JP5330763B2 - Image forming method and image forming apparatus - Google Patents

Abstract

The image forming method is for forming an image on an image formation body by using an ink liquid including a coloring material and an aggregation treatment agent including a component that causes the coloring material to aggregate. The image forming method includes: an aggregation treatment layer formation step of forming, on the image formation body, a semisolid aggregation treatment layer that includes the aggregation treatment agent and has a moisture content ratio not more than 56%; an ink droplet deposition step of ejecting droplets of the ink liquid and depositing the droplets of the ink liquid onto the image formation body where the aggregation treatment layer has been formed; and a solvent removal step of removing a liquid solvent present on the image formation body after the ink droplet deposition step.

Description

  The present invention relates to an image forming method and an image forming apparatus, and more particularly to an image forming method and an image forming apparatus for forming an image on an image forming body using an ink and an aggregating agent.

  The ink jet recording method is a method of recording by ejecting ink droplets from nozzles and attaching the ink droplets to a recording medium or the like, and the noise during the recording operation is lower than other methods, Running costs are low, and high-resolution and high-quality image recording is possible. Ink ejection methods include a piezoelectric method using displacement of a piezoelectric element and a thermal method using thermal energy generated by a heating element.

  In addition, the image forming method in the ink jet recording method is roughly classified into a direct drawing method for directly forming an image on a recording medium (for example, a slow permeable medium such as a coated paper for printing), and a non-permeable medium such as a plastic sheet. There are two methods: an intermediate transfer method in which an image is once formed and transferred to a recording medium.

  By the way, in the ink jet recording method, when ink droplets continuously ejected onto a recording medium are formed with high density so that adjacent dots overlap each other, ink droplets that form adjacent dots are recorded. There is a problem in that landing interference (bleed) occurs in which the dots are formed in a desired shape and size because they are united by the action of surface tension on the medium. When the landing interference described above occurs, the dot shape between the dots of the same color collapses, and not only the dot shape collapses between dots of different colors, but also a problem of color mixing occurs.

  As a technique for preventing such landing interference occurring between ink droplets (dots) on a recording medium, a two-liquid aggregation method using a treatment liquid that aggregates ink by reacting with ink has been proposed. For example, in Patent Document 1, in the two-liquid aggregation method, one of the liquid composition (treatment liquid) and the ink is acidic and the other is alkaline, and the pigment aggregation on the recording medium is controlled to control the optical density and bleeding. Techniques for improving intercolor bleeding (bleed) and drying time are disclosed.

  In addition, as a technique for preventing image degradation and curling of the recording medium due to the liquid solvent (ink solvent, etc.) on the recording medium, an intermediate transfer method for transferring an image formed on the intermediate transfer member to the recording medium has been proposed. ing. For example, in Patent Document 2, before the ink droplets land on the intermediate transfer member, the ink droplets are dissolved or swelled in advance on the intermediate transfer member, and the viscosity of the ink droplets is increased. Further, a technique is disclosed in which a powder layer (water-soluble resin) that can be peeled off from an intermediate transfer member is formed to enable high-speed recording without bleeding on a permeable recording medium.

  In the case of the above-described intermediate transfer system, a medium (non-penetrable medium) that is generally impermeable to ink is applied to the intermediate transfer member from the viewpoint of improving transferability. For this reason, when ink droplets are continuously ejected so that adjacent ink droplets (dots) overlap on the intermediate transfer member, the adjacent ink droplets on the intermediate transfer member are united by their surface tension. As a result, a problem of bleed (landing interference) in which a desired dot cannot be formed occurs, which is an obstacle to achieving high-speed printing.

In order to solve such problems, the following techniques have been proposed.
(1) A method of incorporating a two-liquid aggregation method using ink aggregation by a processing agent into an intermediate transfer method. Patent Documents 3 to 5 disclose techniques for solving bleeding by reducing ink fluidity by applying an ink aggregating agent to an intermediate transfer body before ejecting ink. Aqueous pigment ink is used as the ink, and a polyvalent metal salt or an acidic solution is used as the ink aggregating agent.
(2) Method of forming irregularities on intermediate transfer body Patent Documents 6 and 7 disclose a technique in which irregularities are formed on the surface of an intermediate transfer body and bleeding is prevented by an anchor effect.
(3) Method using water-absorbing particles Patent Document 8 discloses a technique for preventing bleeding by forming a layer of water-soluble or water-swelling particles on an intermediate transfer member and absorbing the ink by the particles. ing.
JP 2004-10633 A Japanese Patent Laid-Open No. 11-188858 JP 2004-90595 A JP 2004-114675 A JP 2005-170036 A JP 2006-137127 A JP 2007-69584 A JP 2000-280460 A

However, the two-liquid aggregation method and the intermediate transfer member method have unsolved problems described below in image formation, and further improvements are desired.
[Problems with the two-liquid aggregation method]
When ink is ejected after applying a treatment liquid (aggregation treatment liquid) to a non-penetration medium (intermediate transfer method) such as a plastic sheet or a slow permeability medium (direct drawing method) such as coated paper for printing, The ink aggregate (color material aggregate) formed by the mixing reaction (aggregation reaction) of the treatment liquid and the ink does not stay at the desired position and moves, and as a result, the output image is greatly disturbed compared to the desired image. It has been found that a new problem occurs.

  Here, a general process of the two-liquid aggregation method according to the prior art will be described with reference to FIG. First, after forming an agglomerated layer (liquid layer) 902 having a predetermined thickness on a non-permeable recording medium (non-permeable medium) 900 (FIG. 40A), the agglomerated layer 902 is formed. Ink droplets 904 are ejected onto the recording medium 900. When the ink droplet 904 lands on the aggregation processing layer 902 on the recording medium 900 (FIG. 40B), the aggregation reaction starts instantaneously on the entire surface of the ink droplet 904, and the ink droplet 904 is applied to the recording medium 900. The agglomeration reaction proceeds before the ink reaches, and ink aggregates (color material aggregates) 906 are formed (FIG. 40C). For this reason, the ink aggregate 906 does not contact the recording medium 900 or contacts the recording medium 900 very weakly (FIG. 40D). As a result, the adhesive force (adhesive force) between the ink aggregate 906 and the recording medium 900 becomes insufficient, and the dots made up of the ink aggregate 906 in the roller state are unstable (for example, the aggregation treatment layer). 902 is a floating state), which causes image deterioration due to color material movement.

  Further, as shown in FIG. 40E, for example, by using an absorbent body 910 such as a solvent absorbing roller whose surface is formed of a porous body, a liquid solvent (ink and a solvent for an aggregating treatment liquid) on the recording medium 900 is used. If the component 908 is absorbed and removed, the adhesion between the ink aggregate 906 and the recording medium 900 is not sufficient as described above, so that a part of the coloring material adheres to the absorber 910. Was found to occur. As a result, problems such as image degradation due to insufficient color material amount on the recording medium 900 and reverse transfer of the color material attached to the absorber 910 to the recording medium 900 also occur.

  Moreover, in the technique described in Patent Document 2, the following problems (A) to (C) are listed.

  (A) Since the color material in the ink is not actively aggregated, when ink droplets are ejected at a high speed of 10 kHz or less, swelling and thickening are not in time, and landing interference between adjacent ink droplets occurs. There is a problem of doing.

  (B) Since the transferred image forming layer swells and absorbs the ink solvent, there is a problem of so-called “pile height” in which the thickness of the image portion is increased. When the image thickness is increased, not only the image quality problem that the appearance of the boundary between the printing part and the non-printing part changes, but also a problem that a step is felt when the part is touched.

  (C) Since the ink solvent is absorbed in the transferred image forming layer, the ink solvent oozes out to the paper surface after the transfer, and paper deformation (so-called cockling) occurs.

  Both (B) and (C) are problems that occur because an image is formed on a recording medium (paper) while containing an ink solvent. Further, any of the above (A) to (C) causes fatal image deterioration in high-quality printing.

[Problems with intermediate transfer system]
The conventional techniques of the intermediate transfer system shown in (1) to (3) shown in the background art have the following problems.

  According to (1) “method using ink aggregation by treatment agent”, according to an experiment conducted by the present inventors, when an image is formed by reacting ink and an aggregating agent, an image agglomeration reaction causes an image It has been found that shrinkage occurs and the image area is lower than intended, and that a good image cannot be formed.

  Here, the problem when the image formation by two-liquid aggregation is applied to the intermediate transfer method will be described in more detail.

  FIG. 41 is a schematic diagram showing the behavior when ink droplets (dots) according to the prior art land on the intermediate transfer member. In the figure, (a) shows a state in which an aggregating treatment agent layer 912 made of an ink aggregating agent (aggregation treatment liquid) is formed on an intermediate transfer member (non-penetrable medium) 910, and (b) (C) before the ink droplet 914 has landed on the intermediate transfer body 910, (c) immediately after the ink droplet 914 has landed, and (d) about 1 after the ink droplet 914 has landed. Each behavior after 2 seconds is shown. First, an aggregation treatment agent is applied on the intermediate transfer member 910 to form an aggregation treatment agent layer 912 having a predetermined thickness (FIG. 41A), and then ink droplets 914 ejected from an inkjet head (not shown). When the ink reaches the aggregation treatment agent layer 912, the aggregation reaction starts from the portion where the aggregation treatment agent layer 912 is reached, and the viscosity of the ink droplets locally increases to form an ink aggregate (coloring material aggregate) 916. (FIG. 41 (b)). Immediately after the ink droplet 914 has landed on the intermediate transfer body 910, the ink droplet 914 spreads on the intermediate transfer body 910 to a certain size by the flying energy, and the aggregation reaction proceeds in the entire ink droplet 914. The viscosity increases (FIG. 41 (c)). When the aggregation reaction further progresses with time, the ink aggregate contracts while discharging the solvent in the ink droplet 914 to the outside (FIG. 41 (d)). At this time, the dot diameter shrinks.

  FIG. 42 is a schematic diagram showing the behavior when an image according to the prior art is drawn. FIG. 42A shows a state immediately after drawing, and a portion (image portion) 920 to which a color material is applied according to input image data and a white background portion (non-image portion) 922 are mixedly formed. . Note that the image portion 920 is formed of a plurality of dots. FIG. 42 (b) shows a state after about 1 second after drawing. As in FIG. 41, the agglomeration reaction proceeds to cause shrinkage of the image portion 920, and the area of the white background portion 922 is larger than desired. turn into.

  Further, in (2) “Method for forming irregularities on the intermediate transfer member”, if the irregularities are formed on the surface of the intermediate transfer member, the contact area between the ink layer and the intermediate transfer member is increased, and the adhesion force between the two is increased. Is excessively strong, and the adhesion between the recording medium and the intermediate transfer member is deteriorated. Further, after the transfer, a process of cleaning the intermediate transfer member is necessary, but there is a problem that the cleaning property is also lowered due to the unevenness formed on the surface of the intermediate transfer member.

  FIG. 43 schematically shows the behavior during transfer according to the prior art. FIG. 43A shows a state in which an image formed on the intermediate transfer body 930 having an uneven surface is transferred to the recording medium 932 while being pressed by a transfer roller (not shown). Reference numeral 934 indicates an ink layer constituting an image formed on the intermediate transfer member 930. FIG. 43B shows a state after the recording medium 932 is peeled (that is, a state after transfer). If the surface of the intermediate transfer member 930 is uneven, the contact area between the ink layer 934 and the intermediate transfer member 930 increases as described above. A part of the toner remains, which causes a transfer failure such as image deterioration.

  Further, in the “method using water-absorbing particles” in (3), the particle layer that has absorbed the ink is transferred to the paper as it is, which causes a problem that the image has a thickness on the paper. For example, when a standard inkjet ink having a pigment concentration of 4 parts by mass in the ink is used, an ink amount of about 10 μm in thickness is required in the high density part of the image, but the image on the paper is 10 μm. If the thickness is too large, the appearance of the printed matter will be very uncomfortable, resulting in a quality problem.

  Thus, there are still points to be improved in the two-liquid aggregation method and the intermediate transfer method.

  The present invention has been made in view of such circumstances, and in a two-liquid aggregation method using ink and an aggregation treatment agent, it is possible to form a high-quality image while preventing deterioration in image quality due to color material movement. An object of the present invention is to provide an image forming method and an image forming apparatus.

  The present invention also provides an image forming method and an image forming method capable of preventing the occurrence of image shrinkage due to the aggregation reaction of the ink color material and improving the transferability and enabling high quality image formation in the intermediate transfer method. An object is to provide an apparatus.

According to a first aspect of the present invention, in order to achieve the above object, an image is formed on an image forming body using an ink liquid containing a color material and an aggregating agent containing a component for aggregating the color material. An aggregating treatment layer forming step for forming a semi-solid agglomeration treating layer comprising the aggregating agent and having a moisture content of 56% or less and 32% or more on the image forming body, An ink droplet ejecting step in which the ink liquid is formed into droplets on the image forming body on which the treatment layer is formed, and a liquid solvent on the image forming body is dried by a drying unit after the ink droplet ejecting step. And a solvent removal step of removing by drying or absorption by an absorber .

According to the first aspect of the present invention, an ink droplet is ejected after forming a semi-solid solution aggregation layer composed of an aggregation treatment agent and having a moisture content of 56% or less and 32% or more on the image forming body. As a result, when ink droplets land on the agglomeration layer, the agglomeration reaction starts instantaneously from the contact surface with the agglomeration layer, and the ink agglomerates (coloring material agglomerates) spread to a predetermined size on the agglomeration layer. A dot consisting of an aggregate is formed. As a result, sufficient adhesion can be obtained between the dots (ink aggregates) and the image forming body, image deterioration due to color material movement is prevented, and high-quality image recording becomes possible.

  Thereby, in the two-liquid aggregation method using the ink and the aggregation treatment agent, it is possible to form a high quality image while preventing the image quality from being deteriorated due to the color material movement.

  The image forming method of the present invention includes a direct drawing method for directly forming an image on an image forming body, and an intermediate transfer method for forming an image once on the non-permeable image forming body and then transferring the image to a recording medium. It can be applied to any of these. In the case of the direct drawing method, the present invention is particularly effective when the image forming body is a recording medium having a slow permeable or non-permeable property. Here, as a recording medium having a slow permeability property, for example, there is a coated paper for printing.

  In the case of the intermediate transfer method, image transfer is performed after the liquid solvent on the intermediate transfer member is removed while suppressing the movement of the color material on the intermediate transfer member. Can be prevented and image quality can be improved.

In the aggregation treatment layer forming step in the present invention, it is preferable to dry the aggregation treatment agent. Thereby, even if the moisture content of the aggregation treatment agent applied on the image forming body is increased, the moisture content of the aggregation treatment layer can be adjusted to 56% or less and 32% or more by drying. Therefore, an aggregating agent having a high water content can be used, so that application on the image forming body is facilitated and clogging when applying with a nozzle can be prevented.

  In addition, a liquid aggregation treatment agent having a high water content is applied on the image forming body and then dried to form a semi-solid solution aggregation processing layer, whereby a semi-solid solution aggregation processing layer is formed on the image formation body. Can be formed uniformly, and there is no variation in the size of the ink aggregates (dots) formed by the aggregation reaction of the ink droplets, and the image quality is improved.

  As means for applying an aggregating treatment liquid in which the aggregating agent is in a liquid state, application means such as an application roller, an inkjet head, or the like can be applied. When using a coating means, for example, a thin layer (aggregation treatment agent layer) having a thickness of about 0.5 to 20 μm can be formed uniformly. Further, when an ink jet head is used, it is possible to selectively apply an aggregating treatment liquid on demand according to a recorded image (image data), and it is possible to reduce the processing agent and the drying energy.

  In addition, as the solvent removal step in the present invention, any of the step of removing the liquid solvent on the image forming body by drying or the step of removing the liquid solvent on the image forming body by absorbing it to the absorber can be suitably used. .

  In particular, when an absorber is used, in the present invention, a sufficient adhesion force can be obtained between the dots (ink aggregates) and the image forming body, thereby preventing the coloring material from adhering to the absorber. Accordingly, it is possible to remove a large amount of liquid solvent from the image forming body in a short time without deteriorating the image quality, and the productivity can be improved.

  In the case of the intermediate transfer system, the image forming body used in the present invention is preferably a non-permeable medium such as resin, metal, or rubber. In the case of the direct drawing method, a recording medium having slow permeability such as a coated paper for printing is suitable. By making the image forming body slowly permeable or non-permeable, image deterioration due to color material movement can be effectively suppressed. However, the present invention is not limited only to these slow permeability or non-penetration, and it is also possible to apply a medium having permeability such as plain paper.

Further, in the present invention, the "water content", the mass per unit area of the aggregating treatment agent X _{1 [g} / m ^2] per unit area of the water contained in the aggregating treatment agent to the weight X _{2 [g} / m ² ] ratio (that is, (X ₂ / X ₁ ) × 100). In the present invention, the moisture content of the coagulation treatment layer is 56% or less and is defined by the upper limit, but the preferable lower limit is 32% by mass.

  In the present invention, after the aggregation treatment liquid is applied on the image forming body, the aggregation treatment liquid on the image forming body may be dried to form a semi-solid solution aggregation processing layer on the image forming body, A semisolid solution aggregation treatment agent may be directly applied on the image forming body.

According to a sixth aspect of the present invention, in order to achieve the above object, an image is formed on an image forming body by using an ink liquid containing a color material and an aggregation treatment agent containing a component for aggregating the color material. An image forming apparatus for providing an aggregation treatment liquid application means for applying an aggregation treatment liquid obtained by converting the aggregation treatment agent into a liquid state on the image forming body, and the aggregation treatment liquid applied on the image forming body. An agglomeration treatment liquid drying means for drying and forming a semi-solid solution agglomeration treatment layer comprising the aggregation treatment agent and having a water content of 56% or less and 32% or more is formed on the image forming body, and the aggregation treatment layer is formed. Ink droplet ejecting means for dropletizing the ink liquid onto the image forming body, and after the ink liquid has been ejected onto the image forming body by the ink droplet ejecting means, dry by drying means the liquid solvent on the image forming body Or to provide a solvent removal means for removing the absorption by the absorber, the image forming apparatus characterized by comprising a.

According to the sixth aspect of the present invention, the present invention is configured as an apparatus. With such a configuration, in a two-liquid aggregation method using ink and an aggregation treatment agent, image quality deterioration due to color material movement is prevented and high quality is achieved. Image formation is possible.

The seventh to ninth aspects define preferred embodiments of the image forming apparatus, and the same effects as the third to fifth aspects of the method invention can be obtained.

According to a tenth aspect of the present invention, in order to achieve the above object, a step of applying a liquid containing a component for aggregating an ink coloring material and substantially colorless fine particles on the intermediate transfer member; Drying the liquid applied to the substrate to form a particle layer composed of the fine particles and having a moisture content of 56% or less and 32% or more , and the intermediate transfer in which the particle layer is formed according to image data A step of forming droplets of the ink on the body and ejecting the liquid , a step of removing the liquid solvent on the intermediate transfer member with a drying means or an absorber, and an image formed on the intermediate transfer member as a recording medium And an image forming method.

According to the tenth aspect of the present invention, an ink droplet is ejected after forming a particle layer composed of fine particles and having a water content of 56% or less and 32% or more on the intermediate transfer member. The anchor effect can prevent the occurrence of image shrinkage accompanying the aggregation reaction. In addition, since the contact area between the image (ink layer) and the intermediate transfer member is reduced by the particle layer formed on the intermediate transfer member, the transfer property to the recording medium is improved.

  As a result, in the intermediate transfer method, the occurrence of image shrinkage due to the aggregation reaction of the ink color material is prevented, and the transferability is improved, thereby enabling high-quality image formation.

Here, “substantially colorless” means that when the fine particles of the present invention are applied at 0.1 g / m ² , the absorbance concentration in the visible region is 0.1 or less. The same applies hereinafter.

According to an eleventh aspect of the present invention, in order to achieve the above object, a step of applying a first liquid containing substantially colorless fine particles on the intermediate transfer member, and an ink coloring material on the intermediate transfer member. A step of applying a second liquid containing a component to be aggregated; and at least after the second liquid is applied on the intermediate transfer member, the first liquid and the second liquid on the intermediate transfer member. A step of drying the liquid to form a particle layer composed of the fine particles and having a moisture content of 56% or less and 32% or more , and the intermediate transfer body on which the particle layer is formed according to image data. A step of ejecting ink into droplets, a step of removing the liquid solvent on the intermediate transfer member by drying by a drying means or absorption by an absorber, and an image formed on the intermediate transfer member on a recording medium And a transfer step. To provide an image forming method.

In the eleventh aspect , in contrast to the tenth aspect in which the component for aggregating the ink color material and the substantially colorless fine particles are formed as one liquid, the liquid substantially contains the component for aggregating the ink color material. Are formed as two separate liquids including a liquid containing colorless fine particles. That is, a first liquid containing substantially colorless fine particles and a second liquid containing a component that aggregates the coloring material of the ink are separately applied to the intermediate transfer member. Thereby, generation | occurrence | production of the image shrinkage accompanying agglutination reaction can be prevented by the anchor effect of a particle layer. In addition, since the contact area between the image (ink layer) and the intermediate transfer member is reduced by the particle layer formed on the intermediate transfer member, the transfer property to the recording medium is improved. Also in this case, since the moisture content of the aggregation treatment layer is set to 56% or less and 32% or more , it is possible to remarkably suppress the movement of the color material in the ejected ink liquid in the aggregation treatment layer. Images can be formed.

In the present invention, the average particle diameter of the fine particles is preferably 0.1 to 10.0 μm, and the amount of fine particles applied to the intermediate transfer member is preferably 0.01 to 5.0 g / m ^2. Are more preferably 0.1 to 10.0 μm, an average particle diameter of fine particles of 3 to 5 μm, and an applied amount of particles of 0.1 to 3 g / m ² . The occurrence of image shrinkage can be prevented, image noise can be reduced, and the quality of the printed material can be obtained without feeling uncomfortable.

  In the present invention, the fine particles are preferably organic compounds, and favorable results can be obtained with respect to the glossiness of the recording medium.

  In the present invention, the fine particles are preferably a polymer, and the abrasion resistance of the recording medium is further improved.

  In the present invention, the fine particles are preferably polyolefin, and the transferability to a recording medium is further improved.

According to a sixteenth aspect of the present invention, there is provided a liquid applying means for applying a liquid containing a component for aggregating the coloring material of the ink and substantially colorless fine particles on the intermediate transfer body, and the intermediate transfer. The liquid applied on the body is dried to form a particle layer composed of the fine particles and having a moisture content of 56% or less and 32% or more , and the particle layer is formed according to image data. An ink droplet ejecting means for ejecting the ink into droplets on the intermediate transfer member; a solvent removing means for removing the liquid solvent on the intermediate transfer member by drying by a drying means or absorption by an absorber; and There is provided an image forming apparatus comprising: transfer means for transferring an image formed on an intermediate transfer member to a recording medium.

According to a seventeenth aspect of the present invention, in order to achieve the above object, a first liquid applying means for applying a first liquid containing substantially colorless fine particles on the intermediate transfer member; A second liquid applying means for applying a second liquid containing a component that agglomerates an ink coloring material; and after the second liquid is applied on at least the intermediate transfer member, Drying means for drying the first liquid and the second liquid to form a particle layer composed of the fine particles and having a moisture content of 56% or less and 32% or more , and the particle layer according to image data; Ink droplet ejecting means for dropletizing and ejecting the ink onto the formed intermediate transfer body, and a solvent removing means for removing the liquid solvent on the intermediate transfer body by drying by the drying means or absorption by the absorber. And an image formed on the intermediate transfer member. To provide an image forming apparatus which comprises a transfer unit that transfers the recording medium.

Claims 16 and 17 constitute the present invention as an apparatus, claim 16 constitutes the agglomeration component and substantially colorless fine particles as one liquid, and claim 17 constitutes two separate parts. It is configured as a liquid.

  According to the present invention, this configuration prevents occurrence of image shrinkage due to the aggregation reaction of the ink color material, improves transferability, and enables high-quality image formation.

  In the present invention, it is possible to apply various methods, such as application with an application roller or a blade, and droplet ejection with an inkjet head, to the liquid application means (including the first and second liquid application means). In particular, in the case of an ink jet method, liquid can be accurately patterned and applied on demand according to a recorded image (image data), and drying time and drying energy can be reduced.

According to the image forming method and the image forming apparatus of the present invention, an ink liquid is formed on the image forming body after a semi-solid state coagulation treatment layer made of an aggregation treatment agent and having a moisture content of 56% or less and 32% or more is formed. When the ink droplets land on the aggregating treatment layer by hitting the droplets, the agglomeration reaction starts instantaneously from the contact surface with the aggregating treatment layer, and the ink agglomerates spread to a predetermined size on the agglomeration treatment layer Dots made of (color material aggregates) are formed. As a result, sufficient adhesion can be obtained between the dots (ink aggregates) and the image forming body, image deterioration due to color material movement is prevented, and high-quality image recording becomes possible. In the two-liquid aggregation method using ink and an aggregation treatment agent, it is possible to form a high-quality image while preventing deterioration in image quality due to color material movement.

Further, according to the image forming method and the image forming apparatus of the present invention, an ink droplet is ejected after forming a particle layer composed of fine particles and having a moisture content of 56% or less and 32% or more on the intermediate transfer member. As a result, it is possible to prevent the occurrence of image shrinkage accompanying the aggregation reaction due to the anchor effect of the particle layer. In addition, since the contact area between the image (ink layer) and the intermediate transfer member is reduced by the particle layer formed on the intermediate transfer member, the transfer property to the recording medium is improved.

  Hereinafter, preferred embodiments of an image forming method and an image forming apparatus of the present invention will be described in detail with reference to the accompanying drawings.

  [I] In the first embodiment of the image forming apparatus of the present invention, an image is directly drawn on a recording medium transported by a drum by a two-liquid aggregation method. In the embodiment of the present invention, an example of a typical ink jet recording apparatus will be described as an image forming apparatus.

(Overall configuration of inkjet recording apparatus)
FIG. 1 is a configuration diagram showing the overall configuration of the inkjet recording apparatus 1 of the present embodiment. An inkjet recording apparatus 1 shown in FIG. 1 is an apparatus that forms an image on a recording surface of a recording medium 22, and mainly includes a paper feeding unit 10, a processing liquid application unit 12, a drawing unit 14, a drying unit 16, a fixing unit 18, and a discharge unit. 20. A recording medium 22 (sheets) is stacked on the paper supply unit 10, and the recording medium 22 is sent from the paper supply unit 10 to the treatment liquid application unit 12, and the treatment liquid application unit 12 processes the treatment liquid on the recording surface. Is applied to the recording surface by the drawing unit 14. The recording medium 22 to which ink is applied is transported by the discharge unit 20 after the image is fastened by the fixing unit 18. As a recording medium, conveyance up to the maximum chrysanthemum half (469 mm × 636 mm) size is possible.

  In addition, the inkjet recording apparatus 1 includes intermediate conveyance units 24, 26, and 28 between the respective units, and the recording medium 22 is transferred by the intermediate conveyance units 24, 26, and 28. That is, a first intermediate transport unit 24 is provided between the processing liquid application unit 12 and the drawing unit 14, and the recording medium 22 from the processing liquid application unit 12 to the drawing unit 14 is provided by the first intermediate transport unit 24. Is delivered. Similarly, a second intermediate transport unit 26 is provided between the drawing unit 14 and the drying unit 16. The recording medium 22 is transferred from the drawing unit 14 to the drying unit 16 by the second intermediate transport unit 26. Done. Further, a third intermediate transport unit 28 is provided between the drying unit 16 and the fixing unit 18, and the third intermediate transport unit 28 transfers the recording medium 22 from the drying unit 16 to the fixing unit 18. Is called.

  Hereinafter, each unit of the inkjet recording apparatus 1 (the paper feeding unit 10, the processing liquid applying unit 12, the drawing unit 14, the drying unit 16, the fixing unit 18, the discharging unit 20, the first to third intermediate conveying units 24, 26, and 28). ) Will be described.

(Paper Feeder)
The paper feed unit 10 is a mechanism that supplies the recording medium 22 to the drawing unit 14. The paper feed unit 10 is provided with a paper feed tray 50, and the recording medium 22 is fed from the paper feed tray 50 to the processing liquid application unit 12 one by one.

(Processing liquid application part)
The processing liquid application unit 12 is a mechanism that applies the processing liquid to the recording surface of the recording medium 22. The treatment liquid includes a color material aggregating agent that agglomerates or deposits the color material (pigment) in the ink applied by the drawing unit 14, and the ink comes into contact with the color material when the treatment liquid comes into contact with the ink. Separation from the solvent is facilitated.

  The treatment liquid is preferably added with a non-curl solvent. Specific examples of the non-curl solvent include alcohols (for example, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol). , Cyclohexanol, benzyl alcohol), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, hexanetriol, thio Diglycol), glycol derivatives (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol Butyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether , Triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylene) Reamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl) 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone).

  In addition, said organic solvent may be used independently and may use 2 or more types together. Moreover, it is preferable that these organic solvents are contained 1-50 mass% in a process liquid.

  As shown in FIG. 1, the treatment liquid application unit 12 includes a transfer drum 52, a treatment liquid drum 54, a treatment liquid application device 56, a hot air ejection nozzle 58, and an IR heater 60. The transfer drum 52 is disposed between the paper feed tray 50 of the paper feed unit 10 and the treatment liquid drum 54, and the rotation of the transfer drum 52 is controlled by a motor driver 142 (see FIG. 13) described later. The recording medium 22 fed from the paper feed unit 10 is received by the transfer drum 52 and transferred to the processing liquid drum 54. In addition, instead of the transfer drum 52, an intermediate conveyance unit described later may be provided.

  The treatment liquid drum 54 is a drum that holds and rotates the recording medium 22, and the rotation of the treatment liquid drum 54 is controlled by a motor driver 142 (see FIG. 13) described later. Further, the processing liquid drum 54 is provided with claw-shaped holding means (means similar to the holding means 73 in FIG. 4 described later) on the outer peripheral surface thereof, and the front end of the recording medium 22 can be held by this holding means. Yes. The recording medium 22 is rotated and conveyed by rotating the processing liquid drum 54 with the tip held by the holding means. At that time, the recording medium 22 is conveyed with its recording surface facing outward. The processing liquid drum 54 may be provided with a suction hole on the outer peripheral surface thereof and connected to a suction unit that performs suction from the suction hole. As a result, the recording medium 22 can be held in close contact with the peripheral surface of the treatment liquid drum 54.

  On the outside of the processing liquid drum 54, a processing liquid coating device 56, a hot air jet nozzle 58 and an IR heater 60 are provided so as to face the peripheral surface. The treatment liquid coating device 56, the hot air ejection nozzle 58, and the IR heater 60 are sequentially arranged from the upstream side in the rotation direction of the treatment liquid drum 54 (counterclockwise direction in FIG. 1). First, the processing liquid is applied to the recording surface by the processing liquid coating device 56. Further, the hot air jet nozzle 58 and the IR heater 60 are formed of an agglomerated layer formed by being applied onto the recording medium 22 by the processing liquid coating device 56 while the recording medium 22 is being conveyed by the processing liquid drum 54. The water content must be capable of being reduced to 56% or less.

  FIG. 2 is a configuration diagram of the processing liquid coating apparatus 56. As shown in FIG. 2, the processing liquid application device 56 includes a rubber roller 62, an anilox roller 64, a squeegee 66, and a processing liquid container 68. The processing liquid is stored in the processing liquid container 68, and a part of the anilox roller 64 is immersed in the processing liquid. A squeegee 66 and a rubber roller 62 are pressed against the anilox roller 64, and the rubber roller 62 is in contact with the recording medium 22 held and rotated by the processing liquid drum 54, and the rotation direction of the processing liquid drum 54. Is rotated at a predetermined constant speed in the opposite direction (clockwise direction in the figure).

  According to the processing liquid application device 56 configured as described above, the processing liquid is applied to the recording medium 22 by the rubber roller 62 while being measured by the anilox roller 64 and the squeegee 66. At this time, it is desirable that the film thickness of the treatment liquid is sufficiently smaller than the droplet diameter of the ink ejected from the ink jet heads 72C, 72M, 72Y, 72K (see FIG. 1) of the drawing unit 14. For example, when the ink droplet ejection amount is 2 pl, the average droplet diameter is 15.6 μm. At this time, when the film thickness of the processing liquid is large, the ink dots float in the processing liquid without contacting the surface of the recording medium 22. Therefore, in order to obtain a landing dot diameter of 30 μm or more when the ink droplet ejection amount is 2 pl, it is desirable that the film thickness of the treatment liquid is 3 μm or less.

The recording medium 22 coated with the treatment liquid by the treatment liquid coating device 56 is conveyed to the positions of the hot air ejection nozzle 58 and the IR heater 60 shown in FIG. The hot air blowing nozzle 58 is configured to blow high temperature (for example, 70 ° C.) warm air toward the recording medium 22 at a constant air volume (for example, 9 m ³ / min), and the IR heater 60 has a high temperature (for example, 180 ° C.). Be controlled. By the heating by the hot air blowing nozzle 58 and the IR heater 60, the water in the solvent of the processing liquid is evaporated, and a semi-solid solution thin aggregation processing layer having a water content of 56% or less is formed on the recording surface. By thinning the treatment liquid in this way, the dots of ink that are ejected by the drawing unit 14 come into contact with the recording surface of the recording medium 22 to obtain the required dot diameter, and the thinned treatment liquid component Reacts with the colorant to cause aggregation of the coloring material, and an effect of fixing to the recording surface of the recording medium 22 is easily obtained. Moreover, dot movement (coloring material movement) can be prevented by setting the moisture content of the aggregation treatment layer to 56% or less. The processing liquid drum 54 may be controlled to a predetermined temperature (for example, 50 ° C.).

(Drawing part)
As shown in FIG. 4, the drawing unit 14 includes a drawing drum 70 and ink jet heads 72 </ b> C, 72 </ b> M, 72 </ b> Y, and 72 </ b> K that are disposed in proximity to a position facing the outer peripheral surface of the drawing drum 70. The inkjet heads 72C, 72M, 72Y, and 72K correspond to inks of four colors of cyan (C), magenta (M), yellow (Y), and black (K), respectively, and the rotation direction of the drawing drum 70 (see FIG. 4 in the counterclockwise direction) from the upstream side.

  The drawing drum 70 is a drum that holds the recording medium 22 on its outer peripheral surface and rotates and conveys the drum. The rotation of the drawing drum 70 is controlled by a motor driver 142 (see FIG. 13) described later. Further, the drawing drum 70 includes a claw-shaped holding unit 73 on the outer peripheral surface thereof, and the holding unit 73 can hold the leading end of the recording medium 22. The recording medium 22 is rotated and conveyed by rotating the drawing drum 70 with the tip held by the holding means 73. At that time, the recording medium 22 is conveyed with its recording surface facing outward, and ink is applied to the recording surface from the ink jet heads 72C, 72M, 72Y, 72K.

  The inkjet heads 72C, 72M, 72Y, and 72K are full-line inkjet recording heads (inkjet heads) each having a length corresponding to the maximum width of the image forming area on the recording medium 22, and the ink ejection surfaces thereof are arranged on the ink ejection surface. Is formed with a nozzle row in which a plurality of nozzles for ink ejection are arranged over the entire width of the image forming area. Each inkjet head 72C, 72M, 72Y, 72K is fixedly installed so as to extend in a direction orthogonal to the conveyance direction of the recording medium 22 (the rotation direction of the drawing drum 70).

  Corresponding color ink droplets are ejected from the ink jet heads 72C, 72M, 72Y, 72K thus configured toward the recording surface of the recording medium 22 held on the outer peripheral surface of the drawing drum 70. As a result, the ink comes into contact with the treatment liquid applied to the recording surface in advance by the treatment liquid application unit 12, and the color material (pigment) dispersed in the ink is aggregated to form a color material aggregate. Thereby, the color material flow on the recording medium 22 is prevented, and an image is formed on the recording surface of the recording medium 22. At that time, since the drawing drum 70 of the drawing unit 14 is structurally separated from the processing liquid drum 54 of the processing liquid applying unit 12, the processing liquid may adhere to the ink jet heads 72C, 72M, 72Y, 72K. In addition, the cause of ink ejection failure can be reduced.

  In addition, as an example of the reaction between the ink and the treatment liquid, a mechanism for containing an acid in the treatment liquid and destroying and aggregating the pigment dispersion by PH down, color material bleeding, color mixing between inks of each color, and liquid upon landing of ink droplets It is conceivable to avoid droplet ejection interference due to coalescence.

  In addition, the droplet ejection timing of each of the inkjet heads 72C, 72M, 72Y, and 72K is synchronized with an encoder 91 (see FIG. 13) that detects the rotational speed disposed on the drawing drum 70. Thereby, the landing position can be determined with high accuracy. Further, the fluctuation of the speed due to the fluctuation of the drawing drum 70 or the like is learned in advance, and the droplet ejection timing obtained by the encoder 91 is corrected to obtain the fluctuation of the drawing drum 70, the accuracy of the rotation axis, and the speed of the outer peripheral surface of the drawing drum 70. Irregular droplet ejection can be reduced without depending on it.

  Furthermore, maintenance operations such as cleaning the nozzle surfaces of the inkjet heads 72C, 72M, 72Y, and 72K and discharging the thickened ink may be performed by retracting the head unit from the drawing drum 70.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special colors are used as necessary. Ink may be added. For example, it is possible to add an ink head that discharges light-colored ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited. A more detailed description of the inkjet heads 72C, 72M, 72Y, 72K will be described later.

(Drying part)
The drying unit 16 is a step of drying the water contained in the solvent separated by the color material aggregating action, and is disposed at a position facing the drying drum 76 and the outer peripheral surface of the drying drum 76 as shown in FIG. The first IR heater 78, the hot air jet nozzle 80, and the second IR heater 82. The first IR heater 78 is provided upstream of the hot air jet nozzle 80 in the rotation direction of the drying drum 76 (counterclockwise direction in FIG. 1), and the second IR heater 82 is jetted of hot air. Provided downstream of the nozzle 80.

  The drying drum 76 is a drum that holds the recording medium 22 on its outer peripheral surface and rotates and conveys the rotation, and the rotation of the drying drum 76 is controlled by a motor driver 142 (see FIG. 13) described later. Further, the drying drum 76 is provided with a claw-shaped holding means (means similar to the holding means 73 in FIG. 4) on its outer peripheral surface, and the leading end of the recording medium 22 can be held by this holding means. The recording medium 22 is rotated and conveyed by rotating the drying drum 76 with the tip held by the holding means. At that time, the recording surface of the recording medium 22 is conveyed so that the recording surface 22 faces outward, and a drying process is performed on the recording surface by the first IR heater 78, the hot air jet nozzle 80, and the second IR heater 82. Is called.

The hot air jet nozzle 80 is configured to blow hot air controlled to a predetermined temperature (for example, 50 ° C. to 70 ° C.) toward the recording medium 22 at a constant air volume (12 m ³ / min). The IR heater 78 and the second IR heater 82 are each controlled to a predetermined temperature (for example, 180 ° C.). By the first IR heater 78, the hot air jet nozzle 80, and the second IR heater 82, water contained in the ink solvent on the recording surface of the recording medium 22 held on the drying drum 76 is evaporated, and a drying process is performed. Is done. At that time, since the drying drum 76 of the drying unit 16 is structurally separated from the drawing drum 70 of the drawing unit 14, in the inkjet heads 72C, 72M, 72Y, and 72K, the head meniscus portion is dried by thermal drying. Ink ejection failure can be reduced. Moreover, there is a degree of freedom in setting the temperature of the drying unit 16, and an optimal drying temperature can be set.

  The evaporated water may be discharged out of the apparatus together with air by a discharge means (not shown). Further, the recovered air may be cooled by a cooler (radiator) or the like and recovered as a liquid.

  Further, the drying drum 76 is preferably controlled at a predetermined temperature (for example, 60 ° C. or lower) on the outer peripheral surface thereof.

  Further, the drying drum 76 may be provided with suction holes on the outer peripheral surface thereof and connected to suction means for performing suction from the suction holes. As a result, the recording medium 22 can be held in close contact with the peripheral surface of the drying drum 76.

(Fixing part)
As shown in FIG. 6, the fixing unit 18 includes a fixing drum 84, a first fixing roller 86, a second fixing roller 88, and an inline sensor 90. The first fixing roller 86, the second fixing roller 88, and the in-line sensor 90 are disposed at positions facing the peripheral surface of the fixing drum 84, and from the upstream side in the rotation direction of the fixing drum 84 (counterclockwise direction in FIG. 6). Arranged in order.

  The fixing drum 84 is a drum that holds the recording medium 22 on the outer peripheral surface thereof and rotates and conveys the rotation of the fixing drum 84 by a motor driver 142 (see FIG. 13) described later. Further, the fixing drum 84 is provided with a claw-shaped holding means (means similar to the holding means 73 in FIG. 4) on the outer peripheral surface thereof, and the leading end of the recording medium 22 can be held by this holding means. The recording medium 22 is rotated and conveyed by rotating the fixing drum 84 with the tip held by the holding means. At that time, the recording surface of the recording medium 22 is conveyed so that the recording surface faces outward, and fixing processing by the first fixing roller 86 and the second fixing roller 88 and inspection by the in-line sensor 90 are performed on the recording surface. .

  The first fixing roller 86 and the second fixing roller 88 are roller members for fixing an image formed on the recording medium 22 and are configured to pressurize and heat the recording medium 22. In other words, each of the first fixing roller 86 and the second fixing roller 88 is disposed so as to be in pressure contact with the fixing drum 84, and constitutes a nip roller with the fixing drum 84. As a result, the recording medium 22 is sandwiched between the first fixing roller 86 and the fixing drum 84 and between the second fixing roller 88 and the fixing drum 84 and is nipped at a predetermined nip pressure (for example, 1 MPa). The fixing process is performed. Note that an elastic layer may be formed on one surface of the first fixing roller 86, the second fixing roller 88, and the fixing drum 84 to have a uniform nip width with respect to the recording medium 22.

  The first fixing roller 86 and the second fixing roller 88 are constituted by a heating roller in which a halogen lamp is incorporated in a metal pipe such as aluminum having good thermal conductivity, and controlled to a predetermined temperature (for example, 60 to 80 ° C.). Is done. By heating the recording medium 22 with this heating roller, thermal energy equal to or higher than the Tg temperature (glass transition temperature) of the latex contained in the ink is applied, and the latex particles are melted. As a result, pressing and fixing are performed on the unevenness of the recording medium 22, and the unevenness on the surface of the image is leveled to obtain glossiness.

  In the above-described embodiment, an example in which both heating and pressurization are performed is shown, but only one may be performed. Further, the first fixing roller 86 and the second fixing roller 88 may have a plurality of stages depending on the thickness of the image layer and the Tg characteristics of the latex particles. Further, the surface of the fixing drum 84 may be controlled to a predetermined temperature (for example, 60 ° C.).

  On the other hand, the in-line sensor 90 is a measuring unit for measuring a check pattern, a moisture content, a surface temperature, a glossiness, and the like for an image fixed on the recording medium 22, and a CCD line sensor or the like is applied.

  According to the fixing unit 18 configured as described above, latex particles in the thin image layer formed by the drying unit 16 are pressurized and heated by the first fixing roller 86 and the second fixing roller 88 to be melted. Therefore, the recording medium 22 can be fixed and fixed. Further, according to the fixing unit 18, the fixing drum 84 is structurally separated from the other drums. Therefore, the temperature setting of the fixing unit 18 can be freely set separately from the drawing unit 14 and the drying unit 16. be able to.

  The fixing drum 84 may be provided with a suction hole on the outer peripheral surface thereof and connected to a suction unit that performs suction from the suction hole. As a result, the recording medium 22 can be held in close contact with the peripheral surface of the fixing drum 84.

(Discharge part)
As shown in FIG. 1, a discharge unit 20 is provided following the fixing unit 18. The discharge unit 20 includes a discharge tray 92, and a transfer drum 94, a conveyance belt 96, and a tension roller 98 are provided between the discharge tray 92 and the fixing drum 84 of the fixing unit 18 so as to be in contact therewith. It has been. The recording medium 22 is sent to the transport belt 96 by the transfer drum 94 and discharged to the discharge tray 92.

(Intermediate transport section)
Next, the structure of the first intermediate transport unit 24 will be described. Note that the second intermediate conveyance unit 26 and the third intermediate conveyance unit 28 have the same configuration as the first intermediate conveyance unit 24, and a description thereof will be omitted.

  FIG. 7A is a cross-sectional view of the first intermediate transport unit 24, and FIG. 7B is a cross-sectional view taken along line AA of FIG. 7A.

  As shown in these drawings, the first intermediate transport unit 24 mainly includes an intermediate transport body 30 and a transport guide 32. The intermediate transport body 30 is a drum for receiving the recording medium 22 from the preceding drum, rotating and transporting the recording medium 22 to the subsequent drum, and passing it through the bearings 35 and 37 as shown in FIG. The frames 31 and 33 are rotatably attached. The intermediate conveyance body 30 is rotated by a motor (not shown), and the rotation of the intermediate conveyance body 30 is controlled by an intermediate conveyance body rotation drive unit 141 (see FIG. 14) described later.

  Claw-shaped holding means 34 (means similar to the holding means 73 in FIG. 4) are provided on the outer peripheral surface of the intermediate conveyance body 30 at intervals of 90 °. The holding unit 34 rotates while drawing a circular locus, and the tip of the recording medium 22 is held by the operation of the holding unit 34. Therefore, the recording medium 22 can be rotated and conveyed by rotating the intermediate conveyance body 30 with the holding means 34 holding the leading end of the recording medium 22. At that time, the recording medium 22 is rotated and conveyed so that the recording surface faces the inside and the non-recording surface faces the outside. In the present embodiment, the two holding means 34 are provided in the intermediate conveyance body 30, but the number of holding means 34 is not limited to this.

  A plurality of air outlets 36 are formed on the surface of the intermediate conveyance body 30. Further, the inside of the intermediate conveyance body 30 is connected to a blower 38, and air is supplied to the intermediate conveyance body 30 by the blower 38. The air is preferably warm air. For example, warm air of 70 ° C. is sent at an air volume of 1 m 3 / min. Accordingly, warm air is blown out from the air blowing port 36 on the surface of the intermediate conveyance body 30, and the recording medium 22 is supported to float and the recording surface is dried. Therefore, it is possible to prevent the recording surface of the recording medium 22 from coming into contact with the intermediate conveyance body 30 and to prevent the processing liquid from adhering to the intermediate conveyance body 30.

Note that an air blowing restriction guide 40 is provided inside the intermediate conveyance body 30 so that air can be ejected only from the air blowing port 36 on the side carrying the recording medium 22. That is, in the present embodiment, since the recording medium 22 is transported by the lower half of the intermediate transport body 30 in FIG. 7A, the air blowing port 36 of the upper half of the intermediate transport body 30 is sealed by the air flow restriction guide 40. Is done. As a result, the recording medium 22 can be more reliably levitated and supported by the air sent from the air outlet 36.

  As shown in FIG. 7A, the conveyance guide 32 has an arc-shaped guide surface 44, and the guide surface 44 is disposed along the peripheral surface of the lower half of the intermediate conveyance body 30. Therefore, the recording medium 22 that is levitated and supported by the intermediate conveyance body 30 is conveyed while its opposite surface (hereinafter referred to as a non-recording surface) is in contact with the guide surface 44. As a result, tension (hereinafter referred to as back tension) opposite to the transport direction can be applied to the recording medium 22, and the occurrence of floating wrinkles on the recording medium 22 being transported can be prevented.

  A plurality of suction holes 42 are formed uniformly on the guide surface 44 of the transport guide 32. The suction hole 42 communicates with an internal space (hereinafter referred to as a chamber 41) of the conveyance guide 32, and the chamber 41 is connected to a pump 43. Therefore, by driving the pump 43, the chamber 41 can be set to a negative pressure, and air can be sucked from the suction hole 42. As a result, the non-recording surface of the recording medium 22 that is levitated and supported by the intermediate conveyance body 30 can be brought into close contact with the guide surface 44, and the back tension to the recording medium 22 can be reliably applied. Further, the back tension can be adjusted by controlling the pump 43 by a negative pressure control unit 147 described later and adjusting the air suction amount. The negative pressure control unit 147 may control the suction force of the pump 43 according to the specifications of the recording medium 22 (for example, the thickness, void ratio, type, etc. of the recording medium 22).

  According to the first intermediate transport unit 24 configured as described above, when the recording medium 22 is transported by the intermediate transport body 30, the recording surface can be transported in a non-contact manner. Therefore, it is possible to avoid image failures that occur. In addition, according to the first intermediate transport unit 24, the non-recording surface can be transported while being in close contact with the transport guide 32, so that back tension can be applied to the recording medium 22, and the non-recording surface can float on the recording medium 22. It is possible to prevent the occurrence of such a failure. Further, according to the first intermediate transport unit 24, since the warm air is blown from the intermediate transport body 30, the recording surface can be dried while transporting the recording medium 22.

  The recording medium 22 transported by the first intermediate transport unit 24 is transferred to the subsequent drum (that is, the drawing drum 70). At that time, the recording medium 22 is delivered by synchronizing the holding means 34 of the intermediate transport unit 24 and the holding means 73 of the drawing unit 14. The transferred recording medium 22 is held and drawn by the drawing drum 70. At that time, since the recording medium 22 immediately after delivery is conveyed in close contact with the conveyance guide 32, it is possible to prevent a failure such as a floating habit from occurring during delivery.

  In addition, you may provide the back tension provision means different from embodiment mentioned above. For example, the guide surface 44 may be surface-treated to increase the surface roughness, or the guide surface 44 may be formed of a member having a large friction coefficient such as rubber.

  Further, as another back tension applying means, the recording medium 22 may be attracted to the surface of the subsequent drum. For example, the drawing drum 70 shown in FIG. 8 has a suction hole 74 formed on the outer peripheral surface thereof and is connected to a pump 75 so that the recording medium 22 can be adsorbed on the outer peripheral surface thereof. Therefore, when the recording medium 22 is delivered to the drawing drum 70, the leading end side of the recording medium 22 is sucked and conveyed by the drawing drum 70, while the rear end side of the recording medium 22 is transferred to the first intermediate conveying unit. Since it is adsorbed by the 24 conveyance guides 32, back tension can be applied to the recording medium 22. Note that the leading end of the recording medium 22 may be adhered to the drawing drum 70 by electrostatic adsorption.

(Ink head structure)
Next, the structure of each ink head will be described. Since the ink-jet heads 72C, 72M, 72Y, and 72K for each color have the same structure, the ink head is represented by the reference numeral 100 in the following.

  FIG. 9A is a perspective plan view showing an example of the structure of the ink head 100, and FIG. 9B is an enlarged view of a part thereof. In order to increase the dot pitch printed on the recording medium 22, it is necessary to increase the nozzle pitch in the ink head 100. As shown in FIGS. 9A and 9B, the ink head 100 according to this example includes a plurality of ink chamber units (a nozzle 102 serving as an ink discharge port, a pressure chamber 104 corresponding to each nozzle 102, and the like). It has a structure in which droplet ejection elements 108 as recording element units are arranged in a zigzag matrix (two-dimensionally), and thereby, in the longitudinal direction of the head (direction perpendicular to the conveyance direction of the recording medium 22). A high density of substantial nozzle intervals (projection nozzle pitch) projected so as to be aligned along the line is achieved.

  One or more nozzle rows are formed over a length corresponding to the entire width of the image forming area of the recording medium 22 in a direction (arrow M in FIG. 9) substantially orthogonal to the conveyance direction of the recording medium 22 (arrow S in FIG. 9). The form is not limited to the illustrated example. For example, instead of the configuration of FIG. 9 (a), as shown in FIG. 10, a short head module 100 ′ in which a plurality of nozzles 102 are two-dimensionally arranged is arranged in a staggered manner and connected to form a long Therefore, a line head having a nozzle row having a length corresponding to the entire width of the image forming area of the recording medium 22 as a whole may be configured.

  The pressure chamber 104 provided corresponding to each nozzle 102 has a substantially square planar shape (see FIGS. 9A and 9B), and the nozzle 102 is provided at one of the diagonal corners. An outlet for supplying ink (supply port) 106 is provided on the other side. The shape of the pressure chamber 104 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon, other polygons, a circle, an ellipse, and the like.

  FIG. 11 is a cross-sectional view (11 in FIG. 9A) showing a three-dimensional configuration of one-channel droplet discharge elements (ink chamber units corresponding to one nozzle 102) serving as a recording element unit in the ink head 100. FIG. 11 is a cross-sectional view taken along line −11.

  As shown in FIG. 11, each pressure chamber 104 communicates with the common channel 110 through the supply port 106. The common flow path 110 communicates with an ink tank (not shown) as an ink supply source, and ink supplied from the ink tank is supplied to each pressure chamber 104 via the common flow path 110.

  An actuator 116 having an individual electrode 114 is joined to a pressure plate (vibrating plate that also serves as a common electrode) 112 constituting a part of the pressure chamber 104 (the top surface in FIG. 11). By applying a driving voltage between the individual electrode 114 and the common electrode, the actuator 116 is deformed to change the volume of the pressure chamber 104, and ink is ejected from the nozzle 102 due to the pressure change accompanying this. For the actuator 116, a piezoelectric element using a piezoelectric material such as lead zirconate titanate or barium titanate is preferably used. When the displacement of the actuator 116 returns to the original state after ink ejection, new ink is refilled into the pressure chamber 104 from the common flow path 110 through the supply port 106.

  By controlling the driving of the actuator 116 corresponding to each nozzle 102 in accordance with dot data generated by digital halftoning processing from the input image, ink droplets can be ejected from the nozzle 102. A desired image can be recorded on the recording medium 22 by controlling the ink ejection timing of each nozzle 102 in accordance with the conveyance speed while conveying the recording medium 22 in the sub-scanning direction at a constant speed.

  As shown in FIG. 12, the ink chamber unit 108 having the above-described structure is latticed in a fixed arrangement pattern along a row direction along the main scanning direction and an oblique column direction having a constant angle θ not orthogonal to the main scanning direction. The high-density nozzle head of this example is realized by arranging a large number in the shape.

  That is, the pitch P of the nozzles projected (orthographically projected) so as to be aligned in the main scanning direction by a structure in which a plurality of ink chamber units 108 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction. D × cos θ, and in the main scanning direction, each nozzle 102 can be handled equivalently as a linear array with a constant pitch P. With such a configuration, it is possible to realize a substantial increase in the density of nozzle rows projected so as to be aligned in the main scanning direction.

  When driving a nozzle with a full line head having a nozzle row having a length corresponding to the entire printable width, (1) all the nozzles are driven simultaneously, (2) the nozzles are sequentially moved from one side to the other. (3) The nozzles are divided into blocks, and each block is sequentially driven from one side to the other, etc., and one line (by one row of dots) in a direction perpendicular to the conveyance direction of the recording medium 22 Driving a nozzle that prints a line or a line composed of a plurality of rows of dots is defined as main scanning.

  In particular, when driving the nozzles 102 arranged in a matrix as shown in FIG. 12, the main scanning as described in (3) above is preferable. That is, nozzles 102-11, 102-12, 102-13, 102-14, 102-15, 102-16 are made into one block (other nozzles 102-21,..., 102-26 are made into one block, , 102-36 as one block,..., And by sequentially driving the nozzles 102-11, 102-12,. One line is printed in a direction orthogonal to the 22 conveyance direction.

  On the other hand, by moving the full line head and the recording medium 22 relative to each other, printing of one line (a line formed by one line of dots or a line composed of a plurality of lines) formed by the main scanning described above is repeatedly performed. This is defined as sub-scanning.

  The direction indicated by one line (or the longitudinal direction of the belt-like region) recorded by the main scanning is referred to as a main scanning direction, and the direction in which the sub scanning is performed is referred to as a sub scanning direction. That is, in the present embodiment, the conveyance direction of the recording medium 22 is the sub-scanning direction, and the direction orthogonal to the recording medium 22 is the main scanning direction. In implementing the present invention, the nozzle arrangement structure is not limited to the illustrated example.

  In this embodiment, a method of ejecting ink droplets by deformation of an actuator 116 typified by a piezo element (piezoelectric element) is adopted. However, in the practice of the present invention, a method of ejecting ink is not particularly limited. Instead of the piezo jet method, various methods such as a thermal jet method in which ink is heated by a heating element such as a heater to generate bubbles and ink droplets are ejected by the pressure can be applied.

(Description of control system)
FIG. 13 is a principal block diagram showing the system configuration of the inkjet recording apparatus 1. The ink jet recording apparatus 1 includes a communication interface 120, a system controller 122, a print controller 124, a treatment liquid application controller 126, a first intermediate transport controller 128, a head driver 130, a second intermediate transport controller 132, and a drying controller 134. A third intermediate transport control unit 136, a fixing control unit 138, an inline sensor 90, an encoder 91, a motor driver 142, a memory 144, a heater driver 146, an image buffer memory 148, a suction control unit 149, and the like.

  The communication interface 120 is an interface unit that receives image data sent from the host computer 150. As the communication interface 120, a serial interface such as USB (Universal Serial Bus), IEEE 1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted. Image data sent from the host computer 150 is taken into the inkjet recording apparatus 1 via the communication interface 120 and temporarily stored in the memory 144.

  The system controller 122 includes a central processing unit (CPU) and its peripheral circuits, and functions as a control device that controls the entire inkjet recording apparatus 1 according to a predetermined program, and also functions as an arithmetic device that performs various calculations. . That is, the system controller 122 includes the communication interface 120, the treatment liquid application controller 126, the first intermediate transport controller 128, the head driver 130, the second intermediate transport controller 132, the drying controller 134, and the third intermediate transport controller 136. , Fixing control unit 138, memory 144, motor driver 142, heater driver 146, suction control unit 149, and the like to control communication with host computer 150, read / write control of memory 144, etc. A control signal for controlling the motor 152 and the heater 154 is generated.

  The memory 144 is a storage unit that temporarily stores an image input via the communication interface 120, and data is read and written through the system controller 122. The memory 144 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The ROM 145 stores programs executed by the CPU of the system controller 122 and various data necessary for control. The ROM 145 may be a non-rewritable storage unit, or may be a rewritable storage unit such as an EEPROM. The memory 144 is used as a temporary storage area for image data, and is also used as a program development area and a calculation work area for the CPU.

  The motor driver 142 is a driver that drives the motor 152 in accordance with an instruction from the system controller 122. In FIG. 13, a motor 152 disposed in each part of the apparatus is represented by reference numeral 152. For example, the motor 152 shown in FIG. 13 includes a motor that drives the rotation of the transfer drum 52, the treatment liquid drum 54, the drawing drum 70, the drying drum 76, the fixing drum 84, the transfer drum 94, and the like. A drive motor for the pump 75 for sucking negative pressure from the suction hole 74, a motor for a retraction mechanism for the head units of the ink jet heads 72C, 72M, 72Y, 72K, and the like are included.

  The heater driver 146 is a driver that drives the heater 154 in accordance with an instruction from the system controller 122. In FIG. 13, a plurality of heaters provided in the ink jet recording apparatus 1 are represented by reference numeral 154 as a representative. For example, the heater 154 shown in FIG. 13 includes a preheater (not shown) for heating the recording medium 22 to an appropriate temperature in the paper supply unit 10 in advance.

  The print control unit 124 has a signal processing function for performing various processes and corrections for generating a print control signal from the image data in the memory 144 under the control of the system controller 122, and the generated print. It is a control unit that supplies data (dot data) to the head driver 130. Necessary signal processing is performed in the print control unit 124, and the ejection amount and ejection timing of the ink droplets of the ink head 100 are controlled via the head driver 130 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 124 includes an image buffer memory 148, and image data, parameters, and other data are temporarily stored in the image buffer memory 148 when image data is processed in the print control unit 124. In FIG. 13, the image buffer memory 148 is shown in a mode associated with the print control unit 124, but it can also be used as the memory 144. Also possible is an aspect in which the print control unit 124 and the system controller 122 are integrated to form a single processor.

  An outline of the flow of processing from image input to print output is as follows. Image data to be printed is input from the outside via the communication interface 120 and stored in the memory 144. At this stage, for example, RGB image data is stored in the memory 144.

  In the ink jet recording apparatus 1, a pseudo continuous tone image is formed by changing the droplet ejection density and dot size of fine dots with ink (coloring material) to the human eye. It is necessary to convert to a dot pattern that reproduces the gradation (shading of the image) as faithfully as possible. Therefore, the original image (RGB) data stored in the memory 144 is sent to the print control unit 124 via the system controller 122, and the print control unit 124 performs halftoning processing using a threshold matrix, an error diffusion method, or the like. Is converted into dot data for each ink color.

  That is, the print control unit 124 performs a process of converting the input RGB image data into dot data of four colors K, C, M, and Y. Thus, the dot data generated by the print control unit 124 is stored in the image buffer memory 148.

  The head driver 130 is a drive signal for driving the actuator 116 corresponding to each nozzle 102 of the ink head 100 based on print data (that is, dot data stored in the image buffer memory 148) given from the print control unit 124. Is output. The head driver 130 may include a feedback control system for keeping the head driving condition constant.

  When the drive signal output from the head driver 130 is applied to the ink head 100, ink is ejected from the corresponding nozzle 102. An image is formed on the recording medium 22 by controlling the ink ejection from the ink head 100 while conveying the recording medium 22 at a predetermined speed.

  Further, the system controller 122 includes a processing liquid application control unit 126, a first intermediate conveyance control unit 128, a second intermediate conveyance control unit 132, a drying control unit 134, a third intermediate conveyance control unit 136, a fixing control unit 138, and suction control. The unit 149 is controlled.

  The treatment liquid application control unit 126 controls the operation of the treatment liquid application device 56 of the treatment liquid application unit 12 in accordance with an instruction from the system controller 122. Specifically, in the processing liquid application device 56, the processing liquid is supplied to the rubber roller rotation driving unit 156 that drives the rotation of the rubber roller 62, the anilox roller rotation driving unit 158 that drives the rotation of the anilox roller 64, and the processing liquid container 68. The liquid feed pump 160 and the like are controlled by the processing liquid application controller 126.

  The first intermediate conveyance control unit 128 controls the operation of the intermediate conveyance body 30 and the conveyance guide 32 of the first intermediate conveyance unit 24 in accordance with an instruction from the system controller 122. Specifically, in the intermediate conveyance body 30, the rotation drive of the intermediate conveyance body 30 itself, the rotation of the holding means 34 provided in the intermediate conveyance body 30, the drive of the blower 38, and the like are controlled. Further, in the conveyance guide 32, the operation of the pump 43 for performing the suction operation from the suction hole 42 is controlled.

  FIG. 14 is a principal block diagram showing the system configuration of the first intermediate conveyance control unit 128. As shown in FIG. 14, the first intermediate conveyance control unit 128 configures an intermediate conveyance body rotation driving unit 141, a blower control unit 143, and a negative pressure control unit 147.

  The intermediate conveyance body rotation drive unit 141 controls the rotation drive of the intermediate conveyance body 30 itself.

  The air blowing control unit 143 can adjust the temperature and air volume of the air blown from the blower 38 to efficiently control the drying of moisture contained in the treatment liquid and the low viscosity and penetration of the high boiling point solvent. . Further, the magnitude of the positive pressure by the air blowing may be controlled by controlling the amount of air blown from the blower 38 according to the type of the recording medium 22. Further, the magnitude of the positive pressure by the air blowing may be controlled by controlling the air volume of the air blown from the blower 38 according to at least one of the thickness of the recording medium 22 and the porosity of the recording medium 22. Further, the temperature of the air blown from the blower 38 may be controlled according to the type of the recording medium 22 (for example, the type of fine paper, coated paper, etc.).

  The negative pressure control unit 147 controls the pump 43 to perform suction from a non-recording surface that is the surface opposite to the recording surface of the recording medium 22 so that the solvent contained in the processing liquid penetrates. Further, the negative pressure applied by the pump 43 may be controlled to vary based on at least one of the thickness of the recording medium 22 and the porosity of the recording medium 22. Further, the magnitude of the negative pressure applied by the pump 43 may be controlled according to the type of the recording medium 22.

  The second intermediate transfer control unit 132 and the third intermediate transfer control unit 136 have the same system configuration as that of the first intermediate transfer control unit 128, and each of the second intermediate transfer control unit 136 and the second intermediate transfer control unit 136 follows the instructions from the system controller 122. The operation of the intermediate conveyance body 30 and the conveyance guide 32 of the third intermediate conveyance unit 28 is controlled.

  The drying control unit 134 controls the operations of the first IR heater 78, the hot air ejection nozzle 80, and the second IR heater 82 in the drying unit 16 in accordance with instructions from the system controller 122.

  The fixing control unit 138 controls the operations of the first fixing roller 86 and the second fixing roller 88 in the fixing unit 18 in accordance with an instruction from the system controller 122.

  The suction control unit 149 controls the operation of the pump 75 connected to the suction hole 74 of the drawing drum 70 of the drawing unit 14.

  The system controller 122 also receives a check pattern attached to the recording medium 22 from the inline sensor 90 and a detection signal of measurement result data such as the moisture content, surface temperature, and glossiness of the recording medium 22. Further, a detection signal of the rotation speed of the drawing drum 70 is also input from the encoder 91, and the droplet ejection timing of the ink head 100 is controlled via the head driver 130.

[Characteristic effect of inkjet recording apparatus]
The inkjet recording apparatus 1 configured as described above can obtain the following specific effects.

  In the treatment liquid application unit 12, the treatment liquid coated on the recording medium 22 by the treatment liquid coating device 56 is dried by the hot air jet nozzle 58 and the IR heater 60, thereby agglomeration treatment layer having a moisture content of 56% or less. To form. Thereby, it is possible to prevent dot movement (coloring material movement) in which the dots of ink ejected onto the aggregation treatment layer move in the aggregation treatment layer.

  In the drying unit 16, the ink solvent on the recording medium 22 is dried by the first IR heater 78, the hot air ejection nozzle 80, and the second IR heater 82. High-speed and high-quality images can be formed on the recording medium 22 without causing unevenness, ink bleeding or color mixing due to application of a plurality of inks, or deformation of the recording medium such as curl and cockle.

  In the relationship between the drawing unit 14 and the drying unit 16, the inkjet heads 72 </ b> C, 72 </ b> M, 72 </ b> Y, 72 </ b> K, the first IR heater 78, the hot air jet nozzle 80, and the second IR heater 82 are dried with the drawing drum 70. The drum 76 is disposed so as to be structurally separated. Accordingly, the drawing drum 70 itself is not heated, the meniscus of the ink jet heads 72C, 72M, 72Y, 72K is not dried, and the non-ejection phenomenon of the ink jet heads 72C, 72M, 72Y, 72K can be prevented. High-speed and high-quality images can be formed on 22.

  In the relationship between the drawing unit 14, the drying unit 16, and the fixing unit 18, the inkjet heads 72 </ b> C, 72 </ b> M, 72 </ b> Y, 72 </ b> K, the first IR heater 78, the hot air ejection nozzle 80, the second IR heater 82, The first fixing roller 86 and the second fixing roller 88 are arranged structurally separated for each drum. Thereby, the temperature setting by the first fixing roller 86 and the second fixing roller 88 can be freely set.

  In addition, since no other structural member such as the intermediate conveyance body 30 is in contact with the recording surface of the recording medium 22, image failure can be avoided and the recording surface of the recording medium 22 is a semi-wet large recording medium. Even so, it can be conveyed with high accuracy and the position of the recording medium can be ensured with high accuracy. Furthermore, if the air pressure control unit 143 and the negative pressure control unit 147 control the pressure applied to the recording medium 22 by controlling the pump 43 and the blower 38 according to the type of the recording medium 22, the versatility of the recording medium 22 can be improved. Can be dealt with.

  Further, if the air pressure control unit 143 and the negative pressure control unit 147 control the pressure applied to the recording medium 22 according to at least one of the thickness of the recording medium 22 and the porosity of the recording medium 22, the general-purpose recording medium 22 can be used. Can deal with gender.

  Further, if air is sent from the air blowing port 36 of the intermediate carrier 30 to the recording surface of the recording medium 22, the ink that has been deposited on the recording surface of the recording medium 22 penetrates into the recording medium 22. It can be further promoted.

  Further, in the intermediate conveyance body 30, by using the air blowing restriction guide 40 to restrict the direction of the air blowing so as to send out the air from the air blowing port 36 facing the recording surface of the recording medium 22, the recording medium 22 can be more surely provided. The penetration of the high-boiling solvent into the recording medium 22 by the ink hitting the recording surface is promoted.

  Table 1 shows the evaluation results of the viscosity characteristics of the high boiling point solvent with respect to the temperature of the liquid for the liquid containing the high boiling point solvent. Table 1 shows the evaluation results when three kinds of liquid temperatures are set when five kinds of solvent contents of the high boiling point solvent are set. The unit of viscosity is mPa · s (cp).

表１に示すように、液体の温度が高いほど高沸点溶媒の粘度は減少する傾向にあるので、温風を送り出すことにより水性インクの温度を高くして、水性インクの高沸点溶媒を低粘化すれば、水性インクの溶媒の記録媒体２２への浸透を促進させることができる。

As shown in Table 1, the higher the temperature of the liquid, the lower the viscosity of the high boiling point solvent. Therefore, the temperature of the aqueous ink is increased by sending warm air, and the high boiling point solvent of the aqueous ink is decreased. In this case, the penetration of the solvent of the water-based ink into the recording medium 22 can be promoted.

  In the intermediate conveyance body 30, the conveyance guide 32 applies a force (back tension) in a direction opposite to the rotation direction of the recording medium 22 when the recording medium 22 is delivered to the drawing drum 70, the drying drum 76, and the fixing drum 84. Make it work. As a result, the occurrence of wrinkles and floating when the recording medium 22 is conveyed to the drying drum 76 or the fixing drum 84 can be reduced. Therefore, the curling cuckle is reduced on the drying drum 76 to promote drying, and the fixing drum 84 is transported to the fixing unit 18 while applying tension to the fixing unit 18 while reducing sheet floating. The effect of preventing wrinkles is obtained.

  A means for applying a back tension to the recording medium 22 may be a means for sucking the non-recording surface of the recording medium 22. Further, as means for applying a back tension to the recording medium 22, means for sending air to the recording surface of the recording medium 22 can be considered. Note that by partially restricting the air sent to the recording surface of the recording medium 22, for example, the direction of the air blowing so that the air is sent from the air blowing port 36 in the direction facing the recording surface of the recording medium 22 by the air blowing restriction guide 40. If this is regulated, the back tension can be efficiently applied to the recording medium 22. In addition, a method of increasing the surface roughness of the guide surface 44 of the conveyance guide 32 or affixing rubber or the like to increase the frictional force can be considered.

  Further, if the drawing drum 70, the drying drum 76, and the fixing drum 84 are provided with means for bringing the recording medium 22 into close contact with the drum circumferential surface, the recording medium 22 is surely wrinkled and lifted when the recording medium 22 is conveyed to the drawing drum 70. Absent. As means for bringing the recording medium 22 into close contact with the drum peripheral surface, suction means, electrostatic adsorption means, and the like are conceivable.

  Further, in the first intermediate conveyance unit 24, the recording medium 22 is rotated and moved while the leading end of the recording medium 22 is held by the holding means 34 of the intermediate conveyance body 30. At this time, the non-recording surface of the recording medium 22 is supported by the guide surface 44 by performing at least one of sending out air from the air blowing port 36 of the intermediate conveyance body 30 and suction from the suction hole 42 of the conveyance guide 32. It is conveyed while being. Therefore, the recording medium 22 is conveyed without the recording surface coming into contact with the intermediate conveyance body 30. Therefore, the image formed by the water-based ink applied to the recording surface of the recording medium by the drawing unit 14 is maintained as it is.

  Note that by partially restricting the air sent to the recording surface of the recording medium 22, for example, the direction of the air blowing so that the air is sent from the air blowing port 36 in the direction facing the recording surface of the recording medium 22 by the air blowing restriction guide 40. If this is regulated, the back tension can be efficiently applied to the recording medium 22.

  In the first intermediate conveyance unit 24 and the second intermediate conveyance unit 26, at least one of suction from the suction hole 42 of the conveyance guide 32 and sending of blown air from the air blowing port 36 of the intermediate conveyance body 30 is performed. As a result, the high boiling point solvent contained in the aqueous ink applied by the drawing unit 14 penetrates into the recording medium. For this reason, when the image is fixed using the first fixing roller 86 and the second fixing roller 88 in the fixing unit 18 in the post-process, the high boiling point solvent does not exist on the surface of the recording medium 22, so that the aggregated color material and the recording are recorded. Adhesiveness with the surface can be secured, image fixability is improved, image quality is improved, and color material offset to the first fixing roller 86 and the second fixing roller 88 is improved.

  Note that the negative pressure applied from the suction hole 42 by the pump 43 when sucking the non-recording surface of the recording medium 22 is determined by the negative pressure control unit 147 (see FIG. 10) of the control system and the thickness of the recording medium 22 and the recording medium. Control may be made to vary based on at least one of the 22 porosity. Specifically, the greater the thickness of the recording medium 22, the greater the negative pressure applied from the suction hole 42 by the pump 43 in order to promote the penetration of the solvent into the recording medium 22. Further, as the porosity of the recording medium 22 is smaller, the negative pressure applied from the suction hole 42 by the pump 43 is increased in order to promote the penetration of the solvent into the recording medium 22.

  Further, in the first intermediate transport unit 24 and the second intermediate transport unit 26, hot air is sent from the air blowing port 36 of the intermediate transport body 30 to the recording surface of the special paper, so that the high boiling point solvent in the ink has a low viscosity. This promotes penetration into the recording medium 22 and promotes drying of residual moisture in the ink.

  In addition, the temperature and air volume of the air blown from the blower 38 are adjusted by the air blowing control unit 143 (see FIG. 10) of the control system, and the low viscosity of the high boiling point solvent in the ink and the drying of the residual moisture are promoted efficiently. You may make it control to do.

  As described above, the ink jet recording apparatus and the ink jet recording method of the present invention have been described in detail. However, the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.

(recoding media)
In the present invention, a slowly permeable recording medium 22 such as a coated paper for printing can be suitably used. In particular, the following recording media can be preferably used.

Glossy or matte paper such as cast coated paper, art paper, coated paper, fine coated paper, high quality paper, recycled paper, synthetic paper, pressure sensitive paper, embossed paper, etc. is suitably used as an example of the slow-penetrating recording medium 22 Is done. More specifically, OK L Card + (Oji Paper Co., Ltd.), SA Kinto + (Oji Paper Co., Ltd.), Satin Kinto N (Oji Paper Co., Ltd.), OK Top Coat + (Oji Paper Co., Ltd.), New Age (Oji Paper Co., Ltd.), Tokuhishi Art Double Side N (Mitsubishi Paper Co., Ltd.), Tokuhishi Art Single Side N (Mitsubishi Paper Co., Ltd.), New V Matt (Mitsubishi Paper Co., Ltd.), Aurora Coat (Nippon Paper Industries Co., Ltd.), Aurora L (manufactured by Nippon Paper Industries), Ulite (manufactured by Nippon Paper Industries), Recycle Coat T-6 (manufactured by Nippon Paper Industries), Recycle Mat T-6 (manufactured by Nippon Paper Industries), iBest W (manufactured by Nippon Paper Industries) ), Invar Coat M (manufactured by SPAN CORPORATION), Hi McKinley Art (manufactured by Gojo Paper Co., Ltd.), Kinmari Hi-L (manufactured by Hokuetsu Paper Co., Ltd.), Signature True (manufactured by Newpage corporation), Sterling Ultra (manufactured by Newpage corporation) , Anthem (manufactured by Newpage corporation), Hanno ArtSilk (manufactured by Sappi), Hanno Art gro Basis of ss (Sappi), Consort Royal Semimatt (Scheufelen), Consort Royal Gross (Scheufelen), Zanders Ikono Silk (m-real), Zanders Ikono Gross (m-real) Those having 60 to 350 g / m ² are preferably used.

  Furthermore, the present invention can also be applied to non-penetrating media such as plastic films and intermediate transfer media.

[Water-based ink]
Hereinafter, the water-based ink used in the embodiment of the present invention will be described in detail.

  The aqueous ink in the present invention comprises a resin dispersant (A), a pigment (B) dispersed by the resin dispersant (A), self-dispersing polymer fine particles (C), and an aqueous liquid medium (D). It is configured as a dedicated ink containing at least.

(Resin dispersant (A))
The resin dispersant (A) is used as a dispersant for the pigment (B) in the aqueous liquid medium (D), and any resin that can disperse the pigment B may be used. The structure of the agent (A) preferably has a hydrophobic structural unit (a) and a hydrophilic structural unit (b). If necessary, the resin dispersant (A) can include a structural unit (c) different from the hydrophobic structural unit (a) and the hydrophilic structural unit (b).

  The composition of the hydrophilic structural unit (b) and the hydrophobic structural unit (a) depends on the degree of hydrophilicity and hydrophobicity of each, but the hydrophobic structural unit (a) is the entire resin dispersant (A). It is preferable to contain more than 80 mass% with respect to the mass of, and 85 mass% or more is more preferable. That is, the hydrophilic structural unit (b) needs to be 15% by mass or less, and when the hydrophilic structural unit (b) is more than 15% by mass, the aqueous liquid medium alone does not contribute to the dispersion of the pigment. The component dissolved in (D) increases, which deteriorates various properties such as the dispersibility of the pigment (B), and causes the discharge properties of the inkjet recording ink to deteriorate.

<Hydrophobic structural unit (a)>
The resin dispersant (A) in the present invention comprises a hydrophobic structural unit (a) having an aromatic ring that is not directly bonded to an atom forming the main chain of the resin dispersant (A) among the hydrophobic structural units (a) ( a1) at least.

  Here, “not directly bonded” means that the aromatic ring and the atom forming the main chain structure of the resin are bonded via a linking group. By having such a form, an appropriate distance is maintained between the hydrophilic structural unit in the resin dispersant (A) and the hydrophobic aromatic ring. Therefore, the resin dispersant (A) and the pigment (B ) Are easily generated and strongly adsorbed, resulting in improved dispersibility.

<Hydrophobic structural unit (a1) having an aromatic ring>
The hydrophobic structural unit (a1) having an aromatic ring that is not directly bonded to the atom forming the main chain of the resin dispersant (A) is from the viewpoint of dispersion stability, ejection stability, and washability of the pigment. The total amount of the resin dispersant (A) is preferably 40% by mass or more and less than 75% by mass, more preferably 40% by mass or more and less than 70% by mass, and 40% by mass or more and less than 60% by mass. It is particularly preferred.

  An aromatic ring that is not directly bonded to the atoms forming the main chain of the resin dispersant (A) improves the dispersion stability, ejection stability, detergency, and scratch resistance of the pigment. It is preferable that it is 15 to 27 mass% in (A), 15 to 25 mass% is more preferable, and 15 to 20 mass% is especially preferable.

  By setting it as the above range, it is possible to improve the dispersion stability, ejection stability, cleaning property, and scratch resistance of the pigment.

  In the present invention, the hydrophobic structural unit (a1) containing the aromatic ring in the hydrophobic structural unit (a) was introduced into the resin dispersant (A) with a structure represented by the following general formula (1). Form is preferred.

一般式（１）中、Ｒ１は水素原子、メチル基、またはハロゲン原子を表し、Ｌ１は（主鎖側）−ＣＯＯ−、−ＯＣＯ−、−ＣＯＮＲ２−、−Ｏ−、または置換もしくは無置換のフェニレン基を表し、Ｒ２は水素原子、炭素数１〜１０のアルキル基を表す。Ｌ２は単結合または、炭素数１〜３０の２価の連結基を表し、２価の連結基である場合、その好ましい範囲は好ましくは炭素数１〜２５の連結基であり、特に好ましくは炭素数１〜２０の連結基である。ここで、前記置換基としては、ハロゲン原子、アルキル基、アルコキシ基、水酸基等、シアノ基等が挙げられるが、特に限定されない。Ａｒ１は芳香環から誘導される１価の基を表す。

In general formula (1), R1 represents a hydrogen atom, a methyl group, or a halogen atom, and L1 (main chain side) —COO—, —OCO—, —CONR2—, —O—, or substituted or unsubstituted Represents a phenylene group, and R2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. L2 represents a single bond or a divalent linking group having 1 to 30 carbon atoms, and when it is a divalent linking group, its preferred range is preferably a linking group having 1 to 25 carbon atoms, particularly preferably carbon. It is a linking group of formula 1-20. Here, examples of the substituent include, but are not limited to, a halogen atom, an alkyl group, an alkoxy group, a hydroxyl group, and a cyano group. Ar1 represents a monovalent group derived from an aromatic ring.

  Among the above general formula (1), R 1 is a hydrogen atom or a methyl group, L 1 is (main chain side) —COO—, and L 2 is an alkyleneoxy group and / or an alkylene group having 1 to 25 carbon atoms. A combination of structural units that are divalent linking groups is preferred, and more preferably, R1 is a hydrogen atom or a methyl group, L1 is (main chain side) —COO—, and L2 is (main chain side) — ( CH2-CH2-O) n- (where n represents the average number of repeating units and n = 1 to 6) is a combination of structural units.

  The aromatic ring in Ar1 contained in the hydrophobic structural unit (a1) is not particularly limited, but is a benzene ring, a condensed aromatic ring having 8 or more carbon atoms, a hetero ring in which an aromatic ring is condensed, or two Examples of the linked benzene rings are mentioned above.

  The condensed aromatic ring having 8 or more carbon atoms is an aromatic ring in which at least two or more benzene rings are condensed and / or an alicyclic carbonization in which at least one aromatic ring is condensed with the aromatic ring. An aromatic compound having 8 or more carbon atoms in which a ring is formed of hydrogen. Specific examples include naphthalene, anthracene, fluorene, phenanthrene, acenaphthene and the like.

  The heterocyclic ring condensed with the aromatic ring is a compound in which an aromatic compound not containing a hetero atom (preferably a benzene ring) and a cyclic compound having a hetero atom are condensed at least. Here, the cyclic compound having a hetero atom is preferably a 5-membered ring or a 6-membered ring. As a hetero atom, a nitrogen atom, an oxygen atom, or a sulfur atom is preferable. The cyclic compound having a hetero atom may have a plurality of hetero atoms, and in this case, the hetero atoms may be the same as or different from each other. Specific examples of the heterocyclic ring condensed with an aromatic ring include phthalimide, acridone, carbazole, benzoxazole, and benzothiazole.

  Hereinafter, a hydrophobic structural unit containing a monovalent group derived from the benzene ring, a condensed aromatic ring having 8 or more carbon atoms, a hetero ring in which an aromatic ring is condensed, or a benzene ring in which two or more are connected to each other ( Although the specific example of the monomer which can form a1) is given, this invention is not restrict | limited to the following specific examples.

本発明において、前記樹脂分散剤（Ａ）の主鎖を形成する原子と直接に結合していない芳香環を有する疎水性構造単位（ａ１）のなかでも、分散安定性の観点から、ベンジルメタアクリレート、フェノキシエチルアクリレート、及びフェノキシエチルメタクリレートのいずれか１以上に由来する構造単位であることが好ましい。

In the present invention, among the hydrophobic structural units (a1) having an aromatic ring that is not directly bonded to the atoms forming the main chain of the resin dispersant (A), from the viewpoint of dispersion stability, benzyl methacrylate , A structural unit derived from any one or more of phenoxyethyl acrylate and phenoxyethyl methacrylate.

(Hydrophobic structural unit (a2) derived from C1-C4 alkyl ester of acrylic acid or methacrylic acid)
The hydrophobic structural unit (a2) derived from an alkyl ester having 1 to 4 carbon atoms of acrylic acid or methacrylic acid contained in the resin dispersant (A) is at least 15% by mass or more in the resin dispersant (A). And preferably 20% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 50% by mass or less.

  Specific examples of these (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, (iso or tertiary) butyl (meth) acrylate.

  The alkyl group preferably has 1 to 4 carbon atoms, and more preferably has 1 to 2 carbon atoms.

<Hydrophilic structural unit (b)>
The hydrophilic structural unit (b) constituting the resin dispersant (A) in the present invention will be described.

  The hydrophilic structural unit (b) is contained in an amount of more than 0% by mass and 15% by mass or less, preferably 2% by mass to 15% by mass, and preferably 5% by mass to 15% by mass with respect to the total mass of the resin (A). % Or less is preferable, and 8 mass% or more and 12 mass% or less are more preferable.

  The resin (A) contains at least acrylic acid and / or methacrylic acid (b1) as the hydrophilic structural unit (b).

(Hydrophilic structural unit (b1))
The content of the hydrophilic structural unit (b1) needs to be changed depending on the amount of the structural unit (b2) described later, the amount of the hydrophobic structural unit (a), or both.

  That is, the resin dispersant (A) in the present invention may contain an amount exceeding 80% by mass as the hydrophobic structural unit (a) and an amount that makes the hydrophilic structural unit (b) 15% by mass or less. The hydrophobic structural units (a1) and (a2), the hydrophilic structural units (b1) and (b2), and the structural unit (c) are determined.

  For example, when the resin dispersant (A) is composed of only the hydrophobic structural units (a1) and (a2), the hydrophilic structural unit (b1), and the structural unit (b2), acrylic acid and / or methacrylic acid Content of (b1) can be calculated | required by "100- (mass% of hydrophobic structural unit (a1) * (a2))-(mass% of structural unit (b2))." At this time, the sum of (b1) and (b2) must be 15% by mass or less.

  Further, when the resin dispersant (A) is composed of a hydrophobic structural unit (a1), (a2), a hydrophilic structural unit (b1), and a structural unit (c), the inclusion of the hydrophilic structural unit (b1) The amount can be determined by “100− (mass% of hydrophobic structural unit (a1) · (a2)) − (mass% of structural unit (c))”.

  The resin dispersant (A) can also be composed of only the hydrophobic structural unit (a1), the hydrophobic structural unit (a2), and the hydrophilic structural unit (b1).

  The hydrophilic structural unit (b1) can be obtained by polymerizing acrylic acid and / or methacrylic acid.

  Acrylic acid or methacrylic acid can be used alone or in combination.

  The acid value of the resin dispersant (A) in the present invention is preferably 30 mgKOH / g or more and 100 mgKOH / g or less, from 30 mgKOH / g or more and less than 85 mgKOH / g from the viewpoint of pigment dispersibility and storage stability. It is more preferable that it is 50 mgKOH / g or more and 85 mgKOH / g.

  The acid value here is defined by the mass (mg) of KOH required to completely neutralize 1 g of the resin dispersant (A), and is measured by the method described in JIS standards (JISK0070, 1992). be able to.

(Structural unit (b2))
The structural unit (b2) preferably contains a nonionic hydrophilic group. The structural unit (b2) can be formed by polymerizing a monomer corresponding to the structural unit (b2), but a hydrophilic functional group may be introduced into the polymer chain after the polymerization of the polymer.

  The monomer that forms the structural unit (b2) is not particularly limited as long as it has a functional group capable of forming a polymer and a nonionic hydrophilic functional group, and any known monomer is used. However, vinyl monomers are preferred from the viewpoints of availability, handleability, and versatility.

  Examples of these vinyl monomers include (meth) acrylates, (meth) acrylamides, and vinyl esters having a hydrophilic functional group.

  Examples of the hydrophilic functional group include a hydroxyl group, an amino group, an amide group (with a nitrogen atom unsubstituted), and an alkylene oxide polymer such as polyethylene oxide and polypropylene oxide as described later.

  Of these, hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, (meth) acrylamide, aminoethyl acrylate, aminopropyl acrylate, and (meth) acrylate containing an alkylene oxide polymer are particularly preferable.

  The structural unit (b2) preferably includes a hydrophilic structural unit having an alkylene oxide polymer structure.

  As alkylene of the said alkylene oxide polymer, C1-C6 is preferable from a hydrophilic viewpoint, C2-C6 is more preferable, and C2-C4 is especially preferable.

  Moreover, as a polymerization degree of the said alkylene oxide polymer, 1-120 are preferable, 1-60 are more preferable, and 1-30 are especially preferable.

  It is also a preferable aspect that the structural unit (b2) is a hydrophilic structural unit containing a hydroxyl group.

  The number of hydroxyl groups in the structural unit (b2) is not particularly limited, and is preferably 1 to 4 from the viewpoint of the hydrophilicity of the resin (A) and compatibility with the solvent and other monomers during polymerization. 3 is more preferable, and 1-2 is particularly preferable.

<Structural unit (c)>
As described above, the resin dispersant (A) in the present invention is a structural unit having a structure different from the hydrophobic structural unit (a1), the hydrophobic structural unit (a2), and the hydrophilic structural unit (b) ( c) (hereinafter simply referred to as “structural unit (c)”).

  The structural unit (c) different from the hydrophobic structural unit (a1), the hydrophobic structural unit (a2) and the hydrophilic structural unit (b) is different from the above (a1), (a2) or (b). The structural unit (c) having a structure is referred to, and the structural unit (c) is preferably a hydrophobic structural unit.

  The structural unit (c) is a hydrophobic structural unit, but needs to be a structural unit having a structure different from the hydrophobic structural unit (a1) and the hydrophobic structural unit (a2).

  The structural unit (c) is preferably 35% by mass or less, more preferably 20% by mass or less, and still more preferably 15% by mass or less in the total mass of the resin dispersant (A). .

  The structural unit (c) can be formed by polymerizing the corresponding monomer. Moreover, you may introduce | transduce a hydrophobic functional group into a polymer chain after superposition | polymerization of resin.

  The monomer in the case where the structural unit (c) is a hydrophobic structural unit is not particularly limited as long as it has a functional group capable of forming a polymer and a hydrophobic functional group, and any known monomers Can also be used.

  As the monomer capable of forming the hydrophobic structural unit, vinyl monomers and ((meth) acrylamides, styrenes, vinyl esters, etc.) are preferable from the viewpoints of availability, handleability, and versatility.

  Examples of (meth) acrylamides include (meth) acrylamides such as N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-diallyl (meth) acrylamide, and N-allyl (meth) acrylamide. ) Acrylamides.

  Examples of styrenes include styrene, methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, isopropylstyrene, n-butylstyrene, tert-butylstyrene, methoxystyrene, butoxystyrene, acetoxystyrene, chlorostyrene, dichlorostyrene, bromostyrene, Examples thereof include chloromethylstyrene, hydroxystyrene protected with a group that can be deprotected by an acidic substance (for example, t-Boc), methyl vinyl benzoate, and α-methylstyrene, vinylnaphthalene, and the like. Styrene is preferred.

  Examples of the vinyl esters include vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, and vinyl benzoate. Of these, vinyl acetate is preferable.

  These can be used alone or in admixture of two or more.

  The resin dispersant (A) in the present invention may be a random copolymer in which each structural unit is irregularly introduced or a block copolymer in which the structural units are regularly introduced. Each structural unit in the case of a coalescence may be synthesized in any order of introduction, and the same constituent component may be used twice or more, but a random copolymer is versatile and manufactured. From the viewpoint of sex.

  Furthermore, the molecular weight range of the resin dispersant (A) used in the present invention is a weight average molecular weight (Mw), preferably 30,000 to 150,000, more preferably 30,000 to 100,000, and still more preferably 3 10,000 to 80,000.

  By setting the molecular weight within the above range, the steric repulsion effect as a dispersing agent tends to be good, and it is preferable from the viewpoint of the tendency that adsorption to the pigment does not take time due to the steric effect.

  Moreover, it is preferable that it is 1-6, and, as for the molecular weight distribution (represented by the weight average molecular weight value / number average molecular weight value) of resin used by this invention, it is 1-4.

  Setting the molecular weight distribution in the above range is preferable from the viewpoints of ink dispersion stability and ejection stability. Here, the number average molecular weight and the weight average molecular weight are detected with a solvent THF and a differential refractometer using a GPC analyzer using columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all trade names manufactured by Tosoh Corporation). The molecular weight is expressed using polystyrene as a standard substance.

  The resin dispersant (A) used in the present invention can be synthesized by various polymerization methods such as solution polymerization, precipitation polymerization, suspension polymerization, precipitation polymerization, bulk polymerization, and emulsion polymerization. The polymerization reaction can be performed by a known operation such as a batch system, a semi-continuous system, or a continuous system.

  The polymerization initiation method includes a method using a radical initiator, a method of irradiating light or radiation, and the like. These polymerization methods and polymerization initiation methods are, for example, the revised version of Tsuruta Junji “Polymer Synthesis Method” (published by Nikkan Kogyo Shimbun, 1971), Takatsu Otsu, Masato Kinoshita, “Experimental Methods for Polymer Synthesis” It is described in pp. 47-154 published in 1972.

  Among the above polymerization methods, a solution polymerization method using a radical initiator is particularly preferable. Solvents used in the solution polymerization method include, for example, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, benzene, toluene, acetonitrile, A single organic solvent such as methylene chloride, chloroform, dichloroethane, methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol, or a mixture of two or more thereof may be used, or a mixed solvent with water may be used.

  The polymerization temperature needs to be set in relation to the molecular weight of the polymer to be produced, the type of initiator, etc., and is usually about 0 ° C. to 100 ° C., but the polymerization is preferably carried out in the range of 50 to 100 ° C.

The reaction pressure can be appropriately selected, but is usually preferably 1 to 100 kg / cm ² , particularly preferably about 1 to 30 kg / cm ² . The reaction time is about 5 to 30 hours. The obtained resin may be subjected to purification such as reprecipitation.

  Specific preferred examples of the resin dispersant (A) in the present invention are shown below, but the present invention is not limited to the following.

＜顔料（Ｂ）と樹脂分散剤（Ａ）の比率＞
顔料（Ｂ）と樹脂分散剤（Ａ）の比率は、重量比で１００：２５〜１００：１４０が好ましく、さらに好ましくは１００：２５〜１００：５０である。樹脂分散剤が１００：２５以上の場合は分散安定性と耐擦性が良化する傾向となる。樹脂分散剤が１００：１４０以下の場合も、分散安定性が良化する傾向となる。

<Ratio of pigment (B) to resin dispersant (A)>
The weight ratio of the pigment (B) and the resin dispersant (A) is preferably 100: 25 to 100: 140, and more preferably 100: 25 to 100: 50. When the resin dispersant is 100: 25 or more, the dispersion stability and the abrasion resistance tend to be improved. When the resin dispersant is 100: 140 or less, the dispersion stability tends to be improved.

<Pigment (B)>
In the present invention, the pigment (B) is a colored substance (inorganic) which is almost insoluble in water and organic solvents, as described on page 518 of the Chemical Dictionary 3rd edition published on April 1, 1994 (edited by Michinori Oki et al.). In the present invention, organic pigments and inorganic pigments can be used.

  In the present invention, the “pigment (B) dispersed by the resin dispersant (A)” means a pigment dispersed and held by the resin dispersant (A), and the resin dispersed in the aqueous liquid medium (D). The pigment is preferably used as a pigment dispersed and held using the agent (A). The aqueous liquid medium (D) may or may not contain a dispersant.

  In the present invention, the pigment (B) dispersed by the resin dispersant (A) is not particularly limited as long as it is a pigment dispersed and held by the resin dispersant (A). From the viewpoint of ejection stability, a microencapsulated pigment produced by a phase inversion method is more preferable.

  A preferred example of the pigment (B) contained in the present invention is a microencapsulated pigment. The microencapsulated pigment is a pigment in which the pigment is coated with the resin dispersant (A).

  The resin of the microencapsulated pigment needs to use the resin dispersant (A), and is a polymer having self-dispersibility or solubility in water and an anionic group (acidic). It is preferable to use the compound for a resin other than the resin dispersant (A).

(Manufacture of microencapsulated pigments)
The microencapsulated pigment can be produced by a conventional physical or chemical method using the above components such as the resin dispersant (A). For example, the methods disclosed in JP-A-9-151342, JP-A-10-140065, JP-A-11-209672, JP-A-11-172180, JP-A-10-25440, or JP-A-11-43636. Can be manufactured by. The method for producing the microencapsulated pigment is outlined below.

  As the method for producing the microencapsulated pigment, the phase inversion method and acid precipitation method described in JP-A-9-151342 and JP-A-10-140065 can be used. Among these, the phase inversion method is a point of dispersion stability. Is preferable.

a) Phase Inversion Method In the present invention, the phase inversion method is basically a self-dispersion (phase inversion emulsification) in which a mixed melt of a resin having a self-dispersing ability or a dissolving ability and a pigment is dispersed in water. Say the method. Further, the mixed melt may contain the above-described curing agent or polymer compound. Here, the mixed melt means a mixed state without dissolving, a mixed state with dissolved, or a state including both of these states. A more specific production method of the “phase inversion method” may be the same as that disclosed in JP-A-10-140065.

b) Acid precipitation method In the present invention, the acid precipitation method is a preparation of a water-containing cake made of a resin and a pigment, and a part or all of an anionic group contained in the resin in the water-containing cake is a base. This refers to a method for producing a microencapsulated pigment by neutralizing with a functional compound.

  Specifically, the acid precipitation method includes (1) a step of dispersing a resin and a pigment in an alkaline aqueous medium, and heat-treating the resin as necessary to gel the resin, and (2) adjusting the pH. A step of hydrophobizing the resin by making it neutral or acidic, and strongly fixing the resin to the pigment; (3) a step of filtering and washing with water as necessary to obtain a water-containing cake; and (4) water-containing A step of neutralizing a part or all of anionic groups contained in the resin in the cake with a basic compound and then redispersing in an aqueous medium; and (5) if necessary. And a step of performing a heat treatment to gel the resin.

  More specific production methods of the above phase inversion method and acid precipitation method may be the same as those disclosed in JP-A-9-151342 and JP-A-10-140065. The colorant production methods described in JP-A-11-209672 and JP-A-11-172180 can also be used in the present invention.

  The outline of the preferable production method in the present invention basically comprises the following production steps.

  (1) mixing a resin having an anionic group or a solution obtained by dissolving it in an organic solvent with a basic compound aqueous solution to neutralize it; and (2) mixing a pigment into this mixed solution to obtain a suspension. Then, the pigment is dispersed with a disperser or the like to obtain a pigment dispersion, and (3) the aqueous solution in which the pigment is coated with a resin having an anionic group by removing the solvent by distillation as necessary. Obtaining a dispersion.

  In the present invention, the kneading and dispersing processes described above can be performed using, for example, a ball mill, a roll mill, a bead mill, a high-pressure homogenizer, a high-speed stirring type disperser, an ultrasonic homogenizer, or the like.

<Pigment B>
Examples of pigments that can be used in the present invention include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 14C, 16, 17, 24, 34, 35, 37, 42, 53, 55, 65, 73, 74, 75, 81, 83, 93, 95, 97, 98, 100, 101, 104, 108, 109, 110, 114, 117, 120, 128, 129, 138, 150, 151, 153, 154, 155, 180 etc. are mentioned.

  Examples of magenta ink pigments include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 48 (Ca), 48 (Mn), 48: 2, 48: 3, 48: 4, 49, 49: 1, 50, 51, 52, 52: 2, 53: 1, 53, 55, 57 (Ca), 57: 1, 60, 60: 1, 63: 1, 63: 2, 64, 64: 1, 81, 83, 87, 88, 89, 90, 101 (Bengara) ), 104, 105, 106, 108 (cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 163, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 209, 2 9 and the like, in particular, C. I. Pigment Red 122 is preferable.

  Further, as pigments for cyan ink, C.I. I. Pigment blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17: 1, 22, 25, 56, 60, C.I. I. Bat blue 4, 60, 63 and the like. I. Pigment Blue 15: 3 is preferable.

  Examples of other color ink pigments include C.I. I. Pigment orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment green 1, 4, 7, 8, 10, 17, 18, 36, C.I. I. Pigment violet 1 (rhodamine lake), 3, 5: 1, 16, 19 (quinacridone red), 23, 38, and the like. In addition, processed pigments such as graft carbon whose surface is treated with a resin or the like can also be used.

An example of the black type is carbon black. Specific examples of such carbon black include No. 1 manufactured by Mitsubishi Chemical. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B, etc. are Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc., manufactured by Columbia, Regal 400R, Regal 330R, Regal 800R, Mal 80 , Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. are Color Black made by Degussa.
FW1, ColorBlack FW2, Color Black FW2V, Color Black FW18, Color Black FW200, ColorBlack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black4A , Special Black 4 and the like.

  The above pigments may be used alone or in combination of a plurality selected from the above-mentioned groups or between the groups.

  The content of the pigment (B) in the aqueous ink in the present invention is preferably 1 to 10% by mass, more preferably 2 to 8% by mass, and 2 to 6% by mass from the viewpoint of dispersion stability and concentration of the aqueous ink. % Is particularly preferred.

<Self-dispersing polymer particles>
The water-based ink used in the present invention contains at least one kind of self-dispersing polymer fine particles. The self-dispersing polymer fine particles in the present invention are water-insoluble which can be dispersed in an aqueous medium by a functional group (particularly an acidic group or a salt thereof) of the pr resin itself in the absence of other surfactant. It refers to fine particles of a water-insoluble polymer which is a polymer and does not contain a free emulsifier.

  Here, the dispersed state refers to both an emulsified state (emulsion) in which a water-insoluble polymer is dispersed in an aqueous medium and a dispersed state (suspension) in which a water-insoluble polymer is dispersed in an aqueous medium in a solid state. It includes the state of.

  The water-insoluble polymer in the present invention is a water-insoluble polymer that can be in a dispersed state in which the water-insoluble polymer is dispersed in a solid state from the viewpoint of ink aggregation rate and ink fixability when contained in a water-soluble ink. preferable.

  The dispersion state of the self-dispersing polymer fine particles in the present invention refers to a solution in which 30 g of a water-insoluble polymer is dissolved in 70 g of an organic solvent (for example, methyl ethyl ketone), and a neutralizing agent capable of neutralizing 100% of the salt-forming group of the water-insoluble polymer. After mixing and stirring (apparatus: stirring apparatus with stirring blade, rotation speed 200 rpm, 30 minutes, 25 ° C.) (sodium hydroxide if the salt-forming group is anionic, acetic acid if cationic) and 200 g of water The state in which even after removing the organic solvent from the mixed solution, it can be visually confirmed that the dispersed state exists stably at 25 ° C. for at least one week.

  The water-insoluble polymer means a resin having a dissolution amount of 10 g or less when the resin is dried at 105 ° C. for 2 hours and then dissolved in 100 g of water at 25 ° C., and the dissolution amount is preferable. Is 5 g or less, more preferably 1 g or less. The dissolution amount is the dissolution amount when neutralized with sodium hydroxide or acetic acid according to the kind of the salt-forming group of the water-insoluble polymer.

  The aqueous medium is configured to contain water, and may contain a hydrophilic organic solvent as necessary. In the present invention, it is preferably composed of water and 0.2% by mass or less of a hydrophilic organic solvent with respect to water, and more preferably composed of water.

  The main chain skeleton of the water-insoluble polymer is not particularly limited. For example, a vinyl polymer or a condensation polymer (epoxy resin, polyester, polyurethane, polyamide, cellulose, polyether, polyurea, polyimide, polycarbonate, etc.) is used. it can. Of these, vinyl polymers are particularly preferred.

  Preferable examples of the vinyl polymer and the monomer constituting the vinyl polymer include those described in JP-A Nos. 2001-181549 and 2002-88294. In addition, radical transfer of vinyl monomers using dissociable groups (or substituents that can be induced to dissociable groups), polymerization initiators, and iniferters, or dissociable groups on either initiators or terminators A vinyl polymer in which a dissociable group is introduced at the end of a polymer chain by ionic polymerization using a compound having (or a substituent that can be derived from a dissociable group) can also be used.

  Moreover, as a suitable example of the monomer which comprises a condensation type polymer and a condensation type polymer, what is described in Unexamined-Japanese-Patent No. 2001-247787 can be mentioned.

  The self-dispersing polymer fine particles in the present invention preferably contain a water-insoluble polymer containing a hydrophilic constituent unit and a constituent unit derived from an aromatic group-containing monomer from the viewpoint of self-dispersibility.

  The hydrophilic structural unit is not particularly limited as long as it is derived from a hydrophilic group-containing monomer, and even if it is derived from one kind of hydrophilic group-containing monomer, it contains two or more hydrophilic groups. It may be derived from a monomer. The hydrophilic group is not particularly limited, and may be a dissociable group or a nonionic hydrophilic group.

  In the present invention, the hydrophilic group is preferably a dissociable group and more preferably an anionic dissociable group from the viewpoint of promoting self-dispersion and the stability of the formed emulsified or dispersed state. Examples of the dissociable group include a carboxyl group, a phosphoric acid group, and a sulfonic acid group. Among them, a carboxyl group is preferable from the viewpoint of fixability when an ink composition is configured.

  The hydrophilic group-containing monomer in the present invention is preferably a dissociable group-containing monomer from the viewpoints of self-dispersibility and aggregation, and is a dissociable group-containing monomer having a dissociable group and an ethylenically unsaturated bond. It is preferable.

  Examples of the dissociable group-containing monomer include an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, and an unsaturated phosphoric acid monomer.

  Specific examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid. Specific examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylate, and bis- (3-sulfopropyl) -itaconate. It is done. Specific examples of unsaturated phosphoric acid monomers include vinylphosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2- Examples include acryloyloxyethyl phosphate.

  Among the dissociable group-containing monomers, unsaturated carboxylic acid monomers are preferable and acrylic acid and methacrylic acid are more preferable from the viewpoints of dispersion stability and ejection stability.

  The self-dispersing polymer fine particle in the present invention is a first polymer having a carboxyl group and an acid value (mgKOH / g) of 25 to 100 from the viewpoints of self-dispersibility and agglomeration speed when contacting with the reaction solution. It is preferable to contain. Furthermore, the acid value is more preferably from 25 to 80, and particularly preferably from 30 to 65, from the viewpoints of self-dispersibility and the aggregation rate when contacting with the reaction solution. When the acid value is 25 or more, the stability of self-dispersibility is improved. Moreover, cohesiveness improves because an acid value is 100 or less.

  The aromatic group-containing monomer is not particularly limited as long as it is a compound containing an aromatic group and a polymerizable group. The aromatic group may be a group derived from an aromatic hydrocarbon or a group derived from an aromatic heterocycle. In the present invention, an aromatic group derived from an aromatic hydrocarbon is preferable from the viewpoint of particle shape stability in an aqueous medium.

  The polymerizable group may be a condensation polymerizable polymerizable group or an addition polymerizable polymerizable group. In the present invention, from the viewpoint of particle shape stability in an aqueous medium, an addition polymerizable group is preferable, and a group containing an ethylenically unsaturated bond is more preferable.

  The aromatic group-containing monomer in the present invention is preferably a monomer having an aromatic group derived from an aromatic hydrocarbon and an ethylenically unsaturated bond, and more preferably an aromatic group-containing (meth) acrylate monomer. preferable. In the present invention, the aromatic group-containing monomers may be used singly or in combination of two or more.

  Examples of the aromatic group-containing monomer include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, and a styrene monomer. Among them, from the viewpoint of the balance between the hydrophilicity and hydrophobicity of the polymer chain and the ink fixing property, it is preferably at least one selected from phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, and phenyl (meth) acrylate. More preferred is phenoxyethyl (meth) acrylate, and particularly preferred is phenoxyethyl acrylate.

  “(Meth) acrylate” means acrylate or methacrylate.

  The self-dispersing polymer fine particles in the present invention include a structural unit derived from an aromatic group-containing (meth) acrylate monomer, and the content is preferably 10% by mass to 95% by mass. When the content of the aromatic group-containing (meth) acrylate monomer is 10% by mass to 95% by mass, the stability of the self-emulsification or dispersion state can be improved, and further the increase in ink viscosity can be suppressed.

  In the present invention, from the viewpoints of stability in a self-dispersing state, stabilization of particle shape in an aqueous medium due to hydrophobic interaction between aromatic rings, and reduction in the amount of water-soluble components due to appropriate hydrophobicization of particles. More preferably, the content is from mass% to 90 mass%, more preferably from 15 mass% to 80 mass%, and particularly preferably from 25 mass% to 70 mass%.

  The self-dispersing polymer fine particles in the present invention can be composed of, for example, a structural unit composed of an aromatic group-containing monomer and a structural unit composed of a dissociable group-containing monomer. Can further be included.

  The monomer that forms the other structural unit is not particularly limited as long as it is a monomer copolymerizable with the aromatic group-containing monomer and the dissociable group-containing monomer. Among these, an alkyl group-containing monomer is preferable from the viewpoint of flexibility of the polymer skeleton and ease of control of the glass transition temperature (Tg).

  Examples of the alkyl group-containing monomer include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, alkyl (meth) acrylates such as t-butyl (meth) acrylate, hexyl (meth) acrylate, ethylhexyl (meth) acrylate; hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Ethylenically unsaturated monomers having a hydroxyl group such as acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate; Dialkylaminoalkyl (meth) acrylates such as ru (meth) acrylate; N-hydroxyalkyl (meth) such as N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxybutyl (meth) acrylamide Acrylamide; N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N- (n-, iso) butoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-ethoxyethyl (meta And (meth) acrylamides such as N-alkoxyalkyl (meth) acrylamides such as acrylamide and N- (n-, iso) butoxyethyl (meth) acrylamide.

  The molecular weight range of the water-insoluble polymer constituting the self-dispersing polymer fine particles in the present invention is preferably 3000 to 200,000, more preferably 5000 to 150,000, and more preferably 10,000 to 100,000 in terms of weight average molecular weight. More preferably it is. By setting the weight average molecular weight to 3000 or more, the amount of water-soluble components can be effectively suppressed. Moreover, self-dispersion stability can be improved by making a weight average molecular weight into 200,000 or less. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

  From the viewpoint of controlling the hydrophilicity / hydrophobicity of the polymer, the water-insoluble polymer constituting the self-dispersing polymer fine particles in the present invention comprises an aromatic group-containing (meth) acrylate monomer as a copolymerization ratio of 15 to 90% by mass, a carboxyl group-containing monomer, And an alkyl group-containing monomer, preferably having an acid value of 25 to 100 and a weight average molecular weight of 3000 to 200,000, and an aromatic group-containing (meth) acrylate monomer as a copolymerization ratio of 15 to 80 mass. %, A carboxyl group-containing monomer, and an alkyl group-containing monomer, an acid value of 25 to 95, and a weight average molecular weight of 5000 to 150,000 are more preferable.

Specific examples of the water-insoluble polymer constituting the self-dispersing polymer fine particles are listed below as exemplary compounds B-01 to B-19, but the present invention is not limited thereto. In addition, the parenthesis represents the mass ratio of the copolymerization component.
B-01: Phenoxyethyl acrylate / methyl methacrylate / acrylic acid copolymer (50/45/5)
B-02: Phenoxyethyl acrylate / benzyl methacrylate / isobutyl methacrylate / methacrylic acid copolymer (30/35/29/6)
B-03: Phenoxyethyl methacrylate / isobutyl methacrylate / methacrylic acid copolymer (50/44/6)
B-04: phenoxyethyl acrylate / methyl methacrylate / ethyl acrylate / acrylic acid copolymer (30/55/10/5)
B-05: benzyl methacrylate / isobutyl methacrylate / methacrylic acid copolymer (35/59/6)
B-06: Styrene / phenoxyethyl acrylate / methyl methacrylate / acrylic acid copolymer (10/50/35/5)
B-07: benzyl acrylate / methyl methacrylate / acrylic acid copolymer (55/40/5)
B-08: Phenoxyethyl methacrylate / benzyl acrylate / methacrylic acid copolymer (45/47/8)
B-09: Styrene / phenoxyethyl acrylate / butyl methacrylate / acrylic acid copolymer (5/48/40/7)
B-10: benzyl methacrylate / isobutyl methacrylate / cyclohexyl methacrylate / methacrylic acid copolymer (35/30/30/5)
B-11: phenoxyethyl acrylate / methyl methacrylate / butyl acrylate / methacrylic acid copolymer (12/50/30/8)
B-12: benzyl acrylate / isobutyl methacrylate / acrylic acid copolymer (93/2/5)
B-13: Styrene / phenoxyethyl methacrylate / butyl acrylate / acrylic acid copolymer (50/5/20/25)
B-14: Styrene / butyl acrylate / acrylic acid copolymer (62/35/3)
B-15: Methyl methacrylate / phenoxyethyl acrylate / acrylic acid copolymer (45/51/4)
B-16: Methyl methacrylate / phenoxyethyl acrylate / acrylic acid copolymer (45/49/6)
B-17: Methyl methacrylate / phenoxyethyl acrylate / acrylic acid copolymer (45/48/7)
B-18: Methyl methacrylate / phenoxyethyl acrylate / acrylic acid copolymer (45/47/8)
B-19: Methyl methacrylate / phenoxyethyl acrylate / acrylic acid copolymer (45/45/10)
The production method of the water-insoluble polymer constituting the self-dispersing polymer fine particles in the present invention is not particularly limited. For example, emulsion polymerization is carried out in the presence of a polymerizable surfactant to obtain a surfactant and a water-insoluble polymer. Examples include a method of covalent bonding, and a method of copolymerizing a monomer mixture containing the hydrophilic group-containing monomer and the aromatic group-containing monomer by a known polymerization method such as a solution polymerization method or a bulk polymerization method. Among the polymerization methods, a solution polymerization method is preferable and a solution polymerization method using an organic solvent is more preferable from the viewpoint of aggregation speed and droplet ejection stability when an aqueous ink is used.

  The self-dispersing polymer fine particles in the present invention include a first polymer synthesized in an organic solvent from the viewpoint of aggregation rate, and the first polymer has a carboxyl group and has an acid value of 20 to 100. In addition, it is preferable that at least a part of the carboxyl groups of the first polymer is neutralized and prepared as a resin dispersion having water as a continuous phase.

  That is, the method for producing self-dispersing polymer fine particles in the present invention includes a step of synthesizing the first polymer in an organic solvent, and an aqueous dispersion in which at least a part of the carboxyl groups of the first resin is neutralized. And a dispersion step.

  The dispersion step preferably includes the following step (1) and step (2).

  Step (1): A step of stirring the mixture containing the first polymer (water-insoluble polymer), the organic solvent, the neutralizing agent, and the aqueous medium.

  Step (2): A step of removing the organic solvent from the mixture.

  The step (1) is a treatment in which the first polymer (water-insoluble polymer) is first dissolved in an organic solvent, and then a neutralizer and an aqueous medium are gradually added, mixed and stirred to obtain a dispersion. It is preferable. Thus, by adding a neutralizing agent and an aqueous medium to a water-insoluble polymer solution dissolved in an organic solvent, a self-dispersing polymer particle having a particle size with higher storage stability without requiring strong shearing force. Can be obtained. There is no restriction | limiting in particular in the stirring method of this mixture, Dispersing machines, such as a generally used mixing stirring apparatus and an ultrasonic disperser, a high-pressure homogenizer, can be used as needed.

  Preferred examples of the organic solvent include alcohol solvents, ketone solvents, and ether solvents. Examples of the alcohol solvent include isopropyl alcohol, n-butanol, t-butanol, ethanol and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone. Examples of ether solvents include dibutyl ether and dioxane. Among these solvents, ketone solvents such as methyl ethyl ketone and alcohol solvents such as isopropyl alcohol are preferable. It is also preferable to use isopropyl alcohol and methyl ethyl ketone in combination for the purpose of moderating the polarity change during the phase inversion from oil to water. By using this solvent in combination, self-dispersing polymer fine particles having a fine particle size with high dispersion stability can be obtained without agglomeration and sedimentation or fusion between particles.

  The neutralizing agent is used so that a part or all of the dissociable groups are neutralized and the self-dispersing polymer forms a stable emulsified or dispersed state in water. When the self-dispersing polymer of the present invention has an anionic dissociative group (for example, carboxyl group) as a dissociable group, the neutralizing agent used is a basic compound such as an organic amine compound, ammonia, or an alkali metal hydroxide. Is mentioned. Examples of organic amine compounds include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine, dipropylamine, monoethanolamine, diethanolamine, triethanolamine, N, N-dimethyl-ethanolamine, N, N-diethyl-ethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, N-methyldiethanolamine, N-ethyldiethanolanine, monoisopropanolamine, di Examples include isopropanolamine and triisopropanolamine. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Among these, sodium hydroxide, potassium hydroxide, triethylamine, and triethanolamine are preferable from the viewpoint of stabilizing the dispersion of the self-dispersing polymer fine particles of the present invention in water.

  These basic compounds are preferably used in an amount of 5 to 120 mol%, more preferably 10 to 110 mol%, still more preferably 15 to 100 mol%, based on 100 mol% of the dissociable group. . By setting it as 15 mol% or more, the effect which stabilizes dispersion | distribution of the particle | grains in water expresses, and there exists an effect which reduces a water-soluble component by setting it as 100 mol% or less.

  In the step (2), the aqueous dispersion of the self-dispersing polymer particles is obtained by distilling off the organic solvent from the dispersion obtained in the step (1) by a conventional method such as distillation under reduced pressure and phase-inversion into an aqueous system. You can get things. The organic solvent in the obtained aqueous dispersion has been substantially removed, and the amount of the organic solvent is preferably 0.2% by mass or less, more preferably 0.1% by mass or less.

  The average particle size of the self-dispersing polymer fine particles in the present invention is preferably in the range of 10 to 400 nm, more preferably 10 to 200 nm, and further preferably 10 to 100 nm. Manufacturability is improved when the average particle diameter is 10 nm or more. Moreover, storage stability improves by setting it as an average particle diameter of 400 nm or less.

  Further, the particle size distribution of the self-dispersing polymer fine particles is not particularly limited, and may be either a wide particle size distribution or a monodispersed particle size distribution. Further, two or more kinds of water-insoluble particles may be mixed and used.

  The average particle size and particle size distribution of the self-dispersing polymer fine particles can be measured using, for example, a light scattering method.

  The self-dispersing polymer fine particles of the present invention can be suitably contained in, for example, an aqueous ink composition, and can be used alone or in combination of two or more.

<Aqueous liquid medium (D)>
In the inkjet recording water-based ink, the aqueous liquid medium (D) represents a mixture of water and a water-soluble organic solvent. Water-soluble organic solvents (hereinafter also referred to as “water-soluble organic solvents”) are used for the purpose of drying inhibitors, wetting agents or penetration enhancers.

  An anti-drying agent is used for the purpose of preventing clogging due to drying of the ink-jet ink at the ink ejection port of the nozzle, and a water-soluble organic solvent having a vapor pressure lower than that of water is preferable as the anti-drying agent or wetting agent. . In addition, a water-soluble organic solvent is suitably used as a penetration accelerator for the purpose of allowing ink jet ink to penetrate better into a recording medium (such as paper).

  Examples of water-soluble organic solvents include glycerin, 1,2,6-hexanetriol, trimethylolpropane, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, 2-butene -1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-pentanediol, Alkanediols (polyhydric alcohols) such as 4-methyl-1,2-pentanediol; vulose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol, (sorbitol), maltose, cello Sugars such as aose, lactose, sucrose, trehalose, maltotriose; sugar alcohols; pearronic acids; so-called solid wetting agents such as ureas; alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, isopropanol Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, Diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl Ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n -Glycol ethers such as propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, phor Examples thereof include muamide, acetamide, dimethyl sulfoxide, sorbite, sorbitan, acetin, diacetin, triacetin, sulfolane and the like, and one or more of these can be used.

  For the purpose of drying inhibitors and wetting agents, polyhydric alcohols are useful. For example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol. 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, tetraethylene glycol, 1,6-hexanediol, 2-methyl-2, Examples include 4-pentanediol, polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol, and the like. These may be used individually by 1 type and may use 2 or more types together.

  For the purpose of the penetrant, a polyol compound is preferable. Examples of the aliphatic diol include 2-ethyl-2-methyl-1,3-propanediol, 3,3-dimethyl-1,2-butanediol, 2, 2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2,5-dimethyl-2,5-hexane Examples include diol, 5-hexene-1,2-diol, and 2-ethyl-1,3-hexanediol. Among these, preferred examples include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

  A water-soluble organic solvent may be used independently or may be used in mixture of 2 or more types. The content of the water-soluble organic solvent is 1 to 60% by mass, preferably 5 to 40% by mass in the ink.

  The amount of water added is not particularly limited in the ink, but is preferably 10% by mass to 99% by mass, and more preferably 30% by mass to 80% by mass. More preferably, it is 50 mass% or more and 70 mass% or less.

  The aqueous liquid medium (D) in the present invention is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less from the viewpoints of dispersion stability and ejection stability in the ink.

<Surfactant>
It is preferable to add a surfactant (hereinafter also referred to as a surface tension adjusting agent) to the water-based ink in the invention. Examples of the surfactant include nonionic, cationic, anionic and betaine surfactants. The addition amount of the surface tension adjusting agent is preferably an amount for adjusting the surface tension of the water-based ink in the present invention to 20 to 60 mN / m, more preferably 20 to 45 mN / m, in order to eject ink droplets well by inkjet. More preferably, the amount can be adjusted to 25 to 40 mN / m.

  As the surfactant, a compound having a structure having both a hydrophilic part and a hydrophobic part in the molecule can be used effectively. Anionic surfactant, cationic surfactant, amphoteric surfactant, nonionic surfactant Any of the surfactants can be used. Furthermore, the above-mentioned polymer substance (polymer dispersing agent) can also be used as a surfactant.

  Specific examples of the anionic surfactant include, for example, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium alkyldiphenyl ether disulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium stearate, potassium oleate, Sodium dioctylsulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium dialkylsulfosuccinate, sodium stearate, sodium oleate, t-octylphenoxy Examples include sodium ethoxypolyethoxyethyl sulfate, and one or more of these are selected. Rukoto can.

  Specific examples of the nonionic surfactant include, for example, polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl phenyl ether, polyoxyethylene nonyl phenyl ether, oxyethylene / oxypropylene block copolymer, t- Examples include octylphenoxyethyl polyethoxyethanol, nonylphenoxyethyl polyethoxyethanol, and the like, and one or more of these can be selected.

  Examples of the cationic surfactant include tetraalkylammonium salts, alkylamine salts, benzalkonium salts, alkylpyridium salts, imidazolium salts, and the like. Specific examples thereof include dihydroxyethyl stearylamine and 2-heptadecenyl. -Hydroxyethyl imidazoline, lauryl dimethyl benzyl ammonium chloride, cetyl pyridinium chloride, stearamide methyl pyridium chloride and the like.

  The amount of the surfactant added to the inkjet recording water-based ink in the present invention is not particularly limited, but is preferably 1% by mass or more, more preferably 1 to 10% by mass, and still more preferably 1%. ˜3 mass%.

<Other ingredients>
The water-based ink used in the present invention may contain other additives. Other additives include, for example, ultraviolet absorbers, antifading agents, antifungal agents, pH adjusters, rust inhibitors, antioxidants, emulsion stabilizers, preservatives, antifoaming agents, viscosity modifiers, and dispersion stabilizers. Known additives such as agents and chelating agents are included.

  Examples of the UV absorber include benzophenone UV absorbers, benzotriazole UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers, nickel complex salt UV absorbers, and the like.

  As the antifading agent, various organic and metal complex antifading agents can be used. Organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, etc. Complex, zinc complex and the like.

  Antifungal agents include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one, sodium sorbate, sodium pentachlorophenol, etc. Can be mentioned. These are preferably used in the ink in an amount of 0.02 to 1.00% by mass.

  The pH adjuster is not particularly limited as long as it can adjust the pH to a desired value without adversely affecting the recording ink to be prepared, and can be appropriately selected according to the purpose. Amines (eg, diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol), alkali metal hydroxides (eg, lithium hydroxide, sodium hydroxide, potassium hydroxide), ammonium Examples thereof include hydroxides (for example, ammonium hydroxide and quaternary ammonium hydroxides), phosphonium hydroxides, alkali metal carbonates, and the like.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Examples of the antioxidant include phenol antioxidants (including hindered phenol antioxidants), amine antioxidants, sulfur antioxidants, phosphorus antioxidants, and the like.

  Examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like.

[Description of treatment liquid (aggregation treatment liquid)]
The treatment liquid used in the first embodiment of the present invention is preferably a treatment liquid that causes aggregation of pigments and polymer fine particles contained in the ink by changing the pH of the ink.

  Treatment liquid components include polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, orthophosphoric acid, pyrrolidone It is preferably selected from carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof.

  Moreover, as a preferable example of the treatment liquid, a treatment liquid to which a polyvalent metal salt or polyallylamine is added can be exemplified. These compounds may be used alone or in combination of two or more.

  From the viewpoint of pH aggregation performance with the ink, the treatment liquid preferably has a pH of 1 to 6, more preferably 2 to 5, and particularly preferably 3 to 5.

  The amount of the component that aggregates the ink pigment and polymer fine particles in the treatment liquid is preferably 0.01% by weight or more and 20% by weight or less based on the total weight of the liquid. When the amount is 0.01% by weight or less, concentration dispersion does not proceed sufficiently when the treatment liquid and the ink are in contact with each other, and an agglomeration effect due to pH change may not occur sufficiently. On the other hand, if it is 20% by weight or more, the dischargeability from the ink jet head may deteriorate.

  The treatment liquid preferably contains water and other additive-soluble organic solvents for the purpose of preventing clogging of the nozzles of the inkjet head due to drying. Such water and other additive-soluble organic solvents include wetting agents and penetrants.

  These solvents can be used alone or in combination with water and other additives.

  The content of water and other additive-soluble organic solvents is preferably 60% by weight or less based on the total weight of the treatment liquid. When the amount is more than 60% by weight or more, the viscosity of the treatment liquid increases, and the dischargeability from the inkjet head may deteriorate.

  The treatment liquid may further contain a resin component in order to improve fixability and abrasion resistance. The resin component may be any resin component that does not impair the ejection properties from the head when the treatment liquid is ejected by the ink jet method and has storage stability, and water-soluble resins and resin emulsions can be used freely.

  Examples of the resin component include acrylic, urethane, polyester, vinyl, and styrene. In order to sufficiently develop the function of improving the fixing property, it is necessary to add a relatively high polymer to a high concentration of 1% by weight to 20% by weight. However, if it is attempted to dissolve the above material in a liquid and add it, the viscosity becomes high, and the discharge property is lowered. In order to add an appropriate material at a high concentration and suppress an increase in viscosity, a means of adding as a latex is effective. Latex materials include alkyl acrylate copolymers, carboxy-modified SBR (styrene-butadiene latex), SIR (styrene-isoprene) latex, MBR (methyl methacrylate-butadiene latex), NBR (acrylonitrile-butadiene latex), and the like. Conceivable. The glass transition point Tg of the latex is a value that has a strong influence upon fixing in the process, and is preferably 50 ° C. or higher and 120 ° C. or lower in order to achieve both stability at room temperature storage and transferability after heating. Further, the minimum film-forming temperature MFT is a value that has a strong influence upon fixing in the process, and is 100 ° C. or lower, more preferably 50 ° C. or lower in order to obtain sufficient fixing at a low temperature.

  The coagulability may be further increased by including polymer fine particles having a polarity opposite to that of the ink in the treatment liquid and aggregating the pigment and polymer fine particles in the ink.

  In addition, a curing agent corresponding to the polymer fine particle component contained in the ink is contained in the treatment liquid, and after the two liquids contact, the resin emulsion in the ink component aggregates and crosslinks or polymerizes to increase the cohesiveness. Also good.

  The treatment liquid can contain a surfactant.

  Examples of surfactants include fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, Anionic surfactants such as oxyethylene alkyl sulfate esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines Nonionic surfactants such as glycerin fatty acid ester and oxyethyleneoxypropylene block copolymer are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred.

  Further, pages (37) to (38) of JP-A-59-157636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used. In addition, fluorine (fluorinated alkyl) and silicone surfactants as described in JP-A Nos. 2003-322926, 2004-325707, and 2004-309806 are also used. Can do. These surface tension modifiers can also be used as antifoaming agents, and fluorine-based, silicone-based compounds, chelating agents represented by EDTA, and the like can also be used.

  This is effective in reducing the surface tension and enhancing the wettability on the image forming body (recording medium, intermediate transfer body, etc.). Further, even when ink is ejected in advance, the wettability on the ink is enhanced, and the cohesive action is effectively promoted by increasing the contact area of the two liquids.

  The surface tension of the treatment liquid according to the present invention is preferably 10 to 50 mN / m. When direct recording is performed, the penetrability into the permeable recording medium, or when recording is performed by an intermediate transfer method, From the viewpoint of achieving both wettability on the intermediate transfer member, fine droplet formation and ejection properties, it is more preferably 15 to 45 mN / m.

  The viscosity of the treatment liquid according to the present invention is preferably 1.0 to 20.0 cP.

  In addition, pH buffering agents, antioxidants, fungicides, viscosity modifiers, conductive agents, ultraviolet rays, absorbents, and the like can be added as necessary.

[II] In the second embodiment of the image forming apparatus of the present invention, this is an embodiment of an intermediate transfer system in which an image is once formed on an intermediate transfer member by a two-liquid aggregation method and the image is transferred to a recording medium.
FIG. 15 is a schematic configuration diagram of an ink jet recording apparatus according to the second embodiment. The ink jet recording apparatus 200 shown in FIG. 15 employs a two-liquid aggregation method and an intermediate transfer recording method, and uses an ink and an aggregation treatment agent to form an ink image composed of an ink aggregate (color material aggregate) on the intermediate transfer body 202. And an ink image formed on the intermediate transfer body 202 is transferred to the recording medium 204.

  As shown in FIG. 15, the inkjet recording apparatus 100 according to the second embodiment includes an aggregation treatment liquid application unit 206 that applies a liquid aggregation treatment agent (aggregation treatment liquid) to the intermediate transfer body 202, and intermediate transfer. A heating and drying unit 208 that heats and dries the aggregating treatment liquid applied on the body 202; and a printing unit (ink droplet ejection unit) 210 that forms a plurality of ink droplets on the intermediate transfer body 202 and ejects them. , A solvent removing unit 212 that removes the liquid solvent (ink and liquid components of the aggregating treatment liquid) on the intermediate transfer body 202, and a transfer that transfers the ink image formed on the intermediate transfer body 202 to the recording medium 204. The unit 214 is mainly configured.

  An endless belt is applied to the intermediate transfer member 202 shown in FIG. 15, and the intermediate transfer member (endless belt) 202 is wound around a plurality of stretching rollers (seven stretching rollers 220A to 220G are shown in FIG. 15). The intermediate transfer member 202 has a counterclockwise direction in FIG. 15 by transmitting the power of a motor (not shown in FIG. 15) to at least one of the stretching rollers 220A to 220G. It is driven in the direction indicated by arrow A in FIG.

  The intermediate transfer member (endless belt) 202 has an image forming region (not shown) on which at least a primary image (ink image) is formed on a surface (image forming surface) 202 </ b> A facing the printing unit 210. And non-penetrable so that ink droplets such as rubber cannot penetrate. Further, at least the image forming area of the intermediate transfer member 202 is configured to form a horizontal surface (flat surface) having a predetermined flatness.

  Note that the amount (thickness) of the aggregating treatment liquid is reduced between the image forming area of the intermediate transfer body 202 and a medium having a slow permeation rate with respect to the aggregating treatment liquid (from the time when the aggregating treatment liquid is applied to the position immediately below the printing unit 210 A medium having a low permeability of 10% or less may be applied. That is, the intermediate transfer body 202 has a low permeability of 1% or less in decrease in the amount (thickness) of the aggregation treatment liquid after the aggregation treatment liquid is applied to the intermediate transfer body 202 until the intermediate transfer body 202 moves to the printing area immediately below the printing unit 210. It is also possible to apply a medium having non-permeability including a medium and a medium having low permeability in which the reduction amount of the aggregation treatment liquid is 10% or less.

  In FIG. 15, an endless belt is shown as one embodiment of the intermediate transfer member 202, but the intermediate transfer member applied to the present invention may be in the form of a drum or a flat plate.

  As a preferable material used for the surface layer including the image forming surface 202A of the intermediate transfer member 202, for example, polyimide resin, silicon resin, polyurethane resin, polyester resin, polystyrene resin, polyolefin resin, polybutadiene resin And publicly known materials such as polyamide resins, polyvinyl chloride resins, polyethylene resins, and fluorine resins.

  Further, it is preferable that the surface tension of the surface layer of the intermediate transfer member 202 is 10 mN / m or more and 40 mN / m or less. When the surface tension of the surface layer of the intermediate transfer body 202 is 40 mN / m or more, the difference in surface tension from the recording medium 204 to which the primary image is transferred is eliminated (or extremely small), and the transferability of the ink aggregate is improved. Getting worse. Further, when the surface tension of the surface layer of the intermediate transfer body 202 is 10 mN / m or less, the surface tension of the surface layer of the intermediate transfer body 202 is set to the surface tension of the aggregation processing liquid when the wettability of the aggregation processing liquid is taken into consideration. Therefore, it is difficult to make the surface tension of the aggregation treatment liquid 10 mN / m or less, and the design freedom (selection range) of the intermediate transfer body 202 and the aggregation treatment liquid is narrowed.

  In addition, it is preferable that the surface layer of the intermediate transfer body 202 has irregularities with a surface roughness (Ra) of about 0.3 μm because the movement of ink droplets and ink aggregates is suppressed.

  Aggregation treatment liquid application unit 206 is disposed on the most upstream side in the intermediate transfer member conveyance direction (the direction indicated by arrow A in FIG. 15), and includes application roller 206A and application liquid container 206B that stores the aggregation treatment liquid. Composed. The application roller 206A is driven to rotate with respect to the intermediate transfer body 202, or the application roller 206A is driven independently to control the rotation. As described above, the application roller 206 </ b> A rotates to apply the aggregation processing liquid stored in the application liquid container 206 </ b> B to the image forming surface 202 </ b> A of the intermediate transfer body 202.

  The coating thickness of the aggregation treatment liquid on the intermediate transfer body 202 is preferably set in the range of 0.5 to 20 μm. When the coating thickness is 0.5 μm or less, film non-uniformity is likely to occur due to liquid breakage, which causes a quality problem. On the other hand, when the coating thickness is 20 μm or more, the energy addition in the drying process increases, and the surface condition also deteriorates.

  In order to control the coating thickness of the aggregating treatment liquid, it is preferable to control the contact time between the coating roller 206A and the intermediate transfer body 202. When the contact time between the coating roller 206A and the intermediate transfer body 202 is relatively long, the coating thickness of the aggregating treatment liquid becomes relatively large. When the contact time between the coating roller 206A and the intermediate transfer body 202 is relatively short, the aggregation is performed. The coating thickness of the treatment liquid becomes relatively small.

  The application roller 206A is preferably a porous material or a material with irregularities on the surface, and for example, a gravure roll can be used.

  FIG. 15 illustrates an embodiment using the application roller 206A as one form of the aggregation treatment liquid application form, but the application form of the aggregation treatment liquid is not limited to this example, and application by a blade, droplet ejection by an inkjet head It is possible to apply various methods. In particular, in the case of the inkjet method, the aggregation treatment liquid can be accurately patterned and applied according to the recorded image (image data), and the heating time of the heating / drying unit 208 disposed in the subsequent stage can be shortened or the heating energy can be reduced. Reduction is possible.

The heating and drying unit 208 disposed on the downstream side in the conveyance direction of the intermediate transfer member with respect to the aggregation treatment liquid application unit 206 includes a heater (not shown in FIG. 15) provided on the back surface 202B side of the image forming surface 202A of the intermediate transfer member 202. The intermediate transfer body 202 that is configured to include the aggregation treatment liquid is dried by blowing hot air heated by a heater from the back surface 202B side.

  The heating temperature of the heater disposed in the heating / drying unit 208 is set according to various conditions such as the type of the aggregating treatment liquid, the application amount (thickness) of the aggregating treatment liquid, the environmental temperature, and the like. On the transfer body 202, a semi-solid aggregation layer having a water content of 56% or less is formed.

  For example, after applying the aggregation treatment liquid with a film thickness of about 10 μm on the intermediate transfer body 202 by the application roller 206A disposed in the aggregation treatment liquid application unit 206, drying with hot air at 70 ° C. is performed by the heater of the heating drying unit 208. Thus, a semi-solid solution treatment aggregation layer of about 4 μm can be formed on the intermediate transfer member 202.

  In this embodiment, an aggregation treatment liquid is applied on the intermediate transfer body 202, and the aggregation treatment liquid on the intermediate transfer body 202 is dried by heating to form a semisolid solution aggregation treatment layer on the intermediate transfer body 202. However, the present invention is not limited to this example, and there is also a mode in which a semi-solid solution processing agent is directly applied onto the intermediate transfer member 202.

  As a mode of directly applying a semi-solid solution aggregation treatment agent onto the intermediate transfer body 202, for example, known powder spraying such as fluidized dipping, electrostatic fume, spraying, electrostatic dry spraying, spraying, etc. The method can be used. In addition, the powder may be sprayed using a container having an opening provided with an openable / closable lid and capable of storing powder (semi-solid solution aggregation treatment agent) inside. Is possible. At this time, open the lid only when passing through the transfer body, spray the powder on the transfer body, close the lid when not in use, and control the powder so that it is not sprayed. It is also possible to control it.

  The printing unit 210 disposed on the downstream side in the intermediate transfer member conveyance direction of the heating and drying unit 208 includes cyan (C), magenta (M), yellow (Y), black (from the upstream side in the intermediate transfer member conveyance direction. Ink jet heads (hereinafter simply referred to as “heads”) 210C, 210M, 210Y, and 210K corresponding to the respective colors K) are provided in order. Corresponding color ink droplets are ejected from the heads 210C, 210M, 210Y, and 210K onto the image forming surface 202A of the intermediate transfer body 202.

  As shown in FIG. 16, each of the heads 210C, 210M, 210Y, and 210K has a length corresponding to the maximum width of the image forming area in the intermediate transfer member 202, and the entire width of the image forming area is formed on the ink discharge surface thereof. This is a full-line head in which a plurality of nozzles for ink ejection (not shown in FIG. 16) are arranged. Each head 210C, 210M, 210Y, 210K is fixedly installed so as to extend in a direction perpendicular to the intermediate transfer member conveyance direction.

  According to the configuration in which a full line head having a nozzle row that covers the entire width of the image forming area of the intermediate transfer body 202 is provided for each ink color, the intermediate transfer body 202 in the transport direction (sub-scanning direction) of the intermediate transfer body 202. The primary image can be recorded in the image forming area of the intermediate transfer body 202 only by performing the relative movement of the printing unit 210 once (that is, by one sub-scan). As a result, high-speed printing is possible and printing productivity can be improved as compared with the case where a serial (shuttle) type head that reciprocates in the direction (main scanning direction) orthogonal to the intermediate transfer member conveyance direction is applied. it can.

  In this example, the minimum droplet ejection amount (ejection volume) of ink droplets ejected from the nozzles of the heads 210C, 210M, 210Y, and 210K is 2 pl, and the maximum recording density (maximum dot density) is the main scanning direction ( Both in the direction orthogonal to the intermediate transfer member conveyance direction) and the sub-scanning direction (intermediate transfer member conveyance direction) are 1200 dpi.

  In this example, the configuration of CMYK standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink, dark ink, and special colors are used as necessary. Ink may be added. For example, it is possible to add an ink head that discharges light-colored ink such as light cyan and light magenta, and the arrangement order of the color heads is not particularly limited.

  The ink storage / loading unit 222 includes ink tanks (not shown in FIG. 15) that store color inks corresponding to the heads 210C, 210M, 210Y, and 210K, and each ink tank passes through a required flow path. Are communicated with corresponding heads. Further, the ink storage / loading unit 222 includes notifying means (display means, warning sound generating means) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. ing.

  The solvent removal unit 212 is disposed on the downstream side of the printing unit 210 in the intermediate transfer member conveyance direction, and includes a solvent absorption roller 212A. The solvent absorbing roller 212A of this example is provided at a position facing the roller 220B with the intermediate transfer member 202 interposed therebetween. The solvent absorbing roller 212A is composed of a roller-shaped porous body (absorbing body). In the solvent removing unit 212, the solvent absorbing roller 212A is brought into contact with the liquid solvent (the solvent component of the ink and the aggregation treatment liquid) on the intermediate transfer body 202, and the liquid solvent is put inside the porous body by the capillary force of the porous body. By absorbing the liquid solvent, the liquid solvent is removed from the intermediate transfer member 202.

  The solvent absorbing roller 212A may be driven to rotate in accordance with the movement (conveyance) of the intermediate transfer member 202, or may be rotated independently. Further, it is preferable that the intermediate transfer body 202 is configured to be separated from the image forming surface 202A.

  The surface energy of the surface of the solvent absorbing roller 212A (the surface that contacts the image forming surface 202A of the intermediate transfer body 202) is preferably smaller than the surface energy of the image forming surface 202A of the intermediate transfer body 202. A member having a surface energy of 30 mN / m or less is applied to the roller 212A.

  By removing the solvent using the solvent absorbing roller 212A that satisfies the above-described surface energy conditions, the liquid solvent on the intermediate transfer body 202 can be absorbed and removed while preventing the coloring material from adhering to the solvent absorbing roller 212A. It becomes possible.

  Instead of the solvent absorbing roller 212A, a method of removing excess solvent from the intermediate transfer member 202 with an air knife, heating the intermediate transfer member 202 (for example, heating with a flat plate heater), or blowing dry air. A method of evaporating and removing the solvent may be applied. The solvent removal method may be any of the methods exemplified above, but it is more preferable to use a method that does not rely on heating.

  In the method of heating the surface of the intermediate transfer member 202 or the method of applying heat to the ink aggregate on the intermediate transfer member 202 to evaporate the solvent, the solvent is excessively removed by overheating of the ink aggregate, and the transfer is performed. In some cases, the preferred viscoelasticity of the aggregate cannot be maintained, and the transferability to the recording medium 204 may deteriorate. Furthermore, there is a concern that the heat generated by overheating affects the ejection performance of each head 210C, 210M, 210Y, 210K.

  On the other hand, in the aspect in which the solvent on the image forming surface 202A of the intermediate transfer member 202 is absorbed and removed by the solvent absorbing roller 212A, even when a large amount of solvent remains on the intermediate transfer member 202, it takes less time than other methods. Since a large amount of solvent can be removed, a large amount of solvent (dispersion medium) is not transferred to the recording medium 204 by the transfer unit 214 at the subsequent stage. Therefore, even when papers are used as the recording medium 204, problems characteristic to aqueous solvents such as curls and cockles do not occur.

  Further, by removing excess solvent from the ink aggregate using the solvent removal unit 212, the ink aggregate can be concentrated and the internal aggregating force can be further increased. As a result, a stronger internal cohesive force can be applied to the ink aggregate until the transfer process by the transfer unit 214. Further, effective concentration of the ink aggregates by removing the solvent can impart good fixability and gloss to the image even after the image is transferred to the recording medium 204.

  Note that it is not always necessary to remove all of the solvent on the intermediate transfer body 202 by the solvent removal unit 212. If the ink aggregates are excessively removed by excessive removal, the adhesion force of the ink aggregates to the intermediate transfer body 202 becomes too strong, and an excessive pressure is required for transfer, which is not preferable. Rather, in order to maintain viscoelasticity suitable for transferability, it is preferable to leave a small amount.

  The effects obtained by leaving a small amount of the solvent on the intermediate transfer member 202 include the following. That is, since ink aggregates are hydrophobic and solvent components that are difficult to volatilize (mainly organic solvents such as glycerin) are hydrophilic, ink aggregates and residual solvent components are separated after solvent removal, and residual solvent components A thin liquid layer is formed between the ink aggregate and the intermediate transfer member. Accordingly, the adhesion force of the ink aggregate to the intermediate transfer member 202 becomes weak, which is advantageous for improving transferability.

  The solvent removal control described above can be performed by changing the pressure applied to the intermediate transfer body 202 by the solvent absorbing roller 212A. When the solvent removal amount is relatively large, the pressure on the intermediate transfer body 202 of the solvent absorption roller 212A is increased, and when the solvent removal amount is relatively small, the intermediate transfer body of the solvent absorption roller 212A. What is necessary is just to make the press to 202 small.

  In addition, a mode in which a plurality of solvent absorption rollers having different absorption characteristics are provided and the solvent absorption roller to be used is selectively switched according to the amount of solvent removal is also possible.

  In the ink jet recording apparatus 200 shown in FIG. 15, a preheating unit 224 is provided between the solvent removal unit 212 and the transfer unit 214. The preheating unit 224 includes a heater (not shown in FIG. 15) provided on the back surface 202B side of the image forming surface 202A of the intermediate transfer body 202, and the intermediate transfer on which the primary image (ink image) is formed. The body 202 is preheated from the back surface 202B side by a heater. A flat plate heater is preferably used for the preheating unit 224 of this example. Further, in this example, the configuration in which the heater is disposed outside the intermediate transfer member 202 is shown, but an aspect in which the heater is incorporated in the intermediate transfer member 202 is also possible.

  The heating temperature range of the heater disposed in the preheating unit 224 is 40 to 80 ° C., and is set lower than the heating temperature at the time of transfer. By preheating the image forming area of the intermediate transfer body 202, the heating temperature of the transfer unit 214 can be set lower than when no preheating is performed, and the transfer time of the transfer unit 214 is further reduced. be able to.

  In the preheating unit 224, heating is performed so that the temperature of the image forming surface 202A of the intermediate transfer member 202 (the temperature of the region where the image is formed) exceeds the glass transition temperature Tg of the polymer fine particles contained in the ink. The temperature is preferably set.

  The transfer unit 214 disposed downstream of the preheating unit 224 in the conveyance direction of the intermediate transfer member includes a transfer heating roller 214A having a heater (not shown in FIG. 15), and a heating and pressing nip disposed opposite to the transfer heating roller 214A. The intermediate transfer body 202 and the recording medium 204 are sandwiched between the rollers 214A and 214B, and heated at a predetermined temperature and pressurized with a predetermined pressure (nip pressure). Thus, the primary image formed on the intermediate transfer member 202 is transferred to the recording medium 204.

  The heating temperature (transfer temperature) by the transfer unit 214 is preferably 80 ° C. to 170 ° C., and more preferably 100 ° C. to 150 ° C. from the viewpoint of transferability. When the heating temperature by the transfer unit 214 is 170 ° C. or higher, there is a problem such as deformation of the intermediate transfer body 202, and when it is 80 ° C. or lower, there is a problem that transferability is deteriorated.

  The nip pressure by the transfer unit 214 is preferably 1.5 to 2.0 MPa. As a means for adjusting the nip pressure at the time of transfer in the transfer unit 214, for example, a mechanism (drive means) for moving the transfer heating roller 214A in the vertical direction (shown by reference C) in FIG. That is, when the transfer heating roller 214A is moved away from the heating counter roller 214B, the nip pressure decreases, and when it is moved closer to the heating counter roller 214B, the nip pressure increases.

  As a configuration of the paper supply unit 226 that supplies the recording medium 204 to the transfer unit 214, a mode in which a magazine for rolled paper (continuous paper) is provided, or in place of or in combination with a magazine for rolled paper, cut paper is used. There is a mode in which paper is supplied by a cassette loaded with stacks. In the case of an apparatus configuration using roll paper, a cutter for cutting is provided, and the roll paper is cut into a desired size by the cutter. A plurality of magazines and cassettes having different paper widths and paper qualities may be provided.

  When a plurality of types of recording media can be used, an information recording body such as a barcode or a wireless tag that records the media type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Thus, it is preferable to automatically determine the type of recording medium (media type) to be used and perform ink ejection control so as to realize appropriate ink ejection according to the media type.

  As the recording medium 204 applied to this example, the same recording medium as described in the first embodiment can be used.

  A mode in which the cooling unit 228 is arranged on the downstream side of the transfer unit 214 in the conveyance direction of the intermediate transfer member is preferable. The cooling unit 228 cools the intermediate transfer member 202 and the recording medium 204 that are past each other through the transfer unit 214. The cooling unit 228 is preferably applied with a mode in which cool air is blown by a cooling fan or the like, and the cooling temperature or the like can be adjusted. The cooling unit 228 shown in this example has a configuration in which a moving time (cooling time) of the intermediate transfer body 202 for cooling to a desired temperature is secured. By peeling the intermediate transfer body 202 and the recording medium 204 after cooling, transfer defects due to temperature unevenness or the like can be prevented, and stable image transfer (peeling) becomes possible.

  A peeling unit 230 is disposed downstream of the cooling unit 228 in the conveyance direction of the intermediate transfer member. The peeling unit 230 is configured to peel the recording medium 204 from the intermediate transfer body 202 with the rigidity (waist strength) of the recording medium 204 by the winding curvature of the peeling roller 220E of the intermediate transfer body 202. The peeling part 230 may be used in combination with means for promoting peeling such as a peeling nail.

  A fixing unit 232 is disposed downstream of the peeling unit 230 in the recording medium conveyance direction (the direction indicated by arrow B in FIG. 15). The fixing unit 232 includes a heating roller pair 232A whose temperature can be adjusted in a range of 100 ° C. to 180 ° C., and the recording medium 204 is heated and pressed while being sandwiched between the heating roller pair 232A. The image transferred to the image is fixed.

  The heating temperature of the fixing unit 232 is preferably set according to the glass transition temperature of the polymer fine particles contained in the ink. In this example, the heating temperature of the fixing unit 232 is set to 130 ° C. Further, it is preferable that the nip pressure of the fixing unit 232 is 2.5 to 3.0 MPa. Note that if the transfer unit 214 can achieve both image transfer and fixing, a mode in which the fixing unit 232 is omitted is also possible.

  A cleaning unit 234 is disposed downstream of the peeling unit 230 in the conveyance direction of the intermediate transfer member. The cleaning unit 234 wipes off post-transfer residues (such as ink aggregates) while contacting the image forming surface 202A of the intermediate transfer body 202 as a means for cleaning the intermediate transfer body 202 after the image transfer to the recording medium 204. It includes a blade (not shown) to be removed and a collection unit (not shown) for collecting the removed post-transfer residue.

  The structure of the cleaning means for removing the post-transfer residue from the intermediate transfer member 202 is not limited to the above example, but a method of niping a brush roll, a water absorption roll, etc., an air blow method of blowing clean air, an adhesive roll There are methods or combinations thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Note that the head arranged in the printing unit 210 is the same as the head described in the first embodiment, and a description thereof will be omitted.

  [III] In the third embodiment of the image forming apparatus of the present invention, in the intermediate transfer system in which an image is once formed on the intermediate transfer member by the two-liquid aggregation method, and the image is transferred to a recording medium. In this embodiment, one treatment liquid containing a component for aggregating the color material of the ink and substantially colorless fine particles is applied.

The substantially colorless fine particles used in the present invention may be any fine particles as long as they are substantially colorless fine particles. “Substantially colorless” means that when 0.1 g / m ² of the fine particles of the present invention is applied, the absorbance density in the visible region is 0.1 or less.

Specific examples of substantially colorless fine particles include polymer fine particles such as polyolefin, polyacrylate, polyester, polystyrene, polyurethane, polyisocyanate, paraffin, ester (carbana wax, montanic ester wax), stearic acid, stearic acid amide. ethylene bis-stearic acid amide, low-molecular organic compound microparticles such as zinc stearate, silicone oil microparticles, colorless inorganic microparticles _{(TiO 2, CaCO 3, ZnO} , SiO 2, AlO 3 , etc.) and the like, also, such as polyurethane There may also be mentioned microcapsule type fine particles in which an organic compound is encapsulated in a polymer thin film.

  Among these, fine particles of an organic compound are preferable from the viewpoint of melting or softening at the time of heat-fixing to express image glossiness, and a polymer is preferable from the viewpoint of abrasion resistance after fixing. In addition, polyolefin fine particles having a low surface energy are preferably used from the viewpoint that it is necessary to exhibit good releasability during transfer.

  The molecular weight of the polymer is preferably a low molecular weight from the viewpoint of having a low softening point, and the preferred molecular weight is 1000 to 100,000, more preferably 1000 to 5000.

  The treatment liquid according to the present invention can contain a surfactant.

  Examples of surfactants include fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, Anionic surfactants such as oxyethylene alkyl sulfate esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylamines Nonionic surfactants such as glycerin fatty acid ester and oxyethyleneoxypropylene block copolymer are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred.

  Further, pages (37) to (38) of JP-A-59-157636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used. In addition, fluorine (fluorinated alkyl) -based and silicone-based surfactants as described in JP-A Nos. 2003-322926, 2004-325707, and 2004-309806 are also used. it can. These surface tension modifiers can also be used as antifoaming agents, and fluorine-based, silicone-based compounds, chelating agents represented by EDTA, and the like can also be used.

  This is effective for lowering the surface tension and improving wettability on the intermediate transfer member.

  The surface tension of the treatment liquid is preferably 10 to 50 mN / m. When direct recording is performed, the penetrability into the permeable recording medium, and when recording is performed by an intermediate transfer method, Is more preferably 15 to 45 mN / m from the viewpoint of achieving both wettability with water droplets, fine droplet formation and dischargeability.

  The viscosity of the treatment liquid is preferably 1.0 to 20.0 cP.

  In addition, pH buffering agents, antioxidants, fungicides, viscosity modifiers, conductive agents, ultraviolet rays, absorbents, and the like can be added as necessary.

  The ink jet recording apparatus 400 used in the third embodiment of the present invention uses a processing liquid (aggregation processing liquid) containing a component that aggregates the coloring material of ink and substantially colorless fine particles as an intermediate. Any apparatus may be used as long as it forms an ink image composed of an ink aggregate (color material aggregate) on a transfer body and transfers the ink image formed on the intermediate transfer body to a recording medium.

  FIG. 17 shows an example of an ink jet recording apparatus 400 suitable for the third embodiment of the present invention, which is basically the same as the intermediate transfer type ink jet recording apparatus 200 shown in FIG.

  As shown in FIG. 17, the inkjet recording apparatus 400 heats and dries the aggregation treatment liquid application unit 416 that applies the aggregation treatment liquid onto the intermediate transfer body 412 and the aggregation treatment liquid applied onto the intermediate transfer body 412. A heating / drying unit 418 for printing, and a printing unit for forming ink droplets of each color of cyan (C), magenta (M), yellow (Y), and black (K) onto the intermediate transfer body 412 (ink ejection) Part) 420, a solvent removing unit 424 for removing the liquid solvent (ink and liquid components of the aggregating treatment liquid) on the intermediate transfer body 412, and the ink image formed on the intermediate transfer body 412 on the recording medium 414. The transfer unit 426 mainly performs transfer.

  An endless belt is applied to the intermediate transfer body 412 shown in FIG. 17, and the intermediate transfer body (endless belt) 412 includes a plurality of stretching rollers (in FIG. 17, two stretching rollers 428A and 428B and a transfer heating roller). The intermediate transfer body 412 has a structure wound around a heating counter roller 426B (not shown in FIG. 17) and the power of a motor (not shown in FIG. 17) is transmitted to at least one of these rollers. In FIG. 17, it is driven in the counterclockwise direction (the direction indicated by the arrow A in FIG.

  The intermediate transfer member (endless belt) 412 has an image forming area (not shown) on which at least a primary image (ink image) of a surface (image forming surface) 412A facing the printing unit 420 is formed, resin, metal And non-penetrable so that ink droplets such as rubber cannot penetrate. Further, at least the image forming area of the intermediate transfer body 412 is configured to form a horizontal surface (flat surface) having a predetermined flatness.

  Note that the amount (thickness) of the aggregating treatment liquid is reduced between the image forming area of the intermediate transfer body 412 and a medium having a slow permeation speed with respect to the aggregating treatment liquid (from the time when the aggregating treatment liquid is applied to the position immediately below the printing unit 420). A medium having a low permeability of 10% or less may be applied. That is, the intermediate transfer body 412 has a low permeability of 1% or less in the decrease in the amount (thickness) of the aggregation treatment liquid after the aggregation treatment liquid is applied to the intermediate transfer body 412 until the intermediate transfer body 412 moves to the printing area immediately below the printing unit 420. It is also possible to apply a medium having non-permeability including a medium and a medium having low permeability in which the reduction amount of the aggregation treatment liquid is 10% or less.

  In FIG. 17, an endless belt is shown as one embodiment of the intermediate transfer member 412, but the intermediate transfer member applied to the present invention may be a drum shape or a flat plate shape.

  A preferable material used for the surface layer including the image forming surface 412A of the intermediate transfer body 412 and a preferable surface tension of the intermediate transfer body 412 are the same as those in the ink jet recording apparatus described in FIG.

  Further, it is preferable that the surface tension of the surface layer of the intermediate transfer member 412 is 10 mN / m or more and 40 mN / m or less. When the surface tension of the surface layer of the intermediate transfer body 412 is 40 mN / m or more, the difference in surface tension from the recording medium 414 to which the primary image is transferred is eliminated (or extremely small), and the transferability of the ink aggregate is improved. Getting worse. Furthermore, when the surface tension of the surface layer of the intermediate transfer body 412 is 10 mN / m or less, the surface tension of the surface layer of the intermediate transfer body 412 is set to the surface tension of the aggregation processing liquid in consideration of the wettability of the aggregation processing liquid. It is difficult to make the surface tension of the aggregation treatment liquid 10 mN / m or less, and the design freedom (selection range) of the intermediate transfer body 412 and the aggregation treatment liquid is narrowed.

  The surface layer of the intermediate transfer member 412 is preferably composed of a smooth surface having a surface roughness (Ra) of 1.0 μm or less. If the surface roughness (Ra) of the surface layer of the intermediate transfer body 412 exceeds 1.0 μm, the contact area between the ink layer and the intermediate transfer body 412 increases, and the transferability to the recording medium 414 decreases. According to the present invention, as described later, a particle layer composed of substantially colorless fine particles is formed on the surface of the intermediate transfer body 412 without directly forming irregularities on the surface of the intermediate transfer body 412. Image shrinkage can be suppressed by the anchor effect of the layer, and transferability can also be improved.

  An aggregation processing liquid application unit 416 that applies an aggregation processing liquid on the intermediate transfer body 412 is disposed on the most upstream side in the intermediate transfer body conveyance direction (the direction indicated by arrow A in FIG. 17). The aggregation treatment liquid application unit 416 includes an application roller 416A and a coating liquid container (not shown) that stores the aggregation treatment liquid. The application roller 416A rotates following the intermediate transfer body 412 or can be independently driven and controlled to rotate. The application roller 416A is accommodated in the application liquid container according to the rotation of the application roller 416A. The aggregation processing liquid is applied to the image forming surface 412A of the intermediate transfer member 412.

  The coating thickness of the aggregation treatment liquid on the intermediate transfer body 412 is preferably set in the range of 0.5 to 20 μm, and in this example, it is uniformly applied with a film thickness of about 4 μm. If the coating thickness is less than 0.5 μm, film non-uniformity is liable to occur due to liquid breakage, resulting in a quality problem. On the other hand, when the coating thickness exceeds 20 μm, energy addition in the drying process increases, and the surface condition also deteriorates.

  In order to control the coating thickness of the aggregation treatment liquid, a mode in which the contact time between the coating roller 416A and the intermediate transfer member 412 is controlled is preferable. When the contact time between the application roller 416A and the intermediate transfer body 412 is relatively long, the coating thickness of the aggregation treatment liquid becomes relatively large. When the contact time between the application roller 416A and the intermediate transfer body 412 is relatively short, the aggregation is performed. The coating thickness of the treatment liquid becomes relatively small.

  For the application roller 416A, a porous material or a material with irregularities on the surface is desirable, and for example, a gravure roll can be used.

  FIG. 17 illustrates an example in which the application roller 416A is used as one mode of application of the aggregation treatment liquid. However, the application mode of the aggregation treatment liquid is not limited to this example, and application by a blade and droplet ejection by an inkjet head are illustrated. It is possible to apply various methods. In particular, in the case of the inkjet method, the aggregation treatment liquid can be accurately patterned and applied according to the recorded image (image data), and the heating time of the heating and drying unit 418 disposed in the subsequent stage can be shortened or the heating energy can be reduced. Reduction is possible.

  A heat drying unit 418 for drying the aggregation treatment liquid applied on the intermediate transfer body 412 is disposed on the downstream side of the aggregation processing liquid application unit 416 in the conveyance direction of the intermediate transfer body. The heating and drying unit 418 includes a heater (not shown in FIG. 17) provided on the back surface 412B side of the image forming surface 412A of the intermediate transfer member 412, and the intermediate transfer member 412 to which the aggregation processing liquid is applied. The aggregating treatment liquid on the intermediate transfer body 412 is dried by blowing hot air heated by a heater from the back surface 412B side. The heating temperature of the heater disposed in the heating and drying unit 418 is set according to various conditions such as the type of the aggregation treatment liquid, the application amount (thickness) of the aggregation treatment liquid, and the environmental temperature. In this example, hot air drying at 70 ° C. is performed.

  By drying by the heat drying unit 418, a thin layer is formed on the intermediate transfer body 412 by the aggregation treatment agent and particles (substantially colorless fine particles) that prevent image shrinkage. In the drying step, it is not always necessary to completely evaporate the water in the treatment liquid, and it is sufficient to increase the viscosity of the treatment liquid so that the particle layer does not flow.

  The printing unit 420 disposed on the downstream side in the intermediate transfer member conveyance direction of the heating and drying unit 418 includes cyan (C), magenta (M), yellow (Y), and black from the upstream side in the intermediate transfer member conveyance direction. Ink jet heads (hereinafter simply referred to as “heads”) 420C, 420M, 420Y, and 420K corresponding to the respective colors of (K) are provided in order. In accordance with the image data (image signal), the corresponding color ink is formed into droplets from the heads 420C, 420M, 420Y, and 420K onto the image forming surface 412A of the intermediate transfer body 412 and ejected.

  A solvent removal unit 424 is disposed downstream of the printing unit 420 in the conveyance direction of the intermediate transfer member. The solvent removal unit 424 includes a solvent absorption roller 424A, and the solvent absorption roller 424A is brought into contact with the liquid solvent (the ink and the solvent component of the aggregating treatment liquid) on the intermediate transfer body 412 to form a porous capillary tube. The liquid solvent is removed from the intermediate transfer body 412 by absorbing the liquid solvent into the porous body by force.

  The solvent absorbing roller 424A may be driven to rotate according to the movement (conveyance) of the intermediate transfer body 412 or may be rotated independently. Further, it is preferable that the intermediate transfer body 412 be configured to be separated from the image forming surface 412A.

  The surface energy of the surface of the solvent absorbing roller 424A (the surface in contact with the image forming surface 412A of the intermediate transfer member 412) is preferably smaller than the surface energy of the image forming surface 412A of the intermediate transfer member 412, and in this example, the solvent absorption A member having a surface energy of 30 mN / m or less is applied to the roller 424A.

  By removing the solvent using the solvent absorbing roller 424A that satisfies the above-mentioned surface energy conditions, the liquid solvent on the intermediate transfer body 412 can be absorbed and removed while preventing the coloring material from adhering to the solvent absorbing roller 424A. It becomes possible.

  Instead of the solvent absorbing roller 424A, a method of removing excess solvent from the intermediate transfer body 412 with an air knife, heating the intermediate transfer body 412 (for example, heating with a flat plate heater), or blowing dry air. A method of evaporating and removing the solvent may be applied. The solvent removal method may be any of the methods exemplified above, but it is more preferable to use a method that does not rely on heating.

  In the method of heating the surface of the intermediate transfer member 412 or the method of applying heat to the ink aggregate on the intermediate transfer member 412 to evaporate the solvent, the solvent is excessively removed by overheating of the ink aggregate, and the transfer is performed. In some cases, the preferred viscoelasticity of the aggregate cannot be maintained, and the transferability to the recording medium 414 may be deteriorated. Furthermore, there is a concern that the heat generated by overheating affects the ejection performance of each head 420C, 420M, 420Y, 420K.

  On the other hand, in the mode in which the solvent on the image forming surface 412A of the intermediate transfer member 412 is absorbed and removed by the solvent absorbing roller 424A, even when a large amount of solvent remains on the intermediate transfer member 412, it takes less time than other methods. Since a large amount of solvent can be removed, a large amount of solvent (dispersion medium) is not transferred to the recording medium 414 by the transfer unit 426 in the subsequent stage. Therefore, even when paper is used as the recording medium 414, there is no problem characteristic to the aqueous solvent such as curl and cockle.

  Further, by removing excess solvent from the ink aggregate using the solvent removing unit 424, the ink aggregate can be concentrated and the internal aggregating force can be further increased. Thereby, a stronger internal cohesive force can be imparted to the ink aggregate up to the transfer process by the transfer section 426. Further, effective concentration of the ink aggregates by removing the solvent can impart good fixability and gloss to the image even after the image is transferred to the recording medium 414.

  Note that it is not always necessary to remove all of the solvent on the intermediate transfer body 412 by the solvent removal unit 424. If the ink aggregate is concentrated too much by excessively removing it, the adhesion force of the ink aggregate to the intermediate transfer body 412 becomes too strong, and an excessive pressure is required for transfer. Rather, in order to maintain viscoelasticity suitable for transferability, it is preferable to leave a small amount.

  The effects obtained by leaving a small amount of the solvent on the intermediate transfer body 412 include the following. That is, since the ink aggregate is hydrophobic and solvent components that are difficult to volatilize (mainly organic solvents such as glycerin) are hydrophilic, the ink aggregate and the residual solvent component are separated after solvent removal, and the residual solvent component A thin liquid layer is formed between the ink aggregate and the intermediate transfer member 412. Therefore, the adhesive force of the ink aggregate to the intermediate transfer member 412 is weak, which is advantageous for improving transferability.

  The solvent removal control described above can be performed by changing the pressure applied to the intermediate transfer body 412 by the solvent absorbing roller 424A. When the solvent removal amount is relatively large, the pressure on the intermediate transfer member 412 of the solvent absorption roller 424A is increased, and when the solvent removal amount is relatively small, the intermediate transfer member of the solvent absorption roller 424A. What is necessary is just to make the press to 412 small.

  In addition, a mode in which a plurality of solvent absorption rollers having different absorption characteristics are provided and the solvent absorption roller to be used is selectively switched according to the amount of solvent removal is also possible.

  In the ink jet recording apparatus 400 shown in FIG. 17, a preheating unit 430 is provided between the solvent removal unit 424 and the transfer unit 426. The preheating unit 430 includes a heater (not shown in FIG. 17) provided on the back surface 412B side of the image forming surface 412A of the intermediate transfer member 412, and is an intermediate transfer on which a primary image (ink image) is formed. The body 412 is preheated from the back surface 412B side by a heater. A flat plate heater is preferably used for the preheating unit 430 of this example. In addition, although the configuration in which the heater is disposed outside the intermediate transfer member 412 is shown, an aspect in which the heater is incorporated in the intermediate transfer member 412 is also possible.

  The heating temperature (preheating temperature) by the preheating unit 430 is preferably set lower than the heating temperature (transfer temperature) at the time of transfer, and is set to 90 ° C. in this example. By preheating the image forming area of the intermediate transfer body 412, the heating temperature of the transfer unit 426 can be set lower than when no preheating is performed, and the transfer time of the transfer unit 426 is further reduced. be able to.

  In the preheating unit 430, heating is performed so that the temperature of the image forming surface 412A of the intermediate transfer body 412 (the temperature of the region where the image is formed) exceeds the glass transition temperature Tg of the polymer fine particles contained in the ink. The temperature is preferably set.

  A transfer unit 426 is disposed downstream of the preheating unit 430 in the intermediate transfer member conveyance direction. The transfer unit 426 includes a transfer heating roller 426A having a heater (not shown in FIG. 17), and a heating counter roller 426B for a heating and pressurizing nip disposed to face the roller 426A. A primary image formed on the intermediate transfer body 412 is sandwiched between 426A and 426B, and is pressed at a predetermined pressure (nip pressure) while being heated at a predetermined temperature. Is transferred to the recording medium 414.

  The heating temperature (transfer temperature) by the transfer unit 426 is preferably 80 ° C. to 170 ° C., and more preferably 100 ° C. to 150 ° C. from the viewpoint of transferability. The heating temperature (transfer temperature) in this example is set to 120 ° C. When the heating temperature by the transfer unit 426 is 170 ° C. or higher, there is a problem such as deformation of the intermediate transfer body 412. On the other hand, when the heating temperature is 80 ° C. or lower, the transfer property is deteriorated.

  The nip pressure by the transfer unit 426 is preferably 1.5 to 2.0 MPa. As a means for adjusting the nip pressure at the time of transfer in the transfer unit 426, for example, a mechanism (drive means) for moving the transfer heating roller 426A in the vertical direction (shown by C) in FIG. That is, when the transfer heating roller 426A is moved away from the heating counter roller 426B, the nip pressure decreases, and when it is moved closer to the heating counter roller 426B, the nip pressure increases.

  As a configuration of the paper feed unit 432 that supplies the recording medium 414 to the transfer unit 426, an embodiment including a roll paper (continuous paper) magazine, or a cut paper instead of or in combination with the roll paper magazine. There is a mode in which paper is supplied by a cassette loaded with stacks. In the case of an apparatus configuration using roll paper, a cutter for cutting is provided, and the roll paper is cut into a desired size by the cutter. A plurality of magazines and cassettes having different paper widths and paper qualities may be provided.

  When a plurality of types of recording media can be used, an information recording body such as a barcode or a wireless tag that records the media type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Thus, it is preferable to automatically determine the type of recording medium (media type) to be used and perform ink ejection control so as to realize appropriate ink ejection according to the media type.

  A specific example of the recording medium 414 applied to this example is the same as the case of the intermediate transfer type inkjet recording apparatus shown in FIG.

  In this embodiment, the recording medium 414 that has passed between the rollers 426A and 426B of the transfer unit 426 is peeled off from the intermediate transfer body 412, but after the transfer to the recording medium 414, the recording medium 414 is performed. There is also a mode in which a certain interval is provided until the peeling of the sheet is performed, and the state in which the intermediate transfer body 412 and the recording medium 414 are pasted through the transfer unit 426 is cooled by a cooling fan or a cooling member. . It is further preferable that the cooling temperature and the like can be adjusted. By peeling the intermediate transfer body 412 and the recording medium 414 after cooling, transfer failure due to temperature unevenness or the like can be prevented, and stable image transfer (peeling) becomes possible.

  A fixing unit 434 is disposed downstream of the transfer unit 426 in the recording medium conveyance direction (the direction indicated by arrow B in FIG. 17). The fixing unit 434 includes a heating roller pair 434A whose temperature can be adjusted within a range of 100 ° C. to 180 ° C., and the recording medium 414 is heated and pressed while being pressed between the heating roller pair 434A. The image transferred to the image is fixed.

  The heating temperature (fixing temperature) by the fixing unit 434 is preferably set according to the glass transition temperature of the polymer fine particles contained in the ink. The heating temperature (fixing temperature) in this example is set to 130 ° C. The nip pressure of the fixing unit 434 is preferably 2.5 to 3.0 MPa. Note that the fixing unit 434 may be omitted if the transfer unit 426 can achieve both image transfer and fixing.

  A cleaning unit 436 is disposed on the downstream side of the transfer unit 426 in the conveyance direction of the intermediate transfer member. The cleaning unit 436 serves as a means for cleaning the intermediate transfer body 412 after the image transfer to the recording medium 414, and a post-transfer residue (ink aggregate or the like) while contacting the image forming surface 412A of the intermediate transfer body 412. ) And a recovery unit (not shown) for recovering the removed post-transfer residue.

  The structure of the cleaning means for removing the post-transfer residue from the intermediate transfer body 412 is not limited to the above example, but a system that nips a brush / roll, a water absorbing roll, etc., an air blow system that blows clean air, an adhesive roll There are methods or combinations thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  In FIG. 17, while the intermediate transfer member 412 is conveyed in the intermediate transfer member conveyance direction (the direction indicated by arrow A in FIG. 17), the aggregation treatment liquid is first transferred to the intermediate transfer member by the application roller 416A of the aggregation treatment liquid application unit 416. 412 is applied (aggregation treatment liquid application step). Subsequently, the heat drying unit 418 dries the aggregation treatment liquid on the intermediate transfer body 412, and the intermediate transfer body 412 has a solid or high viscosity composed of the aggregation treatment agent and particles (substantially colorless fine particles). A liquid thin layer (aggregation treatment agent layer, particle layer) is formed (aggregation treatment liquid drying step). A process for forming the thin layer on the intermediate transfer member 412 will be described later.

  After a thin layer of solid or high viscosity liquid is formed on the intermediate transfer body 412, ink droplets of each color are ejected by the respective heads 420C, 420M, 420Y, 420K of the printing unit 420 (ink ejection). Process). When the ink droplets land on the intermediate transfer member 412 on which the thin layer is formed, the aggregation reaction of the color material contained in the ink droplets is instantly started and spreads to a predetermined size on the intermediate transfer member 412. An ink aggregate (coloring material aggregate) is formed. At this time, the shrinkage of the image due to the aggregation reaction of the ink is prevented by the anchor effect by the particle layer. Further, image deterioration due to color material movement is also prevented.

  Next, the solvent absorbing roller 424A of the solvent removing unit 424 absorbs and removes the liquid solvent (the ink and the solvent component of the aggregation treatment liquid) on the intermediate transfer body 412 (solvent removing step). Dots composed of ink aggregates (color material aggregates) can obtain a sufficient adhesion force with the particle layer formed on the surface of the intermediate transfer body 412. Thereby, it is possible to prevent the coloring material from adhering to the solvent absorbing roller 424A.

  As described above, after the ink image formed of the ink aggregate is formed on the intermediate transfer body 412 while preventing the image shrinkage and the movement and adhesion of the color material, the ink image on the intermediate transfer body 412 is formed by the preheating unit 430. Is heated to a predetermined temperature (preliminary heating step), and the ink image formed on the intermediate transfer body 412 is transferred to the recording medium 414 by the transfer unit 426 (transfer step). At this time, the contact area between the intermediate transfer body 412 and the ink image (ink layer) is reduced by the solid or high-viscosity liquid thin layer (particle layer) formed on the intermediate transfer body 412, and the recording medium 414. Improves the transferability.

  After the transfer, the recording medium 414 peeled off from the intermediate transfer body 412 is heated and pressed while being sandwiched between the heating roller pair 434A of the fixing unit 434, so that the transferred ink image is fixed (fixing step).

  On the other hand, after the transfer, the intermediate transfer body 412 from which the recording medium 414 has been peeled is removed by the cleaning unit 436 after the transfer (cleaning process).

  Thereafter, the above-described steps are sequentially repeated.

  Next, a process for forming a solid or high-viscosity liquid thin layer (aggregation treatment agent layer, particle layer) on the intermediate transfer member 412 will be described.

  FIG. 18 is a schematic diagram showing the behavior when ink droplets (dots) according to the present invention land on the intermediate transfer member (as compared with FIG. 41 shown in the prior art). FIG. 18A shows a state in which the aggregation treatment agent 302 having a predetermined thickness is applied onto the intermediate transfer member 412. In the aggregation treatment agent 302 applied on the intermediate transfer member 412, substantially colorless fine particles 304 are dispersed and in a state having fluidity. FIG. 18B shows a state after the drying process is performed. As the moisture in the aggregation treatment agent 302 evaporates in the drying process, a particle layer (concave / convex layer) composed of fine particles 304 is formed on the intermediate transfer body 12. Further, the aggregation treatment agent 302 dissolved in the drying process is localized around the fine particles 304 due to the surface tension. When the drying process is completed and the water is evaporated, a solid or high viscosity liquid thin layer (aggregation treatment agent layer, particle layer) 306 composed of the aggregation treatment agent and particles (fine particles 304) is formed. FIG. 18C shows the behavior immediately after the ink droplet 310 has landed on the intermediate transfer body 412 on which the thin layer 306 of solid or high viscosity liquid is formed. Since the aggregation treatment agent 302 is localized near the fine particles 304, the aggregation reaction of the ink droplets 310 proceeds from the vicinity of the fine particles 304 and the viscosity increases. FIG. 18D shows a state in which the aggregation treatment agent 302 has been diffused and aggregation has progressed in the entire ink droplet 310 (entire dot) to increase the viscosity. Since the agglomeration locally proceeds in this manner, the adhesion with the base material (intermediate transfer body 412) increases and the thin layer (particle layer) 306 acts as an anchor effect. Does not occur.

  FIG. 19 is a schematic diagram showing the behavior when an image according to the present invention is drawn (contrast with FIG. 42 shown in the prior art). FIG. 19A shows a state immediately after the drawing, and shows a state in which a portion (image portion) 312 having a color material and a white background portion 314 are formed according to input image data. Note that the image portion 312 is formed of a plurality of dots. As in the case described with reference to FIG. 18, since the aggregation treatment agent 302 is localized near the fine particles 304, the aggregation reaction proceeds from the vicinity of the fine particles 304 and the viscosity increases. FIG. 19B shows a state in which the aggregation treatment agent 302 has been diffused and aggregation has progressed in the entire image portion 312 to increase the viscosity. As agglomeration proceeds locally in this manner, the adhesion with the base material (intermediate transfer member 412) increases, and the thin layer (particle layer) 306 acts as an anchor effect, so that image shrinkage does not occur.

  FIG. 20 is a schematic diagram showing the behavior during transfer according to the present invention (shown in the prior art and compared with FIG. 43). FIG. 20A shows a state in which an image formed on the intermediate transfer body 412 is transferred to the recording medium 414 while being pressed by a transfer heating roller (not shown in FIG. 20). Reference numeral 320 denotes an ink layer constituting an image formed on the intermediate transfer member 412. FIG. 20B shows a state after the recording medium 414 is peeled (that is, a state after transfer). As shown in FIG. 20A, since a thin layer (particle layer) 306 is formed on the intermediate transfer member 412, the contact area between the intermediate transfer member 412 and the ink layer 320 becomes small, and FIG. As shown in a), good transferability can be obtained without a part of the ink layer 320 remaining on the intermediate transfer body 412 side.

  As a preferred embodiment of the present invention, the average particle size is preferably 0.1 to 10.0 μm with respect to the size of the fine particles. When the particle diameter is less than 0.1 μm, sufficiently large irregularities are not formed on the surface of the particle layer made of fine particles, the anchor effect is lowered, and image shrinkage cannot be suppressed. On the other hand, when the particle diameter exceeds 10.0 μm, the particle size becomes larger than that of the ink layer, and thus noise (image roughness or the like) given to the image becomes remarkable.

Further, regarding the application amount of the fine particles, it is desirable that the weight per unit area on the intermediate transfer body 412 is 0.01 to 5.0 g / m ² . When the weight per unit area is less than 0.01 g / m ² , the amount of particles is too small with respect to the amount of color material, and thus image shrinkage cannot be suppressed. Further, when the weight per unit area exceeds 5.0 g / m ² , the thickness of the particle layer becomes about 5 μm, but when this particle layer is transferred to paper, the texture of the paper looks very uncomfortable, A quality problem occurs.

  [IV] In the fourth embodiment of the image forming apparatus of the present invention, in the intermediate transfer system in which an image is once formed on the intermediate transfer member by the two-liquid aggregation method, and the image is transferred to a recording medium, it is substantially colorless. The first processing liquid containing the fine particles and the second processing liquid containing a component that aggregates the ink coloring material are configured as separate processing liquids.

  Since the fine particles are the same as those described in the third embodiment, description thereof will be omitted, and the configuration of the ink jet recording apparatus will be described.

  FIG. 21 is a schematic configuration diagram showing an inkjet recording apparatus 500 according to the fourth embodiment of the present invention. In FIG. 21, parts that are the same as those in FIG. 17 are given the same reference numerals, and descriptions thereof are omitted.

  In the present embodiment, a first processing liquid containing substantially colorless fine particles and a second processing liquid containing a component that aggregates the coloring material in the ink are used. Since the first treatment liquid is non-acidic, the dispersed state of the fine particles can be kept more stable.

  In the ink jet recording apparatus 500 shown in FIG. 21, the first processing liquid applying unit 402 for applying a first processing liquid containing substantially colorless fine particles on the intermediate transfer body 412 and the intermediate transfer body 412 are applied. The first treatment liquid drying unit 404 for drying the first treatment liquid, the second treatment liquid application unit 406 for applying the second treatment liquid containing a component that aggregates the color material in the ink, and the intermediate transfer body 412 are applied. A second processing liquid drying unit 408 is provided for drying the second processing liquid.

  The first processing liquid application unit 402 and the second processing liquid application unit 406 have the same configuration as the aggregation processing liquid application unit 416 shown in FIG. Further, the same configuration as the heat drying unit 418 shown in FIG. 17 is applied to each of the first processing liquid drying unit 404 and the second processing liquid drying unit 408.

  On the intermediate transfer body 412 that has passed through the cleaning unit 436, the first processing liquid is uniformly applied with a film thickness of, for example, 4 μm in the first processing liquid application unit 402. As described above, substantially colorless fine particles are dispersed in the first treatment liquid. The first processing liquid applied onto the intermediate transfer body 412 is dried by, for example, hot air drying at 70 ° C. in the first processing liquid drying unit 404 on the downstream side in the intermediate transfer body transport direction. As a result, a particle layer made of the fine particles is formed on the intermediate transfer member 412.

  Next, in the second treatment liquid application unit 406, the second treatment liquid is uniformly applied to a thickness of about 4 μm on the intermediate transfer body 412 on which the particle layer is formed. As described above, the second processing liquid contains a component that aggregates the color material in the ink. The second processing liquid applied onto the intermediate transfer body 412 is dried by, for example, hot air drying at 70 ° C. in the second processing liquid drying unit 408 on the downstream side in the intermediate transfer body transport direction. As a result, a thin layer (aggregation treatment agent layer, particle layer) of solid or high viscosity liquid is formed on the intermediate transfer member 412. Specifically, as shown in FIG. 18B, the aggregation treatment agent 302 is localized around the fine particles 304.

  Since other configurations are the same as those of the ink jet recording apparatus 400 (see FIG. 17) of the first embodiment, the description thereof is omitted.

Example 1
Next, by using the direct drawing type ink jet recording apparatus by drum conveyance shown in FIG. 1, the dot movement (when the moisture content of the agglomeration treatment layer is 56% or less) of the present invention is satisfied or not satisfied. A comparison experiment comparing how color material movement and landing interference differ will be described below.

[Inkjet recording apparatus used in the present invention]
With respect to the recording medium 22 fed from the paper supply unit 10 of the ink jet recording apparatus shown in FIG. 1 onto the drawing drum 70, the processing liquid is applied to the entire surface by the processing liquid coating device 56 on the processing liquid drum 54 (diameter 450 mm). A thin film was applied (2.5 μm thick) to the film. At that time, a gravure roller was used as the treatment liquid coating device 56. Next, the recording medium 22 coated with the treatment liquid is dried by a hot air jet nozzle 58 (0-90 ° C. warm air 9 m ³ / min) and an IR heater 60 (0-200 ° C.), and the solvent in the treatment liquid A part of this was dried to form a semi-solid agglomerated layer on the recording medium 22.

  The treatment liquid was dried under six experimental conditions (Experiment 1 to Experiment 6) as described later. The recording medium 22 is conveyed to the drawing unit 14 via the first intermediate conveyance unit 24, and CMY (cyan, magenta, yellow) water-based inks are ejected from the head 72 and ejected in accordance with the image signal. . The ink discharge volume was 2 pl, and the recording density was 1200 dpi and 150 dpi (thinning) in both the main scanning and sub-scanning directions.

Further, since the processing liquid drum 54 and the drying drum 76 are provided separately from the drawing drum 70, even when the processing liquid is dried at a high speed, the adverse effect of the heat and wind does not reach the drawing section, and stable discharge is achieved. Was achieved. Next, on the drying drum 76, the first IR heater 78 (surface temperature 180 ° C.), the hot air jet nozzle 80 (70 ° C. warm air × 12 m ³ / min air volume), and the second IR heater 82 (surface temperature 180 °). C.). The drying time is about 2 seconds.

  Next, the image-formed recording medium 22 was heated and fixed at a nip pressure of 0.30 MPa by a fixing drum 84 at 50 ° C., and a first fixing roller 86 and a second fixing roller 88 at 80 ° C. At this time, as the first fixing roller 86 and the second fixing roller 88, silicon rubber having a hardness of 30 ° is provided on a metal mandrel with a thickness of 6 mm, and a soft PFA coating (50 μm thickness) is provided thereon, A material excellent in adhesion and releasability to an ink image was used.

  The recording medium 22 was conveyed at a conveyance speed of 535 mm / s by drum conveyance by the drums 54, 70, 76, and 84.

[Create water-based ink]
(Synthesis of resin dispersant P-1)
According to the following scheme, a resin dispersant P-1 (Chemical Formula 9), which is one embodiment of the resin dispersant (A), was synthesized.

攪拌機、冷却管を備えた１０００ｍｌの三口フラスコに、メチルエチルケトン８８ｇを加え窒素雰囲気下で７２℃に加熱し、ここにメチルエチルケトン５０ｇにジメチル２，２’−アゾビスイソブチレート０．８５ｇ、ベンジルメタクリレート６０ｇ、メタクリル酸１０ｇ、メチルメタクリレート３０ｇを溶解した溶液を３時間かけて滴下した。そして、滴下終了後、さらに１時間反応した後、メチルエチルケトン２ｇにジメチル２，２’−アゾビスイソブチレート０．４２ｇを溶解した溶液を加え、７８℃に昇温し４時間加熱した。得られた反応溶液は大過剰量のヘキサンに２回再沈殿し、析出した樹脂を乾燥して樹脂分散剤Ｐ−１を９６ｇ得た。

To a 1000 ml three-necked flask equipped with a stirrer and a condenser tube, 88 g of methyl ethyl ketone was added and heated to 72 ° C. under a nitrogen atmosphere. Here, 50 g of methyl ethyl ketone was mixed with 0.85 g of dimethyl 2,2′-azobisisobutyrate and 60 g of benzyl methacrylate. A solution in which 10 g of methacrylic acid and 30 g of methyl methacrylate were dissolved was dropped over 3 hours. And after completion | finish of dripping, after reacting for further 1 hour, the solution which melt | dissolved dimethyl 2,2'- azobisisobutyrate 0.42g in 2 g of methyl ethyl ketone was added, and it heated up at 78 degreeC, and heated for 4 hours. The obtained reaction solution was reprecipitated twice in a large excess of hexane, and the precipitated resin was dried to obtain 96 g of a resin dispersant P-1.

  The composition of the obtained resin dispersant P-1 was confirmed by H-NMR, and the weight average molecular weight (Mw) determined by GPC was 44600. Furthermore, when the acid value of this polymer was calculated | required by the method of JIS specification (JISK0070: 1992), it was 65.2 mgKOH / g.

(Synthesis of self-dispersing polymer fine particles B-01)
According to the following scheme, self-dispersing polymer fine particles B-01, which is one embodiment of the self-dispersing polymer fine particles (C), were synthesized.

  That is, 360.0 g of methyl ethyl ketone was charged into a reaction vessel formed of a 2 liter three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas introduction tube, and the temperature was raised to 75 ° C.

  Next, while maintaining the temperature in the reaction vessel at 75 ° C., 180.0 g of phenoxyethyl acrylate, 162.0 g of methyl methacrylate, 18.0 g of acrylic acid, 72 g of methyl ethyl ketone, and “V-601” (Wako Pure Chemical Industries, Ltd.) (Manufactured) A mixed solution consisting of 1.44 g was added dropwise at a constant speed so that the addition was completed in 2 hours.

  After completion of the dropwise addition, a solution consisting of 0.72 g of “V-601” and 36.0 g of methyl ethyl ketone was added, stirred for 2 hours at 75 ° C., and then a solution consisting of 0.72 g of “V-601” and 36.0 g of isopropanol was added. After stirring at 75 ° C. for 2 hours, the temperature was raised to 85 ° C. and stirring was further continued for 2 hours.

  The weight average molecular weight (Mw) of the obtained copolymer was 64000, and the acid value was 38.9 (mgKOH / g). The weight average molecular weight (Mw) was calculated in terms of polystyrene by gel permeation chromatography (GPC). The columns used were TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ200 (manufactured by Tosoh Corporation).

  Next, 668.3 g of the copolymer solution was weighed, 388.3 g of isopropanol and 145.7 ml of 1 mol / L NaOH aqueous solution were added, and the temperature in the reaction vessel was raised to 80 ° C. Next, 720.1 g of distilled water was added dropwise at a rate of 20 ml / min to disperse in water. Thereafter, the temperature in the reaction vessel was maintained at 80 ° C. for 2 hours, 85 ° C. for 2 hours, and 90 ° C. for 2 hours under atmospheric pressure, and then the reaction vessel was depressurized, and isopropanol, methyl ethyl ketone, and distilled water totaled 913. 7 g was distilled off. As a result, an aqueous dispersion (emulsion) of self-dispersing polymer fine particles (B-01) having a solid content concentration of 28.0% was obtained.

  The chemical structural formula of self-dispersing polymer fine particles B-01 is shown below. The number of each structural unit represents a mass ratio.

（シアン顔料含有樹脂粒子の分散物の作成）
ピグメントブルー１５：３（大日精化株式会社製 フタロシアニンブル−Ａ２２０）１０質量部と、表１に記載の樹脂分散剤（Ｐ−１）５質量部と、メチルエチルケトン４２質量部と、１規定ＮａＯＨ水溶液５．８質量部と、イオン交換水８６．９質量部を混合し、ビーズミルで０．１ｍｍΦジルコニアビーズを使い、２〜６時間分散した。

(Creation of dispersion of cyan pigment-containing resin particles)
CI Pigment Blue 15: 3 (Phthalocyanine-A220 manufactured by Dainichi Seika Co., Ltd.), 5 parts by mass of the resin dispersant (P-1) shown in Table 1, 42 parts by mass of methyl ethyl ketone, and 1 N aqueous NaOH solution 5.8 parts by mass and 86.9 parts by mass of ion-exchanged water were mixed and dispersed with a bead mill using 0.1 mmΦ zirconia beads for 2 to 6 hours.

  Methyl ethyl ketone was removed from the obtained dispersion at 55 ° C. under reduced pressure, and a part of water was further removed to obtain a dispersion of cyan pigment-containing resin particles having a pigment concentration of 10.2% by mass.

(Preparation of cyan ink composition C-1)
Next, using the obtained dispersion of cyan pigment-containing resin particles and an aqueous dispersion (emulsion) of self-dispersing polymer fine particles (B-01), a water-soluble cyan ink composition C-1 having the following composition was prepared. Prepared.
-Dispersion of pigment-containing resin particles 39.2 parts by mass-Aqueous dispersion of self-dispersing polymer fine particles (B-01) 28.6 parts by mass-20.0 parts by mass of glycerin-10.0 parts by mass of diethylene glycol-Olfin E1010 (Manufactured by Nissin Chemical Industry Co., Ltd.) 1.0 part by mass, 1.2 parts by mass of ion-exchanged water (Preparation of magenta ink composition M-1)
Pigment Blue 15: 3 (phthalocyanine blu-A220 manufactured by Dainichi Seika Co., Ltd.) used in the preparation of the cyan pigment dispersion was replaced with Cromophtal Jet Magenta DMQ (PR-122) manufactured by Ciba Specialty Chemicals. Prepared a magenta ink composition M-1 in the same manner as the cyan ink composition.

(Preparation of yellow ink composition Y-1)
Cyan ink, except that Pigment Blue 15: 3 (Phthalocyaniburu-A220 manufactured by Dainichi Seika Co., Ltd.) used in the preparation of the cyan pigment dispersion was replaced with Irgalite Yellow GS (PY74) manufactured by Ciba Specialty Chemicals A yellow ink composition Y-1 was prepared in the same manner as the preparation of the composition.

(Preparation of black ink composition Bk-1)
Similar to the preparation of the cyan ink composition, except that Pigment Blue 15: 3 (Phthalocyanine A220 manufactured by Dainichi Seika Co., Ltd.) used in the preparation of the cyan pigment dispersion was replaced with carbon black MA100 manufactured by Mitsubishi Chemical Corporation. Thus, a black ink composition Bk-1 was prepared.

(Preparation of Cyan Ink Composition C-2, Magenta Ink Composition M-2, Yellow Ink Composition Y-2, Black Ink Composition Bk-2)
Further, as the water-based ink satisfying the conditions of the present invention, the high-boiling solvents of the above-described cyan ink composition C-1, magenta ink composition M-1, yellow ink composition Y-1 and black ink composition Bk-1 are used. In place of glycerin, GP-250 (trioxypropylene glyceryl ether, Sannix GP250, manufactured by Sanyo Chemical Industries, Ltd.)) is replaced in half, and in place of diethylene glycol, DEGmEE (diethylene glycol monoethyl ether) is replaced in half. The difference was further supplemented with water. Thus, cyan ink composition C-2, magenta ink composition M-2, yellow ink composition Y-2, and black ink composition Bk-2 were prepared.

(Cyan ink composition C-3, magenta ink composition M-3, yellow ink composition Y-3, black ink composition Bk-3)
As another example, the amount of B-01 of the cyan ink composition C-2, the magenta ink composition M-2, the yellow ink composition Y-2, and the black ink composition Bk-2 is 14.3 parts by mass. Cyan ink composition C-3, magenta ink composition M-3, yellow ink composition Y-3, and black ink composition Bk-3 were prepared.

[Preparation of treatment solution]
The processing liquid was prepared by mixing each component so that it might become the following composition.

Composition of treatment liquid • Malonic acid (Wako Pure Chemical Industries): 15.0%
・ Diethylene glycol monomethyl ether (Wako Pure Chemical Industries): 20.0%
・ Ion exchange water: 65.0%
When the physical properties of the treatment liquid were measured, the viscosity was 4.9 mPa · s, the surface tension was 24.3 mN / m, and the pH was 1.5.

[recoding media]
As a recording medium, Tohoku Art Double Sided N (manufactured by Mitsubishi Paper Industries) was used.

[experimental method]
Under the conditions of the ink jet recording apparatus, ink, processing liquid, and recording medium described above, the heating conditions of the hot air blowing nozzle 58 and the IR heater 60 after applying the processing liquid on the recording medium 22 are changed to dry the processing liquid. The degree was changed. Then, the color material movement and landing interference at that time were evaluated.

For the evaluation of color material movement, a solid image is formed with a 150 dpi grid pattern, and for the evaluation of the line width and liquid pool, a solid image is formed with a 1200 dpi grid pattern. did.
(Evaluation criteria for colorant movement)
X: The average deviation amount with respect to the pitch between dots is 7% or more (11.9 μm or more).
Δ: The average deviation with respect to the pitch between dots is 5% or more (8.47 μm or more).
A: The average deviation amount with respect to the pitch between dots is 3% or more and less than 5% (5.08 to 8.47 μm).
A: The average deviation amount with respect to the pitch between dots is less than 3% (less than 5.08 μm).
(Evaluation criteria for landing interference: Evaluated by line width and liquid pool)
X: Uneven line width or line breakage, or liquid pool occurred. O: Uneven line width or line breakage, or liquid pool did not occur. The experimental results are shown in the table of FIG. The “water content” is a unit area of water contained in the aggregation treatment agent (or aggregation treatment layer) with respect to the total mass X1 [g / m ² ] per unit area of the aggregation treatment agent (or aggregation treatment layer). Is defined as a ratio of weight X2 [g / m ² ] (ie, (X2 / X1) × 100).

[Experimental result]
As can be seen from the table of FIG. 22, in Experiment 1 (Comparative Example) in which the aggregation treatment liquid is not dried,
The moisture content of the coagulation treatment layer was 64.80%, and the color material movement was large and the evaluation was x. Then, as shown in Experiment 2 to Experiment 6, when the moisture content of the agglomeration treatment layer was reduced by gradually increasing the degree of drying of the agglomeration treatment liquid, the movement of the coloring material was still at the moisture content of Experiment 59.63%. Although the evaluation was large ×, the evaluation of “◯” indicating that the movement of the coloring material was small when the water content of Experiment 3 was 56.12%. In Experiments 4 to 6 in which the water content was further reduced, the color material movement was further evaluated as ◎. From this, it can be seen that when the moisture content of Experiment 3 is 56.12% as a guide, if the moisture content of the agglomeration treatment layer is 56% or less, the color material does not move.

  On the other hand, when the moisture content was decreased, the landing interference (line width, liquid pool) was evaluated as “good” until Experiment 5 with a moisture content of 32.82%, but the experiment with a moisture content of 12.87%. No. 6 causes problems such as line width and liquid accumulation. This is presumably because if the coagulation treatment agent is almost completely solidified, the coagulation reaction is delayed due to a loss of time for the coagulant solidified when it coagulates with the ink.

  Therefore, it is possible to solve both the problem of color material movement and the problem of line width and liquid pool by making the moisture content of the coagulation treatment layer 32 to 56% semi-solid solution.

  By the way, in order to avoid the movement of the coloring material, there is a mode in which after the aggregation treatment liquid is applied on the recording medium, the ink droplet is ejected in a state where the treatment liquid layer does not exist on the recording medium after waiting for the penetration of the treatment liquid. Conceivable. However, if the treatment liquid completely penetrates into the recording medium, the aggregating agent that has once penetrated needs to exude to the ink on the recording medium again in order to aggregate the ink that has landed on the recording medium. High speed aggregation cannot be realized. Further, when ink is ejected after the treatment liquid has completely penetrated, it is necessary to increase the distance between the treatment liquid application unit and the ink ejection unit, which causes a problem that the apparatus becomes larger.

  In addition, if the aggregating agent is dried more than necessary, the ink droplets land directly on the coated paper. Therefore, due to the restriction of the ink contact angle, the dots spread more than when landing on the semi-solid solution aggregating liquid layer. I don't get it. Since the contact angle of the ink is reduced by setting it in a semi-solid solution state, the spreading rate can be ensured.

  Here, the ink spreading ratio is a ratio between the droplet diameter d1 in terms of the true sphere of the discharged ink and the dot diameter d2 after fixing, and means d2 / d1. When the dot spread rate is small, the ink solvent drying energy after ink droplet ejection is large. In order to evaporate ink ejected onto a chrysanthemum (469 mm × 636 mm) size paper at a high speed conveyance such as a paper conveyance speed of 535 mm / sec, in the case of a dot spread rate of 1.660, a 30 kW class A heater is required. In order to obtain a desired fixed dot diameter when the dot spread rate is reduced, it is necessary to increase the volume of the ejected droplet. Since the drying energy is related to the volume of the droplet, if the spreading rate is small, the drying energy is effective by the third power of the droplet diameter. Therefore, if the spreading rate is smaller than 1.660, the power consumption of the printing machine exceeds the practicality. Also from this viewpoint, the moisture content of 32% is the lower limit.

(Example 2)
Next, in Example 2, an evaluation experiment was performed with three types of aggregation treatment agents, acid, polyvalent metal salt, and cationic polymer.

  For the evaluation of color material movement, a solid image is formed with a 150 dpi grid pattern for ink ejection, and for the evaluation of line width and liquid pool, the transport speed is changed to 215 mm / sec. A solid image was formed with a grid pattern of 1200 dpi.

  The experimental conditions and evaluation results are shown in the table of FIG. 23, and the evaluation criteria for colorant movement and landing interference are the same as in Example 1.

  The composition of the treatment liquids 1 to 7 in the table of FIG. 23 and the acid used in each treatment liquid are as follows. % Of each composition is mass%.

<Composition of treatment liquid>
・ Flocculant: 15.0%
・ Diethylene glycol monomethyl ether (Wako Pure Chemical Industries): 20.0%
・ Ion exchange water: 65.0%
When the physical properties of the treatment liquid were measured, the viscosity was 4.9 mPa · s, the surface tension was 24.3 mN / m, and the pH was 1.5.

<Types of flocculants>
Treatment liquid 1 ... Malonic acid Treatment liquid 2 Citric acid Treatment liquid 3 Succinic acid Treatment liquid 4 2-Pyrrolidone-5-carboxylic acid Treatment liquid 5 Calcium chloride Treatment liquid 6 Calcium nitrate Treatment Liquid 7: Polyethyleneimine [Experimental result]
As can be seen from the evaluation result of the color material movement in the table of FIG. 23, even if the type of the flocculant changes, by drying the treatment liquid applied on the recording medium (the moisture content of the agglomeration treatment layer is 56% or less) The color material movement was extremely small.

  On the other hand, when the landing interference evaluation result is seen, when drawing is performed at 1200 dpi under a high-speed conveyance at a conveyance speed of 215 mm / sec, the droplet ejection interval between adjacent dots becomes 100 μsec, which is extremely short. For this reason, in the case other than the acid agglomeration method using an acid as the aggregating agent, the agglomeration rate cannot catch up, and the evaluation of the line width and the liquid reservoir becomes x. Therefore, in the case of high-speed droplet ejection with a droplet ejection interval of 100 μsec or less, it is desirable to use an acid treatment agent to form a semi-solid solution treatment liquid.

(Example 3)
FIG. 24 is a recorded image of Experiment 4 (the present invention) in Example 1, and FIG. 25 is a recorded image of Experiment 1 (Comparative Example). Each of the recorded images shown in these drawings is an enlarged schematic representation of a photographic image taken by an imaging device.

  In the image 600 of Experiment 4 (present invention) shown in FIG. 24, the error in the formation position of each dot 602 is ½ or less of the pitch between dots, and each dot 602 is fixed at a predetermined landing position. confirmed. On the other hand, in the image 620 of Experiment 1 (comparative example) shown in FIG. 25, the dot became unstable with the agglomeration reaction, and the clear movement of the dot 602 was confirmed. In FIG. 25, a lateral position shift occurs, and a formation position error exceeding 1/2 of the inter-dot pitch occurs. Also, the two dots indicated by reference numeral 624 are integrated as well as misaligned. Further, there is no dot to be originally formed at the position indicated by reference numeral 626. In other words, in Experiment 4 to which the present invention was applied, a positional deviation (color material movement) of dots due to aggregation did not occur, and a preferable solid image was formed.

  Although not shown, predetermined characters were drawn under the same experimental conditions as described above, and the drawn characters were compared and evaluated.

  As a result, in Experiment 4 (the present invention), the drawn characters were clear and the characters could be accurately recognized visually. On the other hand, in Experiment 1 (Comparative Example), the drawn characters were unclear and could not be accurately recognized visually. That is, in Experiment 4 to which the present invention is applied, dot misregistration (coloring material movement) due to aggregation does not occur, and preferable characters can be drawn.

  Next, the treatment liquid (aggregation treatment liquid) applied on the recording medium is dried to form a semi-solid solution aggregation layer having a water content of 56% or less, thereby moving the color material of the ejected ink dots. An estimation model that eliminates the problem will be described.

  A treatment liquid is applied to the recording medium 1000 shown in FIG. 26A and dried to form a semi-solid solution treatment layer 1012 having a moisture content of 56% or less on the recording medium 1000 (FIG. 26). (B)).

  Next, ink droplets 1014 are ejected onto the recording medium 1000 on which the semi-solid solution aggregation processing layer 1012 is formed (FIG. 26C). By forming a semi-solid solution aggregation treatment layer 1012 on the recording medium 1000 and then ejecting ink droplets 1014, the ink aggregation (coloring material aggregation) spread to a predetermined size on the aggregation treatment layer 1012. Dots consisting of (collected) 1016 are formed (FIG. 26D).

  FIG. 27 is a schematic diagram showing in detail how dots (ink aggregates) are formed. As shown in FIG. 27A, when the ink droplet 1014 lands on the semi-solid solution aggregation layer 1012 formed on the recording medium 1000, the aggregation reaction instantly starts from the contact surface with the aggregation treatment layer 1012. Initiated and ink aggregates 1016 are formed. Thereafter, the ink droplet 1014 gradually enlarges the contact surface with the aggregation treatment layer 1012 and the vicinity of the contact surface with the aggregation treatment layer 1012 due to the balance relationship between the flying energy and surface energy (interface energy) of the ink droplet 1014. Since the agglomeration reaction is performed, the ink aggregate 1016 also gradually expands along the contact surface with the aggregation treatment layer 1012 (FIG. 27B). In this way, as shown in FIG. 27C, dots composed of the ink aggregate 1016 spreading to a predetermined size are formed on the semi-solid solution aggregation processing layer 1012. A predetermined contact area is ensured between the ink aggregate (dot) 1016 and the aggregation treatment layer 1012, so that sufficient adhesion can be obtained.

  Further, as shown in FIG. 26E, since the ink aggregate 1016A has already been formed in the ink droplet 1014A that has landed on the aggregation treatment layer 1012 by the above-described aggregation reaction, Even when the ink droplet 1014B is subsequently ejected so as to come into contact with the droplet 1014A, the ink droplets 1014A and 1014B do not coalesce (landing interference). Ink droplets 1014B landed on the aggregation treatment layer 1012 later also form an ink aggregate 1016B by an aggregation reaction (FIG. 26 (f)). In other words, even when a plurality of ink droplets are ejected at adjacent positions, a desired dot shape and dot size can be obtained without causing landing interference between these ink droplets, and high-quality image formation Is possible. Further, in the case of ink droplets of different colors, mixed color bleeding can be prevented.

  The semi-solid solution aggregation treatment layer 1012 formed on the recording medium 1000 is dissolved in the ink solvent separated from the ink aggregate 1016 and covers the ink aggregate 1016 to cover the liquid aggregate (the solvent component of the ink and the aggregation treatment liquid). ) 1017 is formed on the recording medium 1000 (FIG. 26G). At this time, since the ink aggregate 1016 has already spread to a predetermined size, even after the aggregation treatment layer 1012 is dissolved by the action of the ink solvent, as shown in FIG. Aggregates (dots) 1016 have a predetermined contact area with the recording medium 1000, so that sufficient adhesion can be obtained. Therefore, it is possible to prevent image deterioration due to color material movement.

  Next, the liquid solvent 1017 on the recording medium 1000 is removed. In this example, as shown in FIG. 27 (h), the solvent absorbing roller 1018 whose surface is composed of a porous body (absorber) is brought into contact with the liquid solvent 1017 on the recording medium 1000, whereby the recording medium 1000 A method of absorbing and removing the liquid solvent 17 (solvent absorption method) is applied. As described above, since the ink aggregate (dot) 1016 formed by the aggregation reaction can obtain a sufficient adhesion force with the recording medium 1000, the liquid aggregation is prevented while preventing the color material from adhering to the solvent absorbing roller 1018. The solvent 1017 can be absorbed and removed.

Example 4
Example 4 uses the intermediate transfer type ink jet recording apparatus shown in FIG. 15 to perform dot movement (color) in the case of satisfying the “moisture content of the aggregation treatment layer of 56% or less” of the present invention or not. A comparison experiment comparing how the material movement and the landing interference differ will be described below.

  In the experiment, when the aggregation treatment liquid is applied to a polyimide intermediate transfer body 202 with a film thickness of about 10 μm, and the moisture content of the aggregation treatment layer on the intermediate transfer body 202 is changed by drying, the coloring material moves and lands. Interference was evaluated. Specifically, the heating condition of the heating and drying unit 208 is appropriately changed to change the moisture content of the aggregation treatment layer on the intermediate transfer member 202 to form a primary image (ink image) on the intermediate transfer member 202. The primary image before solvent removal was evaluated. The landing interference was performed by evaluating the line width and the liquid pool.

  The composition of the ink used and the aggregation treatment liquid is as shown in FIG. In addition, the ink ejection conditions in all the experiments (A to E) shown in the table of FIG. 29 are the same conditions, and the ink ejection amount (volume) is 2 pl, and the droplet ejection density (dot density) in the main scanning direction and the sub scanning direction, respectively. ) Dropping was performed at 1200 dpi.

  The experimental results of Example 4 are shown in the table of FIG. Evaluation criteria for colorant movement and landing interference (line width, liquid pool) are the same as those in Example 1.

  As shown in the table of FIG. 29, Experiment A (Comparative Example) is a case where the step of drying the aggregation treatment layer (liquid layer) on the intermediate transfer body 202 is omitted, and the moisture content of the aggregation treatment layer is 87. It was 00%. As a result, the positional deviation (color material movement) of the ink dots was large, and the evaluation was x, and image deterioration was confirmed.

  Experiment B (comparative example) is a case where the moisture content is 61.98% by slightly drying the aggregation treatment layer (liquid layer) on the intermediate transfer body 202. Also in this case, the color material movement was evaluated as x, and image degradation was confirmed.

  On the other hand, Experiment C (the present invention) is a case where the moisture content was 57.52% by further drying the aggregation treatment layer (liquid layer) on the intermediate transfer body 202 than Experiment B. As a result, although there was some color material movement, it was inconspicuous in terms of image quality and was evaluated as “Good”.

  Experiment D (invention) is a case where the moisture content was 28.96% by further drying the aggregation treatment layer (liquid layer) on the intermediate transfer body 202 than in Experiment C. In this case, it was evaluated as ◎ with no color material movement, and good image quality could be obtained.

  Experiment E (Comparative Example) is a case where the moisture content was reduced to 15.00% by further drying the aggregation treatment layer (liquid layer) on the intermediate transfer body 202 than in Experiment D. In this case, an evaluation of “◎” indicating no movement of the coloring material was obtained, but an evaluation of “x” was given for landing interference.

  From the above results, in Example 4, by forming a semi-solid aggregation layer (moisture content of 28 to 57%) on the intermediate transfer body 202 and then ejecting ink droplets, the color material moves. It was possible to confirm the effect of the present invention that high-quality image formation is possible while preventing image deterioration.

  When the result of Example 1 (direct drawing method) and the result of the present Example 4 (intermediate transfer method) are combined, a direct drawing method for directly drawing on the recording medium and an intermediate for transferring an image from the intermediate transfer member to the recording medium. In any case of the transfer method, it has been found that when the moisture content of the aggregating treatment layer is set to 56% or less, the color material movement of the ejected ink can be effectively prevented. In addition, when the appropriate moisture content of the coagulation treatment layer is considered including the evaluation of landing interference, it is considered that 56% or less and 32% or more are good from the results of Examples 1 and 4.

(Example 5)
Example 5 uses a direct drawing type inkjet recording apparatus that directly draws an image on a belt-conveyed recording medium, and the relationship between the moisture content of the aggregation treatment layer and the degree of adhesion of the coloring material to the solvent absorbing roller 810 Is an experiment.

  FIG. 30 shows an experimental apparatus 800 of the ink jet recording apparatus used in Example 5. The experimental apparatus 800 includes a treatment liquid droplet ejection head 804, a hot air drying unit 806, and an ink droplet ejection head in this order from the upstream side in the conveyance direction (the direction from right to left in FIG. 30) of the recording medium 802 conveyed by the belt. 808 and a solvent absorbing roller 810 are arranged.

  Experimental conditions and experimental methods of Example 5 performed using such an experimental apparatus 800 are as follows.

  The center-to-center distance between the ink droplet ejection head 808 and the solvent absorption roller 810 was set to 350 mm.

  A polyimide film (Kapton H type manufactured by Toray DuPont Co., Ltd.) was used for the recording medium 802.

  The droplet ejection conditions of the treatment liquid droplet ejection head 804 and the ink droplet ejection head 808 are the same, the ink ejection amount (volume) is 3 pl, and the droplet ejection density (dot density) in the main scanning direction and the sub-scanning direction. Is 1200 dpi.

  The solvent absorbing roller 810 was wound with Kydry 62701 (manufactured by Crecia Co., Ltd.) around the surface of the porous body in order to see whether the coloring material adhered.

  -The conveyance speed of the recording medium 802 was 500 mm / s. Accordingly, it takes 0.7 sec from ink droplet ejection by the ink droplet ejection head 808 to contact with the solvent absorbing roller 810.

  Then, the degree of adsorption of the coloring material to the solvent absorbing roller 810 was examined depending on whether the treatment liquid applied to the recording medium was dried or not. The determination of the degree of adsorption was performed by measuring the optical density of the surface of the Keidry 62701 wound around the solvent absorption roller 810 (Xrite 938, manufactured by Xrite), and evaluating the magnitude of color material adhesion. The colorimetric conditions are 0/45, D50, and 2 degree visual field.

  The experimental results of Example 5 are shown in the table of FIG.

  Experiment a: This is a case where the moisture content of the coagulation layer is lowered to 56% by drying, and the time from the ink droplet ejection to the absorber (solvent absorbing roller 810) is 0.7 sec.

Experiment b: This is a case where the moisture content of the coagulation treatment layer is lowered to 52% by drying, and the time from ink ejection to the absorber (solvent absorption roller 810) is 0.7 sec.
Experiment c: This is a case where the moisture content of the aggregating treatment layer is 87% without drying, and the time from the ink droplet ejection to the absorber (solvent absorbing roller 810) is 0.7 sec.
Experiment d: The case where the moisture content of the agglomeration treatment layer is 87% without drying, and after the ink is ejected, the conveyance of the recording medium is temporarily stopped and then conveyed again, whereby the ink droplet is removed from the absorber (solvent absorption roller). The time until 810) was increased to 30 seconds.

  As a result, as can be seen from the table in FIG. 31, when the time from ink ejection to the absorber was compared in the same experiments a, b, and c, drying was performed to reduce the moisture content of the coagulation treatment layer to 56% or less. Experiment a (present invention) and experiment b (present invention) were compared with experiment c (comparative example) in which the moisture content of the agglomerated layer was as high as 87% without drying, and Keidry 62701 wound around the solvent absorbing roller 810. The optical density of the surface of the film was significantly reduced. Furthermore, as in Experiment d (Comparative Example), the time from ink ejection to the absorber is greatly extended to 30 seconds, and even when compared with the condition where the coloring material is difficult to adhere to the absorber, Experiment a (this Invention), the optical density of Experiment b (Invention) was reduced.

  Thus, the ink aggregate (dot) is formed on the recording medium 802 by forming ink droplets after forming a semi-solid aggregation treatment layer having a moisture content of 56% or less on the recording medium 802 by drying. As a result, it was confirmed that a sufficient adhesion force can be obtained, and adhesion of the coloring material to the solvent absorbing roller 810 can be prevented.

  On the other hand, in Experiment a, since the amount of the coloring material attached to the solvent absorbing roller 810 is large, the solvent absorbing ability of the solvent absorbing roller 810 is deteriorated by the coloring material accumulated over time. Experiment b is a mode in which the process speed is extremely slow and is not practical.

(Example 6)
Example 6 is an experiment conducted to confirm the effect of adding fine particles to the processing liquid, which is a feature of the invention of the third embodiment.

  The composition of the aggregating agent and ink used in the experiment of Example 6 is shown in FIG.

  As shown in FIG. 33, as the aggregating agent (aggregating treatment liquid), a solution obtained by adding a polyolefin particle dispersion to an acidic solution in which an organic acid (2-pyrrolidone-5-carboxylic acid) was dissolved was used. As the polyolefin particle dispersion, Chemipearl (registered trademark) W400 manufactured by Mitsubishi Chemical Corporation was used (average particle diameter: 4.0 μm). In addition, a fluorosurfactant was added from the viewpoint of imparting a treatment agent to the intermediate transfer member having a low surface energy. The ink used was a pigment color material dispersed.

  In Example 6, a predetermined character was drawn on the intermediate transfer member using a system equivalent to the intermediate transfer type inkjet recording apparatus 500 shown in FIG. As the intermediate transfer member 412, a belt having a silicone rubber surface layer was used.

  In the experiment of the example satisfying the present invention, drawing was performed using the aggregation treatment agent and ink shown in FIG. On the other hand, in the experiment of the comparative example not satisfying the present invention, the drawing was performed under the same conditions as in the example except that the aggregation treatment agent obtained by removing polyolefin particles from the aggregation treatment agent shown in FIG. 32 was used.

  As an experimental method, a comparison was made for the case where the character “hawk” was drawn on the intermediate transfer member and the case where the same character was drawn in white. The experimental results are shown in FIG.

  As can be seen from FIG. 33, in the comparative example, image shrinkage occurs along with the ink aggregation reaction, and normal characters are drawn thin and white characters are drawn thick.

  On the other hand, in the embodiment, the particle layer exhibits an anchor effect to prevent image shrinkage, and both normal characters and white characters can be drawn with the intended line width, and a good character image can be obtained. Was confirmed. Further, in the present invention, since a smooth surface can be used for the intermediate transfer member, the transferability to paper was very good.

(Example 7)
In Example 7, “image shrinkage”, “image noise”, and “printed matter” when the average particle size and application amount (hereinafter referred to as “particle application amount”) of the fine particles contained in the aggregation treatment agent are changed. The “texture” was evaluated. Here, polyolefin particles were used as the fine particles. In addition, it experimented on the same conditions as Example 6 except the point which changed the average particle diameter and particle application amount of microparticles | fine-particles (polyolefin particle).

  Evaluation criteria for “image shrinkage”, “image noise”, and “printed material texture” are as follows.

[Image shrinkage]
○: No image shrinkage △: Some image shrinkage ×: Some image shrinkage [Image noise]
○: No image noise △: Some image noise ×: Large image noise [Print texture]
○: No discomfort Δ: Some discomfort ×: Great discomfort The experimental results of Example 7 are shown in FIGS. 34 to 36. FIG. 34 shows an evaluation result of “image shrinkage”, FIG. 35 shows an “image noise”, and FIG. 36 shows an evaluation result of “printed material texture”.

As for “image shrinkage”, as can be seen from FIG. 34, an average particle diameter of 0.1 to 20 μm and a particle application amount of 0.01 to 10 g / m ² are preferable, and an average particle diameter of 1 to 20 μm and a particle application amount of 0 are more preferable. 1 to 10 g / m ² .

As for “image noise”, as can be seen from FIG. 35, an average particle diameter of 0.01 to 10 μm and a particle application amount of 0.001 to 10 g / m ² are preferable, and an average particle diameter of 0.01 to 5 μm and more preferable. The amount is 0.001 to 10 g / m ² .

As for “printed material texture”, as can be seen from FIG. 36, an average particle size of 0.001 to 20 μm and a particle application amount of 0.001 to 5 g / m ² are preferable, and an average particle size of 0.001 to 20 μm and particle application is more preferable. The amount is 0.001 to 3 g / m ² .

FIG. 37 shows the results of comprehensive evaluation of the experimental results shown in FIGS. As the evaluation criteria in FIG. 37, regarding the evaluation result of each evaluation item, the case where there are three circles is “◎”, the circle is two, and the triangle is one “◯”, one is The case where Δ is two is “Δ”, and the case where there are one or more X is “×”. For example, in the case of an average particle diameter of 3 μm and a particle application amount of 0.1 g / m ² , the evaluation results for the evaluation items of “image shrinkage”, “image noise”, and “printed material texture” are all ○, In this case, the overall evaluation is “◎”. On the other hand, when the average particle diameter is 5 μm and the particle application amount is 0.001 g / m ² , the evaluation results of “image noise” and “printed material texture” are “good”, but the evaluation result of “image shrinkage” is “poor”. In this case, the overall evaluation is “x”.

As can be seen from FIG. 37, from the three viewpoints of “image shrinkage”, “image noise”, and “printed material texture”, the preferred range of the particle diameter and the amount of particles applied to the aggregation treatment agent is an average particle If diameter 0.1 to 10 [mu] m, a particle application amount 0.01-5 g / ^{m 2,} more preferably from the preferred ranges, the average particle diameter of 0.1 [mu] m, a particle application amount 5 g / ^{m 2,} average When the particle diameter is 10 μm and the particle application amount is 0.01 g / m ^2, it is a range excluding the case where the average particle diameter is 10 μm and the particle application amount is 5 g / m ² , and more preferably, the average particle diameter is 3 to 5 μm. The amount of applied particles is 0.1 to 3 g / m ² .

  As a result, in the present invention, it was possible to confirm a preferable range of the average particle diameter and the amount of applied particles of the fine particles contained in the aggregation treatment agent.

(Example 8)
In Example 8, “image shrinkage”, “transferability”, “glossiness”, and “abrasion resistance” when the type of fine particles contained in the aggregation treatment agent was changed were evaluated. In addition, it experimented on the same conditions as Example 6 and Example 7 mentioned above except the point which changed the kind of microparticles | fine-particles.

  Evaluation criteria for “image shrinkage”, “transferability”, “glossiness”, and “rubbing resistance” are as follows.

[Image shrinkage]
○: No image shrinkage Δ: Some image shrinkage ×: Large image shrinkage [Transferability]
A: Excellent transferability (no residual color material on the transfer body)
○: Excellent transferability (almost no residual color material on the transfer body)
Δ: Transferability slightly insufficient (slightly remaining color material on transfer body)
×: Transferability defect (many remaining color material on transfer body)
[Glossiness]
○: High glossiness of image after heat-fixing △: Slightly insufficient glossiness of image after heat-fixation ×: Low glossiness of image after heat-fixation [Abrasion resistance]
○: Image film strength after heat-fixing is good △: Image film strength after heat-fixation is slightly insufficient ×: Image film strength after heat-fixation is insufficient By visual observation of the sample. “Rubbing resistance” is based on visual observation of an image surface destruction state after a piece of paper (recording medium) is placed on the image surface and rubbed with a finger.

  The experimental results are shown in FIG.

  As can be seen from FIG. 38, when metal fine particles (titanium oxide fine particles: Thailand Park R980 manufactured by Ishihara Sangyo Co., Ltd.) are used, they do not melt when heated and fixed, resulting in slightly inferior “glossiness” and “scratch resistance”. It was.

  In addition, when using a low molecular weight organic compound (paraffin wax fine particles: Torusol PF60 manufactured by Chukyo Yushi Co., Ltd.), the result was that the “rubbing resistance” was slightly inferior because of poor toughness.

  In addition, when acrylic polymer fine particles (Jurimer FC-30 manufactured by Nippon Pure Chemical Industries, Ltd.) were used, favorable results were shown for “image shrinkage”, “transferability”, “glossiness”, and “abrasion resistance”. Further, when “polyolefin particles” are used, more preferable “transferability” is exhibited.

  As can be seen from the experimental results of Examples 6 to 8, the aggregating agent containing components that agglomerate the ink coloring material and substantially colorless fine particles before applying the ink onto the intermediate transfer body 12. (Aggregating treatment liquid) is applied onto the intermediate transfer member 412, and a particle layer composed of the fine particles is formed on the intermediate transfer member 412, whereby the shrinkage of the image accompanying the ink aggregation reaction due to the anchor effect of the particle layer. Can be suppressed. Further, the contact area between the image (ink layer) and the intermediate transfer body 412 is reduced by the particle layer formed on the intermediate transfer body 412, and the transferability to the recording medium 414 is also improved.

Example 9
Example 9 is an experiment for confirming the effect of the fine particles contained in the first treatment liquid when the first treatment liquid and the second treatment liquid are separate liquids.

  The compositions of the first treatment liquid, the second treatment liquid, and the ink used in Example 9 are shown in FIG.

  As shown in FIG. 39, the first treatment liquid contains a polyolefin particle dispersion (Chemipearl (registered trademark) W400 manufactured by Mitsubishi Chemical Corporation). Since the first treatment liquid is non-acidic, the dispersion state of the fine particles can be kept stable. In addition, an acidic solution in which an organic acid (2-pyrrolidone-5-carboxylic acid) was dissolved was used as the second treatment liquid. Further, from the viewpoint of applying the treatment liquid to the intermediate transfer body 12 having a low surface energy, a fluorine-based surfactant was added to each treatment liquid.

  As an example of the present invention, drawing was performed using the first processing liquid, the second processing liquid, and the ink shown in FIG. On the other hand, as a comparative example, drawing was performed under the same conditions as in the example except that the first processing liquid shown in FIG. 39 was not applied onto the intermediate transfer member.

  Similar to Example 6 described above, when the character “hawk” is drawn on the intermediate transfer member and when the same character is drawn in white, the comparison example shows that the image shrinkage is caused. In contrast to the occurrence and poor drawability, it was confirmed that in the examples, the particle layer exhibited an anchor effect to prevent image shrinkage and a good image was obtained. Also, in the examples, very good results were obtained for the transferability to paper.

  Accordingly, the first processing liquid containing substantially colorless fine particles is applied on the intermediate transfer body 412 before the ink and the second processing liquid containing a component that causes the ink coloring material to aggregate on the intermediate transfer body 12 are applied. By forming a particle layer composed of the fine particles on the intermediate transfer body 12, it is possible to suppress image shrinkage due to an agglomeration reaction of the ink due to the anchor effect of the particle layer. Further, the contact area between the image (ink layer) and the intermediate transfer member 412 is reduced by the particle layer formed on the intermediate transfer member 412, and the transfer property to the recording medium 414 is improved.

1 is an overall configuration diagram schematically showing an ink jet recording apparatus according to a first embodiment of the present invention. The block diagram which shows the process liquid application apparatus of a process liquid application part The block diagram which shows the drying means of a process liquid provision part Configuration diagram showing the drawing unit Configuration diagram showing the drying section Configuration diagram showing the fixing unit Sectional drawing which shows the structure of a 1st intermediate conveyance part Sectional drawing which shows structure of drawing drum Plane perspective view showing the internal structure of the head Plan view showing another configuration example of the head Sectional drawing which follows the 11-11 line in FIG. Plan view showing an example of nozzle arrangement of the head Main block diagram showing the system configuration of the inkjet recording apparatus Main block diagram showing the system configuration of the first intermediate transfer control unit Overall configuration diagram schematically showing an ink jet recording apparatus according to a second embodiment of the present invention. Plan view of the main part around the printing unit of an inkjet recording apparatus Overall configuration diagram schematically showing an ink jet recording apparatus according to a third embodiment of the present invention. Schematic diagram showing the behavior when ink droplets land on the intermediate transfer member Schematic diagram showing the behavior when drawing an image Schematic diagram showing the behavior during transfer Overall configuration diagram schematically showing an ink jet recording apparatus according to a fourth embodiment of the present invention. Explanatory drawing of Example 1 of this invention Explanatory drawing of Example 2 of this invention Explanatory drawing of Example 3 of this invention Explanatory drawing which showed the recorded image in a comparative example Explanatory drawing which shows an example of the image formation method in this invention Explanatory drawing showing how dots are formed Explanatory drawing of Example 4 of this invention Results explanatory diagram of Example 4 of the present invention Explanatory drawing of the experimental apparatus of the inkjet recording apparatus used in Example 5 of the present invention Results explanatory diagram of Example 5 Composition diagram of ink and treatment liquid of Example 6 Results explanatory diagram of Example 6 Explanatory drawing of the result of image shrinkage in Example 7 Image noise explanatory diagram of Example 7 Results explanatory diagram of printed material texture of Example 7 Explanatory drawing of the results of comprehensive evaluation of Example 7 Results explanatory diagram of Example 8 Composition diagram of ink and treatment liquid of Example 9 Explanatory drawing which shows the general process of the 2 liquid aggregation system based on a prior art Explanatory drawing explaining the behavior when ink droplets according to the prior art land on the intermediate transfer member Explanatory drawing explaining the action at the time of drawing the image concerning a prior art Explanatory drawing explaining the behavior during transfer according to the prior art

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Inkjet recording apparatus, 10 ... Paper feed part, 12 ... Processing liquid provision part, 14 ... Drawing part, 16 ... Drying part, 18 ... Fixing part, 20 ... Discharge part, 22 ... Recording medium, 24 ... 1st middle Conveying unit, 26 ... second intermediate conveying unit, 28 ... third intermediate conveying unit, 30 ... intermediate conveying member, 32 ... conveying guide, 34 ... conveying guide, 36 ... blower port, 38 ... blower, 40 ... blower regulation Guide, 42 ... Suction hole, 43 ... Pump, 70 ... Drawing drum, 72C, 72M, 72Y, 72K ... Ink head, 73 ... Holding means, 74 ... Suction hole, 76 ... Drying drum, 84 ... Fixing drum, 86 ... No. 1 fixing roller, 88... Second fixing roller, 143 .. air blowing control unit, 147... Negative pressure control unit

Claims (17)

An image forming method for forming an image on an image forming body using an ink liquid containing a color material and an aggregation treatment agent containing a component that aggregates the color material,
An aggregation treatment layer forming step of forming a semi-solid solution aggregation treatment layer comprising the aggregation treatment agent on the image forming body and having a water content of 56% or less and 32% or more ;
An ink droplet ejection step of dropletizing and ejecting the ink liquid onto the image forming body on which the aggregation treatment layer is formed;
An image forming method comprising: a solvent removing step of removing the liquid solvent on the image forming body by drying with a drying unit or absorption with an absorber after the ink droplet ejection step.   The image forming method according to claim 1, wherein the aggregation treatment agent is dried in the aggregation treatment layer forming step.   The image forming method according to claim 1, wherein the image forming method is a direct drawing method in which an image is directly formed on the image forming body.   The image forming method according to claim 1, wherein the image forming body is a recording medium in which a liquid has a slow penetrability or non-penetrability characteristic.   5. The image forming method according to claim 1, wherein the image forming method is an intermediate transfer method in which an image is once formed on the impermeable image forming body and then transferred to a recording medium. Image forming method. An image forming apparatus that forms an image on an image forming body using an ink liquid containing a color material and an aggregation treatment agent containing a component that aggregates the color material,
An aggregation treatment liquid application means for applying an aggregation treatment liquid in which the aggregation treatment agent is in a liquid state on the image forming body;
The aggregating treatment liquid applied on the image forming body is dried, and a semi-solid aggregating treatment layer composed of the aggregating agent and having a moisture content of 56% or less and 32% or more is formed on the image forming body. An aggregating treatment liquid drying means;
Ink droplet ejecting means for dropletizing and ejecting the ink liquid onto the image forming body on which the aggregation treatment layer is formed;
A solvent removing unit that removes the liquid solvent on the image forming body by drying by the drying unit or absorption by the absorber after the ink liquid is ejected onto the image forming body by the ink droplet ejecting unit; An image forming apparatus comprising: The image forming apparatus according to claim 6 , wherein the image forming apparatus is a direct drawing type apparatus that directly forms an image on the image forming body. The image forming apparatus according to claim 6 , wherein the image forming body is a recording medium in which a liquid has a slow permeable or non-permeable property. Wherein the image forming apparatus, after temporarily forms an image on a non-penetration of said image forming member, it is a device of an intermediate transfer type for transferring the recording medium to any one of claims 6-8, characterized in The image forming apparatus described. Applying a liquid containing a component for aggregating the coloring material of the ink and substantially colorless fine particles on the intermediate transfer member;
Drying the liquid applied onto the intermediate transfer member to form a particle layer comprising the fine particles and having a moisture content of 56% or less and 32% or more ;
In accordance with image data, a step of dropletizing the ink into the intermediate transfer body on which the particle layer is formed and ejecting the ink;
Removing the liquid solvent on the intermediate transfer member with a drying means or an absorber;
And a step of transferring an image formed on the intermediate transfer member to a recording medium. Applying a first liquid containing substantially colorless fine particles on the intermediate transfer member;
Applying a second liquid containing a component for aggregating the colorant of the ink on the intermediate transfer member;
At least after the second liquid is applied onto the intermediate transfer body, the first liquid and the second liquid on the intermediate transfer body are dried to form the fine particles and have a moisture content of 56%. A step of forming a particle layer of 32% or more ,
In accordance with image data, a step of dropletizing the ink into the intermediate transfer body on which the particle layer is formed and ejecting the ink;
Removing the liquid solvent on the intermediate transfer member by drying by a drying means or absorption by an absorber ;
And a step of transferring an image formed on the intermediate transfer member to a recording medium. The fine particles have an average particle size of 0.1 to 10.0 μm,
12. The image forming method according to claim 10 , wherein an amount of the fine particles applied to the intermediate transfer member is 0.01 to 5.0 g / m ² . The image forming method according to claim 10, wherein the fine particles are an organic compound. The image forming method according to claim 13 , wherein the fine particles are a polymer. The image forming method according to claim 14 , wherein the fine particles are polyolefin. A liquid applying means for applying a liquid containing a component that aggregates the coloring material of the ink on the intermediate transfer member and substantially colorless fine particles; and
Drying means for drying the liquid applied onto the intermediate transfer member to form a particle layer composed of the fine particles and having a moisture content of 56% or less and 32% or more ;
In accordance with image data, ink droplet ejecting means for ejecting the ink into droplets with respect to the intermediate transfer body on which the particle layer is formed;
A solvent removing means for removing the liquid solvent on the intermediate transfer member by drying by a drying means or absorption by an absorber ;
An image forming apparatus comprising: transfer means for transferring an image formed on the intermediate transfer member to a recording medium. First liquid applying means for applying a first liquid containing substantially colorless fine particles on the intermediate transfer member;
A second liquid applying means for applying a second liquid containing a component that causes the ink coloring material to aggregate on the intermediate transfer member;
At least after the second liquid is applied onto the intermediate transfer body, the first liquid and the second liquid on the intermediate transfer body are dried to form the fine particles and have a moisture content of 56%. A drying unit that forms a particle layer of 32% or more , and an ink droplet ejection unit that droplets the ink onto the intermediate transfer body on which the particle layer is formed according to image data;
A solvent removing means for removing the liquid solvent on the intermediate transfer member by drying by a drying means or absorption by an absorber ;
An image forming apparatus comprising: a transfer unit configured to transfer an image formed on the intermediate transfer member to a recording medium.

Images