easy to spread and spread as a whole, the surface remaining amount of the pretreatment liquid 40 remaining on the surface of the medium 22a can be increased, and the covering area can be increased. Therefore, as shown in case 5 in FIG. Not only the aggregation of the ink 41 hardly occurs, but also the reactivity with the ink 41 can be improved, and the wetting and spreading property can be improved. In addition, since the second pretreatment liquid 40b having a higher penetrability serves as a sealant for the first pretreatment liquid 40a having a lower penetrability, the fixability of the pretreatment liquid 40 can be improved. Color developability can also be improved. Thereby, compared with the case where only the 2nd pretreatment liquid 40b with high permeability is used, the printing image quality can be further improved. Even if the same permeable pretreatment liquid is stacked, the pretreatment liquid will permeate the medium 22a in the same manner until the ink 41 is landed, and remains on the surface of the medium 22a. The remaining amount of the surface cannot be increased, and the high image quality as in the first embodiment cannot be obtained.

  On the other hand, as shown in the case 6 of FIG. 6, the medium 22b having low absorbability is landed with the second pretreatment liquid 40b with high permeability and then the first pretreatment liquid 40a with low permeability is landed. And repeat. In case 6 of FIG. 6, the surface remaining amount of the pretreatment liquid 40 is “medium”, and the covering area is also “medium”. According to the case 6, the first pretreatment liquid 40a having low permeability is landed first, thereby suppressing the way in which the second pretreatment liquid 40b having high penetrability landed later is wet and spread, while reacting with the ink 41. Can increase the sex. That is, in the medium 22b having low absorbability, it is difficult for the second pretreatment liquid 40b having high permeability to penetrate. Therefore, by reducing the amount of liquid droplets in the second pretreatment and making the dots smaller, wetting and spreading properties are reduced. Can be suppressed. In addition, even if the amount of liquid droplets in the second pretreatment is reduced, the reactive components can be supplemented by the first pretreatment liquid 40a that has low permeability that lands later, so that the reactivity with the ink 41 is increased. Can do. Accordingly, the surface remaining amount of the pretreatment liquid 40 can be increased while controlling the way of spreading and spreading as a whole. As shown in the second row of FIG. Further, it is possible to improve wettability while increasing the reactivity with the landed ink 41. Thereby, compared with the case where only the 1st pretreatment liquid 40a with low permeability is used, printing quality can be further improved.

(Liquid jetting method of the first embodiment)
Based on the above, the liquid ejecting method of the first embodiment will be described by taking control of the liquid ejecting head 36 as an example. FIG. 8 is a flowchart illustrating control of the liquid ejecting head 36 in print control. The control unit 30 reads a predetermined program from the ROM 301 in accordance with an instruction from the management apparatus, and executes print control on the medium 22. In the printing control, the control unit 30 controls the liquid ejecting head 36 shown in FIG.

  First, in step S101, the determination unit 303 determines the type of the medium 22 to be printed. For example, the determination unit 303 determines the type of the medium 22 based on the above-described medium data table. Specifically, the determination unit 303 compares the medium 22 selected by the user with the medium 22 in the medium data table, and determines whether the medium 22 is a highly absorbent medium 22a or a less absorbable medium 22b. In step S101, the medium 22 may be determined based on the detection signal from the medium sensor 37 as described above. If the determination unit 303 determines in step S101 that the medium 22a has a high absorbency, the control unit 30 moves the carriage 342 forward in step S102 and moves the nozzle N [U] of the preprocessing nozzle row LP2. The second pretreatment liquid 40b having high penetrability is ejected and landed on the medium 22a. Subsequently, in step S103, the control unit 30 ejects the first pretreatment liquid 40a having low permeability from the nozzle N [S] of the pretreatment nozzle row LP1 while moving the carriage 342 backward to land on the medium 22a. Then, the first pretreatment liquid 40a is overlaid on the second pretreatment liquid 40b.

  Thereafter, in step S106, the control unit 30 moves from the nozzles N [C], N [M], N [Y], and N [K] of the ink nozzle rows LI1 to LI4 while moving the carriage 342 forward. The color ink 41 is ejected to land on the medium 22a. The controller 30 repeatedly executes the control of the liquid ejecting head 36 while conveying the medium 22a. When the printing of the medium 22a for one sheet is finished, the control of the liquid ejecting head 36 is finished.

  On the other hand, when the determination unit 303 determines that the medium 22b has low absorbency in step S101, the control unit 30 moves the carriage 342 in step S104 while moving the carriage 342 forward. The first pretreatment liquid 40a having low permeability is ejected from the nozzle N [S] to land on the medium 22b. Subsequently, in step S105, the control unit 30 causes the second pretreatment liquid 40b having high permeability to be ejected from the nozzle N [U] of the pretreatment nozzle row LP2 while moving the carriage 342 backward, and landed on the medium 22b. Then, the second pretreatment liquid 40b is overlaid on the first pretreatment liquid 40a. Thereafter, in step S106, the control unit 30 requires the nozzles N [C], N [M], N [Y], and N [K] of the ink 41 nozzle rows LI1 to LI4 while moving the carriage 342 forward. A color ink 41 is ejected to land on the medium 22b. The controller 30 repeatedly executes the control of the liquid jet head 36 while conveying the medium 22b. When the printing of the medium 22b for one sheet is finished, the control of the liquid ejecting head 36 is finished.

  As described above, according to the printing control of the first embodiment, when the determination unit 303 determines that the medium 22a has high absorbability, the control unit 30 applies the second pretreatment liquid 40b having high permeability on the medium 22a. The first pretreatment liquid 40a having low permeability is deposited and landed, and then the ink 41 is landed. On the other hand, if the determination unit 303 determines that the medium 22b has low absorbability, the control unit 30 causes the second pretreatment liquid 40b to have high permeability to the first pretreatment liquid 40a having low permeability on the medium 22b. Are landed, and then ink 41 is landed. As a result, in both the medium 22a having high absorbency and the medium 22b having low absorbency, the wettability can be increased while increasing the reactivity of the pretreatment liquid 40, so that printing can be performed regardless of the type of the medium 22. Image quality can be improved.

  Further, according to the configuration of the liquid ejecting head 36 shown in FIG. 2, the order of ejecting the first pretreatment liquid 40a and the second pretreatment liquid 40b is changed depending on whether the liquid ejecting head 36 moves forward or backward. Since the liquid jet head reciprocates, the jet order of the first pretreatment liquid 40a and the second pretreatment liquid 40b can be changed according to the type of the medium 22. According to this, the carriage 342 is not returned as compared with the case where the first pretreatment liquid 40a and the second pretreatment liquid 40b are ejected only when the liquid ejecting head 36 moves forward (or only when the liquid ejecting head 36 moves backward). Therefore, the time required to overlap the first pretreatment liquid 40a and the second pretreatment liquid 40b on the medium 22 can be shortened accordingly.

  As described above, in the first embodiment, the control unit 30 makes the ink 41 after landing the first pretreatment liquid 40a and the second pretreatment liquid 40b on the medium 22 while reciprocating the carriage 342 in the X direction. To land. For this reason, the landing time difference from when the first pretreatment liquid 40a and the second pretreatment liquid 40b are overlapped until the ink 41 is landed differs depending on the position in the X direction. Since the dots of the pretreatment liquid 40 spread out with increasing landing time difference, even if the pretreatment liquid 40 is landed with the same amount of droplets, the pretreatment liquid 40 arranged in the X direction before the ink 41 is landed. The size of the dots (the surface remaining amount of the pretreatment liquid 40 remaining on the surface of the medium 22 and the covering area where the remaining pretreatment liquid 40 covers the surface of the medium 22) changes. Therefore, it is preferable that the size of the dots of the pretreatment liquid 40 arranged in the X direction is adjusted to be approximately the same immediately before the ink 41 is landed.

  FIG. 9 is a diagram for explaining a case where the dot size of the pretreatment liquid 40 is adjusted. Here, a case where the first pretreatment liquid 40a, the second pretreatment liquid 40b, and the ink 41 are landed in this order on the medium 22b having low absorbability will be described as an example. First, as shown in the first stage of FIG. 9, when the controller 30 landes the first pretreatment liquid 40a while moving the carriage 342 forward, the amount of liquid droplets is as much as the first pretreatment liquid 40a to be landed later. Reduce the number of landing dots by reducing the number of dots. Next, as shown in the second stage of FIG. 9, when the controller 30 lands the second pretreatment liquid 40 b while moving the carriage 342 backward, the second pretreatment liquid 40 b to be landed later is reduced. Decrease the amount and reduce the number of landing dots. Thereafter, the control unit 30 causes the ink 41 to land while moving the carriage 342 forward. The amount of liquid droplets by the liquid ejecting head 36 can be adjusted by the ejection duty (the amount of ejection per unit time with respect to the unit area of the medium 22).

  Thus, by adjusting the injection amount per unit time of each pretreatment liquid 40a, 40b, as shown in the third stage of FIG. 9, the first pretreatment liquid 40a and the second pretreatment liquid 40b are overlapped. Therefore, it is possible to control the wetting and spreading properties of the dots that have landed in such a manner that the size of the dots (covering area of the pretreatment liquid 40 on the medium 22 and the remaining amount of the surface) immediately before the landing of the ink 41 can be made uniform. Therefore, the effect of improving the print image quality can be enhanced. Moreover, the portion where the amount of liquid droplets of the first pretreatment liquid 40a is small increases the amount of liquid droplets of the second pretreatment liquid 40b, and the portion where the amount of liquid droplets of the second pretreatment liquid 40b is small Since the amount of droplets of the 1 pretreatment liquid 40a increases, the size of the dots can be made uniform without reducing the reaction components. According to this, the dot size of the pretreatment liquid 40 can be adjusted without reducing the reactivity with the ink 41, and one kind of reaction component is reduced when the amount of droplets is reduced. Compared with the case where only the pretreatment liquid 40 is used, a higher quality printed image can be provided.

  In addition, although the case where the first pretreatment liquid 40a, the second pretreatment liquid 40b, and the ink 41 are landed in this order on the medium 22b having low absorbency is illustrated, the present invention is not limited to this, and the medium 22a having high absorbency is used. On the other hand, when the second pretreatment liquid 40b, the first pretreatment liquid 40a, and the ink 41 are landed in this order, it is also possible to adjust the size of the dots as in FIG. Further, FIG. 9 illustrates the case where the dot size obtained by overlapping the first pretreatment liquid 40a and the second pretreatment liquid 40b is adjusted to be uniform immediately before the ink 41 is landed. Alternatively, it is possible to adjust the size of the dots obtained by overlapping the first pretreatment liquid 40a and the second pretreatment liquid 40b to a desired size.

  In the first embodiment, the configuration of the liquid ejecting head 36 is not limited to that illustrated in FIG. 2, and may be a configuration as illustrated in FIG. 10, for example. FIG. 10 is a plan view of the ejection surface 360 of the liquid ejection head 36 according to a modification of the first embodiment. The liquid ejecting head 36 shown in FIG. 10 is different from the liquid ejecting head 36 shown in FIG. 2 in the arrangement of the preprocessing nozzle rows LP1 and LP2 in the X direction. That is, in the liquid jet head 36 shown in FIG. 2, each of the pretreatment nozzle rows LP1 to LP2 is arranged on the positive side in the X direction when viewed from the ink nozzle rows LI1 to LI4, whereas FIG. In the liquid ejecting head 36 shown in FIG. 4, the pretreatment nozzle row LP1 is arranged on the negative side in the X direction and the pretreatment nozzle row LP2 is arranged on the positive side in the X direction when viewed from the ink nozzle rows LI1 to LI4. However, the present invention is not limited to this, and the preprocessing nozzle row LP1 may be arranged on the positive side in the X direction, and the preprocessing nozzle row LP2 may be arranged on the negative side in the X direction.

  In the liquid jet head 36 shown in FIG. 10 configured as described above, the control shown in FIG. 8 can be performed similarly to the liquid jet head 36 shown in FIG. The order of stacking the first pretreatment liquid 40a and the second pretreatment liquid 40b can be changed. Thereby, the same effect as the liquid jet head 36 shown in FIG. 2 is obtained.

  The liquid ejecting head 36 according to the first embodiment is divided into a liquid ejecting head 36 including a nozzle that ejects the pretreatment liquid 40 and a liquid ejecting head 36 including a nozzle that ejects the ink 41. Each of the liquid ejecting heads 36 may be mounted on a separate carriage 342. In this way, by separating the carriage 342, it becomes easier to adjust the timing at which the pretreatment liquid 40 is landed on the medium 22 and the timing at which the ink 41 is landed on the medium 22, and the surface remaining amount and the coating area of the pretreatment liquid 40 can be reduced. It is easy to adjust, and as a result, the consumption of the pretreatment liquid 40 can be suppressed.

Second Embodiment
A second embodiment of the present invention will be described. In the first embodiment, the liquid ejecting apparatus 10 including the serial head in which the carriage 342 on which the liquid ejecting head 36 is mounted moves in the X direction is illustrated. However, in the second embodiment, the direction intersecting the transport direction of the medium 22 ( Here, the liquid ejecting apparatus 10 including the liquid ejecting head 36 configured as a long line head in the X direction) is illustrated. 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.

  FIG. 11 is a partial configuration diagram of the liquid ejecting apparatus 10 according to the second embodiment of the invention. The liquid ejecting head 36 in the liquid ejecting apparatus 10 shown in FIG. 11 is a line head in which three pretreatment nozzle arrays LP1 to LP3 and four ink nozzle arrays LI1 to LI4 are arranged in the Y direction with a space therebetween. is there. Each of the pretreatment nozzle rows LP1 to LP3 and each of the ink nozzle rows LI1 to LI4 is a set of a plurality of nozzles N arranged in a straight line along the X direction. Each of the pretreatment nozzle rows LP1 to LP3 and each of the ink nozzle rows LI1 to LI4 can be a plurality of rows (for example, a staggered arrangement or a staggered arrangement).

  The first pretreatment liquid 40a supplied from the liquid container 24 is ejected from the nozzles N [S] of the pretreatment nozzle arrays LP1, LP3, and the liquid container 24 is ejected from the nozzles N [U] of the pretreatment nozzle array LP2. The second pretreatment liquid 40b supplied from is injected. On the other hand, from the nozzles N [C], N [M], N [Y], and N [K] of the ink nozzle rows LI1 to LI4, inks 41 of different colors, that is, cyan (C) and magenta (M), respectively. , Yellow (Y) and black (K) inks 41 are ejected.

  In the liquid ejecting head 36 shown in FIG. 11, the pretreatment nozzle rows LP1 to LP3 are arranged on the negative side in the Y direction (that is, upstream in the transport direction of the medium 22) as viewed from the ink nozzle rows LI1 to LI4. For example, assuming a straight line G parallel to the X direction on the ejection surface 360, each pretreatment nozzle row LP1 to LP3 is located on the negative side in the Y direction (upstream side in the transport direction of the medium 22) from the straight line G, and each ink The nozzle rows LI1 to LI4 are located on the positive side in the Y direction as viewed from the straight line G (on the downstream side in the transport direction of the medium 22). In the case of a line head as shown in FIG. 11, the liquid ejecting head 36 is fixed. In order to overlap the first pretreatment liquid 40a and the second pretreatment liquid 40b on the medium 22, at least the nozzles N [S] of the pretreatment liquid 40 nozzles LP1 and LP3 and the nozzle N [ U] is preferably overlapped in a plan view in the Y direction, since the X direction in Fig. 11 is perpendicular to the Y direction, the positions of the nozzles N [S] of the pretreatment liquid nozzles LP1 and LP3 in the X direction , Nozzle N [U of pretreatment liquid 40 nozzles LP2 The position of the X direction are identical.

  In the liquid jet head 36 shown in FIG. 11 configured as described above, the control shown in FIG. 8 can be performed similarly to the liquid jet head 36 shown in FIG. The order of stacking the first pretreatment liquid 40a and the second pretreatment liquid 40b can be changed. Specifically, when the second pretreatment liquid 40b is landed after the first pretreatment liquid 40a has landed (steps S104 and S105), the control unit 30 starts from the nozzle N [S] of the pretreatment nozzle row LP1. The first pretreatment liquid 40a is ejected, and the second pretreatment liquid 40b is ejected from the nozzle N [U] of the pretreatment nozzle row LP2. On the other hand, when the first pretreatment liquid 40a is landed after the second pretreatment liquid 40b has landed (steps S102 and S103), the control unit 30 performs the second pretreatment from the nozzle N [U] of the pretreatment nozzle row LP2. The liquid 40b is ejected, and the first pretreatment liquid 40a is ejected from the nozzle N [S] of the pretreatment nozzle row LP3. Thereby, the same effect as the liquid jet head 36 shown in FIG. 2 is obtained.

  Further, the control unit 30 selects either the pretreatment nozzle row LP1 or the pretreatment nozzle row LP3 and ejects the first pretreatment liquid 40a, thereby conveying the first pretreatment liquid 40a only to the positive side in the Y direction. The landing order of the pretreatment liquid 40a and the second pretreatment liquid 40b can be changed and overlapped. Therefore, even if the liquid ejecting head 36 is a line head, the first front treatment liquid 40a and the second pretreatment liquid 40b are overlapped with each other in the first front as compared with the case where the medium 22 is returned to the negative side in the Y direction. The order in which the treatment liquid 40a and the second pretreatment liquid 40b are stacked can be easily changed.

  In the liquid jet head 36 shown in FIG. 11, a line head provided with three pre-processing nozzle rows is taken as an example. For example, as shown in FIG. 12, the line head is provided with two pre-processing nozzle rows. Also good. The liquid jet head 36 in FIG. 12 is different from the liquid jet head 36 in FIG. 11 in that the first pretreatment liquid 40a is provided in each of the two pretreatment nozzle rows LP1, LP2 without providing the pretreatment nozzle row LP3. The nozzle N [S] for spraying the nozzle and the nozzle N [U] for spraying the second pretreatment liquid 40b are arranged. As shown in the enlarged view of FIG. 12, the nozzles N [S] and N [U] are alternately arranged along the X direction in the two preprocessing nozzle rows LP1 and LP2. Also in the case of a line head as shown in FIG. 12, since the liquid jet head 36 is fixed as in the case shown in FIG. 11, the first pretreatment liquid 40a and the second pretreatment liquid 40b are placed on the medium 22. In order to overlap, the nozzle N [S] of one nozzle row of at least two preprocessing nozzle rows LP1 and LP2 and the nozzle N [U] of the other nozzle row overlap in a plan view in the Y direction. It is preferable. Since the X direction in FIG. 12 is perpendicular to the Y direction, the position in the X direction of the nozzle N [S] of one nozzle row of the two preprocessing nozzle rows LP1, LP2 and the nozzle N of the other nozzle row The position of [U] in the X direction matches. If the nozzles N [S] and the nozzles N [U] overlap in the Y direction in plan view as described above, the nozzles N [S] and the nozzles N [U] are not necessarily arranged alternately. Also good.

  In the liquid jet head 36 shown in FIG. 12 configured as described above, the control shown in FIG. 8 can be performed similarly to the liquid jet head 36 shown in FIG. The order of stacking the first pretreatment liquid 40a and the second pretreatment liquid 40b can be changed. Specifically, when the second pretreatment liquid 40b is landed after the first pretreatment liquid 40a has landed (steps S104 and S105), the control unit 30 starts from the nozzle N [S] of the pretreatment nozzle row LP1. The first pretreatment liquid 40a is ejected, and the second pretreatment liquid 40b is ejected from the nozzle N [U] of the pretreatment nozzle row LP2. On the other hand, when the first pretreatment liquid 40a is landed after the second pretreatment liquid 40b has landed (steps S102 and S103), the control unit 30 performs the second pretreatment from the nozzle N [U] of the pretreatment nozzle row LP1. The liquid 40b is ejected, and the first pretreatment liquid 40a is ejected from the nozzle N [S] of the pretreatment nozzle row LP2. Thereby, the same effect as the liquid jet head 36 shown in FIG. 2 is obtained.

  Further, the control unit 30 selects the nozzle N [U] from the preprocessing nozzle row LP1 and the nozzle N [S] from the preprocessing nozzle row LP2 or the nozzle N [S] from the preprocessing nozzle row LP1 and the preprocessing nozzle. By selecting the nozzle N [U] from the row LP2, the landing order of the first pretreatment liquid 40a and the second pretreatment liquid 40b is changed while conveying the medium 22 in one direction (positive side in the Y direction). be able to. Even in this case, the first pretreatment liquid 40a and the second pretreatment liquid are compared with the case where the medium 22 is returned to the negative side in the Y direction in order to overlap the first pretreatment liquid 40a and the second pretreatment liquid 40b. The order of stacking 40b can be easily changed.

  Note that the liquid jet head 36 of the second embodiment also functions as a pretreatment liquid coating mechanism that coats the pretreatment liquid 40 onto the medium 22, similarly to the liquid jet head 36 of the first embodiment. Specifically, in the liquid ejecting head 36, the component that ejects the ink 41 functions as a liquid ejecting unit, and the component that ejects the first pretreatment liquid 40a and the second pretreatment liquid 40b is the pretreatment liquid coating. Acts as a mechanism.

<Modification>
Each embodiment illustrated above can be variously modified, for example, can be appropriately combined within a range not contradicting each other. Further, the following examples may be combined with each embodiment.

(1) The structure of the liquid jet head 36 is appropriately changed. For example, in each of the above-described embodiments, the piezoelectric liquid ejecting head 36 using a piezoelectric element that imparts mechanical vibration to the pressure chamber is exemplified, but a heating element that generates bubbles in the pressure chamber by heating is used. It is also possible to employ a thermal type liquid jet head. Further, the configuration of the plurality of nozzles N in the liquid ejecting head 36 is not limited to the illustrations of the above-described embodiments. For example, the pretreatment nozzle row and the ink nozzle row may be configured separately. In each of the above-described embodiments, the case where two pretreatment liquids 40 are landed and stacked on the medium has been described. However, the present invention is not limited to this, and three or more pretreatment liquids 40 are landed. You may make it overlap.

(2) In each of the above-described embodiments, the case where the liquid ejecting head 36 functions as a pretreatment liquid coating mechanism that coats the medium 22 with the pretreatment liquid 40 is exemplified, but the present invention is not limited thereto, and the pretreatment is performed. The liquid coating mechanism may be provided separately from the liquid ejecting head 36. In this case, the pretreatment liquid coating mechanism may be constituted by a spray mechanism that coats the medium 22 by spraying different pretreatment liquids. For example, the spray mechanism is divided into three blocks extending in the X direction (the width direction of the medium 22), and each block is arranged in the Y direction. Each block is provided with a total of three rows of sprays, one row in the X direction. The three rows of sprays consist of a spray of the first pretreatment liquid, a spray of the second pretreatment liquid, and a spray of the first pretreatment liquid. The three rows of sprays may be arranged in the order of the first pretreatment liquid spray, the second pretreatment liquid spray, and the first pretreatment liquid spray from the positive side to the negative side in the Y direction. You may arrange | position with the spray of a process liquid, the spray of a 1st pre-process liquid, and the spray of a 2nd pre-process liquid. Each of these three rows of sprays is configured to control the spray amount of the first pretreatment liquid or the second pretreatment liquid in the width direction (X direction) of the medium 22.

(3) The liquid ejecting apparatus exemplified in each of the above-described embodiments 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 ejecting apparatus of the present invention is not limited to printing. For example, a liquid ejecting apparatus that ejects a solution of a coloring material is used as a manufacturing apparatus that forms a color filter of a liquid crystal display device. Further, a liquid ejecting apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes of a wiring board.

DESCRIPTION OF SYMBOLS 10 ... Liquid ejecting apparatus, 22 ... Medium, 22a ... Highly absorbable medium, 22b ... Low absorbable medium, 24 ... Liquid container, 30 ... Control part, 301 ... ROM, 302 ... RAM, 303 ... Discrimination part, 32 ... transport mechanism, 322 ... supply roller, 324 ... discharge roller, 34 ... movement mechanism, 40 ... pretreatment liquid, 40a ... first pretreatment liquid, 40a '... pretreatment liquid with low permeability, 40b ... second pretreatment Liquid, 40b '... Pretreatment liquid with high permeability, 41 ... Ink, 342 ... Carriage, 344 ... Conveyor belt, 36 ... Liquid ejecting head, 360 ... Ejecting surface, 37 ... Media sensor, 71 ... Channel substrate, 712 ... Opening, 714 ... Branching channel, 716 ... Communication channel, 72 ... Pressure chamber substrate, 722 ... Opening, 73 ... Diaphragm, 74 ... Piezoelectric element, 75 ... Support, 754 ... Introduction channel, 76 ... Nozzle Board, LI1, LI2, LI3, I4 ... ink nozzle row, LP1, LP2, LP3 ... preprocessing nozzle rows, N ... nozzle, SC ... pressure chamber, SR ... common liquid chamber.

Claims (9)

A pretreatment liquid coating mechanism for coating a medium with a plurality of pretreatment liquids having different permeability;
A liquid ejecting unit that ejects ink onto the medium;
A discriminator for discriminating the type of the medium;
A control unit for controlling the pretreatment liquid coating mechanism and the liquid ejecting unit with respect to the medium;
The control unit controls the order of coating the plurality of pretreatment liquids according to the type of the medium determined by the determination unit, and changes the order in which the plurality of pretreatment liquids are stacked on the medium. Injection device. The liquid ejecting apparatus according to claim 1, wherein the control unit adjusts the amount of the plurality of pretreatment liquids so that a surface remaining amount and a covering area of the plurality of pretreatment liquids on the medium are uniform. 3. The liquid ejecting apparatus according to claim 1, wherein the determination unit determines whether the medium is a type having a high liquid absorbency or a type having a low liquid absorbency. The plurality of pretreatment liquids are a first pretreatment liquid and a second pretreatment liquid that has higher permeability to the medium than the first pretreatment liquid,
The controller is
When the discriminating unit discriminates that the medium has a high liquid absorbency, the second pretreatment liquid is superimposed on the second pretreatment liquid on the medium. After coating the pretreatment liquid, coating the first pretreatment liquid,
In the case where the discriminating unit discriminates that the medium is of a type having low liquid absorbency, the first pretreatment liquid overlaps the first pretreatment liquid on the medium. The liquid ejecting apparatus according to claim 3, wherein the second pretreatment liquid is coated after the pretreatment liquid is coated. A transport mechanism for transporting the medium in a first direction;
A liquid ejecting head comprising the pretreatment liquid coating mechanism and the liquid ejecting section;
A moving mechanism for reciprocating the liquid jet head in a second direction intersecting the first direction,
The pretreatment liquid coating mechanism includes a nozzle that ejects the first pretreatment liquid and a nozzle that ejects the second pretreatment liquid,
The liquid ejecting unit includes a nozzle that ejects the ink,
5. The liquid according to claim 4, wherein the nozzle that ejects the first pretreatment liquid and the nozzle that ejects the second pretreatment liquid are disposed upstream of the nozzle that ejects the ink in the first direction. Injection device. The liquid ejecting apparatus according to claim 5, wherein the control unit changes the ejection order of the first pretreatment liquid and the second pretreatment liquid depending on when the liquid ejecting head moves forward and backward. A transport mechanism for transporting the medium in a first direction;
A liquid ejecting head including the pretreatment liquid coating mechanism and the liquid ejecting unit;
The pretreatment liquid coating mechanism includes a nozzle that ejects the first pretreatment liquid and a nozzle that ejects the second pretreatment liquid,
The liquid ejecting unit includes a nozzle that ejects the ink,
The liquid ejecting head is a line head that is long in a second direction intersecting the first direction,
The nozzle that ejects the first pretreatment liquid, the nozzle that ejects the second pretreatment liquid, and the nozzle that ejects the ink are arranged along the second direction,
5. The liquid ejection according to claim 4, wherein the nozzle for ejecting the first pretreatment liquid and the nozzle for ejecting the second pretreatment liquid are disposed upstream of the nozzle for ejecting the ink in the first direction. apparatus. The plurality of pretreatment liquid nozzles consists of two nozzle rows,
In each of the two nozzle rows, a nozzle that ejects the first pretreatment liquid and a nozzle that ejects the second pretreatment liquid are arranged along the second direction,
Of the two nozzle arrays, a nozzle that ejects the first pretreatment liquid from one nozzle array and a nozzle that ejects the second pretreatment liquid from the other nozzle array are viewed in plan in the first direction. The liquid ejecting apparatus according to claim 7, which overlaps with each other. A liquid ejecting method for ejecting ink onto the medium after coating the medium with a pretreatment liquid,
Liquid ejection that determines the type of the medium and changes the order in which the plurality of pretreatment liquids are stacked on the medium by controlling the order of coating the plurality of pretreatment liquids according to the determined type of the medium Method.

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