JP2023068388A - Inkjet recording method and inkjet recording device - Google Patents

Abstract

To provide a transfer type inkjet recording method which is excellent in transferability of an intermediate image to a recording medium and can stably record a high quality image on the recording medium.SOLUTION: There is provided an inkjet recording method for recording an image on a recording medium 108 using an aqueous ink. The method comprises, in this order: an intermediate image forming step of applying an aqueous ink to a transfer body 101, followed by applying an aqueous transfer acceleration liquid to at least a portion of the area of the transfer body 101 to which the aqueous ink is applied to form an intermediate image; and a transfer step of transferring the intermediate image by bringing the intermediate image into contact with the recording medium 108, wherein the transfer acceleration liquid contains polyester resin particles and acrylic resin particles.SELECTED DRAWING: Figure 1

Description

The present invention relates to an inkjet recording method and an inkjet recording apparatus.

An inkjet recording method is useful as a method for directly recording an image on a recording medium into which ink easily permeates. In recent years, the inkjet recording method has also been used as a method for directly recording an image on a recording medium such as printed paper, which is difficult for ink to permeate, among coated papers. Furthermore, it is also applied to a so-called transfer type recording method in which an intermediate image formed on an ink-impermeable transfer member such as silicone rubber is transferred to a recording medium.

In order to record a high-quality image on a recording medium using a transfer type ink jet recording apparatus, it is required that the intermediate image has good transferability from the transfer body to the recording medium. For example, there are transfer failures in which part of the intermediate image on the transfer medium is not transferred, and transfer failure in which the intermediate image separates internally and is divided between the transfer medium and the recording medium, resulting in only part of the image being transferred. When this occurs, the quality of the resulting image is degraded.

In order to improve the transferability of an intermediate image from a transfer body to a recording medium, an inkjet recording method has been proposed in which a liquid containing a water-soluble resin (transfer accelerating liquid) is applied to the transfer body (Patent Document 1). In Patent Document 1, by applying a transfer accelerating liquid to a transfer body before applying ink, the releasability of an image from the transfer body is improved, and after applying the ink, the transfer accelerating liquid is applied to the transfer body. in which the adhesion of an image to a recording medium is improved.

JP 2005-170036 A

In order to stably record a high-quality image on a recording medium using a transfer-type inkjet recording apparatus, it is important to improve the transferability to the recording medium. However, as a result of studies by the present inventors, it has been found that even the method proposed in Patent Document 1 is not so satisfactory in terms of image transferability, and that there is room for further improvement.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a transfer-type ink jet recording method which is excellent in transferability of an intermediate image to a recording medium and capable of stably recording a high-quality image on the recording medium. Another object of the present invention is to provide an inkjet recording apparatus for use in this inkjet recording method.

That is, according to the present invention, there is provided an inkjet recording method for recording an image on a recording medium using water-based ink, wherein after the water-based ink is applied to a transfer body, a region of the transfer body to which the water-based ink is applied and an intermediate image forming step of forming an intermediate image by applying a water-based transfer accelerating liquid to at least a part of the intermediate image; An inkjet recording method is provided, wherein the accelerator liquid contains polyester resin particles and acrylic resin particles.

According to the present invention, it is possible to provide a transfer-type ink jet recording method which is excellent in transferability of an intermediate image to a recording medium and capable of stably recording a high-quality image on the recording medium. Further, according to the present invention, it is possible to provide an inkjet recording apparatus used for this inkjet recording method.

1 is a schematic diagram showing an embodiment of an inkjet recording apparatus of the present invention; FIG.

The present invention will be further described in detail below with reference to preferred embodiments. In the present invention, when the compound is a salt, the salt is dissociated into ions in the ink, and for the sake of convenience, it may be expressed as "containing the salt". Further, water-based inks and water-based transfer promoting liquids for inkjet are sometimes simply referred to as "ink" and "transfer promoting liquid". Unless otherwise specified, physical property values are values at normal temperature (25° C.), normal humidity (50% relative humidity), and normal pressure (1 atm). "(Meth)acrylic acid" and "(meth)acrylate" mean "acrylic acid, methacrylic acid" and "acrylate, methacrylate", respectively.

The inventors of the present invention have studied a recording method using the transfer accelerating liquid proposed in Patent Document 1. First, when a transfer promoting liquid containing polyester resin particles was used, the transferability of the image was good. It has been found that a phenomenon (image shift phenomenon) occurs in which the coloring material is fixed in the area where the toner has been removed. The interaction between the polyester resin particles and the recording medium makes it difficult for the interfacial separation between the intermediate image and the recording medium to occur, improving transferability. It is considered that the volume of the intermediate image shrinks as it progresses, resulting in image movement.

As a result of further studies, the present inventors have found that the transfer accelerating liquid contains polyester resin particles and acrylic resin particles, resulting in the present invention. By using a transfer accelerating liquid containing polyester resin particles and acrylic resin particles, it is possible to further improve transferability while suppressing image movement. Not only recording media into which ink hardly permeates, such as printed paper, but also recording media such as plain paper, coated paper, and general printing paper usually contain cellulose, which is a paper fiber. In the molecular structure of cellulose, in addition to the carbon skeleton, there are periodically hydrogen-bonded hydrophilic moieties. Also in the molecular structure of the polyester resin, ester bonds are periodically present in addition to the highly hydrophobic carbon skeleton. The cellulose and polyester resins of the recording medium tend to interact with each other due to their similar structures. That is, it is thought that the affinity between the recording medium and the polyester resin is high, so that the adhesion between the intermediate image and the recording medium is increased, and the transferability is improved.

Moreover, acrylic resins and polyester resins are both resins having an ester bond. For this reason, the acrylic resin particles and the polyester resin particles have high compatibility, and at the time of aggregation accompanied by moisture evaporation after application to the transfer body, they are aggregated while being entangled with each other. As a result, compared with the transfer promoting liquid containing only polyester resin particles, the transfer promoting liquid containing acrylic resin particles and polyester resin particles has a higher viscosity after being applied to the transfer body, and is affected by moisture evaporation and the like. Image shrinkage is suppressed and good images are recorded. Furthermore, it is believed that the increase in the viscosity of the transfer accelerating liquid improves the adhesiveness between the recording medium and the ink aggregates, thereby improving the transferability.

<Inkjet recording method and inkjet recording apparatus>
The inkjet recording method of the present invention (hereinafter also simply referred to as "recording method") is a method of recording an image on a recording medium using water-based ink. The recording method of the present invention has an intermediate image forming process and a transfer process in this order. That is, the recording method of the present invention is a transfer type ink jet recording method. The intermediate image forming step is a step of applying a water-based ink to the transfer body and then applying a water-based transfer accelerating liquid to at least a part of the area of the transfer body to which the water-based ink has been applied to form an intermediate image. The transfer step is a step of contacting and transferring the intermediate image to the recording medium. The recording method of the present invention may further include a reaction liquid applying process, a liquid absorbing process, a heating process, a washing process, and the like, if necessary. The reaction liquid applying step is a step of applying a water-based reaction liquid containing a reactant that reacts with the water-based ink to the transfer body. The liquid absorption step is a step of absorbing a liquid component from the intermediate image formed on the transfer body. The heating step is a step of heating the intermediate image formed on the transfer body. The cleaning step is a step of cleaning the transfer body after the transfer step.

Further, the inkjet recording apparatus of the present invention (hereinafter also simply referred to as "recording apparatus") is an apparatus used for recording an image on a recording medium using water-based ink. The recording apparatus of the present invention comprises ink application means, transfer accelerating liquid application means, and transfer means. That is, the recording apparatus of the present invention is a so-called transfer type ink jet recording apparatus. The ink applying means is a means for applying water-based ink to the transfer body by ejecting the water-based ink by an inkjet method. The transfer accelerating liquid applying means is a means for forming an intermediate image by applying a water-based transfer accelerating liquid to at least a part of the area of the transfer member to which the water-based ink has been applied. The transfer means is means for transferring the intermediate image by bringing it into contact with the recording medium. The recording apparatus of the present invention may further include reaction liquid application means, liquid absorption means, heating means, cleaning means, and the like, if necessary. The reaction liquid applying means is a means for applying a water-based reaction liquid containing a reactant that reacts with the water-based ink to the transfer member. The liquid absorbing means is means for absorbing liquid components from the intermediate image formed on the transfer body. The heating means is means for heating the intermediate image formed on the transfer body. The cleaning means is means for cleaning the transfer body after transfer.

FIG. 1 is a schematic diagram showing one embodiment of the inkjet recording apparatus of the present invention. A transfer-type inkjet recording apparatus 100 shown in FIG. 1 is a sheet-fed inkjet recording apparatus that transfers an intermediate image onto a recording medium 108 via a transfer body 101 to produce a recorded matter. The X direction, Y direction, and Z direction respectively indicate the width direction (full length direction), depth direction, and height direction of the transfer-type inkjet recording apparatus 100 . The recording medium is conveyed in the X direction.

The transfer type inkjet recording apparatus 100 includes a transfer body 101 , a reaction liquid applying device 103 , an ink and transfer accelerating liquid applying device 104 , a liquid absorbing device 105 and a pressing member 106 . A transfer member 101 is supported by a support member 102 . The reaction liquid application device 103 is a device that applies a reaction liquid containing a reaction agent that reacts with ink to the transfer body 101 . The ink and transfer accelerating liquid application device 104 includes a recording head that applies ink and transfer accelerating liquid to the transfer body 101 to which the reaction liquid has been applied to form an intermediate image. The liquid absorbing device 105 is a device that absorbs liquid components from the intermediate image. The pressing member 106 is a member for transferring the intermediate image from which the liquid component has been removed to a sheet-like recording medium 108 such as paper. Further, the transfer-type inkjet recording apparatus 100 has a transfer body cleaning member 109 that cleans the surface of the transfer body 101 after transfer. The transfer body 101, the reaction liquid applying device 103, the recording head of the ink and transfer accelerating liquid applying device 104, the liquid absorbing device 105, and the transfer body cleaning member 109 correspond to the recording medium 108 used in the Y direction, respectively. has a length of

The transfer body 101 rotates in the direction of the arrow A around the rotating shaft 102a of the supporting member 102. As shown in FIG. An intermediate image is formed on the transfer body 101 by applying the reaction liquid from the reaction liquid applying device 103 to the rotating transfer body 101 and then applying ink from the ink and transfer accelerating liquid applying device 104 . As the transfer body 101 rotates, the intermediate image formed on the transfer body 101 moves to a position where it comes into contact with the liquid absorbing member 105 a of the liquid absorbing device 105 .

A liquid absorbing member 105 a that constitutes the liquid absorbing device 105 moves (rotates) in the direction of arrow B in synchronization with the rotation of the transfer body 101 . The intermediate image formed on the transfer member 101 contacts the moving liquid absorbing member 105a. Meanwhile, the liquid absorbing member 105a absorbs and removes the liquid component from the intermediate image. From the viewpoint of efficiently absorbing the liquid component of the intermediate image, the liquid absorbing member 105a is preferably pressed against the transfer body 101 with a predetermined pressing force. The intermediate image is formed of reaction liquid, ink, and transfer accelerating liquid, which are used as necessary. Therefore, absorbing the liquid component of the intermediate image means absorbing the liquid component of the reaction liquid, ink, and transfer accelerating liquid that are used as necessary. It can also be said that absorbing the liquid component from the intermediate image means concentrating the ink or the like. Concentration of ink increases the ratio of solids such as coloring materials and resins to liquid components.

The intermediate image from which the liquid component has been removed and the ink has been concentrated moves to the transfer portion 111 that contacts the recording medium 108 conveyed by the recording medium conveying device 107 due to the rotation of the transfer body 101 . The intermediate image and the recording medium 108 are sandwiched between the transfer body 101 and the pressing member 106 and pressed from the pressing member 106 side to come into contact with each other. When the roller-shaped transfer body 101 and the cylindrical pressing member 106 are used, the intermediate image and the recording medium 108 are in linear contact along the Y direction. When the transfer body 101 made of an elastic material is used, the transfer body 101 is dented by pressing, so that the intermediate image and the recording medium 108 come into surface contact. For this reason, the line or surface where the intermediate image and the recording medium 108 contact is defined as a "region", and the portion including this region is defined as a transfer portion 111. FIG. While the intermediate image is in contact with the recording medium 108 , the pressing member 106 presses the transfer body 101 to transfer the intermediate image to the recording medium 108 and record a desired image on the recording medium 108 . The image after transfer is the reverse image of the intermediate image before transfer.

When the reaction liquid is applied to the transfer body using the roller-shaped reaction liquid applying member 103c, the reaction liquid is applied to the entire transfer body. Since an intermediate image is formed by applying ink to the transfer body to which the reaction liquid has been applied, the reaction liquid that has not reacted with the ink remains in areas of the transfer body to which the ink has not been applied. The liquid absorbing member 105a can remove not only the intermediate image but also the liquid component of the unreacted reaction liquid. The liquid component contained in the ink or the transfer accelerating liquid does not have a fixed shape, has fluidity, and exists in a substantially fixed volume. A liquid component contained in the ink or the transfer accelerating liquid is specifically an aqueous medium or the like.

Principal parts of the transfer type ink jet recording apparatus will be described below. Specifically, [1] transfer body, [2] support member, [3] reaction liquid applying device, [4] ink and transfer accelerating liquid applying device, [5] liquid absorbing device, [6] heating device, [7] pressing member, [8] recording medium, [9] recording medium conveying device, and [10] cleaning device will be described.

[1] Transfer Body The transfer body 101 has a surface layer including a surface on which an intermediate image is formed. Examples of the material forming the surface layer include resins and ceramics. From the viewpoint of durability, etc., a material having a high compression modulus is preferable. In order to improve the wettability of the ink and the transfer accelerating liquid, the surface may be treated before use.

The transfer member preferably has a compression layer having a function of absorbing pressure fluctuations between the surface layer and the support member. The compressive layer distributes local pressure fluctuations and absorbs deformation of the surface layer. Therefore, by providing the compression layer, good transferability can be maintained even in the case of high-speed recording. As a material for forming the compression layer, an elastic material such as a rubber material can be used. Among them, a rubber material having a porous structure obtained by blending a foaming agent, hollow fine particles, and a filler such as a salt with a raw rubber and molding the vulcanizing agent and vulcanization accelerator is preferable. In such an elastic material, when the pressure fluctuates, the void portion is compressed with a change in volume, so deformation in directions other than the direction of compression is small. Therefore, transferability and durability can be improved. Examples of the porous structure include a continuous pore structure in which pores are interconnected and an independent pore structure in which pores are independent of each other.

The transfer body preferably further has an elastic layer between the surface layer and the compression layer. Examples of the material forming the elastic layer include resin materials and ceramic materials. Among them, an elastic material such as a rubber material is preferable because it is easy to process, has a small change in elastic modulus due to temperature, and is excellent in transferability.

Each layer (surface layer, elastic layer, compression layer) constituting the transfer member can be adhered to each other using an adhesive or double-sided tape. A reinforcing layer having a high compressive elastic modulus may be provided in order to suppress lateral stretching and maintain stiffness when attached to a device. A woven fabric or the like can be used as the reinforcing layer. Among the layers constituting the transfer body, layers other than the surface layer can be optionally combined with an elastic layer or a compression layer. The size of the transfer body can be freely selected according to the recording speed and image size. Examples of the shape of the transfer body include sheet-like, roller-like, belt-like, and endless web-like shapes.

[2] Support member The transfer member 101 is supported on a support member 102 . The transfer member can be placed on the support using, for example, an adhesive or double-sided tape. The transfer member 101 may be arranged on the support member 102 using an installation member made of a material such as metal, ceramic, or resin. The support member 102 is required to have a certain degree of structural strength from the viewpoint of transportation accuracy and durability. Examples of materials for the support member include metal, ceramic, and resin. Among them, it is preferable to use a metal material such as aluminum. By using a metal material, it is possible to improve the responsiveness of control by reducing the inertia during operation, as well as the rigidity and dimensional accuracy that can withstand the stress during transfer.

[3] Reaction Liquid Application Device The recording method of the present invention may have a reaction liquid application step of applying the reaction liquid to the transfer body before the intermediate image forming step. The reaction liquid contains a reactant that reacts with the ink when it comes into contact with the ink and agglomerates components having anionic groups such as resins and self-dispersing pigments in the ink. After the application of the ink, the reaction liquid may be further applied so that at least a part of the area to which the ink is applied overlaps.

A transfer-type inkjet recording apparatus 100 shown in FIG. This reaction liquid application device 103 is a gravure offset roller having a reaction liquid storage section 103a that stores a reaction liquid, and reaction liquid application members 103b and 103c that apply the reaction liquid in the reaction liquid storage section 103a to the transfer body 101. . Examples of the reaction liquid application device include a gravure offset roller and an inkjet recording head. Among them, it is preferable to use a roller to apply the reaction liquid to the transfer body.

[4] Applicator for Ink and Transfer Accelerating Liquid The transfer type inkjet recording apparatus 100 shown in FIG. . It is preferable to use an ink-jet type recording head as an ink applying device and apply the ink by ejecting the ink. Also, the means for applying the transfer accelerating liquid is not particularly limited, but it is preferable to use an inkjet recording head and apply the transfer accelerating liquid by ejecting it, as in the case of the ink. As a recording head, for example, a form in which ink is ejected by causing film boiling in ink by an electro-thermal transducer to form air bubbles; a form in which ink is ejected by an electro-mechanical transducer; can be exemplified. Among them, a recording head using an electro-thermal converter is preferable because it can record an image at a higher speed and a higher density.

It is preferable that the area to which the transfer accelerating liquid is applied to the intermediate transfer member includes at least the area to which ink is applied. That is, it is preferable to apply the ink and the transfer accelerating liquid in layers. Of course, the transfer accelerating liquid may be applied to areas of the intermediate transfer member to which no ink is applied. In the region to which the ink and the transfer promoting liquid are applied, the ratio of the amount of ink applied per unit area is 0.1 times or more and 10.0 times or less as a mass ratio of the amount of applied ink to the amount of applied transfer promoting liquid. is preferred.

The recording head is a full-line head extending in the Y direction, and ejection openings are arranged in a range covering the width of the image recording area of the maximum size recording medium that can be used. The recording head has an ejection port surface in which ejection ports are opened on the lower surface (on the side of the transfer member 101). The ejection port surface faces the surface of the transfer member 101 with a minute gap (of the order of several millimeters).

The ink and transfer accelerating liquid application device 104 has a plurality of recording heads for applying inks of respective colors such as cyan, magenta, yellow, and black (CMYK) and transfer accelerating liquid to the transfer body 101 . good too. For example, when an intermediate image is formed using four types of CMYK inks and a transfer accelerating liquid, the ink applying device has five recording heads for ejecting the four types of CMYK inks and the transferring accelerating liquid. These print heads are arranged along the X direction.

[5] Liquid Absorbing Device The liquid absorbing device 105 has a liquid absorbing member 105 a and a pressing member 105 b for liquid absorption that presses the liquid absorbing member 105 a against the intermediate image on the transfer body 101 . When the pressure member 105b has a cylindrical shape and the liquid absorption member 105a has a belt shape, the pressure member 105b presses the liquid absorption member 105a against the transfer body 101 to absorb the liquid component from the intermediate image. The liquid component can also be absorbed from the intermediate image by pressing a cylindrical pressing member having a liquid absorbing member attached to its outer peripheral surface against the transfer member. Considering the space in the recording apparatus, the shape of the liquid absorbing member 105a is preferably belt-like. The liquid absorbing device 105 having the belt-like liquid absorbing member 105a may have a stretching member such as a stretching roller 105c for stretching the liquid absorbing member 105a.

By bringing the liquid absorbing member 105a including the porous layer into contact with the intermediate image using the pressing member 105b, the liquid component contained in the intermediate image can be absorbed by the liquid absorbing member 105a. As a method of absorbing the liquid component contained in the intermediate image, in addition to the method of contacting the liquid absorbing member, a method of heating, a method of blowing low-humidity air, a method of reducing pressure, and the like may be combined. Also, these methods may be applied to the intermediate image before and after absorbing the liquid component.

The liquid absorbing member 105a rotates as the transfer body 101 rotates. Therefore, the shape of the liquid absorbing member 105a is preferably a shape capable of repeatedly absorbing liquid, and specific examples thereof include an endless belt shape and a drum shape. The liquid component absorbed by the liquid absorbing member 105a including the porous layer is removed from the liquid absorbing member 105a by a method of absorbing from the back surface of the porous layer, a method of using a member that compresses and squeezes the porous member, or the like. can do. After removing the liquid component, the liquid absorbing member 105a is rotated and brought into contact with a new intermediate image, whereby the liquid component contained in the intermediate image can be efficiently absorbed.

[6] Heating device The recording method of the invention preferably further includes a heating step of heating the intermediate image formed on the transfer member. By heating the intermediate image on the transfer member, the liquid component such as the water-soluble organic solvent contained in the intermediate image is volatilized, the strength of the intermediate image is increased, and the transferability to the recording medium can be further improved. In the heating step, it is preferable to heat the intermediate image to 40° C. or higher. By bringing the intermediate image heated to a predetermined temperature or higher into contact with the recording medium, the ability of the intermediate image to follow the unevenness of the recording medium is enhanced, and the transferability can be further improved. When a transfer accelerating liquid containing polyester resin particles and acrylic resin particles, which will be described later, is used, in the heating step, the intermediate image to be transferred in contact with the recording medium is heated to a temperature equal to or higher than the minimum film-forming temperature of the polyester resin in the transfer accelerating liquid. Heating to temperature is preferred. When the intermediate image heated to the minimum film-forming temperature or higher of the polyester resin is brought into contact with the recording medium, the followability of the intermediate image to the unevenness of the recording medium is enhanced, and the transferability can be further improved.

Examples of the heating method include a method of heating from the surface direction of the intermediate image; a method of heating from the back surface direction of the intermediate image; and a method combining these methods. The heating means may be either contact or non-contact. Heating means include non-contact heating mechanisms such as warm air heating mechanisms such as dryers, radiation heating mechanisms using halogen heaters and infrared heaters, and electromagnetic induction heating mechanisms; contact heating mechanisms such as iron press heating mechanisms. heating mechanism of the formula; Among them, from the viewpoint of heating efficiency, a heating mechanism using radiation using an infrared heater or the like is preferable.

[7] Pressing member The recording apparatus of the present invention includes transfer means for contacting and transferring the intermediate image to the recording medium. Specifically, as shown in FIG. 1, the intermediate image after liquid removal on the transfer body 101 is brought into contact with the recording medium 108 conveyed by the recording medium conveying device 107 at the transfer portion 111 by the pressing member 106 and transferred. do. By transferring the intermediate image from which the liquid component has been removed to the recording medium 108, curling and cockling of the recording medium 108 can be suppressed.

It is preferable that the pressing member 106 has an appropriate structural strength from the viewpoint of transportation accuracy and durability of the recording medium 108 . Examples of materials for the pressing member 106 include metals, ceramics, and resins. Among them, a metal such as aluminum is preferable from the viewpoint of not only having rigidity and dimensional accuracy capable of withstanding the stress during transfer, but also from the viewpoint of reducing inertia during operation and improving control responsiveness.

The time (pressing time) during which the pressing member 106 presses the transfer body 101 when transferring the intermediate image to the recording medium 108 is preferably 5 milliseconds or more and 100 milliseconds or less. By setting the pressing time as described above, good transfer can be performed and damage to the transfer body 101 can be suppressed. The pressing time is the time during which the recording medium 108 and the transfer body 101 are in contact. The pressing time can be calculated by measuring the surface pressure using a pressure distribution measuring system and dividing the length of the pressurized area in the conveying direction by the conveying speed. Specifically, a surface pressure distribution measuring system (trade name “I-SCAN” manufactured by Nitta) or the like can be used.

When the intermediate image is transferred to the recording medium 108, the pressure (pressing force) with which the pressing member 106 presses the transfer body 101 is 9.8 N/cm ² (1 kg/cm ² ) or more and 294.2 N/cm ² (30 kg). /cm ² ) or less. By using the above pressing force, good transfer can be performed, and damage to the transfer body 101 can be suppressed. The pressing force is the nip pressure between the recording medium 108 and the transfer body 101 . The pressing force can be calculated by measuring the surface pressure using a pressure distribution measurement system and dividing the load in the pressurized area by the area. Specifically, a surface pressure distribution measuring system (trade name “I-SCAN” manufactured by Nitta) or the like can be used.

The temperature at which the pressing member 106 presses the transfer member 101 for transfer is preferably a temperature equal to or higher than the minimum film-forming temperature of the polyester resin particles in the transfer accelerating liquid. In order to control the temperature, the recording apparatus preferably has heating means for heating the intermediate image on the transfer body 101 , the transfer body 101 and the recording medium 108 . The shape of the pressing member 106 may be, for example, a roller shape.

[8] Recording Medium As the recording medium 108, any known recording medium can be used. Examples of the recording medium include a long material wound into a roll; and a sheet cut into a predetermined size. Materials constituting the recording medium include paper such as coated paper and plain paper; films such as plastic and metal; wood board; corrugated board.

[9] Recording Medium Conveying Device The recording medium conveying device 107 conveys the recording medium 108 in the direction of arrow C. As shown in FIG. The recording medium conveying device 107 is composed of a recording medium delivery roller 107a and a recording medium take-up roller 107b. The transport speed of the recording medium 108 is preferably determined in consideration of the speed required in each process.

[10] Cleaning Device As shown in FIG. 1, the recording apparatus of the present invention preferably has a cleaning device, which is cleaning means for cleaning the transfer body 101 by applying a water-based cleaning liquid. The cleaning device includes, for example, a transfer body cleaning member 109 that applies a cleaning liquid to the transfer body 101 to clean it. By cleaning the transfer body 101 with the transfer body cleaning member 109, deterioration in image quality can be suppressed. As the transfer member cleaning member 109, a member having a shape such as a roller or a web can be used. The cleaning device can be provided with a cleaning liquid supply unit that supplies cleaning liquid to the transfer member cleaning member 109 .

Further, the cleaning device preferably includes a cleaning liquid removing member 110 that removes cleaning liquid and residue remaining on the transfer body 101 after cleaning. By removing the cleaning liquid remaining on the transfer body 101 with the cleaning liquid removing member 110, deterioration of the image quality can be more effectively suppressed. Methods for removing the cleaning liquid remaining on the transfer body 101 include blade removal, brush removal, liquid absorption by an absorber, and the like. Among others, it is preferable to remove the cleaning liquid remaining on the transfer body 101 by liquid absorption by the absorbent. As the cleaning liquid removing member 110, a porous body or the like used as a liquid absorbing member can be used.

(ink)
The ink used in the recording method of the present invention is a water-based ink for inkjet. Each component used in the ink will be described in detail below.

[Color material]
The ink can contain a coloring material. A pigment or a dye can be used as the coloring material. The content (% by mass) of the coloring material in the ink is preferably 0.5% by mass or more and 15.0% by mass or less, and 1.0% by mass or more and 10.0% by mass or less, based on the total mass of the ink. More preferably: A pigment is preferably used as the coloring material.

Specific examples of pigments include inorganic pigments such as carbon black and titanium oxide; and organic pigments such as azo, phthalocyanine, quinacridone, isoindolinone, imidazolone, diketopyrrolopyrrole and dioxazine.

As a method of dispersing the pigment, a resin-dispersed pigment using a resin as a dispersing agent, or a self-dispersing pigment having a hydrophilic group bonded to the particle surface of the pigment can be used. Further, a resin-bonded pigment in which an organic group containing a resin is chemically bonded to the surface of a pigment particle, or a microcapsule pigment in which the surface of a pigment particle is coated with a resin or the like can be used. Among them, it is preferable to use a resin-dispersed pigment in which a resin as a dispersant is physically adsorbed on the particle surface of the pigment instead of a resin-bonded pigment or a microcapsule pigment.

As the resin dispersant for dispersing the pigment in the aqueous medium, it is preferable to use one that can disperse the pigment in the aqueous medium by the action of an anionic group. As the resin dispersant, a resin as described later, especially a water-soluble resin can be used. The content (% by mass) of the pigment in the ink is preferably 0.3 times or more and 10.0 times or less as a mass ratio with respect to the content of the resin dispersant.

As the self-dispersing pigment, those in which an anionic group such as a carboxylic acid group, a sulfonic acid group, or a phosphonic acid group is bonded directly to the particle surface of the pigment or through another atomic group (-R-) is used. be able to. The anionic group may be in either an acid form or a salt form, and in the case of a salt form, it may be in a partially dissociated state or in a completely dissociated state. When the anionic group is in the salt form, cations that serve as counter ions include alkali metal cations, ammonium and organic ammonium. Specific examples of other atomic groups (-R-) include linear or branched alkylene groups having 1 to 12 carbon atoms; arylene groups such as phenylene groups and naphthylene groups; carbonyl groups; imino groups; amide groups; groups; ester groups; ether groups, and the like. Moreover, the group which combined these groups may be sufficient.

As the dye, it is preferable to use one having an anionic group. Specific examples of dyes include dyes such as azo, triphenylmethane, (aza)phthalocyanine, xanthene, and anthrapyridone. The coloring material contained in the ink is preferably a pigment, more preferably a resin-dispersed pigment.

[resin]
The ink can contain a resin. The resin content (% by mass) in the ink is preferably 0.1% by mass or more and 20.0% by mass or less, and 0.5% by mass or more and 15.0% by mass or less, based on the total mass of the ink. is more preferable.

The resin can be added to the ink to (i) stabilize the dispersed state of the pigment, that is, as a resin dispersant or as an adjunct thereto. In addition, (ii) it can be added to the ink in order to improve various characteristics of the recorded image. Forms of the resin include block copolymers, random copolymers, graft copolymers, combinations thereof, and the like. Moreover, the resin may be a water-soluble resin that is soluble in an aqueous medium, or resin particles that are dispersed in an aqueous medium. Resin particles do not need to contain a coloring material.

As used herein, the phrase "the resin is water-soluble" means that when the resin is neutralized with an alkali equivalent to its acid value, it is water-soluble in a state in which particles whose particle size can be measured by a dynamic light scattering method are not formed. means present in the medium. Whether or not the resin is water-soluble can be determined according to the method described below. First, a liquid (resin solid content: 10% by mass) containing a resin neutralized with an acid value equivalent alkali (sodium hydroxide, potassium hydroxide, etc.) is prepared. Next, the prepared liquid is diluted 10-fold (by volume) with pure water to prepare a sample solution. Then, when the particle size of the resin in the sample solution is measured by the dynamic light scattering method, if particles having the particle size are not measured, it can be determined that the resin is water-soluble. The measurement conditions at this time can be, for example, as follows.
[Measurement condition]
SetZero: 30 seconds Number of measurements: 3 Measurement time: 180 seconds

As the particle size distribution analyzer, a particle size analyzer using dynamic light scattering (for example, trade name “UPA-EX150” manufactured by Nikkiso Co., Ltd.) can be used. Of course, the particle size distribution measuring device and measurement conditions to be used are not limited to those described above.

The acid value of the water-soluble resin is preferably 100 mgKOH/g or more and 250 mgKOH/g or less. The acid value of the resin constituting the resin particles is preferably 5 mgKOH/g or more and 100 mgKOH/g or less. The weight average molecular weight of the water-soluble resin is preferably 3,000 or more and 15,000 or less. The weight-average molecular weight of the resin constituting the resin particles is preferably 1,000 or more and 2,000,000 or less. The volume-based cumulative 50% particle diameter (D50) of the resin particles measured by a dynamic light scattering method is preferably 50 nm or more and 500 nm or less.

Examples of resins include acrylic resins, urethane resins, and olefin resins. Among them, acrylic resins and urethane resins are preferable, and acrylic resins composed of units derived from (meth)acrylic acid or (meth)acrylate are more preferable.

As the acrylic resin, one having a hydrophilic unit and a hydrophobic unit as structural units is preferable. Among them, a resin having a hydrophilic unit derived from (meth)acrylic acid and a hydrophobic unit derived from at least one of a monomer having an aromatic ring and a (meth)acrylic acid ester-based monomer is preferable. In particular, a resin having a hydrophilic unit derived from (meth)acrylic acid and a hydrophobic unit derived from at least one monomer of styrene and α-methylstyrene is preferred. Since these resins easily interact with pigments, they can be suitably used as resin dispersants for dispersing pigments.

A hydrophilic unit is a unit having a hydrophilic group such as an anionic group. A hydrophilic unit can be formed, for example, by polymerizing a hydrophilic monomer having a hydrophilic group. Specific examples of hydrophilic monomers having hydrophilic groups include acidic monomers having carboxylic acid groups such as (meth)acrylic acid, itaconic acid, maleic acid and fumaric acid, and anions such as anhydrides and salts of these acidic monomers. organic monomers, and the like. Examples of cations constituting salts of acidic monomers include ions such as lithium, sodium, potassium, ammonium and organic ammonium. A hydrophobic unit is a unit that does not have a hydrophilic group such as an anionic group. A hydrophobic unit can be formed, for example, by polymerizing a hydrophobic monomer that does not have a hydrophilic group such as an anionic group. Specific examples of hydrophobic monomers include monomers having an aromatic ring such as styrene, α-methylstyrene, and benzyl (meth)acrylate; methyl (meth)acrylate, butyl (meth)acrylate, (meth)acrylic acid 2 -(Meth)acrylic acid ester-based monomers such as ethylhexyl.

A urethane-based resin can be obtained, for example, by reacting a polyisocyanate with a polyol. Moreover, what made the chain extension agent further react may be used. Examples of olefinic resins include polyethylene and polypropylene.

[Aqueous medium]
The ink used in the recording method of the present invention is an aqueous ink containing at least water as an aqueous medium. The ink can contain water or an aqueous medium that is a mixed solvent of water and a water-soluble organic solvent. As water, it is preferable to use deionized water or ion-exchanged water. The water content (% by mass) in the water-based ink is preferably 50.0% by mass or more and 95.0% by mass or less based on the total mass of the ink. Also, the content (% by mass) of the water-soluble organic solvent in the water-based ink is preferably 3.0% by mass or more and 50.0% by mass or less based on the total mass of the ink. As the water-soluble organic solvent, alcohols, (poly)alkylene glycols, glycol ethers, nitrogen-containing compounds, sulfur-containing compounds, and the like, which can be used for inkjet inks, can be used.

[Other additives]
In addition to the above ingredients, various other agents such as antifoaming agents, surfactants, pH adjusters, viscosity adjusters, rust inhibitors, antiseptics, anti-mold agents, antioxidants, and anti-reduction agents may be added to the ink. may contain additives. However, it is preferable that the ink does not contain a reactant used for the reaction liquid described later. When the reactive agent is contained in the ink, the content of the reactive agent in the ink is preferably very small (for example, about 0.05% by mass or less).

[Physical properties of ink]
The inks described above are water-based inks applicable to the inkjet system. Therefore, from the viewpoint of reliability, it is preferable to appropriately control the physical property values. Specifically, the surface tension of the ink at 25° C. is preferably 20 mN/m or more and 60 mN/m or less. Also, the viscosity of the ink at 25° C. is preferably 1.0 mPa·s or more and 10.0 mPa·s or less. The pH of the ink at 25° C. is preferably 7.0 or more and 9.5 or less, more preferably 8.0 or more and 9.5 or less.

(transcription promoting liquid)
The recording method of the present invention has an intermediate image forming step of applying a water-based transfer accelerating liquid to at least a part of the ink-applied area of the transfer body after applying the ink to the transfer body to form an intermediate image. . The transfer accelerating liquid is a water-based liquid, and is preferably applied to a predetermined area of the transfer body by being ejected from an ink jet recording head. Since it is preferable that the recorded image is not affected, the transfer accelerating liquid does not need to contain a coloring material. Further, since the recording method of the present invention may further include a reaction liquid applying step, the transfer accelerating liquid may contain a "reactant" to be contained in the reaction liquid in anticipation of imparting reactivity, or It is not necessary to contain the "coloring material" to be contained. Each component used in the transfer accelerating liquid will be described in detail below.

[Polyester resin particles]
The transfer accelerating liquid contains polyester resin particles. The polyester resin particles are formed of a polyester resin that is a polycondensate of a polyhydric alcohol component and a polycarboxylic acid component. The content (% by mass) of the polyester resin particles in the transfer accelerating liquid is preferably 1.0% by mass or more and 20.0% by mass or less, and is preferably 3.0% by mass or more, based on the total mass of the transfer accelerating liquid. It is more preferably 15.0% by mass or less. The polyester resin particles are present in the transfer promoting liquid in the form of a resin emulsion in a dispersed state. The polyester resin particles may not contain a coloring material. The ratio (% by mass) of the polyester resin in the resin forming the resin particles is preferably 90% by mass or more, more preferably 100% by mass, based on the total mass of the resin. That is, resin particles formed only from a polyester resin are particularly preferred.

Dihydric to tetrahydric polyhydric alcohols can be given as examples of the polyhydric alcohol, which is a unit derived from a polyhydric alcohol and which constitutes the polyester resin by reaction. Examples of polyhydric alcohols include polyhydric alcohols having an aliphatic group, polyhydric alcohols having an aromatic group, and sugar alcohols. Polyhydric alcohols include ethylene glycol (1,2-ethanediol), neopentyl glycol (2,2-dimethyl-1,3-propanediol), 1,3-propanediol, 1,4-butanediol, benzene diols, dihydric alcohols such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A); trihydric alcohols such as glycerin, trimethylolethane and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; can be mentioned. As the polyhydric alcohol, an oligomer (a low-molecular-weight polymer having a molecular weight of 1,000 or less) can also be used. Dihydric or trihydric polyhydric alcohols are preferably used because the weight average molecular weight of the polyester resin can be easily adjusted.

Divalent to tetravalent polyvalent carboxylic acids can be mentioned as the polyvalent carboxylic acid that becomes a unit derived from the polyvalent carboxylic acid that constitutes the polyester resin by reaction. Examples of the structure of the polycarboxylic acid include polycarboxylic acids having an aliphatic group, polycarboxylic acids having an aromatic group, and nitrogen-containing polycarboxylic acids. Examples of polyvalent carboxylic acids include divalent carboxylic acids such as glutaric acid, adipic acid, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid; trivalent carboxylic acids such as trimellitic acid; tetravalent acids such as ethylenediaminetetraacetic acid. Carboxylic acids etc. can be mentioned. Oligomers (low-molecular-weight polymers having a molecular weight of 1,000 or less) can also be used as polyvalent carboxylic acids. It is preferable to use divalent or trivalent polyvalent carboxylic acids because the weight average molecular weight and acid value of the polyester resin can be easily adjusted.

The acid value of the polyester resin is preferably 10 mgKOH/g or less. When the acid value is more than 10 mgKOH/g, part of the polyester resin dissolves in the transfer accelerating liquid, so that the volume shrinkage of the image tends to occur, and the effect of suppressing the image movement may slightly decrease.

The weight average molecular weight of the polyester resin is preferably 20,000 or more and 100,000 or less. If the weight-average molecular weight of the polyester resin is more than 100,000, the molecular weight distribution will be broadened, so even if the resin is heated to the minimum film-forming temperature or higher, the fluidity will hardly increase, and the effect of improving the transferability will be slightly reduced. There is The weight average molecular weight of the polyester resin is a polystyrene-equivalent value measured by gel permeation chromatography.

The minimum film-forming temperature of the polyester resin particles is preferably 120° C. or less. When the minimum film-forming temperature of the polyester resin particles is higher than 120° C., the adhesion between the recording medium and the intermediate image may deteriorate, and the transfer efficiency may slightly decrease.

By providing a heating step for heating the intermediate image formed on the transfer body, the transferability of the image can be further improved. Polyester resins are polycondensates of units derived from polyhydric alcohols and units derived from polycarboxylic acids. It has characteristics. Therefore, when the polyester resin is heated, the fluidity rises sharply near the minimum film-forming temperature. Therefore, when the intermediate image containing the polyester resin particles is heated, the fluidity of the intermediate image increases, and the intermediate image comes into contact with the recording medium while following the unevenness of the surface of the recording medium. It is believed that this increases the contact area between the recording medium and the intermediate image, further improving the transferability of the image.

On the other hand, if the fluidity of the polyester resin is abruptly increased, image movement tends to occur and image quality tends to deteriorate. Therefore, by adding the acrylic resin particles to the transfer accelerating liquid together with the polyester resin particles, it is possible to suppress the deterioration of the image quality. Since the acrylic resin constituting the acrylic resin particles is produced by addition polymerization, it often has a wider molecular weight distribution than general polycondensates. Therefore, the acrylic resin does not soften rapidly even near the minimum film-forming temperature, and the fluidity is less likely to increase than the polyester resin. Therefore, when the acrylic resin particles are present in the intermediate image together with the polyester resin particles, even if the polyester resin is rapidly softened by heating, the hard-to-soften acrylic resin suppresses shrinkage of the polyester resin, thereby suppressing deterioration in image quality. can do. As described above, the polyester resin and the acrylic resin both have an ester bond and thus have high compatibility, and when heated, the polyester resin softens while being entangled with each other. Therefore, by using a transfer accelerating liquid containing both polyester resin particles and acrylic resin particles, the image movement is suppressed even when the formed intermediate image is heated, and the image quality is improved while further improving the transferability. images can be recorded.

The volume-based cumulative 50% particle diameter (D50) of the polyester resin particles is preferably 10 nm or more and 300 nm or less, more preferably 50 nm or more and 200 nm or less. In the present specification, the "volume-based cumulative 50% particle diameter (D50) of resin particles" means that, in the particle diameter accumulation curve, based on the total volume of the measured particles, 50% accumulated from the small particle diameter side. is the diameter of the particle. The volume-based cumulative 50% particle diameter (D50) of the resin particles can be measured by a dynamic light scattering method under the same conditions as the method for determining whether the resin is water-soluble.

Polyester resin particles can be produced, for example, by granulating a polyester resin. Moreover, the polyester resin can be synthesized by reacting (esterification reaction) a polyhydric alcohol and a polycarboxylic acid. If necessary, the molecular weight of the resulting polyester resin can be adjusted by adding either a polyhydric alcohol or a polycarboxylic acid to the reaction system and performing a transesterification reaction in which some of the ester bonds are cut. can.

Examples of the method of granulating the polyester resin to form resin particles include a dispersion method and a phase inversion (emulsification) method. Dispersion methods include methods (1) and (2) shown below.
(1) A method in which a solution obtained by dissolving a polyester resin in an organic solvent is added to an aqueous liquid medium to disperse the polyester resin. (2) A polyester resin is added to an organic solvent, and then an aqueous liquid medium is added. and mix to disperse the polyester resin

As a phase inversion (emulsification) method, an aqueous liquid medium is added to a solution obtained by dissolving a polyester resin in an organic solvent, and the polyester resin is precipitated in the form of particles during the phase inversion from the solvent system to the aqueous system. There are methods. In any method, it is preferable to adjust the particle size of the obtained resin particles by using a known dispersing machine to form particles while applying an appropriate shearing force.

[Acrylic resin particles]
The transfer accelerating liquid contains acrylic resin particles. As the acrylic resin particles, those made of an acrylic resin having the same structure as the acrylic resin that can be contained in the ink can be used. The content (% by mass) of acrylic resin particles in the transfer promoting liquid is preferably 1.0% by mass or more and 20.0% by mass or less, based on the total mass of the transfer promoting liquid, and is preferably 2.0% by mass or more. It is more preferably 10.0% by mass or less. The acrylic resin particles exist in the transfer promoting liquid in the form of a resin emulsion in a dispersed state. The acrylic resin particles may not contain a coloring material. Moreover, the ratio (% by mass) of the acrylic resin in the resin forming the resin particles is preferably 90% by mass or more, more preferably 100% by mass, based on the total mass of the resin. That is, resin particles formed only from an acrylic resin are particularly preferred.

The weight average molecular weight of the acrylic resin is preferably 2,000,000 or less. The weight average molecular weight of the acrylic resin is a polystyrene-equivalent value measured by gel permeation chromatography.

The amount of acid groups introduced into the acrylic resin particles is preferably 250 μmol/g or less. If the amount of acid groups introduced into the acrylic resin particles is more than 250 μmol/g, the dispersed state is too stabilized, making it difficult for the particles to aggregate, which may slightly reduce the effect of suppressing image movement. The amount of acid groups introduced into the acrylic resin particles is preferably 120 μmol/g or more. The volume-based cumulative 50% particle diameter (D50) of the acrylic resin particles is preferably 10 nm or more and 1,000 nm or less, more preferably 40 nm or more and 500 nm or less.

The content (% by mass) of the polyester resin particles in the transfer accelerating liquid is preferably 1.0 to 9.0 times the content (% by mass) of the acrylic resin particles. When the mass ratio is more than 9.0 times, the volume of the intermediate image tends to shrink, and the effect of suppressing image movement may be slightly reduced. On the other hand, if the above mass ratio is less than 1.0 times, the interaction between the polyester resin particles and the recording medium is reduced, and the effect of improving the transferability may be slightly reduced.

[Other ingredients]
The transfer promoting liquid may further contain various other components as required. Other components can be selected from the same resins, aqueous media, and other additives listed as components that can be contained in the ink. Above all, it is preferable that the transfer accelerating liquid further contains a resin (another resin) other than the polyester resin particles and the acrylic resin particles. Other resins include water-soluble resins and resin particles listed as resins that can be contained in the ink. By using a transfer accelerating liquid containing a resin, the adhesiveness between the ink layer and the transfer accelerating liquid layer is further increased, so that the transferability of the intermediate image can be further improved.

[Physical Properties of Transfer Accelerator]
The transfer promoting liquid is, for example, a water-based liquid that is applied to the ink jet method. Therefore, it is preferable to appropriately control the physical property values from the viewpoint of reliability. The surface tension of the transfer accelerating liquid at 25° C. is preferably 20 mN/m or more and 60 mN/m or less. The surface tension of the transfer accelerating liquid is preferably lower than that of the ink. A transfer accelerating liquid whose surface tension is lower than the surface tension of the ink spreads easily on the ink layer, so that the adhesion between the ink layer and the transfer accelerating liquid layer is likely to increase, and the transferability can be further improved.

The viscosity of the transfer accelerating liquid at 25° C. is preferably 1.0 mPa·s or more and 10.0 mPa·s or less. The pH of the transfer accelerating liquid at 25° C. is preferably 7.0 or more and 9.5 or less, more preferably 8.0 or more and 9.5 or less.

(Reaction solution)
The recording method of the present invention preferably further includes a reaction liquid applying step of applying a water-based reaction liquid containing a reactive agent that reacts with the ink to the transfer member. This reaction liquid applying step is preferably performed prior to the intermediate image forming step. The reaction liquid reacts with the ink when it comes into contact with the ink, aggregates components in the ink (components having anionic groups such as resins and self-dispersing pigments), and contains a reactant. Examples of the reactant include polyvalent metal ions, cationic components such as cationic resins, and organic acids.

The reaction liquid may further contain various components (other components) other than the reactant, if necessary. Other components include the same resins, aqueous media, additives, etc. that can be contained in the ink.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited by the following examples as long as the gist thereof is not exceeded. "Parts" and "%" regarding component amounts are based on mass unless otherwise specified.

<Resin analysis conditions>
The acid value of the resin and the amount of acid group introduced were measured and calculated by potentiometric titration with a potassium hydroxide/ethanol titrant using an automatic potentiometric titrator. The weight average molecular weight (converted to polystyrene) of the resin was measured by gel permeation chromatography. Further, whether or not the resin was water-soluble was confirmed according to the method shown below. First, a liquid (resin content: 10%) containing a resin neutralized with potassium hydroxide corresponding to an acid value was prepared. Next, the resin-containing liquid was diluted with pure water to prepare a sample having a resin (solid content) content of 1.0%. The particle size of the resin in the prepared sample was then measured by dynamic light scattering, and the resin was judged to be water soluble when no particles with a particle size were measured. The measurement conditions at this time are shown below. As a particle size distribution analyzer, a particle size analyzer (trade name “UPA-EX150” manufactured by Nikkiso Co., Ltd.) using dynamic light scattering method was used.
[Measurement condition]
SetZero: 30 seconds Number of measurements: 3 Measurement time: 180 seconds

The minimum film-forming temperature of the resin particles was measured according to JISK6828-2:2003 (Synthetic resin emulsion Part 2: Determination of whitening temperature and minimum film-forming temperature). Specifically, a test plate of a simple film forming temperature measuring device (manufactured by Imoto Seisakusho) was coated with an aqueous dispersion containing resin particles using a blade cord (0.3 mm applicator), and then left to stand for 30 minutes. dried. The obtained dried product was used as a sample, and the coated surface of the dried product was traced with a glass rod at any time while the temperature was raised.

<Synthesis of polyester resin>
Monomers of the type and amount (unit: parts) shown in Table 1 were placed in a reaction vessel installed in an autoclave, and the monomers were heated at 250° C. for 6 hours to carry out an esterification reaction. 0.8 g of antimony trioxide and 0.15 g of phosphoric acid were added, the temperature was raised to 270° C. and the pressure was gradually reduced to 13 Pa after 1.5 hours. gone. Nitrogen gas was introduced to return the pressure to normal pressure, and when the temperature reached 265°C, 15 parts of hydrous trimellitic acid was added and stirred at 265°C for 2 hours for depolymerization reaction. After that, nitrogen gas was introduced to pressurize, and the sheet-like resin was taken out. After the resin was taken out and cooled to 25° C., it was pulverized with a crusher to obtain a polyester resin. The meaning of the abbreviation of each component in Table 1 is shown below.
・tPA: terephthalic acid ・iPA: isophthalic acid ・HAD: adipic acid ・BTA: trimellitic acid ・EG: ethylene glycol ・NPG: neopentyl glycol ・BPA: bisphenol A

<Production of polyester resin particles>
150 g of a polyester resin of the type shown in Table 2 and 350 g of tetrahydrofuran are placed in a 2 L beaker equipped with a stirrer (trade name “Tornado Standard SM-101”, manufactured by AS ONE) and mixed at 25° C. to dissolve the resin. let me A 5% aqueous sodium hydroxide solution was added in such an amount that the degree of neutralization of acid groups would be the value shown in Table 2, and the mixture was stirred for 30 minutes to obtain a slurry. 700 g of deionized water was added dropwise at a rate of 20 mL/min while stirring at 25° C. and the stirring speed shown in Table 2. The temperature was raised to 60° C. and the pressure was reduced to distill off tetrahydrofuran and part of the water. After stirring for the time shown in Table 2 while heating in a water bath at 85° C., the mixture was filtered through a 150-mesh wire mesh (a filter in which 150 stainless steel wires are woven into each length and width of a 1-inch square). An appropriate amount of deionized water was added to obtain an aqueous dispersion of polyester resin particles. The content of the polyester resin particles in the resulting aqueous dispersion was 25%.

<Production of acrylic resin particles>
A four-necked flask equipped with a stirrer, a reflux condenser, and a nitrogen gas inlet tube was charged with monomers of the types and amounts (unit: parts) shown in Table 3, a polymerization initiator (2,2′-azobis(2-methyl 2.0 parts of butyronitrile)) and 2.0 parts of n-hexadecane were added. Nitrogen gas was introduced into the reaction system and the mixture was stirred for 0.5 hour. 78.0 parts of a 6.0% aqueous solution of an emulsifier (trade name "NIKKOL BC15", manufactured by Nikko Chemicals) was added dropwise, and the mixture was further stirred for 0.5 hours to obtain a mixture. After emulsifying the mixture by irradiating it with ultrasonic waves for 3 hours using an ultrasonic irradiator, a polymerization reaction was carried out at 80° C. for 4 hours in a nitrogen atmosphere. After cooling to 25° C., filtration was performed, and an appropriate amount of pure water was added to obtain aqueous dispersions of acrylic resin particles 1 to 4 having a resin particle content of 40.0%. Table 3 shows the properties of the obtained acrylic resin particles. The meanings of the abbreviations of the monomers in Table 3 are shown below.
・EMA: Ethyl methacrylate ・BMA: Butyl methacrylate ・MAA: Methacrylic acid

<Preparation of pigment dispersion>
A mixture of 10.0 parts of a pigment, 15.0 parts of a resin-containing liquid, and 75.0 parts of ion-exchanged water was placed in a batch-type vertical sand mill (manufactured by Imex) filled with 200 parts of zirconia beads having a diameter of 0.3 mm. , dispersed for 5 hours. As the pigment, carbon black (trade name “Monac 1100”, manufactured by Cabot) was used. As the resin-containing liquid, an aqueous solution having a resin content of 20.0%, which is obtained by dissolving a water-soluble resin in water containing potassium hydroxide in an equimolar amount to the acid value, was used. A styrene-ethyl acrylate-acrylic acid copolymer having an acid value of 150 mgKOH/g and a weight average molecular weight of 8,000 was used as the water-soluble resin. After removing coarse particles by centrifugation, pressure filtration was performed with a microfilter having a pore size of 3.0 μm (manufactured by FUJIFILM Corporation) to obtain a pigment dispersion. The pigment content in the resulting pigment dispersion was 10.0%, and the resin content was 6.0%.

<Preparation of reaction solution>
After each component shown below was mixed and sufficiently stirred, the mixture was filtered under pressure through a microfilter with a pore size of 3.0 μm (manufactured by FUJIFILM Corporation) to prepare each reaction solution. "Acetylenol E100" is a trade name of a nonionic surfactant (manufactured by Kawaken Fine Chemicals).

[Reaction solution 1]
・Malic acid: 30.0%
・Glycerin: 7.0%
・Acetylenol E100: 5.0%
・Ion-exchanged water: 58.0%
[Reaction liquid 2]
・ Calcium chloride: 30.0%
・Glycerin: 7.0%
・Acetylenol E100: 5.0%
・Ion-exchanged water: 58.0%

<Ink preparation>
After each component shown below was mixed and sufficiently stirred, the mixture was filtered under pressure through a microfilter with a pore size of 3.0 μm (manufactured by FUJIFILM Corporation) to prepare an ink. As the aqueous solution of the water-soluble resin, a styrene-butyl acrylate-acrylic acid copolymer was neutralized with potassium hydroxide having an acid value and an equimolar amount, and the resin content was adjusted to 20.0% with deionized water. used things. The styrene-butyl acrylate-acrylic acid copolymer had an acid value of 132 mgKOH/g, a weight average molecular weight of 7,700, and a glass transition temperature of 78°C.

[ink]
・Pigment dispersion: 40.0%
Aqueous dispersion of acrylic resin particles 1: 12.5%
・Aqueous solution of water-soluble resin: 5.0%
・Glycerin: 7.0%
・Acetylenol E100: 0.5%
・Ion-exchanged water: 35.0%

<Preparation of Transfer Accelerator>
After each component shown below was mixed and sufficiently stirred, the mixture was pressure-filtered through a microfilter having a pore size of 3.0 μm (manufactured by Fuji Film) to prepare each transfer accelerating liquid. As the aqueous solution of the water-soluble resin, a styrene-butyl acrylate-acrylic acid copolymer was neutralized with potassium hydroxide having an acid value and an equimolar amount, and the resin content was adjusted to 20.0% with deionized water. used things. The styrene-butyl acrylate-acrylic acid copolymer had an acid value of 132 mgKOH/g, a weight average molecular weight of 7,700, and a glass transition temperature of 78°C. Table 4 shows the characteristics of the obtained transfer promoting liquid.

[Transfer accelerating liquids 1 to 22]
Aqueous dispersion of polyester resin particles of the type shown in Table 4: content (%) shown in Table 4
Aqueous dispersion of acrylic resin particles of the type shown in Table 4: content (%) shown in Table 4
・Glycerin: 7.0%
・Aqueous solution of water-soluble resin: 5.0%
・Acetylenol E100: 0.5%
・Ion-exchanged water: Remaining amount (%) when the total of components is 100.0%

<Evaluation>
In the present invention, in the following evaluation criteria for each item, "A" and "B" were defined as acceptable levels, and "C" was defined as an unacceptable level. Table 5 shows evaluation conditions and evaluation results.

(Transferability)
The combinations shown on the left side of Table 5 were used for the reaction solution and the transfer promoting solution. Then, in the transfer type inkjet recording apparatus 100 having the configuration shown in FIG. They were filled in the order of the transfer promoting liquid. The configuration of the transfer type inkjet recording apparatus 100 used is shown below.

A cylindrical drum made of an aluminum alloy was used as the support member 102 . As the surface layer member of the transfer member 101, a polyethylene terephthalate film having a thickness of 0.5 mm and a silicone rubber having a rubber hardness (durometer type A) of 40° (trade name “KE12”, manufactured by Shin-Etsu Chemical Co., Ltd.) having a thickness of 0.2 mm. was coated to a thickness of . Plasma surface treatment is performed on this surface layer member using an atmospheric pressure plasma treatment apparatus (trade name "ST-7000", manufactured by Keyence) under the conditions of treatment distance: 5 mm, plasma mode: High, treatment speed: 100 mm / sec. provided. Further, the surface of the surface layer member was immersed for 10 seconds in an aqueous surfactant solution prepared by diluting a commercially available neutral detergent (sodium alkylbenzene sulfonate) with pure water to a concentration of 3%, and then dried. It was used as a surface layer member of the transfer member 101 . The transfer member 101 was fixed to the support member 102 using double-sided adhesive tape. A heater was incorporated in the transfer body 101 and the temperature of the intermediate image was adjusted to the temperature shown in Table 5 by heating the transfer body.

Using the reaction liquid application device 103, the reaction liquid was applied onto the transfer body 101 so as to be 1.0 g/m ² . A recording head of a type that ejects ink and transfer accelerating liquid by an on-demand system, which is equipped with an electro-thermal conversion element, is used as the ink and transfer accelerating liquid applying device 104. A transfer promoting liquid can be applied. The recording medium feeding roller 107a and the recording medium take-up roller 107b were driven to convey the recording medium 108 at a speed equivalent to the moving speed of the transfer body 101 . The intermediate image was brought into contact with the recording medium 108 between the transfer body 101 and the pressing member 106, and the intermediate image was transferred from the transfer body 101 to the recording medium 108 to record a solid image. As the recording medium 108, coated paper (trade name “Vent Nouveau V”, manufactured by Daio Paper Products, basis weight 157 g/m ² ) was used. A nip pressure between the transfer member 101 and the pressing member 106 was adjusted to 3 kg/cm ² .

Using the transfer-type inkjet recording apparatus 100 having the above configuration, an intermediate image of 5 cm×5 cm was formed on the transfer member 101 with a recording duty of 20% for each of the ink and the transfer accelerating liquid. In this transfer-type inkjet recording apparatus 100, an image recorded under the condition that one droplet of 3.0 ng is applied to a unit area of 1/1,200 inch×1/1,200 inch is recorded at a recording duty of 100%. Define that there is. The area of the intermediate image formed on the transfer member and the area of the intermediate image remaining on the transfer member after transfer were each measured using an optical microscope. Then, the transfer rate is calculated from the formula: transfer rate=[1−(area of the intermediate image remaining on the transfer body after transfer)/(area of the intermediate image formed on the transfer body)}]×100 (%). , and the transferability was evaluated according to the evaluation criteria shown below.
A: The transfer rate was 80% or more.
B: The transfer rate was 50% or more and less than 80%.
C: The transfer rate was less than 50%.

(Suppression of image movement)
The images recorded in the evaluation of transferability were observed with an optical microscope, and the suppression of image movement was evaluated according to the evaluation criteria shown below. In the case where the above evaluation of transferability was "C", suppression of image movement could not be evaluated, so evaluation was performed by observing the intermediate image on the transfer member with an optical microscope.
A: There was no color loss.
B: There was color omission in part.
C: Color loss occurred, and an image could not be recorded.

Claims (9)

An inkjet recording method for recording an image on a recording medium using a water-based ink,
an intermediate image forming step of applying a water-based transfer accelerating liquid to at least a part of a region of the transfer body to which the water-based ink has been applied after applying the water-based ink to the transfer body to form an intermediate image;
a transfer step of contacting and transferring the intermediate image to the recording medium, in this order;
An inkjet recording method, wherein the transfer accelerating liquid contains polyester resin particles and acrylic resin particles. 2. The ink jet recording method according to claim 1, further comprising a reaction liquid applying step of applying a water-based reaction liquid containing a reactant that reacts with the water-based ink to the transfer member. 3. The inkjet recording method according to claim 1, further comprising a heating step of heating the intermediate image formed on the transfer body. 2. The content (mass %) of the polyester resin particles in the transfer accelerating liquid is 1.0 times or more and 9.0 times or less as a mass ratio with respect to the content (mass %) of the acrylic resin particles. 4. The inkjet recording method according to any one of items 1 to 3. 5. The inkjet recording method according to claim 3, wherein in the heating step, the intermediate image is heated to a temperature equal to or higher than the minimum film-forming temperature of the polyester resin particles. The inkjet recording method according to any one of claims 1 to 5, wherein the polyester resin forming the polyester resin particles has an acid value of 10 mgKOH/g or less. The inkjet recording method according to any one of claims 1 to 6, wherein the polyester resin forming the polyester resin particles has a weight average molecular weight of 20,000 or more and 100,000 or less. The inkjet recording method according to any one of claims 1 to 7, wherein the amount (µmol/g) of acid groups introduced into the acrylic resin particles is 250 µmol/g or less. An inkjet recording apparatus used for recording an image on a recording medium using water-based ink,
Ink applying means for applying the water-based ink to a transfer body by ejecting the water-based ink by an inkjet method;
transfer accelerating liquid applying means for applying a water-based transfer accelerating liquid to at least a part of the area of the transfer body to which the water-based ink has been applied to form an intermediate image;
a transfer unit that contacts and transfers the intermediate image to the recording medium;
An inkjet recording apparatus, wherein the transfer accelerating liquid contains acrylic resin particles and polyester resin particles.

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