JP7151244B2 - Droplet ejection system, image forming apparatus, droplet ejection method - Google Patents

Description

The present invention relates to a droplet ejection system, an image forming apparatus, and a droplet ejection method.

2. Description of the Related Art A printer employing an inkjet method (hereinafter referred to as an “inkjet device”) is known as one aspect of a device used to output electronic information. In image formation output, which is one mode of information output in an inkjet device, droplets of ink or the like used for image formation are ejected from a recording head and adhered to a medium (for example, paper) that is an object on which an image is to be formed.

By controlling the amount of ink deposited on the medium, the size of the ink dots forming the image is set to a predetermined size, and the ink dots are deposited on the medium so as to form an image in a two-dimensional direction. can do. In the image forming output using the inkjet method, the gradation and gradation of the image can be expressed delicately by adjusting the size of the ink dots and adjusting the arrangement of the dots.

However, the inkjet method has a problem that causes deterioration of the quality of the image formed on the medium. That is, depending on the wetting speed of the ink, when the ink adhered to the medium flows on the medium, the ink spreads on the medium and a beading phenomenon occurs in which ink dots are connected to each other. In addition, the flow of ink causes a bleeding phenomenon in which ink dots bleed. When such a phenomenon occurs, the quality of the image formed on the medium deteriorates.

In contrast, a pretreatment agent is applied to the medium before the droplets are ejected to change the viscosity of the ink ejected onto the medium, thereby controlling the speed at which the ink spreads on the medium, that is, the behavior of the ink on the medium. A control technique has been disclosed (see, for example, Patent Document 1).

In Japanese Patent Laid-Open No. 2002-200001, the pretreatment is uniformly performed on one surface of the recording medium regardless of the position on the recording medium. Therefore, even if the size of the droplet is adjusted to improve the image quality, the ink may flow on the medium depending on the speed at which the ink spreads, resulting in deterioration of the image quality.

Therefore, even if the technology disclosed in Patent Document 1 is applied, the speed at which ink spreads on the medium, that is, the behavior of droplets such as ink, is controlled so as to be suitable for the image formed on the medium. This is a factor that degrades the quality of the image formed on the medium.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the quality of an image formed on a medium by controlling the behavior of droplets ejected from an inkjet device.

In order to solve the above problems, one aspect of the present invention provides a preprocessing execution unit that performs preprocessing on a medium, and a preprocessing execution unit that controls the execution mode of the preprocessing based on image information of an image formation output target. A control unit, a droplet ejection unit that ejects droplets onto the medium based on the image information, a print control unit that controls the droplet ejection unit, and controls the print control unit and the preprocessing execution control unit. the pretreatment execution unit is capable of ejecting a plurality of types of pretreatment agents from a pretreatment agent ejection head, and causes the pretreatment agent to adhere to the medium, and the liquid droplet ejection unit is capable of ejecting a plurality of types of the droplets, and the control unit refers to a table storing combinations of the types of the droplets and the types of the pretreatment agent to select the combination, Dots formed by the droplets adhering to the medium are controlled , and the pretreatment agent contains a polyvalent metal salt, glycerin, and a betaine compound having a molecular weight of 100 or more and 200 or less, and The total content of glycerin and the betaine compound is 1.05 to 2.50 times the content of the polyvalent metal salt on a mass basis .

According to the present invention, the behavior of droplets ejected from an inkjet device can be controlled to improve the quality of an image formed on a medium.

Explanatory drawing explaining the fluidity|liquidity of a droplet. FIG. 4 is a diagram showing a dispersed state of pigment particles in a solvent; FIG. 4 is a diagram showing dots formed by droplets adhering to a recording medium; 1 is a diagram showing an outline of an inkjet system according to a first embodiment of the present invention; FIG. 1 is a configuration diagram of an ejection head that ejects liquid droplets according to a first embodiment of the present invention; FIG. 1 is a cross-sectional view showing a schematic configuration of a coloring agent ejection head according to a first embodiment of the present invention; FIG. 1 is a diagram showing an operation mode of an inkjet system according to a first embodiment of the present invention; FIG. FIG. 2 is a diagram showing the hardware configuration of the DFE according to the first embodiment of the present invention; FIG. 1 is a block diagram showing functional configurations of an inkjet device and a pretreatment device according to a first embodiment of the present invention; FIG. 2 is a block diagram showing the functional configuration of the DFE according to the first embodiment of the invention; FIG. FIG. 2 is a block diagram showing the functional configuration of a main control section according to the first embodiment of the present invention; FIG. The figure which shows the structure of the characteristic information data table which concerns on the 1st Embodiment of this invention. FIG. 4 is a diagram showing how a pretreatment agent applied region is formed according to the first embodiment of the present invention; 4A and 4B are diagrams showing a droplet ejection mode according to the first embodiment of the present invention; FIG. The figure which illustrated the positional information which concerns on the 1st Embodiment of this invention. 4 is a flow chart showing the flow of processing for calculating the amount of pretreatment agent according to the first embodiment of the present invention. The figure which shows the outline of the inkjet system which concerns on the 2nd Embodiment of this invention. FIG. 4 is a perspective view of an image forming apparatus according to a second embodiment of the invention; FIG. 4 is a perspective view of an image forming apparatus according to a second embodiment of the invention; FIG. 6 is a diagram showing the functional configuration of an image forming apparatus according to a second embodiment of the present invention; FIG. 11 is a sequence diagram showing the flow of processing for image formation output according to the second embodiment of the present invention; The figure which shows the outline of the inkjet system which concerns on the 3rd Embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments described below, an image, which is an example of an image formed product, is formed by ejecting ink, which is an example of an image forming agent according to the present invention, onto printing paper, which is an example of a medium. First, the fluidity of ink droplets will be described as an example of the behavior of ink droplets ejected onto a recording medium such as printing paper.

FIGS. 1A to 1C are explanatory diagrams for explaining the fluidity of droplets LD, which are ink droplets containing pigment particles P as a coloring agent, on a recording medium M. FIG. FIG. 1(a) is a diagram showing a state immediately before droplets LD are ejected and come into contact with a recording medium M, which is printing paper. As shown in FIG. 1(a), the droplet LD is composed of the pigment particles P and the solvent L. As shown in FIG.

It is also assumed that the surface of the recording medium M is coated with an aggregating agent AG, which is a reactive agent that changes the dispersed state of the pigment particles P to aggregate the pigment particles P. FIG. The process of applying the aggregating agent AG to the surface of the recording medium M is called "pretreatment". The pretreatment is performed in advance before the droplets LD are ejected onto the recording medium M. As shown in FIG. By this pretreatment, a pretreatment agent application area PC is formed on the surface of the recording medium M, which is the ejection destination of the droplets LD.

FIG. 1(a) is a diagram showing the dispersed state of the pigment particles P in the solvent L immediately before the droplets LD contact the recording medium M. FIG. As shown in FIG. 1A, droplets LD are formed in a state in which pigment particles P are dispersed in solvent L. As shown in FIG. In the case of a pigment ink containing a pigment as a colorant, pigment particles P are uniformly dispersed in a solvent L such as a solvent or resin.

FIG. 1(b) is a diagram showing the dispersed state of the pigment particles P in the solvent L at the moment the droplet LD adheres to the recording medium M. FIG. When the droplets LD adhere to the recording medium M, the pigment particles P are aggregated by the aggregating agent AG contained in the pretreatment agent application area PC, and the dispersed state of the pigment particles P in the solvent L is no longer uniform.

FIG. 2 illustrates the dispersed state of the pigment particles P in the solvent L in the liquid droplets LD. In the following description, the droplets LD before adhering to the recording medium M are in the state shown in FIG. Assume that FIG. 2B exemplifies a state in which the distribution of the pigment particles P with respect to the solvent L is uneven due to the effect of the pretreatment agent application area PC formed on the recording medium M. As shown in FIG.

As shown in FIG. 2(a), the size of the pigment particles P uniformly dispersed in the solvent L is the size of the pigment particles uniformly distributed in the solvent L, where r is the particle diameter. When P aggregates with each other as shown in FIG. 2(b), the apparent particle size of the pigment particles P increases from the particle diameter r to the particle diameter r'. Further, the dispersed state of the pigment particles P in the solvent L is not uniform due to aggregation of the pigment particles P.

At this time, the diffusion coefficient D, which is the coefficient when the pigment particles P dispersed in the solvent L moves, is proportional to the absolute temperature T according to the Stokes-Einstein equation shown in Equation 1, Inversely proportional to size. The Stokes-Einstein equation expresses the diffusion state of the pigment particles P dispersed in the solvent L based on the relationship between the viscosity η of the solvent L and the diffusion coefficient D.

In Equation 1, _D is the diffusion coefficient, η is the viscosity of the solvent L, T is the absolute temperature, kB is the Boltzmann constant, and a is the particle radius. As shown in Formula 1, the larger the size of the pigment particles P, the smaller the diffusion coefficient D, and the less freedom the pigment particles P move with respect to the solvent L. Therefore, when the pigment particles P aggregate, the liquid droplets LD become difficult to flow.

In general, the droplet LD attached to the recording medium M flows and spreads toward the periphery of the attachment point, so when the droplet LD adheres on the recording medium M, the droplet LD contacts the recording medium M. The size of the droplet LD becomes larger than that momentarily. However, when the droplets LD become difficult to flow due to the aggregation of the pigment particles P as described above, the size of the droplets LD adhering to the recording medium M also becomes difficult to change, and the liquid droplets LD when fixed on the recording medium M become difficult to flow. The size of the droplet LD is smaller than the size when the droplet LD easily flows. That is, it becomes difficult for the droplet LD to spread from the attachment point to the surroundings.

FIG. 1(c) is a diagram showing how the droplet LD permeates the recording medium M. As shown in FIG. As shown in FIG. 1C, when the recording medium M is a permeable medium such as plain paper, the droplets LD permeate the pretreatment agent application area PC and the recording medium M, stick to. Then, the fixed droplets LD are dried to form dots Dt of the pigment particles P on the recording medium M. FIG.

3A and 3B are diagrams showing dots Dt formed by droplets LD adhering to the recording medium M. FIG. The concentration of the flocculant AG contained in the pretreatment agent application area PC in FIG. is defined as the coagulant concentration AGC2.

When the droplets LD permeate the recording medium M, the droplets LD adhere to the recording medium M due to the balance between the ease of wetting and spreading of the droplets LD and the freedom of movement of the pigment particles P contained in the droplets LD. A difference occurs between the dots Dt formed by this and the dispersed state of the pigment particles P in the dots Dt. Specifically, as shown in FIGS. 3A and 3B, a difference occurs in the uniformity of the distribution concentration of the pigment particles P in the dots Dt.

FIG. 3A is a diagram showing dots Dt-1 of pigment particles P formed on a recording medium M on which a pretreatment agent application area PC is formed by pretreatment agent PCA having an aggregating agent concentration AGC1. . In the dot Dt-1, the distribution density of the pigment particles P decreases from the center of the dot toward the outer periphery.

FIG. 3(b) is a diagram showing dots Dt-2 of pigment particles P formed on a recording medium M on which a pretreatment agent application area PC is formed by pretreatment agent PCA having an aggregating agent concentration AG2. . The dot Dt-2 has a constant distribution density of the pigment particles P regardless of the position within the dot. Incidentally, as shown in FIGS. 3A and 3B, the dot Dt-1 is larger than the dot Dt-2. In other words, the size of dot Dt-2 is smaller than that of dot Dt-1.

The coagulant concentration AGC in the pretreatment agent application region PC is a factor that changes the speed at which the droplet LD spreads on the recording medium M. For example, the contact angle of the droplet LD with respect to the recording medium M, the coagulant It affects the speed at which AG diffuses into the solvent L of the droplet LD. Therefore, the difference in the uniformity of the distribution concentration of the pigment particles P is due to the difference in the coagulant concentration AGC in the pretreatment agent application region PC.

Since the contact angle of the droplet LD when it contacts the recording medium M changes depending on the coagulant concentration AGC, the contact area between the droplet LD and the recording medium M also changes. At this time, as an example showing the difference in the speed at which the droplet LD spreads on the recording medium M, that is, the behavior of the droplet LD on the recording medium M, the size of the contact angle of the droplet LD on the surface of the recording medium M determines the recording. The wettability, which is an index indicating the degree of adhesion of the droplet LD to the medium M, can be evaluated.

At this time, the smaller the contact angle of the droplet LD with respect to the recording medium M, the better the wettability. Therefore, the better the wettability, the larger the contact area between the droplet LD and the recording medium M, and the faster the wetting and spreading of the droplet LD on the recording medium M. Therefore, the size of the dot Dt formed on the recording medium M also increases. growing.

On the other hand, the poorer the wettability, the smaller the contact area between the droplet LD and the recording medium M, the slower the wetting and spreading of the droplet LD on the recording medium M, and the size of the dot Dt formed on the recording medium M. becomes smaller.

As described above, when the aggregating agent concentration AGC in the pretreatment agent application region PC is different, the degree of aggregation of the pigment particles P in the droplets LD is also different, so the behavior of the droplets LD with respect to the recording medium M changes. do. Therefore, the uniformity of distribution density of the pigment particles P in the dots Dt formed by the liquid droplets LD varies depending on the coagulant concentration AGC in the pretreatment agent application region PC. Such a phenomenon changes depending on the combination of the properties of the material contained in the droplets LD and the properties of the material contained in the pretreatment agent application area PC.

Even if the size of the adhering droplets LD changes, the uniformity of the distribution concentration of the pigment particles P in the dots Dt is said to vary depending on the coagulant concentration AGC in the pretreatment agent application region PC. Relationships are maintained.

Due to the difference in the distribution concentration of the pigment particles P in the dots Dt caused by the change in the behavior of the droplets LD, the quality of the image formed on the recording medium M by ejecting the droplets LD is degraded. Sometimes. For example, when an image including characters and thin lines is formed on the recording medium M, if the size of the dots Dt is large and the distribution density of the pigment particles P in the dots Dt is not constant, the image formed on the recording medium M will be characters and lines may be blurred.

On the other hand, when an image including a photograph or the like is formed on the recording medium M, if the size of the dots Dt is small and the distribution density of the pigment particles P in the dots Dt is constant, the image formed on the recording medium M There is a possibility that the grainy feeling of the For example, if characters or fine lines are blurred, or graininess is conspicuous in an image including a photograph, the quality of the formed image is lowered.

Therefore, in the present invention, the behavior of the droplets LD attached to the recording medium M is controlled. At this time, pretreatment of the recording medium M for controlling the behavior of the droplets LD is performed based on the type of image to be image-formed and output. In other words, the behavior of the droplets LD with respect to the recording medium M is controlled by controlling the execution mode of the preprocessing based on the type of image to be output. It is the gist of the present invention that this makes it possible to execute image formation output with higher quality.

The type of image is, for example, text or a photograph. The type of image may include a type such as a table. Further, in the present invention, for example, changing the amount of the pretreatment agent to be ejected onto the recording medium M, changing the pretreatment agent to be ejected onto the recording medium M to a pretreatment agent having a different coagulant concentration ACG, It is assumed that the execution mode of preprocessing is controlled. A specific control method will be described later.

Embodiment 1.
In the present embodiment, a line head type inkjet apparatus that conveys a recording medium and performs image formation output by droplets ejected from a fixed ejection head will be described as an example.

FIG. 4 is a diagram showing an outline of the inkjet system 4 according to this embodiment. As shown in FIG. 4, the inkjet system 4 according to the present embodiment includes a DFE (Digital Front End) 1, an inkjet device 2, a pretreatment device 3, and a roll paper Md, which is a recording medium M, arranged along the transport direction Xm. It is equipped with a carrying-in section 17, a drying section 30 and a carrying-out section 60 which are arranged.

The DFE 1 transmits command information to each unit that configures the inkjet system 4 to control the operation of each unit to perform image formation output. Therefore, the DFE 1 functions as an image formation output control device. Also, the DFE 1 executes RIP (Raster Image Processor) processing based on the information of the image to be output by image formation to generate raster data.

The DFE 1 causes the inkjet device 2 and the preprocessing device 3 to perform image formation output using raster data, bitmap data input to the DFE 1, and the like. Therefore, the bitmap data input to the DFE 1 and the raster data generated by the DFE 1 correspond to drawing information referred to by the inkjet device 2 and the preprocessing device 3 when executing image formation output. This drawing information is a part of the image forming information that controls the operation of the preprocessing device 3 and the operation of the inkjet device 2, as will be described later.

The inkjet device 2 includes four colorant ejection heads 21K, 21C, 21M, and 21Y (hereinafter referred to as "colorant ejection heads 21") of black (K), cyan (C), magenta (M), and yellow (Y). ). In the following description, symbols in parentheses are used to indicate colors of droplets LD ejected from the coloring agent ejection head 21. FIG.

Further, in the present embodiment, it is assumed that colored liquid droplets such as ink containing pigment particles P as a coloring agent are ejected from the inkjet device 2 . Therefore, the coloring agent ejection head 21 functions as a droplet ejection section.

The pretreatment device 3 is a liquid droplet ejecting device including pretreatment agent ejection heads 31H and 31L that eject an aggregating agent AG having a property of changing the dispersed state of the pigment particles P. As shown in FIG. The pretreatment agent ejection head 31H is an ejection head that ejects the pretreatment agent AGH as droplets LD (first treatment droplets) having a high concentration of the aggregating agent AG, and functions as a first droplet ejection section. Also, the pretreatment agent ejection heads 31 including the pretreatment agent ejection heads 31H and 31L function as a pretreatment execution unit.

The pretreatment agent ejection head 31L is an ejection head that ejects the pretreatment agent AGL as droplets LD (second treatment droplets) having a low concentration of the aggregating agent AG, and functions as a second droplet ejection section. The pretreatment agent ejection heads 31H and 31L function as treatment droplet ejection units that eject the pretreatment agent AGL as treatment droplets.

In this embodiment, the recording medium M is a roll of continuous paper (hereinafter referred to as “roll paper Md”). As the continuous paper, instead of being wound in a roll, continuous paper such as continuous form or continuous form having perforations formed at predetermined intervals may be used. Also, the recording medium M may be cut paper cut into a predetermined size. Furthermore, it may be a film instead of paper.

The carry-in section 17 has a paper feed section 18 and a plurality of carry-in side transport rollers 19 , and uses the carry-in side transport rollers 19 to carry the roll paper Md in the paper feed section 18 into the preprocessing device 3 . The pretreatment device 3 discharges droplets LD containing the aggregating agent AG onto the roll paper Md transported from the carry-in unit 17 to form the pretreatment agent application area PC on the surface of the roll paper Md.

The inkjet device 2 forms an image on the surface of the roll paper Md by ejecting droplets containing a pigment or dye as a coloring agent onto the roll paper Md on which the pretreatment agent application area PC is formed. The drying section 30 dries the roll paper Md on which the image is formed, for example, by heating. The unloading unit 60 unloads the roll paper Md on which the image is formed, and winds the roll paper Md on which the image is formed around the storage unit 61 using the unloading-side transport rollers 62 .

When the roll paper Md is wrapped around the storage roll of the storage unit 61, if the pressure acting on the roll paper Md increases, the storage A drying mechanism may be provided to dry the roll paper Md immediately before it is wound by the unit 61 .

As described above, the inkjet system 4 according to the present embodiment transports the roll paper Md to the pretreatment device 3 and the inkjet device 2 by the carry-in unit 17 to form an image on the surface of the roll paper Md. Then, the roll paper Md on which the image is formed is dried by the drying section 30 and wound up by the discharge section 60 so that it can be discharged to the outside of the inkjet system 4 .

Next, with reference to FIG. 5, the configuration of the ejection head for ejecting droplets LD according to this embodiment will be described. As shown in FIG. 5, the inkjet system 4 includes pretreatment agent ejection heads 31H and 31L and colorant ejection heads 21K, 21C, 21M and 21Y. Pretreatment agent ejection heads 31H and 31L are arranged upstream in the transport direction Xm of the roll paper Md, and coloring agent ejection heads 21K, 21C, 21M and 21Y are arranged downstream of the pretreatment agent ejection heads 31H and 31L. ing.

That is, the inkjet system 4 conveys the roll paper Md, which is a type of medium on which an image is to be formed, while adhering a processing agent to the upstream side of the conveyance direction Xm in order to preprocess the image formation position. Let A region of the roll paper Md to which the processing agent is applied is defined as a processing region, and a coloring agent is adhered to the processing region to form an image.

In this embodiment, the order of arrangement of K, C, M, and Y is exemplified as the configuration of the ejection head, but the order is not limited to this. , K. Also, the combination of colors is not limited to K, C, M, and Y, and may be three colors such as green (G), red (R), and light cyan (LC). Also, the combination of colors may be black (K) alone rather than as a combination.

The coloring agent ejection head 21K includes a first head 21K-1, a second head 21K-2, a third head 21K-3, and a fourth head 21K-4. They are arranged in a staggered manner in a direction orthogonal to the Md transport direction Xm.

In the inkjet device 2, an image is formed on the recording medium M by arranging the first head 21K-1, the second head 21K-2, the third head 21K-3, and the fourth head 21K-4 in a zigzag pattern. Image formation can be performed in the width direction of the area to be covered, that is, in the area in the direction orthogonal to the transport direction Xm of the roll paper Md.

Note that the K, C, M, and Y colorant ejection heads 21 and the pretreatment agent ejection heads 31H and 31L have the same configuration as the black (K) colorant ejection head 21K. , overlapping explanations will be omitted.

FIG. 6 is a cross-sectional view showing a schematic configuration of the coloring agent ejection head 21K. The colorant ejection head 21K has a channel plate 41, a vibration plate 42, a nozzle plate 43, a frame member 44, and a pressure generating portion 45. As shown in FIG. The flow path plate 41 forms a path for ejected droplets LD. The channel plate 41 is made of, for example, a single crystal silicon substrate with a crystal plane orientation of (110).

The channel plate 41 is anisotropically etched with an alkaline etchant such as a potassium hydroxide (KOH) aqueous solution to form the nozzle communication paths 40R and the liquid chambers 40F. Note that the material that can be used for the channel plate 41 is not limited to the single crystal silicon substrate. For example, stainless steel, photosensitive resin, and other materials may be used as the material of the channel plate 41 .

The diaphragm 42 is made of, for example, a metal plate processed by nickel electroforming (for example, electroforming method, electroforming method, etc.). The vibration plate 42 may be a metal plate other than nickel, or a joining member between a metal and a resin plate. The vibration plate 42 is joined to the lower surface of the channel plate 41, that is, inwardly of the colorant ejection head 21K. The vibration plate 42 is deformed by the force applied by the pressure generator 45 .

The nozzle plate 43 is made of, for example, a single crystal silicon substrate. The nozzle plate 43 is processed by anisotropic etching in the same manner as the channel plate 41 . The nozzle plate 43 may have a configuration in which a water-repellent layer is formed on the external surface formed of a metal member via a required layer. The nozzle plate 43 is joined to the upper surface of the channel plate 41, that is, to the outside of the colorant ejection head 21K.

Further, the nozzle plate 43 has a plurality of nozzles 40N for ejecting droplets LD. Specifically, a nozzle 40N having a diameter of 10 to 30 μm is formed in the nozzle plate 43 corresponding to each liquid chamber 40F.

The frame member 44 is made of thermosetting resin such as epoxy resin or polyphenylene sulfite (PPS). In addition, a resin having similar properties may be used as the material of the frame member 44 . The frame member 44 is provided with an accommodation portion 44I for accommodating the pressure generating portion 45, a concave portion serving as the common liquid chamber 40CR, and an ink supply port 40IN for supplying ink from the outside of the ejection head to the common liquid chamber 40CR. It is A frame member 44 holds the peripheral portion of the diaphragm 42 .

The pressure generating section 45 has a piezoelectric element 45P, a base substrate 45B for bonding and fixing the piezoelectric element 45P, and a column portion arranged between the adjacent piezoelectric elements 45P. In addition, an FPC (Flexible Printed Circuits) cable 45C that connects the piezoelectric element 45P to the driving circuit is connected to the pressure generating section 45. As shown in FIG.

As the piezoelectric element 45P, for example, a laminated piezoelectric element (PZT) in which piezoelectric materials and internal electrodes are alternately laminated is used. The internal electrodes have a plurality of individual electrodes and a plurality of common electrodes, and the individual electrodes or the common electrodes are alternately connected to the end face of the piezoelectric element 45P.

The piezoelectric direction of the piezoelectric element 45P is, for example, the direction in which the crystal of the piezoelectric element 45P elongates when an electric field is applied parallel to the polarization direction (hereinafter referred to as "d33 mode"). The pressure generator 45 pressurizes or depressurizes the ink in the liquid chamber 40F using the piezoelectric effect in the d33 mode of the piezoelectric element 45P.

The piezoelectric direction of the piezoelectric element 45P is such that the ink in the liquid chamber 40F is applied to the d31 mode, which is the direction in which the crystal shortens when an electric field is applied to the crystal of the piezoelectric element 45P parallel to the polarization direction. It may be pressurized or depressurized. Further, the pressure generating section 45 may arrange one row of piezoelectric elements for one nozzle 40N, which is an ink ejection port.

In addition, the column portion may be formed simultaneously with the piezoelectric element 45P by dividing the piezoelectric element 45P, which is a piezoelectric element member. In other words, the ejection head 40K may be used as a column part having the piezoelectric element 45P to which no voltage is applied as a member. Note that the K, C, M, and Y colorant ejection heads 21 and the pretreatment agent ejection heads 31H and 31L have the same configuration as the black (K) colorant ejection head 21K. , overlapping explanations will be omitted.

Next, a specific description will be given of the pulling or pushing operation in which the colorant ejection head 21K ejects droplets LD from the nozzles 40N. FIG. 7 is a diagram showing an operation mode of the inkjet system 4 according to this embodiment.

As shown in FIG. 7, the DFE 1 according to the present embodiment instructs and controls the operations of the respective units that make up the inkjet system 4 . Then, the pretreatment device 3 executes a pretreatment of ejecting the pretreatment agent PCA onto the roll paper Md. In addition, the inkjet device 2 forms an image by ejecting droplets LD containing a coloring agent onto the pretreated roll paper Md. The DFE 1 and the inkjet device 2, and the DFE 1 and the preprocessing device 3 are communicably connected by signal lines 70LC and 71LC, respectively.

The print control unit 20Cc shown in FIG. 7 lowers the voltage applied to the piezoelectric element 45P from the reference potential, and shrinks the piezoelectric element 45P in the stacking direction, thereby bending and deforming the diaphragm 42. FIG. The flexural deformation of the vibration plate 42 increases the volume of the liquid chamber 40F. As a result, the droplet LD flows from the common liquid chamber 40CR into the liquid chamber 40F.

Next, the print control unit 20Cc increases the voltage applied to the piezoelectric element 45P to expand the piezoelectric element 45P in the stacking direction, thereby deforming the vibration plate 42 in the direction of the nozzle 40N. Then, the deformation of the vibration plate 42 reduces the volume of the liquid chamber 40F. As a result, pressure is applied to the droplets LD in the liquid chamber 40F, and the droplets LD are ejected from the nozzle 40N.

After that, the print control unit 20Cc restores the voltage applied to the piezoelectric element 45P to the reference potential, and restores the diaphragm 42 to the position before the reference voltage is lowered, that is, the initial position. In the coloring agent ejection head 21K, the pressure in the liquid chamber 40F is reduced by the expansion of the liquid chamber 40F, and the liquid chamber 40F is filled with droplets LD from the common liquid chamber 40CR. Next, the vibration of the meniscus of the nozzle 40N is attenuated, and then the next droplet LD is ejected. In this way, the operation of ejecting droplets LD is repeated.

The driving method of the coloring agent ejection head 21K is not limited to pull-on or push-on, and by controlling the voltage applied to the piezoelectric element 45P (hereinafter referred to as "driving waveform"). You can hit, etc. Note that the ejection heads of the coloring agent ejection heads 21 for the respective colors of K, C, M, and Y have the same configuration as the coloring agent ejection head 21K for black (K), and redundant description will be omitted.

As for the pretreatment agent ejection heads 31H and 31L, the pretreatment controller 30Cc shown in FIG. Execute the process.

It should be noted that the pressure generating section 45 in this embodiment is not limited to the piezoelectric element 45P, and for example, a known technology such as a thermal type or an electrostatic type can be employed. The thermal type is a method of generating air bubbles by heating droplets LD in the liquid chamber 40F using a heating resistor. The electrostatic type is a method in which a diaphragm and an electrode are placed facing each other on the wall surface of the liquid chamber 40F, and the diaphragm is deformed by generating an electrostatic force between the diaphragm and the electrode.

The ink jet system 4 according to the present embodiment uses the coloring agent ejection heads 21K, 21C, 21M, 21Y and the pretreatment agent ejection heads 31H, 31L as described above, and the width direction of the area on which the image is formed on the roll paper Md. Full-color images or monochrome images can be formed over the entire area.

Next, the hardware configuration of the DFE 1 according to this embodiment will be described. As shown in FIG. 8 , the DFE 1 has a CPU (Central Processing Unit) 11 , a ROM (Read Only Memory) 12 and a RAM (Random Access Memory) 13 . DFE 1 further has HDD (hard disk drive) 14 and I/F 15 . Devices such as the CPU 11 that configure the DFE 1 are interconnected by a bus 16 .

The CPU 11 controls the operation of the DFE 1 as a whole. The CPU 11 loads a program stored in the ROM 12 or HDD 14 into the RAM 13 and executes it to control the operation of the DFE 1 . A control program for controlling the CPU 11 is stored in the ROM 12 and the HDD 14 . The RAM 13 is used as a work area for developing programs or intermediate data to be operated by the CPU 11 .

The I/F 15 is used for communication between the DFE 1 and an external device such as a host device, and performs communication corresponding to a protocol such as TCP/IP (Transmission Control Protocol/Internet Protocol).

Further, the I/F 15 may be configured to perform communication by, for example, PCI Express (Peripheral Component Interconnect Bus Express), ISA (Industry Standard Architecture), or the like. Also, the I/F 15 may be configured to have a plurality of channels corresponding to each color of the print image data.

The DFE 1 receives print job data transmitted from an external device such as a host device under the control of the CPU 11 via the I/F 15 and stores the data in the HDD 14 . The DFE 1 generates raster data, which is image information such as bitmap data corresponding to each color of CMYK, based on job data received from a host device such as a PC (Personal Computer). (referred to as “print output data”) to the inkjet device 2 . The inkjet device 2 ejects droplets LD onto the roll paper Md based on the print output data.

Also, the DFE 1 generates data for controlling the printing operation (hereinafter referred to as "control information data") based on the print job data and information input from the host device. The control information data includes print form, print type, paper feed/discharge information, print surface order, print paper size, data size of print image data, resolution, paper type information, gradation, color information, and information on the number of pages to be printed. including data related to printing conditions such as

Further, the control information data may include data relating to ejection of the post-treatment liquid ejected by the post-treatment device. Print output data is transmitted from the DFE 1 to the inkjet device 2 and the preprocessing device 3, respectively.

Further, in the present embodiment, as an example, the DFE 1 analyzes raster data, and based on the analysis result, outputs data (hereinafter referred to as "preprocessing output data") relating to ejection of droplets LD ejected by the preprocessing device 3. ) to the preprocessing device 3 .

FIG. 9 is a block diagram showing the functional configurations of the inkjet device 2 and the pretreatment device 3 according to this embodiment. The inkjet device 2 controls the operation of forming an image on the roll paper Md based on the print output data and control information data input from the DFE 1 . The inkjet device 2 includes a printer controller 20C and a printer engine 20E.

The printer controller 20C includes a CPU 20Cp and a print control section 20Cc, and the CPU 20Cp and the print control section 20Cc are connected by a bus 20Cb so as to be able to transmit and receive. The bus 20Cb is connected to the signal line 70LC via a communication I/F. The CPU 20Cp controls the overall operation of the inkjet device 2 using control programs stored in the ROM.

The print control unit 20Cc transmits/receives information such as commands, parameters, or data to/from the printer engine 20E based on the control information data transmitted from the DFE1. The print control unit 20Cc controls the printer engine 20E by transmitting and receiving information to and from the printer engine 20E.

The printer controller 20C controls the printer engine 20E. The printer controller 20C transmits and receives control information data and the like to and from the DFE 1 via the signal line 20LC. The printer controller 20C transmits and receives control information data and the like to and from a printer engine 20E, which will be described later, via a signal line 20LC.

The printer controller 20C writes the printing conditions and the like included in the transmitted/received control information data to the register of the printing control unit 20Cc, and stores the printing conditions in the register. The printer controller 20C controls the printer engine 20E based on the control information data to execute printing according to the print job data and the control information data.

The printer engine 20E has ejection control units 20EiC, 20EiM, 20EiY, and 20EiK. The ejection control units 20EiC, 20EiM, 20EiY, and 20EiK cause the colorant ejection heads 21C, 21M, 21Y, and 21K to eject droplets LD onto the roll paper Md based on the print output data transmitted from the print control unit 20Cc. , performs an imaging output to form an image.

The printer engine 20E converts bitmap data input from the DFE 1 to the inkjet device 2 into data corresponding to image formation output based on instructions from the printer controller 20C, and outputs the colorant ejection head 21C and the colorant ejection head. 21M, coloring agent ejection head 21Y, and coloring agent ejection head 21K.

For example, the printer engine 20E converts the input 256-bit bitmap data into 4 values of large droplet, medium droplet, small droplet, and no ejection, and the corresponding colorant ejection head 21C, colorant ejection head 21M, and colorant ejection head 21M. The data is divided into data for each of the agent ejection head 21Y and the colorant ejection head 21K.

Based on the preprocessing output data and control information data input from the DFE 1, the preprocessing device 3 ejects droplets LD onto the roll paper Md to form a preprocessed area. Control. The pretreatment device 3 includes a precoat controller 30C and a precoat engine 30E.

The precoat controller 30C according to this embodiment includes a CPU 30Cp and a pretreatment control section 30Cc, and the CPU 30Cp and the pretreatment control section 30Cc are connected via a bus 30Cb so as to be able to transmit and receive. The bus 30Cb is connected to the signal line 71LC via a communication I/F. The CPU 30Cp controls the operation of the entire preprocessing device 3 using control programs stored in the ROM.

The preprocessing control unit 30Cc transmits/receives information such as commands, parameters, or data to/from the precoat engine 30E based on the control information data transmitted from the DFE1. The preprocessing control unit 30Cc controls the precoat engine 30E by transmitting and receiving information to and from the precoat engine 30E.

Precoat controller 30C controls precoat engine 30E. The precoat controller 30C transmits and receives preprocessing execution data and the like to and from the DFE 1 via the signal line 30LC. The precoat controller 30C transmits and receives pretreatment execution data and the like to and from a precoat engine 30E, which will be described later, via a signal line 30LC.

The precoat controller 30C writes the printing conditions and the like included in the transmitted/received control information data to the registers of the preprocessing control section 30Cc, and stores the printing conditions in the registers. The precoat controller 30C controls the precoat engine 30E based on the control information data, and causes the pretreatment execution section to execute pretreatment according to the pretreatment execution data. The preprocessing execution data will be described later.

The precoat engine 30E has pretreatment agent discharge control units 30Eph and 30Epl. The precoat engine 30E converts the bitmap data input from the DFE 1 to the pretreatment device 3 into small value data corresponding to the image formation output based on the instruction from the precoat controller 30C, and the pretreatment agent discharge control section The data is divided into 30 Eph and 30 Epl data.

For example, the precoat engine 30E converts the input 256-bit bitmap data into four values of large droplet, medium droplet, small droplet, and no ejection, and converts it into data for each of the corresponding pretreatment agent ejection control units 30Eph and 30Epl. To divide. The pretreatment agent ejection control units 30Eph and 30Epl respectively cause the pretreatment agent ejection heads 31H and 31L to eject droplets LD onto the roll paper Md based on the pretreatment output data transmitted from the pretreatment control unit 30Cc, A pretreatment agent application area PC is formed on the roll paper Md. If the pretreatment agent ejection heads 31H and 31L do not eject a plurality of types of droplets such as large droplets, medium droplets, and small droplets, the configuration may be such that conversion to four values is not performed.

As described above, in the inkjet system 4 according to the present embodiment, the inkjet device 2 ejects droplets onto the roll paper Md preprocessed by the preprocessing device 3 based on the drawing information input from the DFE 1. The image forming output is executed by Next, the functional configuration of the DFE 1 according to this embodiment will be described with reference to FIG.

As shown in FIG. 10, the DFE 1 includes a controller 100, an input/output device 104, and a network I/F . The input/output device 104 is an output interface that visually displays the state of the DFE 1 and is also an input interface as a touch panel for the user to directly operate the DFE 1 or to input information to the DFE 1 .

That is, the input/output device 104 has a function of displaying an image for receiving an operation by the user. The input/output device 104 is implemented by a display device and an operation device connected to the I/F 15 .

A network I/F 108 is an interface for the DFE 1 to communicate with other devices such as a host terminal via a network, and uses an Ethernet (registered trademark) or USB (Universal Serial Bus) interface. A network I/F 108 is capable of communication using the TCP/IP protocol. Network I/F 108 is implemented by I/F 15 .

The controller 100 includes a main control section 110, an engine control section 120, an image processing section 130, an operation display control section 140 and an input/output control section 150, and is configured by a combination of hardware and software shown in FIG. Specifically, programs stored in the ROM 12, nonvolatile memory, and nonvolatile storage media such as the HDD 14 and optical discs are loaded into a volatile memory (hereinafter referred to as memory) such as the RAM 13. FIG.

The CPU 11 performs calculations according to programs loaded in the RAM 13 or the like. The controller 100 is configured by a software control unit configured by a series of these cooperation and hardware such as an integrated circuit. A controller 100 functions as a control unit that controls the entire DFE 1 .

The printer controller 20C is composed of a software control unit configured by the CPU 20Cp performing calculations according to a program loaded in a volatile memory such as a RAM, and hardware such as an integrated circuit. Similarly, the precoat controller 30C is also composed of a software control unit configured by performing calculations according to a program loaded in a volatile memory such as a RAM by the CPU 30Cp, and hardware such as an integrated circuit.

The main control unit 110 plays a role of controlling each unit included in the controller 100 and gives commands to each unit of the controller 100 . The engine control unit 120 serves as a transmission control unit that outputs signals to the inkjet device 2, the pretreatment device 3, the loading unit 17, and the unloading unit 60, or as a driving unit that drives them. Under the control of the main control unit 110, the image processing unit 130 generates drawing information such as bitmap data based on the information of the image to be printed out. The drawing information is information for drawing an image to be formed in the image forming operation by the inkjet device 2 or the preprocessing device 3, that is, an image to be output for image formation.

The operation display control unit 140 displays information on the input/output device 104 or notifies the main control unit 110 of information input via the input/output device 104 . The input/output control unit 150 inputs information input via the network I/F 108 to the main control unit 110 . The main control unit 110 also controls the input/output control unit 150 to access other devices connected to the network via the network I/F 108 and the network.

As processing executed by the DFE 1 , first, the input/output control unit 150 receives a print job, which is command information for executing image formation output, from a host device or the like via the network I/F 108 . The input/output control unit 150 transfers the received print job to the main control unit 110 . Upon receiving a print job, the main control unit 110 controls the image processing unit 130 to generate drawing information based on document information or image information included in the print job.

In the print job according to the present embodiment, the image information to be output is described in an information format that can be analyzed by the image processing unit 130 of the DFE 1, and parameter information to be set for image formation output. included. The parameter information is, for example, double-sided printing setting, aggregate printing setting, color/monochrome setting, and the like.

When the drawing information is generated by the image processing unit 130, the engine control unit 120 transmits the print output data and the preprocessing output data to the inkjet device 2 and the preprocessing device 3, respectively, and based on the generated drawing information, An image is formed on the paper conveyed from the paper feed table 105 .

As described above, in this embodiment, the main control section 110 controls each section included in the controller 100 . Next, with reference to FIG. 11, the functional configuration of the main control unit 110 according to this embodiment will be described.

A main control unit 110 according to the present embodiment includes a characteristic information storage unit 111, a drawing information analysis unit 112, and a pretreatment agent ejection information generation unit 113, and functions as a pretreatment execution control unit. The property information storage unit 111 includes a medium property information storage unit 114 , a pretreatment agent property information storage unit 115 , and a colorant property information storage unit 116 . Note that the characteristic information data table SD may be stored in the characteristic information storage unit 111 .

In this embodiment, the pretreatment agent ejection information generation unit 113 supplies a predetermined amount of information to each of the pretreatment agent ejection head 31L and the pretreatment agent ejection head 31H, which will be described later, for each pixel that can be ejected by each head. Data may be generated in which 0 and 1 are arranged to indicate whether or not to eject the ink.

Alternatively, data may be generated in which the ejection amount is set for each pixel instead of whether or not ejection is performed. At this time, by combining the ejection amount of the pretreatment agent with a high coagulant concentration ACG and the ejection amount of the pretreatment agent with a low coagulant concentration ACG, the behavior of the ejected droplets LD is controlled for each pixel. Pretreatment can be performed. Also, the ejection amount may be set in units of regions larger than pixels. In the following description, the generation of ejection information includes both information indicating whether or not to eject the pretreatment agent and information setting the ejection amount of the pretreatment agent. do.

As shown in FIG. 12, the characteristic information data table SD shows the distribution of the pigment particles P in the dots Dt formed by the droplets LD adhering to the recording medium M (for example, from the center to the outer periphery of the dots Dt). The relationship between the density uniformity of the pigment particles P, etc.) and the size of the dots Dt is shown as characteristic information for each combination of the type of ink IK and the type of pretreatment agent PCA. Note that the characteristic information data table SD is configured for each type of recording medium M. FIG.

As shown in FIG. 12, for example, when droplets LD containing the coloring agent A and droplets LD containing the pretreatment agent a are used on the recording medium M1, the distribution concentration of the pigment particles P in the dot Dt and the dot Regarding the relationship with the size of Dt, the higher the concentration of the aggregating agent AG contained in the pretreatment agent a, the larger the size of the dots Dt. Less uniformity.

Further, for example, when droplets LD containing the coloring agent B and droplets LD containing the pretreatment agent d are used in the recording medium M1, the difference between the distribution concentration of the pigment particles P in the dots Dt and the size of the dots Dt is The relationship is that the higher the concentration of the aggregating agent AG contained in the pretreatment agent d, the smaller the size of the dots Dt, but the higher the density uniformity of the distribution of the pigment particles P from the center to the periphery of the dots Dt.

That is, by referring to the characteristic information data table SD, it is possible to control the distribution of the pigment particles P in the dots Dt and the size of the dots Dt. In other words, by using the characteristic information data table SD, it is possible to control the behavior of the droplets LD containing the colorant, which is the image forming agent.

In this way, the characteristic information data table SD includes, as characteristic information, the relationship between the distribution density of the pigment particles P in the dots Dt and the size of the dots Dt for each combination of the type of ink IK and the type of pretreatment agent PCA. .

Further, the characteristic information data table SD contains information indicating the relationship between the distribution of the pigment particles P in the dots Dt and the size of the dots Dt for each combination of the type of ink IK and the type of pretreatment agent PCA. It may be configured by input as a result, or may be configured by characteristic information obtained as a result of experiment or simulation. Details of the characteristic information data table SD will be described later.

Note that the characteristic information storage unit 111 does not include the characteristic information data table when the type of recording medium M (eg, plain paper, coated paper, film, etc.) and the type of ink IK have limited effects. It may be a configuration. In the present embodiment, as will be described later, it is sufficient to have information indicating the type of image formed and output, and information indicating the coagulant concentration ACG contained in the droplets LD of the ink IK.

The medium characteristic information storage unit 114 stores medium characteristic information, which is information on physical characteristics of the recording medium M. FIG. Here, the medium characteristic information is information indicating whether the recording medium M is a non-permeable medium or a permeable medium, and is information indicating the degree of penetration of the droplets LD into the recording medium M. be. Films are known as impermeable media, and plain paper and coated paper are known as permeable media.

A difference in the degree of penetration of the droplets LD into the recording medium M will be described with reference to FIG. First, when the pretreatment agent PCA is ejected onto the recording medium M, which is an impermeable medium, the pretreatment agent application area PC is formed on the surface of the recording medium M as shown in FIG. 13(a). . On the other hand, when the pretreatment agent PCA is ejected onto the recording medium M, which is a permeable medium, the pretreatment agent application area PC is formed on the surface of the recording medium M and on the surface of the recording medium M as shown in FIG. 13(b). Formed throughout the tissue.

The pretreatment agent characteristic information storage unit 115 stores pretreatment agent characteristics, which are information on the characteristics of the pretreatment agent PCA1 ejected from the pretreatment agent ejection head 31H and the pretreatment agent PCA2 ejected from the pretreatment agent ejection head 31L. information is stored. The pretreatment agent property information is, for example, information indicating the material and physical properties of the pretreatment agent PCA.

The colorant property information storage unit 116 stores colorant property information, which is information on the property of each ink of YMCK ejected from the colorant ejection head 21 . The colorant property information is, for example, information indicating materials and physical properties of colorants for coloring each color of YMCK.

Note that the main control unit 110 may be configured to refer to the pretreatment agent property information and the coloring agent property information based on the execution result of the image formation output, and add the property information to the property information data table SD. . At this time, for example, image formation output is performed by a combination of the coloring agent B and the pretreatment agent c. As the concentration of the pretreatment agent c increases, the size of the dot Dt becomes smaller, but the distribution of the coloring agent does not change. In this case, the main control unit 110 adds characteristic information as shown in (c) of FIG. 12 to the characteristic information data table SD.

The drawing information analysis unit 112 analyzes the drawing information input from the image processing unit 130 to the main control unit 110 . The drawing information analysis unit 112 may function as an image type determination unit that determines the type of image based on the analysis result. Further, since the analysis result varies depending on the type of image to be formed and output, the drawing information analysis unit 112 sends the analysis result to the pretreatment agent ejection information generation unit 113 without determining the type of image based on the drawing information. may be configured to output.

Hereinafter, a configuration will be described as an example in which the drawing information analysis unit 112 outputs an analysis result that changes according to the type of image to the pretreatment agent ejection information generation unit 113 without determining the type of the image to be formed and output. do. An example of a configuration in which the drawing information analysis unit 112 determines the type of image to be formed and output will be described later.

Also, the drawing information analysis unit 112 may output the type and amount of ink consumed for each pixel as an analysis result. Further, the drawing information analysis unit 112 may analyze the drawing information and output the output form of the image formed and output as the analysis result.

The pretreatment agent ejection information generation unit 113 extracts data from the pretreatment agent ejection heads 31H and 31L based on the analysis result of the drawing information by the drawing information analysis unit 112 and various characteristic information stored in the characteristic information storage unit 111, respectively. It functions as a processing liquid droplet ejection information generation section, a first liquid droplet ejection information generation section, and a second liquid droplet ejection information generation section that generate ejection information of the pretreatment agent to be ejected.

The drawing information analysis unit 112 calculates the spatial frequency based on the drawing information as an analysis method. For example, the drawing information is divided into regions of a predetermined size, and the spatial frequency is calculated by two-dimensional Fourier transforming the drawing information for each divided region. Then, the calculated spatial frequency is transmitted to the pretreatment agent ejection information generation unit 113 . The drawing information analysis method is not limited to the two-dimensional Fourier transform. Also, the method of analyzing the drawing information is not limited to the calculation of the spatial frequency, as long as information that varies depending on the type of image can be obtained.

At this time, the pretreatment agent ejection information generation unit 113 reduces the size of the dots Dt and uniformizes the distribution density of the pigment particles P in the dots Dt, for example, in the image region where the spatial frequency is greater than a predetermined value. It is determined that the image is to be output at the same time, and the ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 is generated.

For example, the pretreatment agent ejection information generation unit 113 determines to output an image with medium size dots Dt for an image region having an intermediate spatial frequency, and pretreatment agent PCA1 and pretreatment agent PCA2. to generate ejection information.

For example, the pretreatment agent ejection information generation unit 113 increases the size of the dots Dt for an image region in which the spatial frequency is smaller than a predetermined value, and the distribution density of the pigment particles P in the dots Dt is set to the center of the dots Dt. It is determined that the image is to be output so that the image becomes darker, and the ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 is generated.

Note that in the inkjet system 4 according to the present embodiment, the area information for designating the area in which the size of the dots Dt is reduced and the image formation output is executed, or the size of the dots Dt is increased to output the image formation output. may be input to the main control unit 110.

In such a case, the drawing information analysis unit 112 outputs the area information as an analysis result, and the pretreatment agent ejection information generation unit 113 generates ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 based on the area information. It may be configured to

Specifically, based on the area information, the pretreatment agent ejection information generation unit 113 reduces the size of the dots Dt and reduces the size of the dots Dt for the areas where the image formation output is to be performed. It is determined to output an image by making the distribution density of the pigment particles P in Dt uniform, and ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 is generated.

On the other hand, in the area where the image formation output is performed by increasing the size of the dots Dt, the size of the dots Dt is increased and the distribution density of the pigment particles P in the dots Dt is set to be darker toward the center of the dots Dt. It is determined that the image is to be output at the same time, and the ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 is generated.

Furthermore, as shown in FIG. 15, the job data input from the DFE 100 includes position information indicating an area on the drawing information where a picture such as a photograph is drawn, and position information indicating an area on the drawing information where characters are drawn. May include location information. FIG. 15A is a diagram exemplifying information of an image to be output by image formation according to this embodiment, and FIG. 15B is a diagram exemplifying drawing information according to this embodiment.

As shown in FIG. 15A, the image information 8A includes line areas 81A1 and 81A2 in which characters and lines are displayed, and a photograph area 82A in which photographs are displayed. In FIG. 15(a), an area other than the line area 81A and the photograph area 82A is shown as an area 83A.

FIG. 15B shows drawing information 8B obtained by performing RIP processing on image information 8A. The drawing information 8B includes line areas 81B1 and 81B2 in which characters and lines are displayed, and a photograph area 82B in which photographs are expressed. In FIG. 15(b), the area other than the line area 81B and the photograph area 82B is shown as an area 83B.

In such a case, the drawing information analysis unit 112 stores image type information such as the line region 81B, the photograph region 82B, and the region 83B, and the coordinates indicating the respective regions of the line region 81B, the photograph region 82B, and the region 83B. Output location information as analysis results. The pretreatment agent ejection information generation unit 113 may be configured to generate ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 based on the position information.

Specifically, based on the position information, the pretreatment agent ejection information generation unit 113 reduces the size of the dots Dt and reduces the size of the pigment particles P in the dots Dt for the area on the drawing information where the characters are drawn. It is determined to output an image with a uniform distribution density, and ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 is generated.

On the other hand, in the drawing information area where a picture such as a photograph is drawn, the size of the dot Dt is increased and the distribution concentration of the pigment particles P in the dot Dt is increased toward the center of the dot Dt. is output, and ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 is generated.

When the drawing information analysis unit 112 determines the type of image to be formed and output based on the drawing information, the drawing information analysis unit 112 determines the type of image from, for example, the spatial frequency. The types of images are characters, photographs, tables, and the like. In this case, the drawing information analysis unit 112 outputs the determined image type and its position information as an analysis result.

For example, the user may input information such as characters and photographs for each area through a user interface such as the input/output device 400 . In such a case, the drawing information analysis unit 112 may determine the type of image based on the input text or photo information, and transmit the determination result to the pretreatment agent ejection information generation unit 113 .

Note that when the user inputs character and photo information for each region, the pretreatment agent ejection information generation unit 113 determines whether the pretreatment agent PCA1 or pretreatment agent PCA2 is selected based on the input character or photo information. Ejection information may be generated.

In this way, the ejection information of the pretreatment agent PCA1 and the pretreatment agent PCA2 calculated by the pretreatment agent ejection information generation unit 113 is transmitted by the main control unit 110 to the pretreatment device 3 via the engine control unit 120. be.

In the present embodiment, the pretreatment device 3 includes a pretreatment agent ejection head 31H for ejecting a pretreatment agent PCA1 having a high concentration of the coagulant AG and a pretreatment agent ejection head 31H for ejecting a pretreatment agent PCA2 having a low concentration of the coagulant AG. Includes head 31L. Then, the pretreatment device 3, as shown in FIG. 14, from the pretreatment agent ejection head 31H and the pretreatment agent ejection head 31L, pretreatment agent PCA1 having a high concentration of the coagulant AG with respect to the recording medium M. A pretreatment agent PCA2 having a low concentration of aggregating agent AG is discharged.

As shown in FIG. 13, a pretreatment agent application area PC1 is formed in the area where the pretreatment agent PCA1 is discharged, and a pretreatment agent application area PC2 is formed in the area where the pretreatment agent PCA2 is discharged. . Here, it is assumed that droplets LD of the combination of (a) in FIG. 12 are ejected onto the pretreatment agent coating region PC shown in FIG.

In the pretreatment agent application region PC1, since the aggregating agent AG has a high concentration, the distribution of the colorant A in the dots Dt is not uniform, and the dots Dt having a large size are formed. On the other hand, in the pretreatment agent application region PC2, since the concentration of the aggregating agent AG is low, dots Dt are formed in which the colorant A is uniformly distributed in the dots Dt and the size of the dots Dt is small. be.

As described above, in the inkjet system 4 according to the present embodiment, the droplets LD containing the colorant adhere to the recording medium M depending on the concentration of the aggregating agent AG in the pretreatment agent application area PC formed on the recording medium M. It controls the size of dots Dt, which are colored regions formed as a result, and the degree of distribution of the coloring agent in the dots Dt.

The pretreatment agent ejection information generation unit 113 causes the pretreatment agent ejection head 31H and the pretreatment agent ejection head 31L to eject the pretreatment agents PCA1 and PCA2 to the same area on the recording medium M, respectively. Alternatively, the ejection amount of the first treatment droplets and the ejection amount of the second treatment droplets, which are the ejection amounts of the pretreatment agents PCA1 and PCA2, may be calculated. At this time, the pretreatment device 3 discharges the pretreatment agent PCA1 and the pretreatment agent PCA2 to the same area to form the pretreatment agent coating area PC.

Next, the flow of processing for calculating the amount (ejection amount) of the pretreatment agent PCA to be ejected in the inkjet system 4 according to this embodiment will be described with reference to the flowchart of FIG. When the main control unit 110 receives the job data ( S<b>1601 ), it transfers the received job data to the image processing unit 130 .

Based on the job data, the image processing unit 130 sets the printing conditions specified in the job data for the image information, executes RIP (Raster Image Processing) processing, and generates a bitmap for executing image formation output. Rendering information such as data is generated (S1602).

At this time, in the job data, as setting information for setting printing conditions and generating drawing information, for example, medium setting information for setting the recording medium M and density of an image to be output by image formation are set. It includes density setting information, color setting information for setting whether to execute image formation output in color or monochrome, and mode setting information for setting when image formation output is to be performed precisely.

The image processing unit 130 transmits the drawing information and setting information generated by the RIP process to the main control unit 110 (S1603). Based on the received drawing information and setting information, the pretreatment agent ejection information generating unit 113 refers to the characteristic information storage unit 111 and acquires characteristic information of the recording medium M (S1604).

Next, the pretreatment agent ejection information generation unit 113 refers to the property information storage unit 111 to acquire pretreatment agent property information and coloring agent property information (S1605). At this time, the pretreatment agent ejection information generation unit 113 may acquire characteristic information from the characteristic information data table SD.

The drawing information analysis unit 112 also analyzes the drawing information based on the received drawing information and setting information, and transmits the analysis result to the pretreatment agent ejection information generation unit 113 (S1606). The pretreatment agent ejection information generation unit 113 calculates the ejection amounts of the pretreatment agents PCA1 and PCA2 for each pixel obtained from the analysis result based on the characteristic information acquired in S1604 and S1605 and the analysis result of the drawing information. (S1607).

In the process of S1607, the ejection amounts of the pretreatment agents PCA1 and PCA2 may be calculated by setting the ejection amount of either the pretreatment agent PCA1 or the pretreatment agent PCA2 to "0". Pretreatment agent amount information, which is information on the calculated ejection amounts of the pretreatment agents PCA1 and PCA2, is transmitted by the main control unit 110 to the pretreatment device 3 via the engine control unit 120 (S1608).

Next, in the inkjet system 4 according to the present embodiment, the flow of processing for forming and outputting an image will be described. After completing the processing shown in the flowchart of FIG. 16, the main control unit 110 transmits preprocessing execution information for causing the preprocessing device 3 to execute preprocessing.

Upon receiving the pretreatment execution information from the DFE1, the pretreatment apparatus 3 ejects the pretreatment agent PCA1 and the pretreatment agent PCA2 onto the recording medium M based on the pretreatment agent amount information received from the DFE1 in S1608. Perform preprocessing.

The main control unit 110 transmits image formation execution information to the inkjet device 2 . The inkjet device 2 performs coloring at the timing when the recording medium M pretreated by the pretreatment device 3 reaches the inkjet device 2 and reaches the respective ejection positions of the colorant ejection heads 21K, 21C, 21M, and 21Y. Colored droplets containing the agent are ejected onto the recording medium M.

The position measured by the measuring device 5A, the position where the pretreatment is performed by the pretreatment device 3, and the position where the coloring agent ejection head 21 ejects are managed as information indicating the transport position of the recording medium M, and the main control unit 110 An image is formed on the recording medium M by operating the measurement device 5A, the pretreatment device 3, and the coloring agent ejection head 21 synchronously according to an instruction from .

Therefore, the main controller 110 functions as a droplet ejection controller that causes the inkjet device 2 and the pretreatment device 3 to eject droplets. The main control unit 110 also includes a treatment droplet ejection execution control unit that ejects treatment droplets such as the pretreatment agent PCA to the pretreatment device 3 , and a coloring droplet ejection execution control unit that ejects colored droplets containing a coloring agent to the inkjet device 2 . It also functions as a droplet discharge execution control unit. The recording medium M on which the image has been formed is discharged from the conveying section 60 .

As described above, in the present embodiment, the amount of pretreatment is controlled based on the type of image to be recorded on the recording medium M, thereby controlling the state of the ejected droplets LD. controls the shape of the dots formed by the pigment particles P contained in . By doing so, it is possible to prevent the quality of the image formed on the recording medium M from deteriorating, and to perform high-quality image formation.

In the present embodiment, a pretreatment agent application area PC1 is formed in the area where the pretreatment agent PCA1 is discharged, and a pretreatment agent application area PC2 is formed in the area where the pretreatment agent PCA2 is discharged. However, the pretreatment agent application area PC may be formed by ejecting the pretreatment agent PCA1 and the pretreatment agent PCA2 onto the same area. By doing so, it is possible to more finely control the coagulant concentration AGC in the pretreatment agent application region PC.

Furthermore, in the present embodiment, an example of controlling the ejection of two types of pretreatment agents having different densities has been described. may be controlled. In this case, one set of the pretreatment agent ejection head 31 may be used.

In addition to pigment particles P, biomolecules such as dyes, proteins, lipids, nucleic acids, hormones, sugars, amino acids, etc., contained in the droplets LD ejected from the inkjet device 2 and the pretreatment device 3 onto the recording medium M. , a resin, a polymer, or the like may be used. In addition to the aggregating agent AG, a chelating agent, a fibrin-based adhesive, hydroxyapatite, a polymerizing agent, and the like may also be used as the reactive agent contained in the pretreatment agent PCA.

Furthermore, the inkjet system 4 according to this embodiment can also be applied to a three-dimensional modeling apparatus such as a 3D printer.

Embodiment 2.
In the present embodiment, a serial head type inkjet apparatus that conveys a recording medium and executes image formation output by droplets ejected from an ejection head that moves in the main scanning direction will be described as an example. In addition, the same reference numerals are assigned to the same configurations as those in the first embodiment, and overlapping descriptions are omitted.

FIG. 17 is a diagram showing an outline of the inkjet system 4 according to this embodiment. The inkjet system 4 is configured by connecting the DFE 1 and the image forming apparatus 5 via a communication line. The image forming apparatus 5 according to the present embodiment is constructed by integrating the inkjet device 2 and the pretreatment device 3 according to the first embodiment into one housing.

Next, the configuration of the image forming apparatus 5 according to the present embodiment will be described with reference to perspective views of the image forming apparatus 5 of FIGS. 18 and 19. FIG. The image forming apparatus 5 includes an inkjet device 2, a preprocessing device 3, and a carriage 101 that moves the inkjet device 2 and the preprocessing device 3 in the main scanning direction inside the apparatus body.

The carriage 101 is slidably disposed in the main scanning direction (perpendicular to the conveying direction) by a main guide rod 107 and a follower guide rod 107b, which are guide members that extend across left and right side plates. An inkjet device 2 and a pretreatment device 3 are mounted on the carriage 101 .

Then, the coloring agent ejection head 21 mounted on the ink jet device 2 ejects the coloring agent of each color of YMCK, and the pretreatment agent ejection head 31 installed on the pretreatment device 3 ejects the pretreatment agent PCA onto the recording medium. Dispense against M. The coloring agent ejection head 21 and the pretreatment agent ejection head 31 are arranged in a direction intersecting the main scanning direction, and the nozzles 40N are configured to open downward. The pretreatment agent ejection head 31 functions as a pretreatment execution unit.

Cartridges 103 for supplying droplets LD containing colorants of respective colors to the coloring agent ejection head 21 and droplets LD containing pretreatment agent PCA to the pretreatment agent ejection head 31 are exchangeably mounted on the carriage 101 . is installed. Further, the cartridge 103 has an air port communicating with the atmosphere in the upper part, and a supply port in the lower part for supplying droplets LD to the coloring agent ejection head 21 or the pretreatment agent ejection head 31 . The cartridge 103 has a porous body filled with droplets LD.

The internal pressure of the cartridge 103 is maintained such that the droplets LD supplied by the capillary force of the porous body have a slight negative pressure. In this embodiment, the coloring agent ejection head 21 is provided for each color, but a single head having nozzles 40N for ejecting droplets LD of YMCK colors may be used. Further, the pretreatment agent ejection head 31 is also provided for each concentration of the aggregating agent AG as an example, but a single head having nozzles 40N for ejecting droplets LD of the aggregating agent AG having different concentrations may be used. . Alternatively, the execution mode of the pretreatment may be controlled by controlling the ejection amount of one type of pretreatment agent PCA ejected from one pretreatment agent ejection head 31 .

The carriage 101 is slidably mounted on a main guide rod 107 at its rear side (downstream side in the paper transport direction) and slidably mounted on a secondary guide rod 107b at its front side (upstream side in the paper transport direction). In order to move and scan the carriage 101 in the main scanning direction, a timing belt 212 is stretched between a driving pulley 210 and a driven pulley 211 which are rotationally driven by the main scanning motor 109 . The timing belt 212 and the carriage 101 are fixed, and the forward and reverse rotation of the main scanning motor 109 drives the carriage 101 to reciprocate.

On the other hand, in order to transport the recording medium M stacked in the paper feed cassette to the lower side of the inkjet head 102, a paper feed roller 213 and a friction pad 214 for separating and feeding the recording medium M from the paper feed cassette 204, and a recording medium a guide member 215 that guides the recording medium M; a transport roller 216 that reverses and transports the transported recording medium M; A tip roller 118 that defines the is provided. The conveying roller 216 is rotationally driven by a sub-scanning motor through a gear train.

A printing member that is a guide member that guides the recording medium M sent out from the conveying roller 216 corresponding to the range in the main scanning direction in which the carriage 101 moves below the coloring agent ejection head 21 and the pretreatment agent ejection head 31 . A receiving member 119 is provided.

On the downstream side of the print receiving member 119 in the direction in which the recording medium M is conveyed, there is rotationally driven to feed the recording medium M in the direction in which it is discharged outside the housing of the image forming apparatus 5 . A conveying roller 220 and a spur 121 are provided. Discharge rollers 122 and spurs 123 for sending the recording medium M to the discharge tray 106, and guide members 124 and 125 for forming a path for discharging the recording medium M outside the housing of the image forming apparatus 5 are further arranged. ing.

Next, with reference to FIG. 20, the functional configuration of the image forming apparatus 5 according to this embodiment will be described. The image forming apparatus 5 according to the present embodiment is configured by adding a transport control section 50C for controlling transport of the recording medium M to the functions of the inkjet device 2 and the pretreatment device 3 shown in FIG.

The transport control unit 50C transports the recording medium M by driving the sub-scanning motor based on the command information received from the print control unit 20Cc and the preprocessing control unit 30Cc. The print control unit 20Cc and the preprocessing control unit 30Cc also function as drive control units that control driving of the main scanning motor 109. FIG. Since other configurations are the same as those in FIG. 9, redundant description is omitted.

In this embodiment, the image forming apparatus 5 is configured by integrating the inkjet device 2 and the pretreatment device 3 into one housing. Therefore, each section of image forming apparatus 5 may be controlled based on information received from main control section 110 by an image forming controller, which is a control section for controlling the operation of image forming apparatus 5 .

In such a case, the image forming controller causes the printer engine 20E to control the operation of the colorant ejection head 21 and the precoat engine 30E to control the operation of the pretreatment agent ejection head 31 based on the information received from the main control unit 110. . Further, at this time, the main control unit 110 functions as a droplet ejection control unit that causes the image forming apparatus 5 to eject droplets.

Using the image forming apparatus 5 configured as described above, the inkjet system 4 according to the present embodiment performs image formation output based on image information. Next, in the inkjet system 4 according to the present embodiment, the flow of processing for image formation output will be described with reference to FIG. 21 .

When the DFE 1 completes the processing shown in the flowchart of FIG. 16, the main control unit 110 transmits preprocessing execution information for causing the preprocessing device 3 to execute preprocessing (S2101). The pretreatment device 3 executes pretreatment by ejecting the pretreatment agent PCA1 and the pretreatment agent PCA2 onto the recording medium M based on the pretreatment execution information received from the DFE1.

When the pretreatment agent ejection heads 31H and 31L eject droplets LD onto the recording medium M, the pretreatment control unit 30Cc drives the pretreatment agent ejection heads 31H and 31L based on the drawing information while moving the carriage 101. , droplets LD containing the pretreatment agent PCA are ejected for one line in the main scanning direction onto the stationary recording medium M (S2102). When ejection for one line is completed, the pretreatment device 3 transmits to the DFE 1 a pretreatment completion notice indicating that pretreatment for one line has been executed (S2103).

Upon receiving the preprocessing completion notification from the preprocessing apparatus 3, the DFE 1 transmits to the image forming apparatus 5 transport execution information for transporting the recording medium M by one line in the sub-scanning direction (S2104). The image forming apparatus 5 causes the transport control unit 50C to drive the sub-scanning motor according to the transport execution information, transports the recording medium M by one line in the sub-scanning direction (S2105), and transmits a transport completion notification to the DFE 1 (S2106). ).

Upon receiving the transport execution notification, the DFE 1 transmits image formation execution information for causing the inkjet device 2 to execute image formation output for one line (S2107). When the coloring agent ejection head 21 ejects droplets LD onto the recording medium M, the print control unit 20Cc drives the coloring agent ejection head 21 of each color based on the drawing information while moving the carriage 101, and stops. A droplet LD containing a colorant of each color is discharged for one line in the main scanning direction onto the recording medium M (S2108).

When one line of ink is discharged, the inkjet device 2 causes the print control unit 20Cc to drive the sub-scanning motor to convey the recording medium M, and transmits an image formation completion notification to the DFE 1 (S2109).

When the image forming output of the drawing information included in the job data is completed, the DFE 1 transmits ejection execution information for ejecting the recording medium M to the image forming apparatus 5 (S2110). is driven to discharge the recording medium M on which the image is formed (S2111). Note that if the image formation output of all the drawing information included in the job data has not been completed, the DFE 1 executes the process from S2101 again.

Embodiment 3.
In the present embodiment, after the pretreatment agent PCA is uniformly adhered to the roll paper Md using a coater, the pretreatment agent PCA containing the coagulant AG is ejected based on the drawing information for pretreatment. An ink jet system 4 including a pretreatment device 3 for executing is described as an example. Also, the same reference numerals are assigned to the same configurations as those in the first embodiment, and overlapping descriptions are omitted.

FIG. 22 is a diagram showing an outline of the inkjet system 4 according to this embodiment. The inkjet system 4 according to this embodiment includes a coater 31CT for applying the pretreatment agent PCA to the recording medium M, instead of the pretreatment agent ejection head 31L in the inkjet system 4 shown in FIG. The coater 31CT functions as a preprocessing execution unit.

Also, the coater 31CT has a width similar to that of the pretreatment agent ejection head 31, and is capable of uniformly applying the pretreatment agent PCA in the main scanning direction of the roll paper Md. A pipe or the like provided with a discharge port may be used. The operation of the coater 31CT is controlled by the preprocessing control section 30Cc.

In this embodiment, after the pretreatment agent PCA2 is applied to the recording medium M from the coater 31CT, the pretreatment agent PCA1 is ejected from the pretreatment agent ejection head 31H onto the recording medium M to form the pretreatment agent application area PC. to form At this time, based on the ejection amounts of the pretreatment agents PCA1 and PCA2 for each pixel calculated by the pretreatment agent ejection information generation unit 113, the pretreatment device 3 performs the process of S1702 to determine the amount of the pretreatment agent PCA2 for one line. The configuration may be such that the pretreatment agent PCA2 with the smallest ejection amount is applied to the recording medium M from the coater 31CT.

Further, based on the ejection amounts of the pretreatment agents PCA1 and PCA2 for each pixel calculated by the pretreatment agent ejection information generation unit 113, the pretreatment device 3 determines the area where the image is to be formed based on the drawing information in the process of S1702. Among the ejection amounts of the pretreatment agent PCA2, the smallest ejection amount of the pretreatment agent PCA2 may be applied to the recording medium M from the coater 31CT.

The DFE 1 described above may be a dedicated device, or may be realized by installing predetermined software in a server device or a personal computer. Also, the DFE 1 does not need to be separate from the inkjet device 2 and may be realized by a controller inside the inkjet device 2 .

Furthermore, the DFE 1, the printer controller 20C in the inkjet device 2, and the precoat controller 30C in the pretreatment device 3 may cooperate to realize the functions of the DFE 1. FIG. Furthermore, the preprocessing device 3 may operate through the printer controller 20C without communicating directly with the DFE 1. FIG.

Further, although the recording medium M is transported in the above-described embodiment, the configuration may be such that the recording medium M is not transported. For example, a flat bed system in which a recording medium M is placed on a table and a carriage on which a coloring agent ejection head 21 and a pretreatment agent ejection head 31 are mounted moves two-dimensionally to form an image on the recording medium M. It is also applicable to inkjet devices.

Moreover, although the pretreatment device 3 described above has been described as an example of a device that discharges a pretreatment agent, it may be a device that performs other pretreatments. For example, the amount of plasma discharge in the plasma device may be controlled based on the type of image to be image-formed and output, thereby controlling the manner in which the pretreatment is performed. At this time, the electrode that performs plasma discharge functions as a pretreatment execution unit that performs pretreatment.

The recording medium used for recording is not particularly limited, but includes plain paper, glossy paper, special paper, cloth, film, OHP sheet, general-purpose printing paper, and the like.

(ink)
Organic solvents, water, coloring materials, resins, additives, and the like used in the ink are described below.

<Resin>
The type of resin contained in the ink is not particularly limited and can be appropriately selected according to the purpose. resins, styrene-butadiene-based resins, vinyl chloride-based resins, acrylic-styrene-based resins, acrylic-silicone-based resins, and the like.
Resin particles made of these resins may also be used. Ink can be obtained by mixing resin particles in a resin emulsion state in which water is dispersed as a dispersion medium with a material such as a coloring material or an organic solvent. As the resin particles, appropriately synthesized ones may be used, or commercially available products may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles.

The volume average particle diameter of the resin particles is not particularly limited and can be appropriately selected according to the intended purpose. 200 nm or less is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle diameter can be measured, for example, using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

The content of the resin is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of fixability and storage stability of the ink, the content is 1% by mass or more and 30% by mass or less based on the total amount of the ink. is preferable, and 5% by mass or more and 20% by mass or less is more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used individually by 1 type, and may use 2 or more types together. Mixed crystals may also be used as pigments.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy color pigments such as gold and silver, and metallic pigments.
As inorganic pigments, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, carbon black produced by known methods such as contact method, furnace method, thermal method, etc. can be used.
Organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , dye chelates (eg, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments for black include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black and channel black, or copper and iron (C.I. Pigment Black 11). , metals such as titanium oxide, and organic pigments such as aniline black (C.I. Pigment Black 1).
Further, for color, C.I. I. Pigment yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52: 2, 53:1, 57:1 (brilliant carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (red red), 104, 105, 106, 108 ( cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (rhodamine lake), 3, 5:1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
As dyes, acid dyes, direct dyes, reactive dyes, and basic dyes can be used without particular limitation, and may be used singly or in combination of two or more.
As a dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. and Reactive Black 3,4,35.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoints of improving image density, good fixability, and ejection stability. It is below.

As a method of dispersing the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing the pigment, and a method of dispersing the pigment using a dispersant. method, etc.
As a method of making a self-dispersing pigment by introducing a hydrophilic functional group into a pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) to make it dispersible in water. is mentioned.
As a method of coating the surface of a pigment with a resin and dispersing it, there is a method of encapsulating the pigment in microcapsules to make it dispersible in water. This can be rephrased as a resin-coated pigment. In this case, all the pigments mixed in the ink need not be coated with a resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. may be
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant typified by surfactants.
As the dispersant, it is possible to use, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. depending on the pigment.
As a dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
Inks can be obtained by mixing materials such as water and organic solvents with pigments. Ink can also be produced by mixing a pigment, water, a dispersant, and the like to form a pigment dispersion, and then mixing materials such as water and an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and optionally other components, and adjusting the particle size. Dispersion should be carried out using a disperser.
The particle diameter of the pigment in the pigment dispersion is not particularly limited, but the dispersion stability of the pigment is improved, and the image quality such as ejection stability and image density is improved. 500 nm or less is preferable, and 20 nm or more and 150 nm or less is more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected according to the purpose. 50% by mass or less is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
It is preferable to filter coarse particles with a filter, a centrifugal separator, or the like, and deaerate the pigment dispersion, if necessary.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- 1,3-pentanediol, petriol and the like.
Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether and the like.
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone and the like. mentioned.
Amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide and the like.
Amines include monoethanolamine, diethanolamine, triethylamine, and the like.
Examples of sulfur-containing compounds include dimethylsulfoxide, sulfolane, thiodiethanol and the like.
Other organic solvents include propylene carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also provides good drying properties.

As the organic solvent, polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose. 20% by mass or more and 60% by mass or less is more preferable.

<Water>
The content of water in the ink is not particularly limited and can be appropriately selected according to the purpose. % or more and 60 mass % or less is more preferable.

<Additive>
Surfactants, antifoaming agents, antiseptic antifungal agents, anticorrosive agents, pH adjusters, etc. may be added to the ink as necessary.

<Surfactant>
Any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used as surfactants.
The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among them, those that do not decompose even at high pH are preferred. Examples of silicone-based surfactants include side chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, single-end-modified polydimethylsiloxane, and side-chain both-end-modified polydimethylsiloxane. Those having a polyoxyethylene group or a polyoxyethylene-polyoxypropylene group as a modifying group are particularly preferred because they exhibit good properties as water-based surfactants. As the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of fluorine-based surfactants include perfluoroalkylsulfonic acid compounds, perfluoroalkylcarboxylic acid compounds, perfluoroalkylphosphoric acid ester compounds, perfluoroalkylethylene oxide adducts, and perfluoroalkyl ether groups in side chains. Polyoxyalkylene ether polymer compounds are particularly preferred due to their low foaming properties. Examples of perfluoroalkylsulfonic acid compounds include perfluoroalkylsulfonic acids, perfluoroalkylsulfonates, and the like. Examples of perfluoroalkylcarboxylic acid compounds include perfluoroalkylcarboxylic acids and perfluoroalkylcarboxylic acid salts. Examples of polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains include sulfuric acid ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in side chains, and polyoxyalkylene ether polymers having perfluoroalkyl ether groups in side chains. Examples thereof include salts of oxyalkylene ether polymers. Counter ions of salts in these _{fluorosurfactants} include Li, Na, K, _NH4 , _NH3CH2CH2OH , _{NH2 ( CH2CH2OH} ) ₂ , and _{NH ( CH2CH2OH} ). ₃ and the like.
Examples of amphoteric surfactants include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine and the like.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and salts of polyoxyethylene alkyl ether sulfates.
These may be used individually by 1 type, or may use 2 or more types together.

The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples include polydimethylsiloxane modified at both ends, and polyether-modified silicone surfactants having polyoxyethylene groups or polyoxyethylene polyoxypropylene groups as modifying groups are particularly preferred because they exhibit good properties as water-based surfactants. .
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. Commercially available products are available from, for example, BYK Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nihon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above polyether-modified silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose. Examples include those introduced into the side chain of the Si portion of siloxane.

(However, in general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)
Commercially available products can be used as the above polyether-modified silicone-based surfactants. 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Corporation), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like.

As the fluorosurfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of fluorine-based surfactants include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain is preferable because of its low foamability, and in particular, fluorine-based compounds represented by general formulas (F-1) and (F-2) Surfactants are preferred.

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.

In the compound represented by the general formula (F-2), Y is H, or CmF _2m+1 and m is an integer of 1 to 6, or CH ₂ CH(OH)CH ₂ -CmF _2m+1 and m is 4 to 6 Integer, or CpH _2p+1 where p is an integer from 1-19. n is an integer of 1-6. a is an integer from 4 to 14;
Commercially available products may be used as the fluorosurfactant. Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fleurard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (both manufactured by Sumitomo 3M); Megafac F-470, F -1405, F-474 (both manufactured by Dainippon Ink and Chemicals); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) Among these, Chemours FS-3100, FS-34, FS- 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omnova Co., Ltd., and Unidyne DSN- manufactured by Daikin Industries, Ltd. 403N is particularly preferred.

The content of the surfactant in the ink is not particularly limited and can be appropriately selected according to the purpose. % or more and 5 mass % or less is preferable, and 0.05 mass % or more and 5 mass % or less is more preferable.

<Antifoaming agent>
The antifoaming agent is not particularly limited, and examples thereof include silicone antifoaming agents, polyether antifoaming agents, and fatty acid ester antifoaming agents. These may be used individually by 1 type, or may use 2 or more types together. Among these, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

<Preservative and antifungal agent>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Antirust agent>
The rust inhibitor is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

<Physical properties of ink>
The physical properties of the ink are not particularly limited and can be appropriately selected depending on the intended purpose. For example, viscosity, surface tension, pH and the like are preferably within the following ranges.
The viscosity of the ink at 25° C. is preferably 5 mPa·s or more and 30 mPa·s or less, more preferably 5 mPa·s or more and 25 mPa·s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. more preferred. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). Measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, 3 minutes.
The surface tension of the ink is preferably 35 mN/m or less, more preferably 32 mN/m or less at 25° C., from the viewpoint that the ink is appropriately leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably from 7 to 12, more preferably from 8 to 11, from the viewpoint of preventing corrosion of metal members in contact with the liquid.

(Pretreatment agent)
The pretreatment agent contains, for example, polyvalent metal salt, organic solvent, cationic polymer, water, etc., and functions as a flocculant. In addition, it may contain a surfactant, an antifoaming agent, a pH adjuster, an antiseptic antifungal agent, an antirust agent, and the like. Organic solvents, surfactants, antifoaming agents, pH adjusters, antiseptic antifungal agents, and antirust agents can be the same materials as those used for ink, and other materials used for known pretreatment agents can be used. .

When the pretreatment agent has a function as a flocculating agent, ejection failure due to mist adhesion or nozzle clogging becomes a problem when the pretreatment agent is ejected from the inkjet head. However, according to the present embodiment, good ejection stability is achieved. can be obtained. In addition, while suppressing ejection abnormalities due to precipitation of the polyvalent metal salt of the pretreatment agent, it is excellent in suppressing abnormal images caused by collapse of the dot shape formed by the ink applied to the area to which the liquid composition is applied. Effective.

<Polyvalent metal salt>
Examples of polyvalent metal salts include those composed of specific polyvalent metal ions having a valence of 2 or more and anions that bind to these polyvalent metal ions.
Examples of metal salts include calcium salts, magnesium salts, nickel salts, aluminum salts, boron salts, zinc salts and the like, with calcium salts and magnesium salts being preferred. Among them, magnesium salts are particularly preferable, but combinations with other metal salts are also possible, and the present invention is not limited to these.

Specific examples of inorganic metal salts include calcium chloride, magnesium chloride, calcium bromide, magnesium bromide, calcium nitrate, magnesium nitrate, magnesium sulfate and the like as calcium salts and magnesium salts, but are limited to these. is not.

In addition to polyvalent metal salts, organic acid metal salts may also be used.
Specific examples of organic acid metal salts include calcium salts and magnesium salts of pantothenic acid, propionic acid, ascorbic acid, acetic acid, and lactic acid, but are not limited thereto.

The content of the polyvalent metal salt in the pretreatment agent preferably satisfies the relationship with the content of the betaine compound and glycerin, which will be described later.

<Physical properties of pretreatment agent>
The pretreatment agent preferably has a 15 ms dynamic surface tension of 35 mN/m or more and 65 mN/m or less. When the 15 ms dynamic surface tension is 35 mN/m or more, the tailing (ligament length) of the droplets during ejection can be shortened, so that the landing pretreatment agent can be made into the targeted droplets. Dot collapse at the time of impact is suppressed. In addition, since it is possible to suppress the generation of mist due to the disappearance of the trailing, it is possible to suppress contamination of the nozzle surface due to the mist, thereby suppressing non-ejection. In addition, when the density is 65 mN/m or less, the generation of satellites can be suppressed, so mist contamination can be suppressed, and ejection failure can be similarly suppressed.

The pretreatment agent preferably has a static surface tension of 20 mN/m or more and 35 mN/m or less. When the static surface tension is 20 mN/m or more, the pretreatment agent can maintain the meniscus of the nozzle, so that the occurrence of non-ejection due to liquid overflow can be suppressed. Further, when the ejection force is 35 mN/m or less, the pretreatment agent can be ejected stably without being affected by the meniscus retention force. This range is preferred because unlike non-Newtonian fluids, such as ink, which contain solids, high-shear viscosity changes do not occur upon ejection.

<Betaine compound>
The pretreatment agent preferably contains a polyvalent metal salt, glycerin, and a betaine compound having a molecular weight of 100 or more and 200 or less, and the total content of glycerin and the betaine compound is equal to the content of the polyvalent metal salt. On the other hand, it is preferably 1.05 times or more and 2.50 times or less on a mass basis.

A pretreatment agent containing a polyvalent metal salt has a problem that as the solvent dissolving the metal salt in the pretreatment agent evaporates, the solubility decreases and the polyvalent metal salt precipitates. When the pretreatment agent is ejected after being decapped, there is a problem that ejection failure occurs due to precipitation. On the other hand, when dots are formed by applying a pretreatment agent containing glycerin to a recording medium and then applying ink, the ink is applied onto the recording medium on which a large amount of glycerin remains. Therefore, there is a problem that the coloring material in the applied ink is wetted and spread by the glycerin, and graininess is deteriorated due to partial collapsing of dots.

By containing the betaine compound, it is possible to improve the moisturizing property of the pretreatment agent, obtain good ejection stability, and improve graininess to obtain good images. In addition, the total content of glycerin and betaine compound is 1.05 times or more and 2.50 times or less of the content of the polyvalent metal salt on a mass basis, so that good ejection stability can be obtained. , graininess can be improved and good images can be obtained.

The total content of glycerin and betaine compound is preferably 1.05 to 1.40 times the content of the polyvalent metal salt on a mass basis. In this case, good ejection stability can be obtained, and graininess can be improved to obtain good images.

The content of the betaine compound is preferably 0.1 to 0.5 times the total content of glycerin and the betaine compound on a mass basis. In this case, good ejection stability can be obtained, and graininess can be improved to obtain good images.

The betaine compound can be selected as appropriate, and examples include trimethylglycine (glycine betaine, molecular weight 117), carnitine (molecular weight 161), γ-butyrobetaine (molecular weight 145), homaline (molecular weight 137), trigonelline (molecular weight 137 ), homoserine betaine (molecular weight 161), valine betaine (molecular weight 159), lysine betaine (molecular weight 188), ornithine betaine (molecular weight 176), alanine betaine (molecular weight 117), stachydrine (proline betaine, molecular weight 185), glutamate betaine (molecular weight 189) and the like. Among these, a betaine compound having a molecular weight of 100 or more and 200 or less is preferable. When the molecular weight is 100 or more and 200 or less, the penetrability of the ink on the paper surface can be enhanced, and the graininess can be improved.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. Further, Examples 1 to 5 refer to Reference Examples 1 to 5 that are not included in the present invention.

(Examples 1 to 5)
<Preparation example of pretreatment agent>
Pretreatment agents 1 to 5 were prepared according to the formulations shown in Table 1 below.
Capstone-FS34 in Table 1 was manufactured by Chemours.

<Dynamic surface tension>
The dynamic surface tension of each pretreatment agent was measured using a portable surface tensiometer (SITA DynoTester, manufactured by Eiko Seiki Co., Ltd.) under conditions of temperature: 25° C., bubblelifetime: 15 msec, 150 msec, and 1500 msec.

<Static surface tension>
The static surface tension of each pretreatment agent was measured at a temperature of 25° C. using a surface tensiometer (DY300, manufactured by Kyowa Interface Co., Ltd.).

<Ejection stability>
Using GXe5500 filled with each pretreatment agent, solid images were continuously printed on 250 sheets of inkjet glossy paper, and the presence or absence of streaks, white spots, and ejection disturbances in solid image areas was visually evaluated. Since the pretreatment agent is colorless, 0.1% of FB 0.005% aqueous solution (FB: Blue No. 1, manufactured by Daiwa Kasei Co., Ltd.) is added to stain and confirm. Among the following evaluation criteria, A and B were regarded as acceptable.
[Evaluation criteria]
A: No streaks, white spots, or jetting disturbances are observed in the solid portion.
B: Slight streaks, white spots, and ejection disturbances are observed in the solid portion.
C: Streaks, white spots, and ejection disturbances are observed in half of the solid prints.
D: Streaks, white spots, and irregular jetting are observed on the entire solid portion.

<Nozzle surface overflow>
Using GXe5500 filled with each pretreatment agent, solid images were continuously printed on 250 sheets of inkjet glossy paper, the condition of the nozzle surface was visually confirmed, and liquid overflow and contamination of the nozzle surface were visually evaluated. Among the following evaluation criteria, A and B were regarded as acceptable.
[Evaluation criteria]
A: No liquid overflow on the nozzle surface (the position of the nozzle cannot be seen visually)
B: A little liquid is scattered on the nozzle surface (the position of the nozzle is unknown, but droplets can be confirmed)
C: Liquid is scattered on the nozzle surface (liquid overflows around the nozzle and the position can be visually confirmed)
D: The liquid is scattered on the nozzle surface, and the liquid pool can be clearly confirmed.

Table 1 shows the composition of the pretreatment agent and the evaluation results. In addition, "%" means "% by mass".

(Examples 6 to 15)
<Synthesis Example of Copolymer A>
Methyl ethyl ketone was added to a reaction vessel of an automatic polymerization reactor (manufactured by Todoroki Sangyo Co., Ltd.: polymerization tester DSL-2AS type) equipped with a reaction vessel equipped with a stirring device, a dropping device, a temperature sensor, and a reflux device having a nitrogen introduction device at the top. 550 g of the mixture was charged, and the inside of the reaction vessel was replaced with nitrogen while stirring. After heating to 80° C. while maintaining the inside of the reaction vessel in a nitrogen atmosphere, 75.0 g of 2-hydroxyethyl methacrylate, 77.0 g of methacrylic acid, and 8 g of styrene were added by a dropping device.
A mixed solution of 0.0 g, 150.0 g of butyl methacrylate, 98.0 g of butyl acrylate, 20.0 g of methyl methacrylate and 40.0 g of "PERBUTYL O" (manufactured by NOF CORPORATION) was added dropwise over 4 hours. did. After the completion of dropping, the reaction was further continued at the same temperature for 15 hours to obtain a methyl ethyl ketone solution of the anionic group-containing styrene-acrylic copolymer A having an acid value of 100, a weight average molecular weight of 21,000, and a Tg (calculated value) of 31°C. got After completion of the reaction, part of the methyl ethyl ketone was distilled off under reduced pressure to obtain a copolymer A solution adjusted to have a non-volatile content of 50%.

<Preparation example of pigment dispersion>
-Preparation of Pigment Dispersion 1-
In a mixing tank equipped with a cooling jacket, 1,000 g of carbon black (trade name: Raven 1080, manufactured by Columbian Carbon Japan Co., Ltd.), 800 g of copolymer A solution, 143 g of 10% aqueous sodium hydroxide solution, and 100 g of methyl ethyl ketone. , and 1,957 g of water were charged and mixed with stirring. The mixed liquid is passed through a dispersing device (manufactured by Mitsui Mining Co., Ltd.: SC Mill SC100) filled with zirconia beads with a diameter of 0.3 mm, and dispersed for 6 hours by a circulation method (a method of returning the dispersed liquid discharged from the dispersing device to the mixing tank). did. The number of rotations of the dispersing device was 2,700 rpm, and cold water was passed through the cooling jacket so as to keep the temperature of the dispersion at 40° C. or less.
After completion of the dispersion, the undiluted dispersion was extracted from the mixing vessel, and then the mixing vessel and the flow path of the dispersing device were washed with 10,000 g of water. The diluted dispersion was placed in a glass distillation apparatus, and the entire amount of methyl ethyl ketone and part of the water were distilled off. After cooling to room temperature, 10% hydrochloric acid was added dropwise with stirring to adjust the pH to 4.5, and then the solid content was filtered with a Nutsche filter (manufactured by Nippon Kagaku Kikai Seisakusho, pressure filter) and washed with water. Take the cake in a container, add 200 g of a 20% aqueous potassium hydroxide solution, disperse it with Disper (TK Homo Disper, manufactured by Tokushu Kika Kogyo Co., Ltd.), and add water to adjust the non-volatile content. A pigment dispersion 1 was obtained, which was dispersed in an aqueous medium as composite particles coated with a carboxyl group-containing styrene-acrylic copolymer in which 20% by mass of carbon black was neutralized in potassium hydroxide.

<Ink preparation example>
-Preparation of Ink 1-
Glycerin 22.0% by mass, 1,3-butanediol 11.0% by mass, 1,3-octanediol 2.0% by mass, surfactant (trade name: E1010, manufactured by Nissin Chemical Industry Co., Ltd.) 2.0 % by weight, 2,4,7,9-tetramethyldecane-4,7-diol 1.1% by weight, Proxel LV (manufactured by Avecia) 0.1% by weight, and 2-amino-2-ethyl-1, 0.5% by mass of 3-propanediol and ion-exchanged water are stirred for 1 hour and mixed uniformly, and 2.0% by mass of rosin-modified maleic acid resin (Harimac R-100, manufactured by Harima Chemicals Co., Ltd.) is added and further mixed for 1 hour. After stirring for a period of time and mixing uniformly, Pigment Dispersion 1 was added so that the solid content was 8.0% by mass, and the mixture was further stirred for 1 hour and mixed uniformly. This mixture was subjected to pressure filtration through a polyvinylidene fluoride membrane filter having an average pore size of 0.8 μm to remove coarse particles and dust, thereby obtaining Ink 1 .

Table 2 shows the composition of Ink 1. In addition, the unit of each numerical value of the composition in Table 2 is "% by mass".

<Preparation of pretreatment agent 6>
22.2% by mass of glycerin, 24.6% by mass of magnesium sulfate heptahydrate (manufactured by Showa Chemical Co., Ltd.), 7.4% by mass of L-carnitine which is a betaine compound, polyoxyalkylene alkyl ether (trade name: Emulgen 103, Kao Corporation) 0.4 mass %, Proxel LV (manufactured by Avecia) 0.1 mass %, and benzotriazole 0.1 mass % were added and stirred for 1 hour to mix uniformly. Furthermore, after adding 1.2% by mass of N-octyl-2-pyrrolidone, ion-exchanged water was added to make the total 100% by mass, and the mixture was uniformly mixed by stirring for 1 hour to obtain a pretreatment liquid composition. Agent 1 was obtained.

<Adjustment of pretreatment agents 7 to 15>
In the preparation of pretreatment agent 6, Examples 6 to 15 were obtained in the same manner as preparation of pretreatment agent 6, except that the composition was changed to that shown in Table 3 below.
In addition, the unit of each numerical value of the composition in Table 3 is "% by mass". In addition, the mass of "polyvalent metal salt" in Table 3 includes the mass of water of hydration contained in the polyvalent metal salt. The mass of the "polyvalent metal salt" used in the calculation of "(glycerin + betaine compound)/polyvalent metal salt" in Table 3 includes the mass of water of hydration contained in the polyvalent metal salt.

In addition, in Table 3, the product names of the components and the names of the manufacturers are as follows.
・ Magnesium nitrate heptahydrate (manufactured by Showa Chemical Co., Ltd.)
・ Magnesium nitrate hexahydrate (manufactured by Showa Chemical Co., Ltd.)

(evaluation)
Next, using the above pretreatment agents 6 to 15 and the above ink 1, graininess and deposition properties were evaluated according to the following methods and evaluation criteria.

<Graininess>
A print sample was obtained by ejecting ink from an image forming apparatus (device name: IPSIO GXe5500, manufactured by Ricoh Co., Ltd.) onto the recording medium onto which the pretreatment agent had been ejected, without drying the recording medium by heat treatment. For the printing chart, a 3 cm square gradation image formed by a dot pattern with gradations was used.
Next, a 3 cm square gradation image formed by a dot pattern with gradations was visually observed, and "graininess" was evaluated based on the following evaluation criteria. Of the following evaluation criteria, a case of B or higher was evaluated as being practicable.
[Evaluation criteria]
A: No deterioration of graininess is observed (dots are not collapsed)
B: Slight deterioration of graininess is observed, but there is no problem (most dots are not collapsed)
C: Deterioration of graininess is observed and clearly visible (most dots are collapsed)

<Ejection stability>
The head of GXe5500 was filled with a pretreatment agent, left in a decapped state at 23°C and 50% humidity for 3 days, and based on the following evaluation criteria, a solid image was printed on one sheet of inkjet glossy paper, The presence or absence of streaks, white spots, and ejection disturbance in the solid image portion was visually evaluated. Since the pretreatment agent is colorless, it is confirmed by adding 0.1% of FB0.005% aqueous solution and dyeing. Among the following evaluation criteria, A and B were regarded as acceptable. When the evaluation was C, many of the nozzles were clogged with deposits when observing the nozzles after ejection.

[Evaluation criteria]
A: No streaks, white spots, or jetting disturbances are observed in the solid portion.
B: Slight streaks, white spots, and ejection disturbances are observed in the solid portion.
C: Streaks, white spots, and ejection disturbances are observed in half of the solid print or on the front surface.

Table 3 shows the composition of the pretreatment agent and the evaluation results.

1 DFEs
2 inkjet device 3 pretreatment device 4 inkjet system 5A, 5B measuring device 6 image forming device 11 CPU
12 ROMs
13 RAM
14 HDDs
15 interfaces
15F Network I/F
16 bus 21 coloring agent ejection head 31 pretreatment agent ejection head 31CT coater 100 controller 110 main control unit 111 characteristic information storage unit 112 drawing information analysis unit 113 pretreatment agent ejection information generation unit 114 medium characteristic information storage unit 115 pretreatment agent characteristics Information storage unit 116 Colorant property information storage unit SD Property information data table

Japanese Patent Application Laid-Open No. 2008-62503

Claims (14)

a preprocessing execution unit that performs preprocessing on a medium;
a pre-processing execution control unit that controls an execution mode of the pre-processing based on image information of an image formation output target;
a droplet ejection unit that ejects droplets onto the medium based on the image information;
a print control unit that controls the droplet ejection unit;
a control unit that controls the print control unit and the preprocessing execution control unit;
including
The pretreatment execution unit is capable of ejecting a plurality of types of pretreatment agents from a pretreatment agent ejection head, and causes the pretreatment agent to adhere to the medium,
The droplet ejection unit is capable of ejecting a plurality of types of droplets,
The control unit refers to a table storing combinations of the types of the droplets and the types of the pretreatment agent, and selects the combinations, thereby forming dots formed by the droplets adhering to the medium. to control the
The pretreatment agent contains a polyvalent metal salt, glycerin, and a betaine compound having a molecular weight of 100 or more and 200 or less,
The liquid droplet ejection system , wherein the total content of the glycerin and the betaine compound is 1.05 to 2.50 times the content of the polyvalent metal salt on a mass basis . The preprocessing execution unit
attaching a pretreatment agent to the medium;
The preprocessing execution control unit
2. The liquid droplet ejection system according to claim 1, wherein the concentration of the reactant contained in the pretreatment agent applied to the medium is controlled. The preprocessing execution unit
attaching a pretreatment agent to the medium;
The preprocessing execution control unit
2. The liquid droplet ejection system according to claim 1, wherein the amount of said pretreatment agent applied to said medium is controlled. the image information includes at least image type information indicating that the image to be output by image formation is any one of text, photograph, and table;
The preprocessing execution control unit
4. The liquid droplet ejection system according to any one of claims 1 to 3, wherein the execution mode of the preprocessing is controlled based on the image type information. an image type determination unit that determines, based on the image information, that the image to be output by image formation is any one of text, a photograph, and a table;
The preprocessing execution control unit
5. The method according to any one of claims 1 to 4, wherein the execution mode of the preprocessing is controlled based on the image information determined to be any one of characters, photographs, and tables. Droplet ejection system. The pretreatment agent contains a flocculating agent,
the droplets contain a coloring agent;
The pretreatment execution unit is capable of ejecting the pretreatment agent having different coagulant concentrations from the pretreatment agent ejection head,
6. The controller according to any one of claims 1 to 5, wherein the controller refers to the table and controls the distribution of the colorant in the dots and the size of the dots by selecting the combination. 3. The liquid droplet ejection system according to claim 1. an image type determination unit that determines, based on the image information, whether the image to be output by image formation is either text or a photograph;
The control unit
When the image to be output by image formation is a photograph, the combination in which the size of the dots is larger than the size of the reference dots is selected, and the density of the colorant of the dots is directed toward the center of the dots. select the combination that becomes darker with
When the image to be output by image formation is a character, the combination is selected in which the size of the dots is smaller than the size of the reference dots, and the density of the colorant of the dots is directed toward the center of the dots. 7. The droplet ejection system of claim 6, wherein the combination is selected to be uniform. The preprocessing execution unit
As the pretreatment, the medium is subjected to a process for changing a dispersion state of a colorant contained in the droplets ejected onto the medium to control the behavior of the droplets. The droplet ejection system according to any one of claims 1 to 7. The preprocessing execution unit
attaching a pretreatment agent to the medium;
9. The droplet ejection system according to any one of claims 1 to 8, wherein the pretreatment agent has a 15 ms dynamic surface tension of 35 mN/m or more and 65 mN/m or less. The preprocessing execution unit
attaching a pretreatment agent to the medium;
10. The droplet ejection system according to any one of claims 1 to 9, wherein the pretreatment agent has a static surface tension of 20 mN/m or more and 35 mN/m or less. 10. The total content of the glycerin and the betaine compound is 1.05 to 1.40 times the content of the polyvalent metal salt on a mass basis. The droplet ejection system according to any one of . 12. The content of the betaine compound is 0.1 times or more and 0.5 times or less on a mass basis with respect to the total content of the glycerin and the betaine compound . A droplet ejection system according to any one of the preceding claims. a preprocessing execution unit that performs preprocessing on a medium;
a pre-processing execution control unit that controls an execution mode of the pre-processing based on image information of an image formation output target;
a droplet ejection unit that ejects droplets onto the medium based on the image information;
a print control unit that controls the droplet ejection unit;
a control unit that controls the print control unit and the preprocessing execution control unit;
including
The pretreatment execution unit is capable of ejecting a plurality of types of pretreatment agents from a pretreatment agent ejection head, and causes the pretreatment agent to adhere to the medium,
The droplet ejection unit is capable of ejecting a plurality of types of droplets,
The control unit refers to a table storing combinations of the types of the droplets and the types of the pretreatment agent, and selects the combinations, thereby forming dots formed by the droplets adhering to the medium. to control the
The pretreatment agent contains a polyvalent metal salt, glycerin, and a betaine compound having a molecular weight of 100 or more and 200 or less,
The image forming apparatus , wherein the total content of the glycerin and the betaine compound is 1.05 to 2.50 times the content of the polyvalent metal salt on a mass basis . controlling the execution mode of the pre-processing when pre-processing the medium based on the image information of the image formation output target;
A droplet ejection method for ejecting droplets onto the medium based on the image information,
performing the pretreatment with a pretreatment agent ejection head capable of ejecting a plurality of types of pretreatment agent;
capable of ejecting a plurality of types of droplets,
controlling dots formed by the droplets adhering to the medium by referring to a table storing combinations of the types of the droplets and the types of the pretreatment agent and selecting the combinations ;
The pretreatment agent contains a polyvalent metal salt, glycerin, and a betaine compound having a molecular weight of 100 or more and 200 or less,
The total content of the glycerin and the betaine compound is 1.05 to 2.50 times the content of the polyvalent metal salt on a mass basis.
A liquid droplet ejection method characterized by:

Images