JP2009190375A - Ink acceptable particle and recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ink acceptable particles which suppress image bleeding and density nonuniformity and can materialize high image quality and a recording device using the particles. <P>SOLUTION: The ink acceptable particles 16 with a shape factor SF1 of 146 or below are applied to the recording device 10 equipped with an intermediate transfer body 12, a particle supply device 18 which supplies the particles 16 in the shape of a layer on the intermediate transfer body 12, an inkjet recording head 20 which supplies ink droplets 20A on an ink acceptable particle layer 16A made of the particles 16 supplied on the intermediate transfer body 12, and a transfer fixing device 22 which transfers and fixes the ink acceptable particle layer 16A provided with the ink droplets 20A to a recording medium 8. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink receiving particle and a recording apparatus.

  As one of recording of images and data using ink, there is an ink jet recording method. The principle of the ink jet recording system is to record on paper, cloth, film, etc. by discharging liquid or molten solid ink from a nozzle, slit, porous film or the like. As for the method of ejecting ink, so-called charge control system that ejects ink using electrostatic attraction force, so-called pressure pulse system that ejects ink using the vibration pressure of piezo elements, and bubbles are formed by high heat. Various methods such as a so-called thermal ink jet method, in which ink is ejected using pressure generated by growth, have been proposed. By these methods, extremely high-definition images and recorded data can be obtained. it can.

  In order to record with high image quality on various recording media such as penetrating media and non-penetrating media, recording methods using ink, including this ink jet recording method, are recorded on an intermediate and then transferred to the recording medium. A scheme has been proposed.

For example, in Patent Document 1, particles that thicken by contact with a liquid are attached onto an intermediate transfer member, and then ink is applied to the particles. The ink-applied particles absorb ink moisture and swell to increase the viscosity, and transfer the particles having increased viscosity to the transfer target.
JP 2001-10114 A

  Since the ink is applied onto the particles supplied onto the intermediate transfer member, the particles are required to have a liquid absorption performance that sufficiently absorbs the ink, but the applied ink is also retained between the particles. For this reason, if the amount of ink held between the particles is non-uniform, image quality degradation may occur.

  An object of the present invention is to provide ink receptive particles capable of suppressing image bleeding and density unevenness and realizing high image quality, and a recording apparatus using the same.

  The above problem is solved by the following means. That is,

The invention according to claim 1 is an ink receiving particle that receives ink and has a shape factor SF1 of 146 or less.
The invention according to claim 2 is the ink receiving particle according to claim 1, wherein the shape factor SF1 is larger than 100.
The invention according to claim 3 is the ink receiving particle according to claim 1 or 2, wherein the particle size distribution GSD is 1.6 or less.

  According to a fourth aspect of the present invention, there is provided an intermediate transfer member, supply means for supplying ink accepting particles having a shape factor SF1 of 146 or less and receiving ink in a layer form on the intermediate transfer member, and the intermediate transfer member. Ink applying means for applying ink to the layer of the ink receiving particles supplied thereon, transfer means for transferring the ink receiving particle layer to a recording medium, and the ink receiving property transferred to the recording medium And a fixing unit for fixing the particle layer.

5. The recording apparatus according to claim 4, further comprising particle density increasing means for increasing a particle density in the ink receiving particle layer supplied onto the intermediate transfer member. Device.
The invention according to claim 6 is characterized in that the particle density increasing means increases the particle density by applying vibration to the layer of the ink receiving particles supplied onto the intermediate transfer member. Item 6. The recording device according to Item 5.

  According to a seventh aspect of the present invention, there is provided supply means for supplying ink receiving particles having a shape factor SF1 of 146 or less and receiving ink in a layered manner on the recording medium, and the ink receiving supplied to the recording medium. And a fixing unit for fixing the ink-receiving particle layer on the recording medium.

  According to the first aspect of the present invention, compared to the case where the present configuration is not provided, there is an effect that image bleeding and density unevenness are suppressed and high image quality can be achieved.

  According to the second aspect of the present invention, compared to the case where this configuration is not provided, the liquid absorbing power of the ink receiving particles can be improved, and the image quality can be improved.

  According to the third aspect of the present invention, compared to the case where the present configuration is not provided, it is possible to further suppress image bleeding and density unevenness and to further improve image quality.

  According to the fourth aspect of the invention, compared to the case where the present configuration is not provided, there is an effect that blurring and density unevenness of an image are suppressed and high image quality can be achieved.

  According to the invention concerning Claim 5, compared with the case where it does not have this structure, there exists an effect that a density nonuniformity and an image missing are further suppressed, and the further image quality improvement can be aimed at.

  According to the invention which concerns on Claim 6, compared with the case where it does not have this structure, there exists an effect that the further image quality improvement can be aimed at by a simple structure.

  According to the seventh aspect of the invention, compared to the case where the present configuration is not provided, it is possible to suppress image bleeding and density unevenness and to achieve high image quality.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is provided to the member which has the substantially same effect | action and function through all the drawings, and the overlapping description may be abbreviate | omitted.

  As shown in FIGS. 1 and 2, the recording apparatus 10 according to the present embodiment includes, for example, an endless belt-shaped intermediate transfer body 12, a charging device 28 that charges the surface of the intermediate transfer body 12, and charging on the intermediate transfer body 12. A particle supply device 18 for supplying the ink receiving particles 16 to the formed region to form a particle layer, a density increasing device 15 for increasing the particle density of the particle layer, and ejecting ink droplets onto the particle layer to form an image The inkjet recording head 20 includes a transfer fixing device 22 that superimposes the recording medium 8 on the intermediate transfer body 12 and transfers and fixes the ink receiving particle layer on the recording medium 8 by applying pressure and heat. Yes. An ink receiving particle storage cartridge 19 is detachably connected to the particle supply device 18 via a supply pipe 19A.

  The ink receptive particles 16 used in the present embodiment, which will be described in detail later, receive ink components when ink comes into contact with the particles. Here, the ink receptivity indicates holding at least a part (at least a liquid component) of the ink component. The ink receiving particles include, for example, at least an organic resin in which the ratio of polar monomers having polar groups to all monomer components is 10 mol% or more and 100 mol% or less. Specifically, the ink receiving particles include, for example, a configuration having particles configured to contain the organic resin (hereinafter referred to as hydrophilic organic particles) (hereinafter including the hydrophilic organic particles). Are called “mother particles”).

The ink receptive particles 16 may have a form in which the base particles are composed of particles (primary particles) of only hydrophilic organic particles, or a form in which the base particles are composed of composite particles in which at least hydrophilic organic particles are aggregated. Also good.
Specifically, for example, as shown in FIG. 5, the ink receiving particles 16 are composed of mother particles 201 composed of single particles (primary particles) of hydrophilic organic particles 201 </ b> A and inorganic particles attached to the mother particles 201. And a form having particles 202. In the case where the mother particles 201 are composed of particles (primary particles) of the hydrophilic organic particles 201A alone, when the ink receiving particles 16 receive ink, if the ink adheres to the ink receiving particles 16, the ink receiving particles. The ink is captured (trapped) in the gap between the sixteen and at least the liquid component of the ink is absorbed by the hydrophilic organic particles 201A.

  Further, as shown in FIG. 6, the ink receptive particles 16 are composed of base particles 201 of composite particles obtained by combining hydrophilic organic particles 201 </ b> A and inorganic particles 201 </ b> B, and inorganic particles 202 attached to the base particles 201. The form which has these. The composite particles 201 have a void structure formed by voids between the particles. In this case, when the ink receiving particles 16 receive the ink, first, when the ink adheres to the ink receiving particles 16, the ink is trapped (captured) in the gap between the ink receiving particles 16 and at least the ink of the ink receiving particles 16. The liquid component is captured (trap) by voids between the particles (at least hydrophilic organic particles) constituting the ink receiving particles 16 as the composite particles (hereinafter, the interparticle voids may be referred to as trap structures). Is done. At this time, among the ink components, the recording material is attached to the surface of the ink receiving particles 16 or trapped by the trap structure. In this way, the ink receiving particles 16 receive ink. Then, the ink receiving particles 16 that have received the ink are transferred to the recording medium 8 to perform recording.

  The trapping (trapping) of the ink liquid component by the trap structure is a physical and / or chemical trapping by voids between particles (physical particle wall structure).

  Then, by applying a form in which the mother particle 201 is composed of at least the composite particles in which the hydrophilic organic particles 201A are aggregated, capture by voids (physical particle wall structure) between the particles constituting the composite particles ( In addition to the trap), the ink liquid component is absorbed and held by the hydrophilic organic particles 201A.

  In addition, after the ink receiving particles 16 are transferred to the recording medium 8, the components of the hydrophilic organic particles 201A constituting the ink receiving particles 16 may be used as a binder resin or a coating resin for the recording material included in the ink. Function. Further, when the ink receiving particles 16 are composite particles, the recording material is trapped in the trap structure. In particular, it is desirable to apply a transparent resin as the component of the hydrophilic organic particles 201 </ b> A constituting the ink receiving particles 16.

  In addition, in order to improve the fixability (rubbing resistance) of an ink (for example, pigment ink) using an insoluble component such as a pigment or a dispersed particulate material as a recording material, it is necessary to add a large amount of resin to the ink. If a large amount of polymer is added to the processing liquid (including the treatment liquid), the reliability such as nozzle clogging of the ink discharge means is deteriorated. On the other hand, in the above configuration, the organic resin component constituting the ink receiving particles 16 can also function as the resin.

  Here, “the void between the particles constituting the composite particle and the void between the ink receiving particles”, that is, the “trap structure” is a physical particle wall structure capable of capturing at least a liquid. The size of the gap is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.3 μm or more and 1 μm or less in terms of the maximum aperture. In particular, the size of the voids is preferably a size capable of trapping a recording material, particularly, for example, a pigment having a volume average particle diameter of 100 nm. Micropores having a maximum opening diameter of less than 50 nm may exist. Moreover, it is good for the space | gap and the capillary tube to have communicated inside the particle | grains.

  The size of the gap is obtained as follows. It can be obtained by reading a scanning electron microscope (SEM) image of the particle surface with an image analysis device, detecting voids by binarization processing, and analyzing the size and distribution of the voids.

  As described above, the trap structure preferably traps not only the liquid component of the ink components but also the recording material. When a recording material, particularly a pigment, is trapped (trapped) together with the ink liquid component in the trap structure, the recording material is held and fixed without being unevenly distributed inside the ink receiving particles. The liquid component of the ink is mainly an ink solvent or a dispersion medium (vehicle liquid).

  Here, the particle diameter of the ink receiving particles 16 in the present embodiment is preferably 0.1 μm to 100 μm, more preferably 1.0 μm to 20 μm, and even more preferably 3 μm to 15 μm. is there. Here, the sphere equivalent average diameter is obtained as follows. Although the optimum method differs depending on the particle size, various methods can be used such as, for example, dispersing particles in a liquid and obtaining the particle size by the light scattering principle, and obtaining a projected image of the particles by image processing. Examples of methods that can be used for general purposes include the Microtrac UPA method and the Coulter counter method.

  In addition, the shape factor SF1 of the ink receiving particles 16 in the present embodiment is in the range of 100 or more and 146 or less, and more preferably in the range of greater than 100 (not including 100) and 140 or less. More preferably, it is in the range of 135 or less.

  It should be noted that the particle size, shape factor SF1, and particle size distribution described below in detail in the present embodiment are the details of the particle size, shape factor, and particle size of the mother particle 201 described above. Distribution is shown. When the ink receiving particles 16 are configured as composite particles as shown in FIG. 6, the particle size, shape factor, and particle size distribution of the base particles 201 as the composite particles are shown.

  When the shape factor SF1 of the ink receiving particles 16 is 100 or more and 146 or less, the shape of the ink receiving particles 16 becomes uniform as compared with the case where the shape coefficient SF1 exceeds the range, so that the ink receiving property supplied to the intermediate transfer body 12 is increased. The thickness of the ink receptive particle layer 16A by the particles 16 and the size of the gap between the ink receptive particles 16 constituting the ink receptive particle layer 16A become more uniform. For this reason, although details will be described in the column of action described later, the ink supplied onto the ink receptive particle layer 16A uniformly penetrates into the gaps between the ink receptive particles 16, resulting in image bleeding and density unevenness. And the occurrence of missing images are suppressed.

  Further, when the shape factor SF1 of the ink receiving particles 16 exceeds 100, that is, when the shape factor SF1 is not 100, the gap between the ink receiving particles 16 is larger than when the shape factor SF1 is 100. From the viewpoint of improving the liquid absorbability of the ink.

Here, the shape factor SF1 is obtained by the following equation (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In the above formula (1), ML represents the absolute maximum length of the ink receiving particles 16, and A represents the projected area of the ink receiving particles 16. SF1 is digitized mainly by analyzing a microscope image or a scanning electron microscope image with an image analyzer. SF1 is considered to be a true sphere as it approaches 100, and the larger the value, the greater the difference between the maximum length and the minimum length of the particle, which means that it becomes indefinite.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated as follows, for example. That is, an optical microscope image of the ink receptive particles 16 spread on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 50 or more ink receptive particles 16 are obtained. ) And obtaining the average value.

  The particle size distribution GSD of the ink receiving particles 16 is preferably 1, 6 or less, more preferably 1.4 or less, and further preferably 1.3 or less. When the particle size distribution GSD is within the above range, the size of the gap between the ink receiving particles 16 constituting the ink receiving particle layer 16A becomes more uniform. For this reason, although details will be described in the column of action described later, the ink supplied onto the ink receptive particle layer 16A uniformly penetrates into the gaps between the ink receptive particles 16, resulting in image bleeding and density unevenness. Is suppressed.

  The particle size distribution is such that the particles are not dissolved and the refractive index is known and the value is different from the particles, and the particles are dispersed in a solvent that transmits visible light. For example, LS 13 320 (manufactured by Beckman Coulter, Inc.) For the divided particle size range (channel), the particle size distribution measured by the light scattering particle size analyzer is drawn from the small diameter side to the cumulative particle size range (channel), and the cumulative distribution is 16%. The particle diameter is defined as a volume average particle diameter D16v, and the particle diameter at which 50% is accumulated is defined as a volume average particle diameter D50v. Similarly, the particle diameter that is 84% cumulative is defined as the volume average particle diameter D84v. At this time, the particle size distribution (GSD) is defined as D84v / D16v. Using these relational expressions, the particle size distribution (GSD) is calculated.

  On the upstream side of the charging device 28, a release agent supply device 14 that supplies the release agent 14D to form the release layer 14A is disposed.

  The surface of the intermediate transfer body 12 on which the charge is formed by the charging device 28 is formed by the particle supply device 18 with the ink receiving particles 16 as a layer, and the ink jet recording head 20 for each color, that is, the ink jet recording head, is formed on the particle layer. 20K, the ink jet recording head 20C, the ink jet recording head 20M, and the ink jet recording head 20Y eject ink droplets of each color to form a color image.

  The particle layer having the color image formed on the surface is transferred to the recording medium 8 together with the color image by a transfer fixing device (transfer fixing roll) 22. Downstream of the transfer fixing device 22, the ink receiving particles 16 remaining on the surface of the intermediate transfer body 12 are removed, and the intermediate transfer body adhering material such as foreign matters other than the particles (such as paper dust of the recording medium 8) is removed. A cleaning device 24 is provided.

  The recording medium 8 to which the color image has been transferred is carried out as it is, and the intermediate transfer body 12 is again charged on the surface by the charging device 28. At this time, the ink receiving particles transferred to the recording medium 8 absorb and hold the ink droplets 20A, so that they can be quickly carried out.

  Further, if necessary, the intermediate transfer body 12 is provided between the cleaning device 24 and the release agent supply device 14 (hereinafter, the term “between A and B” means “not including any unless otherwise specified”). You may arrange | position the static elimination apparatus 29 for removing the electric charge which remains on the surface.

In the present embodiment, the intermediate transfer body 12 has a 400 μm thick ethylene propylene rubber (EPDM) surface layer formed on a 1 mm thick polyimide film base layer. Here, it is desirable that the surface resistance value is about 10 ¹³ Ω / □ and the volume resistance value is about 10 ¹² Ω · cm (semiconductive).

  The intermediate transfer body 12 is rotated, and a release layer 14A is first formed on the surface of the intermediate transfer body 12 by the release agent supply device 14. The release agent 14D is supplied to the surface of the intermediate transfer body 12 by the supply roll 14C of the release agent supply device 14, and the layer thickness is defined by the blade 14B.

  At this time, the release agent supply device 14 may be in continuous contact with the intermediate transfer body 12 or may be configured to be separated from the intermediate transfer body 12 for the purpose of continuous image formation and printing. .

  The release agent 14D may be supplied to the release agent supply device 14 from an independent liquid supply system (not shown) so that the supply of the release agent 14D is not interrupted.

  Next, by applying a positive charge to the surface of the intermediate transfer body 12 by the charging device 28, the surface of the intermediate transfer body 12 is charged with a positive charge. Here, if the ink receiving particles 16 form a potential that can be supplied / adsorbed to the surface of the intermediate transfer body 12 by an electrostatic force due to an electric field that can be formed between the supply roll 18A of the particle supply device 18 and the surface of the intermediate transfer body 12. Good.

  In this embodiment, the charging device 28 is used to apply a voltage between a driven roll 31 (connected to the ground) disposed between the charging device 28 and the intermediate transfer body 12 to charge the surface of the intermediate transfer body 12. The configuration is to let

The charging device 28 forms an elastic layer (foamed urethane resin) in which a conductivity imparting material is dispersed on a rod-like outer peripheral surface made of stainless steel, and has a volume resistivity of 10 ⁶ Ω · cm to 10 ⁸ Ω · cm. A roll-shaped member adjusted to a degree is used. Furthermore, the surface of the elastic layer is covered with a water / oil repellent coating layer (for example, composed of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA)) having a thickness of 5 μm to 100 μm.

  A DC power source is connected to the charging device 28, and the driven roll 31 is electrically connected to the frame ground. The charging device 28 is driven while sandwiching the intermediate transfer body 12 with the driven roll 31, and a predetermined potential difference is generated with the grounded driven roll 31 at the pressed position. An electric charge can be given. Here, for example, a voltage of 1 kv is applied to the surface of the intermediate transfer member 12 by the charging device 28 to charge the surface of the intermediate transfer member 12.

  Further, the charging device 28 may be composed of a corotron or the like.

  Next, when the ink receiving particles 16 are supplied to the surface of the intermediate transfer body 12 by the particle supply device 18, an ink receiving particle layer 16 </ b> A that is a particle layer of the ink receiving particles 16 is formed on the intermediate transfer body 12. Is done. In the particle supply device 18, a supply roll 18 </ b> A is disposed on a portion of the container in which the ink receiving particles 16 are accommodated, facing the intermediate transfer body 12, and a charging blade 18 </ b> B is disposed so as to press the supply roll 18 </ b> A. The charging blade 18B also has a function of regulating the layer thickness of the ink receiving particles 16 supplied to the surface of the supply roll 18A.

  The ink receiving particles 16 are supplied to the supply roll 18A (conductive roll), the ink receiving particle layer 16A is regulated by the charging blade 18B (conductive blade), and the negative polarity is opposite to the charge on the surface of the intermediate transfer body 12. Is charged. The supply roll 18A can be a solid aluminum roll, and the charging blade 18B can be a metal plate (SUS or the like) on which urethane rubber is caught to apply pressure. The charging blade 18B is in contact with the supply roll 18A by a doctor blade method.

  The charged ink receiving particles 16 form, for example, a single particle layer on the surface of the supply roll 18A, and are conveyed to a portion facing the surface of the intermediate transfer body 12. When close to this, the surfaces of the supply roll 18A and the intermediate transfer body 12 are conveyed. The charged ink receiving particles 16 are moved to the surface of the intermediate transfer member 12 by electrostatic force due to the electric field formed by the potential difference between them.

  At this time, the moving speed of the intermediate transfer body 12 and the rotation speed of the supply roll 18A are relatively set so as to form one particle layer on the surface of the intermediate transfer body 12 (peripheral speed ratio). This peripheral speed ratio depends on other parameters such as the charge amount of the intermediate transfer member 12, the charge amount of the ink receiving particles 16, and the positional relationship between the supply roll 18A and the intermediate transfer member 12.

The number of particles supplied onto the intermediate transfer body 12 is increased by relatively increasing the peripheral speed of the supply roll 18A on the basis of the peripheral speed ratio for forming the one ink receptive particle layer 16A. Can be made. When the transferred image density is low (the amount of ink shot is small (for example, 0.1 g / m ² or more and 1.5 g / m ² or less)), the layer thickness is set to the minimum necessary thickness (for example, 1 μm to 5 μm). In addition, when the image density is high (the ink shot amount is large (for example, 4 g / m ² or more and 15 g / m ² or less)), the ink liquid component (solvent or dispersion medium) can be held sufficiently. It is desirable to control the layer thickness (for example, 10 μm or more and 25 μm or less).

  For example, in the case of a character image or the like with a small amount of ink shot, when an image is formed on one ink receptive particle layer on the intermediate transfer member, the image forming material (pigment) in the ink is on the intermediate transfer member. The ink receptive particle layer is captured on the surface of the ink receptive particle layer, and is fixed to the ink receptive particle surface and the internal particle void so that the distribution in the depth direction is reduced.

  For example, when it is desired to provide the particle layer 16C as the protective layer on the image layer 16B as the final image, the ink receiving particle layer 16A has a thickness of about three layers, and the uppermost layer is formed with ink. If so ((see FIG. 4A)), the two particle layers 16C on which image formation is not performed become a protective layer after transfer and fixing, and are formed on the image layer 16B (see FIG. 4B).

  Alternatively, in the case of forming an image with a high ink ejection amount, such as a secondary color or tertiary color image, the ink receptive particle layer can hold an ink liquid component (solvent or dispersion medium) and a recording material (for example, Ink-receptive particles 16 are laminated so that a sufficient number of particles can be captured and not reach the lowermost layer. In this case, the image forming material (pigment) is not exposed on the surface of the image layer after transfer and fixing, and the ink receiving particles 16 that do not perform image formation may be formed on the image surface as a protective layer.

  Next, the density increasing device 15 applies vibration to the ink receiving particle layer 16A. In the present embodiment, as the density increasing device 15, for example, a device in which an ultrasonic transducer that generates ultrasonic waves in a housing is incorporated. Examples of the ultrasonic vibrator include a piezoelectric element (for example, lead zirconate titanate: PZT).

  The density increasing device 15 may be provided so as to face the outer peripheral surface of the intermediate transfer member 12 in a non-contact manner or in contact with the ink receiving particle layer 16A. Further, the intermediate transfer member 12 may be disposed so as to face the inner peripheral surface of the intermediate transfer member 12 in a non-contact manner or in contact therewith. In the present embodiment, the density increasing device 15 is provided in contact with the outer peripheral surface of the intermediate transfer body 12 without contacting the ink receiving particle layer 16A.

In the present embodiment, a case will be described in which the density increasing device 15 increases the density by applying vibration to the ink receiving particle layer 16 </ b> A by the ink receiving particles 16 supplied onto the intermediate transfer body 12. However, the structure which increases a density by providing a pressure may be sufficient.
In this case, a pressure roller may be applied as the density increasing device 15, and the pressure roller may be pressed from the surface side of the ink receiving particle layer 16A to apply pressure.

  Next, the ink jet recording head 20 applies ink droplets 20A to the ink receiving particle layer 16A. The ink jet recording head 20 applies ink droplets 20A to predetermined positions based on predetermined image information.

  Finally, the recording medium 8 and the intermediate transfer body 12 are sandwiched by the transfer fixing device 22, and pressure and heat are applied to the ink receiving particle layer 16A, whereby the ink receiving particle layer 16A is transferred onto the recording medium 8. .

  The transfer fixing device 22 includes a heating roll 22A containing a heating source and a pressure roll 22B facing each other with the intermediate transfer body 12 interposed therebetween. The heating roll 22A and the pressure roll 22B come into contact with each other to form a contact portion. As the heating roll 22A and the pressure roll 22B, a product in which the outer surface of the aluminum core is coated with silicone rubber and further coated with a PFA tube can be used.

  Since the ink receiving particle layer 16A is heated by the heater and pressure is applied at the contact portion between the heating roll 22A and the pressure roll 22B, the ink receiving particle layer 16A is transferred and fixed to the recording medium 8.

  At this time, the organic resin particles constituting the ink receiving particles 16 in the non-image area are softened (or melted) by being heated to the glass transition temperature (Tg) or higher and formed on the surface of the intermediate transfer body 12 by pressure. The ink receiving particle layer 16A is released from the release layer 14A, and is transferred and fixed onto the recording medium 8. Then, the ink receiving particle layer 16A is released from the release layer 14A formed on the surface of the intermediate transfer body 12 by pressure, and is transferred onto the recording medium 8. At this time, the transfer fixing property is improved by heating. In this embodiment, the surface of the heating roll 22A is controlled at 160 ° C. At this time, the ink liquid component (solvent or dispersion medium) held in the ink receiving particle layer 16A is held and fixed in the ink receiving particle layer 16A as it is after the transfer. Further, the intermediate transfer body 12 may be preheated before the transfer fixing device 22.

  In addition, as the recording medium 8, a permeation medium (for example, plain paper, ink jet coated paper, etc.) and a non-penetration medium (for example, art paper, resin film, etc.) can be applied. The recording medium is not limited to these, and includes industrial products such as semiconductor substrates.

  Hereinafter, the image forming process of the recording apparatus 10 according to the present embodiment will be described in more detail. In the recording apparatus 10 according to this embodiment, as shown in FIG. 2, a release layer 14 </ b> A is formed on the surface of the intermediate transfer body 12 by a release agent supply device 14. If the material of the intermediate transfer body 12 is aluminum or PET base, it is particularly desirable to form the release layer 14A. Alternatively, a fluororesin / silicone rubber-based material may be used so that the surface of the intermediate transfer body 12 has releasability.

  Next, the surface of the intermediate transfer member 12 is charged to a polarity opposite to that of the ink receiving particles 16 by the charging device 28. As a result, the ink receiving particles 16 supplied by the supply roll 18 </ b> A of the particle supply device 18 are electrostatically adsorbed, and a layer of the ink receiving particles 16 is formed on the surface of the intermediate transfer body 12.

  Next, the ink receiving particles 16 are supplied to the surface of the intermediate transfer body 12 in a layer form by the supply roll 18 </ b> A of the particle supply device 18. For example, the ink receptive particle layer 16A formed on the intermediate transfer body 12 is formed to have a thickness in which the ink receptive particles 16 are overlapped by about three layers. That is, as described above, the thickness of the ink receiving particle layer 16A transferred to the recording medium 8 is controlled by controlling the ink receiving particle layer 16A to a desired thickness by the gap between the charging blade 18B and the supply roll 18A. Is done. Alternatively, it may be controlled by the peripheral speed ratio between the supply roll 18A and the intermediate transfer body 12.

  Next, vibration is applied to the density increasing device 15 from the surface side of the formed ink receiving particle layer 16A. Specifically, the density increasing device 15 applies vibration to the ink receptive particle layer 16 </ b> A that has been transported to a region facing the density increasing device 15 with the transport of the intermediate transfer body 12 by ultrasonic waves.

  When vibration is applied to the ink receptive particle layer 16A, the particles also vibrate in the particle layer, and extra voids are filled with the ink receptive particle layer 16A, so that the interparticle voids are refined and the ink receptive particles. The particle density in layer 16A is increased. In addition, when the ink receiving particles 16 are composed of composite particles, the composite particles are disassembled and scattered into individual particles, and extra voids in the particle layer are filled with the ink receiving particle layer 16A. Thus, the particle density in the ink receiving particle layer 16A is further increased. At this time, the gap between the ink receiving particles 16 is adjusted so as to have a uniform size.

  When the particle density in the ink receptive particle layer 16A is increased and the interparticle voids are refined, the liquid absorption force (that is, the capillary force) due to the interparticle voids increases, and the ink is retained by the interparticle voids. Is improved.

  Further, the vibration is imparted by the density increasing device 15, thereby suppressing variation in the thickness of the ink receiving particle layer 16 </ b> A and variation in the size of the gap, reducing image quality unevenness, improving gloss unevenness, The variation in the size of the gap between the ink receiving particles 16 in the layer is suppressed, and the ink is liable to stay in the region where the ink is applied, and the spread of the ink is suppressed.

  Here, the vibration frequency by the density increasing device 15 is desirably in the range of 2 kHz to 100 kHz, more desirably 5 kHz to 50 kHz, and further desirably 10 kHz to 40 kHz.

  The voltage is also applied to the density increasing device 15 so that the surface in contact with the ink receiving particle layer 16A is charged with the same polarity as the charging polarity of the ink receiving particles 16. Specifically, when the ink receiving particles 16 are negatively charged, the density increasing device 15 is negatively charged, and when the ink receiving particles 16 are positively charged, the density increases. The device 15 is charged positively.

  When the voltage is applied so as to be charged in this way, when the density increasing device 15 applies vibration to the ink receiving particle layer 16A, the surface of the density increasing device 15 and the ink receiving particles 16 are electrostatically repelled. The action works.

  Next, ink droplets 20A are ejected onto the ink receptive particle layer 16A to which the stimulus is applied by the density increasing device 15 by the ink jet recording head 20 of each color driven by piezoelectric (piezo), thermal, or the like, and the ink An image layer 16B is formed on the receptive particle layer 16A. The ink droplets 20A ejected from the ink jet recording head 20 are driven into the ink receiving particle layer 16A, and the liquid component of the ink is quickly absorbed into the gaps between the ink receiving particles 16 and the gaps constituting the ink receiving particles 16. At the same time, the recording material (for example, pigment) is also trapped on the surface of the ink receiving particles 16 (constituting particles), between the ink receiving particles 16, or between the particles constituting the ink receiving particles 16.

  At this time, the ink liquid component (solvent or dispersion medium) contained in the ink droplet 20A permeates the ink receptive particle layer 16A, but the recording material such as a pigment is captured on the surface of the ink receptive particle layer 16A or the interparticle gap. The That is, the ink liquid component (solvent or dispersion medium) may penetrate to the back surface of the ink receiving particle layer 16A, but the recording material such as a pigment does not penetrate the back surface of the ink receiving particle layer 16A. Thereby, when the recording material 8 is transferred to the recording medium 8, the particle layer 16C into which the recording material such as the pigment does not penetrate forms a layer on the image layer 16B, so that the particle layer 16C encloses the surface of the image layer 16B. An image is formed on which the recording material (for example, a color material such as a pigment) is not exposed on the surface.

Here, as described above, the shape factor SF1 of the plurality of ink receiving particles 16 constituting the ink receiving particle layer 16A is in the range of 100 to 146.
For this reason, when the shape factor SF1 is a value exceeding 146 as in the prior art, as shown in FIGS. 7 (A) and 7 (B), the ink received on the intermediate transfer body 12 is received. Since the particles 17 have a non-uniform shape or a shape far from the true spherical shape, the size of the gap between the ink receiving particles 17 is non-uniform. For this reason, the amount of the ink droplet 20A supplied to the particle layer 17A by the ink receptive particles 17 is varied in the amount held between the ink receptive particles 17 to cause unevenness in image density or to be originally applied. In some cases, the ink droplet 20A may bleed or an image loss may occur in a region other than the print region (see the region indicated by arrow X in FIG. 7) (see the region indicated by arrow Y in FIG. 7). is there.

  On the other hand, in the ink receptive particle layer 16A of the present embodiment, as described above, the shape factor SF1 of the ink receptive particles 16 is in the range of 100 to 146. As shown in A) and FIG. 3B, the ink receiving particles 16 supplied onto the intermediate transfer body 12 are more nearly spherical as compared with the case where the shape factor SF1 value exceeds 146. Because of the shape, the size of the gap between the ink receiving particles 16 constituting the ink receiving particle layer 16A becomes more uniform. For this reason, variation in the amount of the ink droplet 20A supplied to the ink receiving particle layer 16A by the ink receiving particles 16 held between the ink receiving particles 16 is suppressed, and unevenness in image density is suppressed. Occurrence is suppressed. Further, since the size of the gap between the ink receiving particles 16 is uniform as compared with the prior art, the ink droplet 20A applied to the ink receiving particle layer 16A is uniformly held between the ink receiving particles 16. Further, it is possible to prevent the ink droplet 20A from spreading to an area other than the print area (see the area indicated by the arrow X in FIG. 3B) and the occurrence of image loss.

  Furthermore, since the density increasing device 15 causes the ink receiving particle layer 16A to have a density increased on the intermediate transfer body 12 before the ink droplets 20A are applied by the inkjet recording head 20, The ink droplet 20A is held in a substantially uniform amount in the gap between the ink receiving particles 16, and further image quality deterioration is suppressed.

  Next, as shown in FIG. 2, the ink receiving particle layer 16 </ b> A having the image layer 16 </ b> B is transferred / fixed from the intermediate transfer body 12 onto the recording medium 8, thereby forming a color image on the recording medium 8. Is done. The ink receiving particle layer 16 </ b> A on the intermediate transfer body 12 is heated and pressed by a transfer fixing device (transfer fixing roll) 22 heated by a heating means such as a heater and transferred onto the recording medium 8.

  At this time, the glossiness may be controlled by adjusting the unevenness of the image surface by adjusting heating and pressurization as described later. Further, the glossiness may be controlled by performing cooling peeling.

  Residual particles 16D remaining on the surface of the intermediate transfer member 12 after the ink receptive particle layer 16A has been separated are collected by the cleaning device 24 (see FIG. 1), and the surface of the intermediate transfer member 12 is charged again by the charging device 28. Then, the ink receiving particles 16 are supplied to form the ink receiving particle layer 16A.

  Here, FIG. 4 shows an ink receptive particle layer 16A used for image formation according to the present invention. As shown in FIG. 4A, a release layer 14 A is formed on the surface of the intermediate transfer body 12.

  Next, the ink receiving particles 16 are formed as a layer on the surface of the intermediate transfer body 12 by the particle supply device 18. The ink receptive particle layer 16A formed as described above preferably has a thickness in which the ink receptive particles 16 are overlapped by about three layers. The thickness of the ink receiving particle layer 16A transferred to the recording medium 8 is controlled by controlling the ink receiving particle layer 16A to a desired thickness. At this time, the surface of the ink receiving particle layer 16A is leveled so as not to hinder the image formation (formation of the image layer 16B) by the ejection of the ink droplet 20A.

  Further, the recording material such as pigment contained in the ejected ink droplet 20A penetrates to about 1/3 or more and half or less of the ink receiving particle layer 16A as shown in FIG. A particle layer 16C that does not penetrate the recording material remains.

  The ink receptive particle layer 16A formed on the recording medium 8 by heating and pressure transfer by the transfer fixing device (transfer fixing roll) 22 is a particle layer containing no ink on the image layer 16B as shown in FIG. 4B. Since 16C exists, the image layer 16B does not appear directly on the surface and functions as a kind of protective layer. For this reason, at least the ink receiving particles 16 after fixing must be transparent.

  Since the particle layer 16C is heated and pressed by the transfer fixing device (transfer fixing roll) 22, the surface can be flattened, and the glossiness of the image surface can be controlled by heating and pressing.

  Further, drying of the ink liquid component (solvent or dispersion medium) trapped inside the ink receiving particles 16 by heating may be promoted.

  The ink liquid component (solvent or dispersion medium) received / held in the ink receiving particle layer 16A is held in the ink receiving particle layer 16A even after transfer fixing, and is removed by natural drying.

  Through the above steps, image formation is completed. With respect to the intermediate transfer body 12, there are foreign particles such as residual particles 16 </ b> D remaining on the intermediate transfer body 12 after the ink receiving particles 16 are transferred to the recording medium 8, or paper dust released from the recording medium 8. May be removed by the cleaning device 24.

  Further, a static elimination device 29 may be arranged downstream of the cleaning device 24. For example, a semi-conductive or conductive roll is used as the static eliminating device 29 and is sandwiched between the driven roll 31 (ground) and a voltage of about ± 3 kV and about 500 Hz is applied to the surface of the intermediate transfer body 12, so that the intermediate transfer body 12. The surface is neutralized.

  Various other device conditions such as the above-mentioned charging voltage, particle layer thickness, fixing temperature, etc. are optimized because the optimum conditions are determined by the ink receiving particles 16 or ink composition, ink discharge amount, etc. To do.

<Each component>
Next, components of each step of the embodiment will be described in detail.

<Intermediate transfer member>
The intermediate transfer body 12 on which the ink receptive particle layer is formed may be a belt shape or a cylindrical shape (drum shape) as in the embodiment. In order to supply and hold the ink receiving particles on the surface of the intermediate transfer member by electrostatic force, the outer peripheral surface of the intermediate transfer member needs to have a semiconductive or insulating particle holding property. As the electrical characteristics of the surface of the intermediate transfer member, in the case of semi-conductivity, the surface resistivity is 10 ¹⁰ Ω / □ or more and 10 ¹⁴ Ω / □ or less, the volume resistivity is 10 ⁹ Ω · cm or more and 10 ¹³ Ω · cm or less, In the case of insulation, a member having a surface resistivity of 10 ¹⁴ Ω / □ or more and a volume resistivity of 10 ¹³ Ω · cm or more is used.

  In the case of a belt shape, the base material can be driven by a belt in the apparatus, has the required mechanical strength, and particularly has the required heat resistance when using heat during transfer / fixing. Good. Specifically, polyimide, polyamideimide, aramid resin, polyethylene terephthalate, polyester, polyethersulfone, stainless steel and the like are used.

  In the case of a drum shape, aluminum, stainless steel, etc. can be considered as the base material.

  In order to exhibit the heating method by electromagnetic induction in the fixing process in the transfer fixing device (transfer fixing roll) 22, a heat generating layer may be formed on the intermediate transfer body 12 instead of the transfer fixing device (transfer fixing roll) 22. Good. A metal that generates electromagnetic induction is used for the heat generating layer. For example, nickel, iron, copper, aluminum, chromium, or the like can be selected.

<Particle supply process>
First, the release agent supply device 14 forms a release layer 14 </ b> A of the release agent 14 </ b> D on the surface of the intermediate transfer body 12 before supplying the ink receiving particles 16.

  The release layer 14A is supplied by incorporating a release agent 14D, supplying the release agent 14D to the release agent supply member, and supplying the release agent 14D to the surface of the intermediate transfer body 12 by the supply member. A method of forming the layer 14A, a method of forming the release layer 14A on the surface of the intermediate transfer body 12 by a supply member impregnated with the release agent 14D, and the like are used.

  Examples of the release agent 14D include release materials such as silicone oil, fluorine oil, polyalkylene glycol, and surfactant.

Examples of the silicone oil include straight silicone oil and modified silicone oil.
Examples of the straight silicone oil include dimethyl silicone oil and methyl hydrogen silicone oil.
Examples of the modified silicone oil include methylstyryl-modified oil, alkyl-modified oil, higher fatty acid ester-modified oil, fluorine-modified oil, and amino-modified oil.
Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide copolymer, and polybutylene glycol. Among these, polypropylene glycol is preferable.
Examples of the surfactant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Among these, a nonionic surfactant is desirable.

  The viscosity of the release agent 14D is preferably, for example, from 5 mPa · s to 200 mPa · s, more preferably from 5 mPa · s to 100 mPa · s, and even more preferably from 5 mPa · s to 50 mPa · s.

The viscosity is measured as follows. The viscosity of the ink obtained was measured using Rheomatt 115 (manufactured by Contraves) as a measuring device. The measurement was performed by placing the sample in a measurement container and mounting it on the apparatus by a predetermined method, under the conditions of a measurement temperature of 40 ° C. and a shear rate of 1400 s ⁻¹ .

  The surface tension of the release agent 14D is, for example, in the range of 40 mN / m or less (desirably 30 mN / m or less, more desirably 25 mN / m or less).

  The surface tension is measured as follows. In an environment of 23 ± 0.5 ° C. and 55 ± 5% RH, the surface tension of the obtained sample was measured using a Wilhelmy type surface tension meter (manufactured by Kyowa Interface Science Co., Ltd.).

  The boiling point of the release agent 14D is, for example, in the range of 250 ° C. or higher (preferably 300 ° C. or higher, more preferably 350 ° C. or higher) under 760 mmHg.

  The boiling point is measured as follows. Measurement was performed according to JIS K2254, and the initial boiling point was used as the boiling point.

  Next, the charging device 28 charges the surface of the intermediate transfer body 12 to a polarity opposite to that of the ink receiving particles 16. Then, an ink receptive particle layer 16 </ b> A is formed on the surface of the charged intermediate transfer body 12. At this time, as a method of forming the ink receptive particle layer 16A, a method of supplying a general electrophotographic toner to the photoreceptor can be applied. That is, charges are previously supplied to the surface of the intermediate transfer body 12 by a general electrophotographic charging method (charging by the charging device 28, etc.). The ink receiving particles 16 are triboelectrically charged (one-component triboelectric charging method or two-component method) with a polarity opposite to the charge on the surface of the intermediate transfer member 12.

  The ink receiving particles 16 held on the supply roll 18A form an electric field with the surface of the intermediate transfer body 12, and are moved / supplied onto the intermediate transfer body 12 by electrostatic force and held. At this time, the thickness of the ink receptive particle layer 16A may be controlled by the thickness of the image layer 16B formed on the ink receptive particle layer 16A (in accordance with the amount of ink to be applied). At this time, the absolute value of the charge amount of the ink receiving particles 16 is desirably in the range of 5 μc / g to 50 μc / g.

  Here, the thickness of the ink receiving particle layer 16A is desirably 1 μm or more and 100 μm or less, more desirably 1 μm or more and 50 μm or less, and further desirably 5 μm or more and 25 μm or less. Further, the porosity in the ink receptive particle layer (that is, the void ratio between the ink receptive particles + the void ratio in the ink receptive particles (trap structure)) is preferably 10% or more and 80% or less. Is from 30% to 70%, more preferably from 40% to 60%.

  Hereinafter, a particle supply process corresponding to a one-component supply (development) method will be described.

  The ink receiving particles 16 are supplied to the supply roll 18A, the thickness of the particle layer is regulated by the charging blade 18B and charged.

  The charging blade 18B has a function of regulating the layer thickness of the ink receiving particles 16 on the surface of the supply roll 18A. For example, the thickness of the ink receiving particles 16 on the surface of the supply roll 18A is changed by changing the pressure applied to the supply roll 18A. To change. For example, the thickness of the ink receiving particles 16 on the surface of the supply roll 18A is, for example, one layer, and the thickness of the ink receiving particles 16 formed on the surface of the intermediate transfer body 12 is approximately one layer. Further, the pressing force of the charging blade 18B is controlled to be low, the thickness of the ink receiving particles 16 formed on the surface of the supply roll 18A is increased, and the thickness of the ink receiving particles formed on the surface of the intermediate transfer body 12 is increased. It may be increased.

  As another method, when the peripheral speed of the supply roll 18A that forms, for example, one particle layer on the surface of the intermediate transfer body 12 and the intermediate transfer body 12 is set to 1, the peripheral speed of the supply roll 18A is increased and the intermediate transfer is performed. It can be controlled to increase the number of ink receptive particles 16 supplied on the body 12 and increase the thickness of the ink receptive particle layer on the intermediate transfer body 12. It is also possible to control by combining the above methods. In the above configuration, for example, the ink receiving particles 16 are negatively charged, and the surface of the intermediate transfer body 12 is positively charged.

  By controlling the layer thickness of the ink receiving particle layer in this way, it is possible to form a pattern whose surface is covered with a protective layer while suppressing consumption of the ink receiving particle layer.

As the charging roll in the charging device 28, an elastic layer in which a conductivity imparting material is dispersed is formed on the outer peripheral surface of a rod-like or pipe-like member made of aluminum, stainless steel or the like, and the volume resistivity is 10 ⁶ Ω · cm or more 10 A roll having a diameter of 10 mm to 25 mm adjusted to about ⁸ Ω · cm or less can be used.

  The elastic layer is made of a resin material such as urethane resin, thermoplastic elastomer, epichlorohydrin rubber, ethylene-propylene-diene copolymer rubber, silicone rubber, acrylonitrile-butadiene copolymer rubber, or polynorbornene rubber. A preferred material used in the above mixture is urethane foam resin.

  As the foamed urethane resin, a resin obtained by mixing and dispersing a hollow body such as a hollow glass bead or a thermal expansion type microcapsule in a urethane resin to provide a closed cell structure is desirable.

  Furthermore, the surface of the elastic layer may be covered with a water-repellent coating layer having a thickness of 5 μm to 100 μm.

  A DC power source is connected to the charging device 28, and the driven roll 31 is electrically connected to the frame ground. The charging device 28 is driven while the intermediate transfer body 12 is sandwiched between the charging roll 31 and a predetermined potential difference is generated between the charging apparatus 28 and the grounded driven roll 31 at the pressing position.

<Density increase process>
Next, the density of the ink receiving particle layer 16A is increased by the density increasing device 15 with respect to the formed ink receiving particle layer 16A.

  As described above, the density increasing device 15 may be a device having an ultrasonic transducer built in the housing, but is not limited to this device, and may be an eccentric rotating member (for example, an eccentric cam). A tapping member may be applied. The tapping member is provided on the intermediate transfer body 12 so as to be in contact with the ink receiving particle layer 16A, and directly applies vibration. When the tapping member is provided on the inner peripheral surface side of the intermediate transfer body 12, the tapping member is provided so as to be in contact with the inner peripheral surface of the intermediate transfer body 12, and the intermediate transfer body 12 is vibrated. Vibration is imparted to the active particle layer 16A.

When a device for applying pressure is used as the density increasing device 15, the pressure applied to the ink receiving particle layer 16A by the density increasing device 15 is desirably 10 ³ Pa or more and 10 ⁷ Pa or less, and more desirably. Is from 10 ⁵ Pa to 10 ⁷ Pa, more preferably from 10 ⁵ Pa to 10 ⁶ Pa.

<Marking process>
Ink droplets 20A are ejected from the inkjet recording head 20 to the layer of ink receiving particles 16 (ink receiving particle layer 16A) formed on the surface of the intermediate transfer body 12 and applied with pressure, based on the image signal. Is formed. The ink droplets 20A ejected from the ink jet recording head 20 are driven into the ink receiving particle layer 16A, and the ink droplets 20A are quickly absorbed by the interparticle voids formed in the ink receiving particles 16, and the recording material (for example, , The pigment) is trapped (trapped) on the surface of the ink receiving particles 16 or the interparticle voids constituting the ink receiving particles 16.

  In this case, it is desirable to capture (trap) many recording materials (for example, pigments) on the surface of the ink receiving particle layer 16A. The inter-particle voids in the ink-receptive particles 16 exhibit a filter effect, trapping a recording material (for example, pigment) on the surface of the ink-receptive particle layer 16A, and trapping in the inter-particle voids in the ink-receptive particles 16 ( It is expressed by being trapped and fixed.

  In order to reliably trap the recording material (for example, pigment) on the surface of the ink receiving particle layer 16 </ b> A and the interparticle voids in the ink receiving particle 16, the ink and the ink receiving particle 16 are reacted to thereby record the recording material ( For example, a method of quickly insolubilizing (aggregating) the pigment) may be employed. Specifically, it is possible to apply a reaction between the ink and the polyvalent metal salt or a pH reaction type as the reaction.

  In addition, a line type ink jet recording head having a width equal to or larger than the width of the recording medium is desirable. However, using a conventional scan type ink jet recording head, images are sequentially formed on the particle layer formed on the intermediate transfer member. It may be formed. The ink discharge means of the inkjet recording head 20 is not limited as long as it is a means capable of discharging ink, such as a piezoelectric element drive type and a heating element drive type. As the ink itself, an ink using a conventional dye as a coloring material can be used, but a pigment ink is desirable.

<Transfer process>
The ink receiving particle layer 16 </ b> A that receives the ink droplet 20 </ b> A and has an image formed thereon is transferred and fixed to the recording medium 8, thereby forming an image on the recording medium 8. The transfer and fixing may be performed by different processes, but it is desirable that the transfer and fixing be performed substantially simultaneously. Fixing includes either a method of heating or pressurizing the ink receptive particle layer 16A, or a method of using both heating and pressurization. Preferably, a method of performing heating / pressing substantially simultaneously is preferable.

  Further, by controlling the heating / pressurization, it is possible to control the surface physical properties of the ink receiving particle layer 16A and to control the gloss (glossiness). Further, when the recording medium 8 onto which the image (ink-receptive particle layer 16A) has been transferred after being heated / pressurized is peeled off from the intermediate transfer body 12, the ink-receptive particle layer 16A may be peeled off after being cooled. Good. The cooling method may be forced cooling such as natural cooling or air cooling. For these processes, the intermediate transfer member 12 preferably has a belt shape.

  The ink image is formed on the surface layer of the ink receiving particle 16 layer formed on the intermediate transfer body 12 (the recording material (pigment) is trapped on the surface of the ink receiving particle layer 16A) and transferred to the recording medium 8. By doing so, the ink image is preferably formed so as to be protected by the particle layer 16 </ b> C of the ink receiving particles 16.

  The ink liquid component (solvent or dispersion medium) received / held in the ink receiving particle 16 layer is held in the ink receiving particle 16 layer even after the transfer and fixing, and is removed by natural drying.

<Cleaning process>
In order to refresh the surface of the intermediate transfer body 12 to enable repeated use, a process of cleaning the surface with the cleaning device 24 is necessary. The cleaning device 24 includes a cleaning unit and a particle transport / recovery unit (not shown). By the above cleaning, the ink receiving particles 16 (residual particles 16D) remaining on the surface of the intermediate transfer body 12 are removed. The adhering matter adhering to the surface of the intermediate transfer body 12 such as the foreign matter (paper dust of the recording medium 8) is removed. The recovered residual particles 16D may be reused.

<Static removal process>
Before forming the release layer 14 </ b> A, the surface of the intermediate transfer body 12 may be neutralized using the neutralization device 29.

  In the recording apparatus 10 according to the present embodiment described above, the release agent 14D is supplied to the surface of the intermediate transfer member 12 by the release agent supply device 14 to form the release layer 14A, and then the intermediate transfer member is formed by the charging device 28. Charge the surface. Next, the ink receiving particles 16 are supplied from the particle supply device 18 to the region where the release layer of the intermediate transfer body 12 is formed and charged, thereby forming a particle layer. Then, the density increasing device 15 applies vibration to the ink receiving particle layer 16A to increase the particle density, and then the ink jet recording head 20 ejects ink droplets onto the particle layer to form an image. As a result, ink is received by the ink receiving particles 16. Next, the recording medium 8 is overlapped with the intermediate transfer body 12, and pressure and heat are applied by the transfer fixing device 22 to transfer and fix the ink receiving particle layer on the recording medium 8.

  Hereinafter, the ink receiving particles 16 suitably applied in the present embodiment will be described in detail. In the following description, the reference numerals are omitted.

  As described above, the ink receiving particles 16 receive ink components when the ink comes into contact with the particles.

  Hereinafter, the ink receiving particles 16 will be described in more detail. The ink receptive particles 16 may have a form in which the mother particles 201 are composed of the particles (primary particles) of the hydrophilic organic particles 201A alone as described above, and at least the hydrophilic organic particles 201A are aggregated in the mother particles 201. The form comprised with composite particle | grains may be sufficient. Examples of particles other than the hydrophilic organic particles 201A constituting the composite particles include inorganic particles 202 and porous particles (not shown). Of course, the mother particle 201 may be composed of composite particles in which only a plurality of hydrophilic organic particles 201A are aggregated.

  As a specific configuration of the ink receptive particles 16, for example, as shown in FIG. 5, mother particles 201 composed of single particles (primary particles) of hydrophilic organic particles 201 </ b> A, and inorganic adhered to the mother particles 201. And the form of the ink receiving particles 16 having the particles 202. In addition, as shown in FIG. 6, ink receptivity having mother particles 201 of composite particles in which hydrophilic organic particles 201 </ b> A and inorganic particles 202 are combined, and inorganic particles 202 attached to the mother particles 201. The form of the particle | grains 16 is also mentioned. The composite particles have a void structure formed by voids between the particles.

Here, when the mother particle 201 is composed of primary particles, the mass ratio of the hydrophilic organic particles 201A and the inorganic particles 202 (hydrophilic organic particles: inorganic particles) is 99.9: 0.1 or more and 95 in mass ratio. : Within the range of 5 or less, preferably within the range of 99.9: 0.1 or more and 97.5: 2.5 or less, more preferably 99.5: 0.5 or more and 98: 2 or less. Is within the range.
When the mother particle 201 is composed of composite particles, the mass ratio of the hydrophilic organic particles 201A to other particles (hydrophilic organic particles: other particles) is, for example, when the other particles are inorganic particles 202. The range is 5: 1 to 1:10.

  In addition, the particle diameter of the mother particle 201 may be in the range of a sphere-converted average particle diameter of, for example, 0.1 μm or more and 50 μm or less (desirably 0.5 μm or more and 25 μm or less, more desirably 1 μm or more and 10 μm or less).

Moreover, when the base particle 201 is composed of composite particles, the BET specific surface area (N ₂ ) is, for example, in the range of 1 m ² / g or more and 750 m ² / g or less.

  When the mother particle 201 is composed of composite particles, the composite particles are obtained, for example, by granulating the particles in a semi-sintered state. The semi-sintered state refers to a state in which a certain amount of particle shape remains and voids are retained between the particles. Note that when the ink liquid component is trapped in the trap structure, at least part of the particles dissociates, that is, the composite particles are disassembled, and the particles constituting the composite particles may be scattered.

  Next, the hydrophilic organic particles 201A will be described. In the hydrophilic organic particle 201A, for example, the ratio of the polar monomer to the total monomer component is 10 mol% or more and 100 mol% or less, desirably 20 mol% or more and 90 mol% or less, and more desirably 30 mol% or more and 70 mol%. It is comprised including the following organic resins. Specifically, the hydrophilic organic particles 201A preferably include an organic resin having a ratio of the polar monomer (hereinafter referred to as a water-absorbing resin).

  Here, the polar monomer is a monomer containing an ethylene oxide group, a carboxylic acid, a sulfonic acid, a substituted or unsubstituted amino group, a hydroxyl group, an ammonium group, and a salt thereof as a polar group. For example, in the case of imparting positive chargeability, it is desirable to use a monomer having a chlorinated structure such as (substituted) amino group, ammonium group, (substituted) pyridine group, amine salts thereof, and quaternary ammonium salts. In the case of imparting negative charge, a monomer having an organic acid (salt) structure such as carboxylic acid (salt) or sulfonic acid (salt) is desirable.

  In addition, the ratio of a polar monomer is calculated | required as follows. First, the constitution of the organic component is identified from analysis techniques such as mass spectrometry, NMR, and IR. Then, based on JIS K0070 or JIS K2501, the acid value and base number of an organic component are measured. The ratio of the polar monomer can be calculated from the constitution of the organic component and the acid value / base value. The same applies hereinafter.

  The hydrophilic organic particles 201A are made of, for example, a liquid absorbing resin. The absorbed ink liquid component (for example, water or an aqueous solvent) acts as a plasticizer for the resin (polymer), so it can soften and contribute to fixing properties.

  The liquid absorbing resin is preferably a weak liquid absorbing resin. This weak liquid-absorbent resin is, for example, a few percent (≈5%) to several hundred percent (≈500%), preferably about 5% to 150% of the resin mass when absorbing water as a liquid. A lyophilic resin capable of absorbing liquid.

  The liquid-absorbing resin can be composed of, for example, a homopolymer of a hydrophilic monomer or a copolymer composed of both a hydrophilic monomer and a hydrophobic monomer. In order to obtain a weak water-absorbing resin, the copolymer is desirable. In addition, not only the monomer but also a graft copolymer or block copolymer in which other units such as a polymer / oligomer structure are copolymerized as a start may be used.

Here, as a hydrophilic monomer, -OH, -EO unit (ethylene oxide group), -COOM (M is alkali metal, such as hydrogen, Na, Li, and K, ammonia, organic amines, etc.). ), - _SO 3 M (M is, for example, hydrogen, Na, Li, alkali metals K, etc., ammonia, organic amines, etc.), - _NR 3 (R is, for example, H, alkyl, phenyl, etc.). - NR ₄ X (R is, for example, H, alkyl, phenyl, etc., and X is, for example, halogen, sulfate radical, acid anions such as carboxylic acid, BF ₄ , etc.) and the like. It is done. Specific examples include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, acrylamide, acrylic acid, methacrylic acid, unsaturated carboxylic acid, crotonic acid, maleic acid, and the like. Examples of hydrophilic units or monomers include cellulose derivatives such as cellulose, ethyl cellulose, carboxymethyl cellulose, starch derivatives, monosaccharide / polysaccharide derivatives, vinyl sulfonic acid, styrene sulfonic acid, acrylic acid, methacrylic acid, (anhydrous) Polymeric carboxylic acids such as maleic acid, (partially) neutralized salts thereof, vinyl alcohols, vinyl pyrrolidone, vinyl pyridine, derivatives such as amino (meth) acrylate and dimethylamino (meth) acrylate, and oniums thereof Salts, amides such as acrylamide and isopropylacrylamide, polyethylene oxide chain-containing vinyl compounds, hydroxyl group-containing vinyl compounds, polyesters composed of polyfunctional carboxylic acids and polyhydric alcohols, especially trimellitic acid Branched polyester containing a large amount of content and terminal carboxylic acid or hydroxyl functionality more acid as a constituent component, a polyester containing polyethylene glycol structure, etc. may be mentioned.

  Examples of the hydrophobic monomer include monomers having a hydrophobic group. Specifically, for example, olefin (ethylene, butadiene, etc.), styrene, α-methylstyrene, α-ethylstyrene, methyl methacrylate, Examples include ethyl methacrylate, butyl methacrylate, acrylonitrile, vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate, and lauryl methacrylate. Hydrophobic units or monomers include styrene derivatives such as styrene, α-methylstyrene, vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, alkyl acrylate esters, phenyl acrylate esters, alkyl methacrylate esters, methacrylic acid Examples thereof include phenyl ester, methacrylic acid cycloalkyl ester, crotonic acid alkyl ester, itaconic acid dialkyl ester, maleic acid dialkyl ester and the like, and derivatives thereof.

  Specific examples of the liquid absorbing resin that is a copolymer of the hydrophilic monomer and the hydrophobic monomer include, for example, (meth) acrylic acid esters, styrene / (meth) acrylic acid / (anhydrous). ) Preferred are maleic acid copolymers, olefin polymers such as ethylene / propylene (or modified products thereof, or carboxylic acid unit introduced products by copolymerization), branched polyesters and polyamides whose acid value has been improved with trimellitic acid, etc. Can be mentioned.

  Examples of the liquid absorbent resin include a neutral salt structure (for example, carboxylic acid). This neutralized salt structure such as carboxylic acid forms an ionomer by interaction with the cation when ink containing a cation (for example, a monovalent metal cation such as Na or Li) is absorbed.

  It is also desirable that the liquid absorbent resin contains a substituted or unsubstituted amino group or a substituted or unsubstituted pyridine group. The group exerts a bactericidal effect and interaction with a recording material having an anionic group (for example, pigment or dye).

  Here, in the liquid absorbent resin, the molar ratio (hydrophilic monomer: hydrophobic monomer) between the hydrophilic unit (hydrophilic monomer) and the hydrophobic unit (hydrophilic monomer) is, for example, 5:95 to 70:30.

  Further, the absorbent resin may be ion-crosslinked with ions supplied from the ink. Specifically, a unit containing a carboxylic acid in the resin such as a copolymer containing a carboxylic acid such as (meth) acrylic acid or maleic acid or a (branched) polyester having a carboxylic acid is present in the water-absorbing resin. Can do. Ionic crosslinking and acid / base interaction occur between the carboxylic acid in the resin and the alkali metal cation, alkaline earth metal cation, organic amine / onium cation, etc. supplied from the liquid such as water-based ink.

  The common characteristics of the liquid-absorbing resin and the non-liquid-absorbing resin (hereinafter collectively referred to as organic resin) constituting the hydrophobic organic particles will be described.

  The liquid-absorbent resin may have a straight chain structure, but a split structure. Further, the liquid absorbent resin is preferably non-crosslinked or low crosslinked. The liquid-absorbing resin may be a linear random copolymer or block copolymer, but a branched polymer (including a branched random copolymer, block copolymer, and graft copolymer). Can be used more suitably. For example, in the case of polyester synthesized by polycondensation, end groups can be increased in a branched structure. This branched structure is generally synthesized by adding so-called cross-linking agents such as divinylbenzene and di (meth) acrylates during synthesis (for example, adding less than 1%) or adding a large amount of an initiator together with the cross-linking agent. It is one of the practical methods.

The liquid absorbing resin may further contain a charge control agent for electrophotographic toner such as low molecular quaternary ammonium salts, organic borates, and salt-forming compounds of salicylic acid derivatives. The conductivity is controlled by conductivity such as tin oxide or titanium oxide (where conductivity means, for example, a volume resistivity of less than 10 ⁷ Ω · cm. The same applies hereinafter unless otherwise specified.) , Semiconductive (here, semiconductive means, for example, a volume resistivity of 10 ⁷ Ωcm or more and 10 ¹³ Ωcm or less. The same applies hereinafter unless otherwise specified). is there.

  The liquid absorbent resin is preferably an amorphous resin, and the glass transition temperature (Tg) thereof is, for example, 40 ° C. or higher and 90 ° C. or lower. The glass transition temperature (and melting point) was determined from the main maximum peak measured according to ASTM D3418-8. DSC-7 manufactured by Perkin Elmer Co. can be used for measurement of the main maximum peak. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. As the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

  The weight average molecular weight of the liquid absorbent resin is 5,000 or more, preferably 10,000 or more and 1,000,000 or less, more preferably 10,000 or more and 500,000 or less. The weight average molecular weight is measured under the following conditions. For example, GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)” apparatus, and two columns are “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)”. And THF (tetrahydrofuran) was used as the eluent. As experimental conditions, a sample concentration of 0.5% and a flow rate of 0.6 ml / min. The experiment was conducted using a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

  Examples of the acid value of the liquid absorbent resin include 50 mg KOH / g or more and 777 mg KOH / g or less in terms of carboxylic acid group (—COOH). The acid value in terms of this carboxylic acid group (—COOH) was measured as follows.

  The acid value was measured according to JIS K0070 and using a neutralization titration method. That is, an appropriate amount of a sample is taken, 100 ml of a solvent (diethyl ether / ethanol mixed solution) and a few drops of an indicator (phenolphthalein solution) are added, and shaken sufficiently until the sample is dissolved on a water bath. This was titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point was when the red color of the indicator lasted for 30 seconds. When the acid value is A, the sample amount is S (g), the 0.1 mol / l potassium hydroxide ethanol solution used for the titration is B (ml), and f is the factor of the 0.1 mol / l potassium hydroxide ethanol solution. , A = (B × f × 5.611) / S.

  The liquid-absorbing resin described above is used with the ratio of the polar monomer being controlled within the above range regardless of the form.

  When the primary particle is the mother particle 201, the hydrophilic organic particle 201A has a sphere-converted average particle size of, for example, 0.1 μm to 50 μm (preferably 0.5 μm to 25 μm, more preferably 1 μm to 10 μm). The following ranges are included. On the other hand, when composing composite particles, for example, a range of 10 nm or more and 30 μm or less (desirably 50 nm or more and 10 μm or less, more preferably 0.1 μm or more and 5 μm or less) in terms of a sphere-converted average particle diameter can be mentioned.

  The ratio of the hydrophilic organic particles 201A to the entire ink receiving particles 16 is, for example, in the range of 75% or more, desirably 85% or more, and more desirably 90% or more and 99% or less.

  Next, the inorganic particles 202 constituting the composite particles together with the hydrophilic organic particles 201A and the inorganic particles 202 attached to the mother particles 201 will be described. As the inorganic particles 202, either non-porous particles or porous particles can be used. Examples of the inorganic particles include colorless, light-colored or white particles (for example, colloidal silica, alumina, calcium carbonate, zinc oxide, titanium oxide, tin oxide, etc.). These inorganic particles may be subjected to surface treatment (partial hydrophobization treatment, specific functional group introduction treatment, etc.). For example, in the case of silica, the hydroxyl group of silica is treated with a silylating agent such as trimethylchlorosilane or t-butyldimethylchlorosilane to introduce an alkyl group. Hydrochloric acid is generated by the silylating agent, and the reaction proceeds. At this time, if amine is added, hydrochloric acid can be converted into hydrochloride to promote the reaction. It can be controlled by controlling the treatment amount and treatment conditions of a silane coupling agent having an alkyl group or a phenyl group as a hydrophobic group or a coupling agent such as titanate or zirconate. Further, surface treatment with aliphatic alcohols, higher fatty acids and derivatives thereof is also possible. Also, coupling agents having a cationic functional group such as a (substituted) amino group or a silane coupling agent having a quaternary ammonium salt structure, coupling agents having a fluorine-based functional group such as fluorosilane, and other carboxylic acids Surface treatment with a coupling agent having an anionic functional group such as the above is also possible. These inorganic particles 202 may be so-called internally added, which are contained inside the hydrophilic organic particles 201A.

  The particle diameter of the inorganic particles 202 constituting the composite particles is, for example, in the range of from 5 nm to 100 nm, more desirably from 10 nm to 50 μm in terms of volume average primary particle diameter. On the other hand, the particle size of the inorganic particles 202 attached to the mother particles 201 is, for example, in the range of 10 nm to 1 μm (preferably 10 nm to 0.1 μm, more preferably 10 nm to 0.05 μm) in terms of a sphere-equivalent average particle size. Can be mentioned.

  Next, other additives for the ink receiving particles 16 will be described. First, it is desirable that the ink receiving particles 16 include a component that aggregates or thickens the components of the ink.

  The component having this function may be included as a functional group of a resin (resin water-absorbing resin) constituting the liquid-absorbent resin particles, or may be included as a compound. Examples of the functional group include carboxylic acids, polyvalent metal cations, polyamines, and the like.

  Moreover, as the said compound, flocculants, such as an inorganic electrolyte, an organic acid, an inorganic acid, and an organic amine, are mentioned suitably.

  Inorganic electrolytes include alkali metal ions such as lithium ion, sodium ion, potassium ion, aluminum ion, barium ion, calcium ion, copper ion, iron ion, magnesium ion, manganese ion, nickel ion, tin ion, titanium ion, zinc Polyvalent metal ions such as ions, hydrochloric acid, odorous acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, thiocyanic acid, and acetic acid, succinic acid, lactic acid, fumaric acid, fumaric acid, citric acid, salicylic acid, benzoic acid And the like, and organic carboxylic acids such as salts of organic sulfonic acids.

  Specific examples include lithium chloride, sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide, potassium iodide, sodium sulfate, potassium nitrate, sodium acetate, potassium oxalate, sodium citrate, potassium benzoate and the like. Alkali metal salts and aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, sodium aluminum sulfate, potassium aluminum sulfate, aluminum acetate, barium chloride, barium bromide, barium iodide, barium oxide, barium nitrate, thiocyanate Barium acid, calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium benzoate, calcium acetate, salicylic acid Lucium, calcium tartrate, calcium lactate, calcium fumarate, calcium citrate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, oxalic acid Iron, iron lactate, iron fumarate, iron citrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium lactate, manganese chloride, manganese sulfate, manganese nitrate, manganese dihydrogen phosphate , Manganese acetate, manganese salicylate, manganese benzoate, manganese lactate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, thiocyanate Examples thereof include salts of polyvalent metals such as zinc acid and zinc acetate.

  Specific examples of organic acids include arginic acid, citric acid, glycine, glutamic acid, succinic acid, tartaric acid, cysteine, oxalic acid, fumaric acid, phthalic acid, maleic acid, malonic acid, lysine, malic acid, and general formula Examples thereof include compounds represented by (1) and derivatives of these compounds.

Here, in the formula, X represents O, CO, NH, NR ₁ , S, or SO ₂ . R ₁ represents an alkyl group, and R ₁ is preferably CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OH. R represents an alkyl group, and R is preferably CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OH. In addition, R may be included in the formula or may not be included. X is preferably CO, NH, NR, O, and more preferably CO, NH, O. M represents a hydrogen atom, an alkali metal or an amine. M is preferably H, Li, Na, K, monoethanolamine, diethanolamine, triethanolamine or the like, more preferably H, Na, K, and still more preferably a hydrogen atom. n is an integer of 3 to 7. n is preferably a case where the heterocyclic ring is a 6-membered ring or a 5-membered ring, and more preferably a 5-membered ring. m is 1 or 2. The compound represented by the general formula (1) may be a saturated ring or an unsaturated ring as long as it is a heterocyclic ring. l is an integer of 1 to 5.

  Specifically, the compound represented by the general formula (1) has a furan, pyrrole, pyrroline, pyrrolidone, pyrone, pyrrole, thiophene, indole, pyridine, quinoline structure, and further has a carboxyl group as a functional group. Compounds. Specifically, 2-pyrrolidone-5-carboxylic acid, 4-methyl-4-pentanolide-3-carboxylic acid, furan carboxylic acid, 2-benzofuran carboxylic acid, 5-methyl-2-furan carboxylic acid, 2,5 -Dimethyl-3-furancarboxylic acid, 2,5-furandicarboxylic acid, 4-butanolide-3-carboxylic acid, 3-hydroxy-4-pyrone-2,6-dicarboxylic acid, 2-pyrone-6-carboxylic acid, 4-pyrone-2-carboxylic acid, 5-hydroxy-4-pyrone-5-carboxylic acid, 4-pyrone-2,6-dicarboxylic acid, 3-hydroxy-4-pyrone-2,6-dicarboxylic acid, thiophenecarboxylic Acid, 2-pyrrolecarboxylic acid, 2,3-dimethylpyrrole-4-carboxylic acid, 2,4,5-trimethylpyrrole-3-propionic acid, 3-hydroxy-2-yne Carboxylic acid, 2,5-dioxo-4-methyl-3-pyrroline-3-propionic acid, 2-pyrrolidinecarboxylic acid, 4-hydroxyproline, 1-methylpyrrolidine-2-carboxylic acid, 5-carboxy-1-methyl Pyrrolidine-2-acetic acid, 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, pyridinedicarboxylic acid, pyridinetricarboxylic acid, pyridinepentacarboxylic acid, 1,2,5,6-tetrahydro-1-methyl Examples include nicotinic acid, 2-quinolinecarboxylic acid, 4-quinolinecarboxylic acid, 2-phenyl-4-quinolinecarboxylic acid, 4-hydroxy-2-quinolinecarboxylic acid, and 6-methoxy-4-quinolinecarboxylic acid. .

  As the organic acid, desirably, citric acid, glycine, glutamic acid, succinic acid, tartaric acid, phthalic acid, pyrrolidone 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. More desirably, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, or derivatives of these compounds, or salts thereof. More desirable are pyrrolidone carboxylic acid, pyrone carboxylic acid, furan carboxylic acid, coumaric acid, or a derivative of these compounds, or a salt thereof.

  The organic amine compound may be any of primary, secondary, tertiary and quaternary amines and salts thereof. Specific examples include tetraalkylammonium, alkylamine, benzalkonium, alkylpyridium, imidazolium, polyamine, and derivatives or salts thereof. Specifically, amylamine, butylamine, propanolamine, propylamine, ethanolamine, ethylethanolamine, 2-ethylhexylamine, ethylmethylamine, ethylbenzylamine, ethylenediamine, octylamine, oleylamine, cyclooctylamine, cyclobutylamine, cyclohexane Propylamine, cyclohexylamine, diisopropanolamine, diethanolamine, diethylamine, di-2-ethylhexylamine, diethylenetriamine, diphenylamine, dibutylamine, dipropylamine, dihexylamine, dipentylamine, 3- (dimethylamino) propylamine, dimethylethylamine, dimethyl Ethylenediamine, dimethyloctylamine, 1,3-dimethylbutylamine, dimethyl 1,3-propanediamine, dimethylhexylamine, amino-butanol, amino-propanol, amino-propanediol, N-acetylaminoethanol, 2- (2-aminoethylamino) -ethanol, 2-amino-2- Ethyl-1,3-propanediol, 2- (2-aminoethoxy) ethanol, 2- (3,4-dimethoxyphenyl) ethylamine, cetylamine, triisopropanolamine, triisopentylamine, triethanolamine, trioctylamine, Tritylamine, bis (2-aminoethyl) 1,3-propanediamine, bis (3-aminopropyl) ethylenediamine, bis (3-aminopropyl) 1,3-propanediamine, bis (3-aminopropyl) methylamine, Bis (2-ethylhexyl ) Amine, bis (trimethylsilyl) amine, butylamine, butylisopropylamine, propanediamine, propyldiamine, hexylamine, pentylamine, 2-methyl-cyclohexylamine, methyl-propylamine, methylbenzylamine, monoethanolamine, laurylamine, Nonylamine, trimethylamine, triethylamine, dimethylpropylamine, propylenediamine, hexamethylediamine, tetraethylenepentamine, diethylethanolamine, tetramethylammonium chloride, tetraethylammonium bromide, dihydroxyethylstearylamine, 2-heptadecenyl-hydroxyethylimidazoline, lauryl Dimethylbenzylammonium chloride, cetylpyridinium mouth Ride, stearamide methylbiridium chloride, diallyldimethylammonium chloride polymer, diallylamine polymer, monoallylamine polymer and the like can be mentioned.

  More desirably, triethanolamine, triisopropanolamine, 2-amino-2-ethyl-1,3-propanediol, ethanolamine, propanediamine, propylamine and the like are used.

Among these flocculants, polyvalent metal salts (Ca (NO ₃ ), Mg (NO ₃ ), Al (OH ₃ ), polyaluminum chloride, etc.) are preferably used.

  The flocculant may be used alone or in combination of two or more. Moreover, as content of a flocculant, it is desirable that it is 0.01 to 30 mass%. More preferably, it is 0.1 mass% or more and 15 mass% or less, More preferably, it is 1 mass% or more and 15 mass% or less.

  The ink receiving particles 16 may contain a release agent. The release agent may be included in the liquid-absorbent resin, or the release agent particles may be combined with the hydrophilic organic resin particles.

  Examples of the mold release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide. Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, and Fischer-Tropsch wax -Petroleum wax; and modified products thereof. Among these, it is preferable to apply a crystalline compound.

The ink receiving particles 16 of the present embodiment are produced by the following method.
Specifically, first, the mother particle 201 is adjusted by the following method. When the ink receptive particles 16 are in the form in which the mother particles 201 are composed of the particles (primary particles) of the hydrophilic organic particles 201A alone, the resin constituting the hydrophilic organic particles 201A, and other additives as necessary Etc., adjust the resin solution dissolved in the solvent that dissolves these materials, make the adjusted resin solution or slurry into fine droplets and dry with hot air, agglomerate resin coarse powder, A method of obtaining mother particles 201 by using a method of fine particle processing (mechanofusion, hybridization) using pressure bonding, dispersion, or friction, or a resin solid obtained by freeze-drying the resin solution is melted and cooled by an extruder. Thereafter, the mother particles 201 are obtained by pulverizing with a jet mill and classifying with an airflow classifier.

  Further, when the mother particle 201 is configured as a composite particle that is an aggregate of a plurality of hydrophilic organic particles 201A, the resin that constitutes the hydrophilic organic particle 201A, and other additives as necessary, A method of obtaining a mother particle 201 by using a spray drying method or the like in which a liquid obtained by emulsifying or dispersing the material in a solvent is prepared, and the adjusted liquid is formed into fine droplets and dried with hot air. It is done.

  By adjusting the mother particle 201 as described above, as described above, the shape factor SF1 is easily in the range of 100 or more and 146 or less, and the particle size distribution is easily 1.6 or less. Adjusted.

Further, the ink receiving particles 16 of the present embodiment are adjusted by further adding inorganic particles 202 or the like to the base particles 201 by the following method.
Specifically, a resin in which the mother particles 201 are formed, and other additives as necessary are prepared by adjusting a liquid obtained by emulsifying or dispersing these materials in a solvent, and inorganic particles are further added to the adjusted liquid. A spray-drying method in which the dispersed liquid is made into fine droplets and dried with hot air, or fine particle processing (mechano-fusion, hybridization) using inorganic particles mixed with resin coarse powder and pressure bonding, dispersion, or friction ) Method is used to adjust the ink receiving particles 16.

  Next, the ink applied in the above embodiment will be described in detail. Water-based ink is used as the ink. Aqueous ink (hereinafter simply referred to as ink) contains an ink solvent (for example, water, a water-soluble organic solvent) in addition to the recording material. In addition, other additives may be included as necessary.

  First, the recording material will be described. As the recording material, a color material is mainly used. As the color material, either a dye or a pigment can be used, but a pigment is preferable. As the pigment, either an organic pigment or an inorganic pigment can be used. Examples of the black pigment include carbon black pigments such as furnace black, lamp black, acetylene black, and channel black. In addition to black, cyan, magenta, and yellow primary pigments, specific color pigments such as red, green, blue, brown, and white, metallic luster pigments such as gold and silver, colorless or light color extender pigments, plastic pigments, etc. May be used. In addition, a newly synthesized pigment may be used for the present invention.

  It is also possible to use particles, such as silica, alumina, polymer beads, etc., having a dye or pigment fixed on the surface thereof, a dye insoluble lake, a colored emulsion, or a colored latex as the pigment.

  Specific examples of black pigments include Raven7000, Raven5750, Raven5250, Raven5000 ULTRAII, Raven3500, Raven2000, Raven1500, Raven1250, Raven1200, Raven1125, Raven10, Raven10, Raven10 Regal 330R, Regal 660R, Mogul L, Black Pearls L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 140 0 (manufactured by Cabot Corporation), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black FW200, Color Black S150, Color Black P160, Color Black P160, Color Black FW2V, Color Black FW2V, Color Black FW200, Color Black FW200 Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (manufactured by Degussa), No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like can be mentioned, but are not limited thereto.

  Specific examples of the cyan pigment include C.I. I. Pigment Blue-1, -2, -3, -15, -15: 1, -15: 2, -15: 3, -15: 4, -16, -22, -60, and the like. It is not limited.

  Specific examples of the magenta color pigment include C.I. I. Pigment Red-5, -7, -12, -48, -48: 1, -57, -112, -122, -123, -146, -168, -177, -184, -202, C.I. I. Pigment Violet-19 etc. are mentioned, However, It is not limited to these.

  Specific examples of yellow pigments include C.I. I. Pigment Yellow-1, -2, -3, -12, -13, -14, -16, -17, -73, -74, -75, -83, -93, -95, -97, -98, -114, -128, -129, -138, -151, -154, -180, and the like, but are not limited thereto.

  Here, when a pigment is used as the color material, it is desirable to use a pigment dispersant together. Examples of the pigment dispersant that can be used include a polymer dispersant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

  As the polymer dispersant, a polymer having a hydrophilic structure portion and a hydrophobic structure portion is preferably used. As the polymer having a hydrophilic structure portion and a hydrophobic structure portion, a condensation polymer and an addition polymer can be used. Examples of the condensation polymer include known polyester dispersants. Examples of the addition polymer include addition polymers of monomers having an α, β-ethylenically unsaturated group. Desired polymer dispersion by copolymerizing a monomer having an α, β-ethylenically unsaturated group having a hydrophilic group and a monomer having an α, β-ethylenically unsaturated group having a hydrophobic group An agent is obtained. A homopolymer of a monomer having an α, β-ethylenically unsaturated group having a hydrophilic group can also be used.

  Monomers having an α, β-ethylenically unsaturated group having a hydrophilic group include monomers having a carboxyl group, a sulfonic acid group, a hydroxyl group, a phosphoric acid group, such as acrylic acid, methacrylic acid, and crotonic acid. , Itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, vinyl sulfonic acid, styrene sulfonic acid, sulfonated vinyl naphthalene, vinyl alcohol, acrylamide, methacryloxyethyl phosphate, bismethacrylic acid Examples include roxyethyl phosphate, methacrylooxyethyl phenyl acid phosphate, ethylene glycol dimethacrylate, and diethylene glycol dimethacrylate.

  Examples of the monomer having an α, β-ethylenically unsaturated group having a hydrophobic group include styrene derivatives such as styrene, α-methylstyrene, vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, alkyl acrylate esters, Examples include methacrylic acid alkyl esters, methacrylic acid phenyl esters, methacrylic acid cycloalkyl esters, crotonic acid alkyl esters, itaconic acid dialkyl esters, maleic acid dialkyl esters, and the like.

  Examples of desirable copolymers used as polymer dispersants include styrene-styrene sulfonic acid copolymers, styrene-maleic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylic acid copolymers, Vinyl naphthalene-maleic acid copolymer, vinyl naphthalene-methacrylic acid copolymer, vinyl naphthalene-acrylic acid copolymer, alkyl acrylate ester-acrylic acid copolymer, alkyl methacrylate ester-methacrylic acid copolymer, styrene -Methacrylic acid alkyl ester-Methacrylic acid copolymer, Styrene-Acrylic acid alkyl ester-Acrylic acid copolymer, Styrene-Methacrylic acid phenyl ester-Methacrylic acid copolymer, Styrene-Methacrylic acid cyclohexyl ester-Methacrylic acid copolymer Etc. . Moreover, you may copolymerize the monomer which has a polyoxyethylene group and a hydroxyl group with these polymers.

  Examples of the polymer dispersant include those having a weight average molecular weight of 2,000 to 50,000.

  These pigment dispersants may be used alone or in combination of two or more. The amount of the pigment dispersant added varies greatly depending on the pigment, so it cannot be generally stated.

  A pigment that can be self-dispersed in water can also be used as the color material. A pigment that can be self-dispersed in water refers to a pigment that has many water-solubilizing groups on the surface of the pigment and disperses in water without the presence of a polymer dispersant. Specifically, it can be self-dispersed in water by subjecting ordinary so-called pigments to surface modification treatments such as acid / base treatment, coupling agent treatment, polymer graft treatment, plasma treatment, oxidation / reduction treatment, etc. Pigments are obtained.

  Further, as pigments that can be self-dispersed in water, in addition to pigments obtained by subjecting the above pigments to surface modification treatment, Cab-o-jet-200, Cab-o-jet-300, IJX- manufactured by Cabot Corporation Commercially available self-dispersing pigments such as 157, IJX-253, IJX-266, IJX-273, IJX-444, IJX-55, Cabot 260, Microjet Black CW-1, CW-2 manufactured by Orient Chemical Co., etc. can also be used.

  The self-dispersing pigment is desirably a pigment having at least sulfonic acid, sulfonate, carboxylic acid, or carboxylate as a functional group on the surface thereof. More desirably, the pigment has at least a carboxylic acid or a carboxylate as a functional group on the surface.

  Furthermore, a pigment coated with a resin can also be used. This is called a microcapsule pigment, and not only commercially available microcapsule pigments manufactured by Dainippon Ink and Chemicals, Inc., or Toyo Ink, but also microcapsule pigments produced for the present invention may be used. it can.

  In addition, a resin-dispersed pigment in which a polymer substance is physically adsorbed or chemically bonded to the pigment can also be used.

  Other recording materials include hydrophilic anionic dyes, direct dyes, cationic dyes, reactive dyes, dyes such as polymer dyes and oil-soluble dyes, wax powders / resin powders and emulsions colored with dyes, Fluorescent dyes and fluorescent pigments, infrared absorbers, ultraviolet absorbers, magnetic materials such as ferromagnetic materials represented by ferrite and magnetite, semiconductors and photocatalysts represented by titanium oxide and zinc oxide, and other organic and inorganic electrons Examples include material particles.

  The content (concentration) of the recording material is, for example, 5% by mass to 30% by mass with respect to the ink.

  The volume average particle diameter of the recording material is, for example, 10 nm or more and 1000 nm or less.

  The volume average particle size of the recording material refers to the particle size of the recording material itself, or the particle size to which the additive has adhered when an additive such as a dispersant is attached to the recording material. A Microtrac UPA particle size analyzer 9340 (manufactured by Lees & Northrup) was used as a volume average particle diameter measuring apparatus. The measurement was performed according to a predetermined measurement method with 4 ml of ink placed in a measurement cell. As input values at the time of measurement, the viscosity of the ink was used as the viscosity, and the density of the dispersed particles was used as the density of the recording material.

  Next, the water-soluble organic solvent will be described. As the water-soluble organic solvent, polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containing solvents, alcohols, sulfur-containing solvents and the like are used.

  Specific examples of the water-soluble organic solvent include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,5-pentanediol, 1,2-hexanediol, 1,2, Examples thereof include sugar alcohols such as 6-hexanetriol, glycerin, trimethylolpropane, and xylitol, and sugars such as xylose, glucose, and galactose.

  Polyhydric alcohol derivatives include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diglycerin. And ethylene oxide adducts.

Examples of the nitrogen-containing solvent include pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, and triethanolamine. Examples of the alcohol include alcohols such as ethanol, isopropyl alcohol, butyl alcohol, and benzyl alcohol.
Examples of the sulfur-containing solvent include thiodiethanol, thiodiglycerol, sulfolane, dimethyl sulfoxide and the like.

  In addition, as the water-soluble organic solvent, propylene carbonate, ethylene carbonate, or the like can be used.

  At least one kind of water-soluble organic solvent may be used. As content of a water-soluble organic solvent, 1 mass% or more and 70 mass% or less are mentioned, for example.

  Next, water will be described. As water, it is desirable to use ion-exchanged water, ultrapure water, distilled water, or ultrafiltered water in order to prevent impurities from being mixed.

  Next, other additives will be described. A surfactant can be added to the ink.

  Examples of these surfactants include various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and the like. Desirably, anionic surfactants and nonionic surfactants are used. An activator is used.

Specific examples of the surfactant are listed below.
Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, sulfuric acid of higher alcohol ether. Ester salts and sulfonates, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates can be used, preferably , Dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, monobutylbiphenylsulfonate, dibutylphenylsulfonate Nord disulfonic acid salts and the like are used.

  Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, poly Oxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, alkyl alkanolamide, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, polyoxyethylene adduct of acetylene glycol Desirably, polyoxyethylene nonyl pheny is preferable. Ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, polyethylene glycol polypropylene glycol block copolymer Acetylene glycol and polyoxyethylene adducts of acetylene glycol are used.

  In addition, silicone surfactants such as polysiloxane oxyethylene adducts, fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers, spicrispolic acid and rhamnolipids Biosurfactants such as lysolecithin can also be used.

  These surfactants may be used alone or in combination. The hydrophilic / hydrophobic balance (HLB) of the surfactant is preferably in the range of 3 to 20 in consideration of solubility and the like.

  The addition amount of these surfactants is preferably 0.001% by mass to 5% by mass, and particularly preferably 0.01% by mass to 3% by mass.

  In addition, the ink has other properties such as polyethyleneimine, polyamines, polyvinylpyrrolidone, polyethyleneglycol, ethylcellulose, carboxymethylcellulose, etc. for the purpose of controlling properties such as penetrants and ink ejection improvement for the purpose of adjusting permeability. In order to adjust pH, compounds of alkali metals such as potassium hydroxide, sodium hydroxide, lithium hydroxide, etc., pH buffer, antioxidant, antifungal agent, viscosity adjuster, conductive agent as necessary UV absorbers, chelating agents, and the like can also be added.

  Next, preferred characteristics of the ink will be described. First, the surface tension of the ink is 20 mN / m or more and 45 mN / m or less.

  Here, as the surface tension, a value measured in an environment of 23 ° C. and 55% RH using a Wilhelmy type surface tension meter (manufactured by Kyowa Interface Science Co., Ltd.) was adopted.

  The viscosity of the ink may be from 1.5 mPa · s to 30 mPa · s.

Here, as the viscosity, a value measured using a rheomat 115 (manufactured by Contraves) as a measuring device under the conditions of a measurement temperature of 23 ° C. and a shear rate of 1400 s ⁻¹ was adopted.

  The ink is not limited to the above configuration. In addition to the recording material, for example, a functional material such as a liquid crystal material or an electronic material may be included.

  As described above, in the embodiment, the ink droplets 20A are selectively ejected based on the image data from the inkjet recording heads 20 of black, yellow, magenta, and cyan so that a full color image is recorded on the recording medium 8. However, the present invention is not limited to recording characters and images on a recording medium. That is, the apparatus according to the present embodiment is applied to industrially used droplet discharge (ejection) apparatuses in general.

  In the present embodiment, the mode in which the ink receiving particles 16 are supplied onto the intermediate transfer body 12 and the ink droplets 20A are applied onto the ink receiving particle layer 16A supplied onto the intermediate transfer body 12 has been described. Alternatively, the ink receiving particles 16 may be directly supplied onto the recording medium 8 to apply the ink droplets 20A onto the ink receiving particle layer 16A supplied onto the recording medium 8. In this case, the intermediate transfer body 12 is configured as an intermediate transfer belt of a conventionally known image forming apparatus, and a conventionally known method for conveying the recording medium 8 onto the intermediate transfer belt is used. The ink receiving particle layer 16A on the recording medium 8 may be used as a fixing device for fixing the recording medium 8 to the recording medium 8.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. Unless otherwise specified, “part” means “part by mass”.

  In Examples, the shape factor SF1, the volume average particle diameter, and the particle size distribution GSD were measured using the following methods.

-Measurement of shape factor SF1-
The shape factor SF1 is digitized by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated, for example, as follows. That is, an optical microscope image of the ink receptive particles 16 spread on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 50 or more ink receptive particles 16 are obtained. ) And the average value was obtained (SF1 = (ML ² / A) × (π / 4) × 100 (1)).

―Measurement of volume average particle size―
The volume average particle size of the mother particles in the examples was measured with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

-Measurement of particle size distribution GSD-
The particle size distribution was measured by a dry method using LS 13 320 (Beckman Coulter, Inc.). The measured particle size distribution is drawn from the smaller diameter side with respect to the volume of the individual ink receiving particles 16 with respect to the divided particle size range (channel), and the particle size that becomes 16% is the volume average particle size D16v. And the particle diameter at a cumulative 50% is defined as the volume average particle diameter D50v. Similarly, the particle diameter that is 84% cumulative is defined as the volume average particle diameter D84v. At this time, the particle size distribution (GSD) is defined as D84v / D16v. Using these relational expressions, a particle size distribution (GSD) was calculated.

<Adjustment of ink receiving particles>

-Ink-receptive particles A1-
・ To 100 parts of styrene / nbutyl methacrylate / acrylic acid copolymer (Mw = 40000, polar monomer ratio 45 mol%, partially neutralized with sodium hydroxide), water / IPA solution (with respect to 90 parts by weight of water, A resin solution dissolved in 10 parts by weight of isopropyl alcohol (IPA) was prepared.

  This prepared resin solution is supplied to a spray drying apparatus (manufactured by BUCHI, mini spray dryer B290 type) and spray-dried, whereby the volume average particle diameter is 7 μm, the shape factor SF1 is 105, and the particle size distribution GSD is 1. Thus, mother particles A1 having a shape with a dent on the surface (result of observation with an electron microscope) were obtained.

  The spray drying conditions were as follows: the spray gun diameter used was 0.7 mm, the inlet temperature was 150 ° C., the aspirator setting was 100%, the pump setting was 20%, and the spray flow was 35 mm.

  Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particles A1 and stirring and mixing (about 30 seconds in a sample mill), silica particles are added to the mother particles A1. The ink receiving particles A1 with externally added particles were prepared.

-Ink-receptive particles A2-

The base particle A1 obtained from the ink receptive particles A1 is further subjected to a classification process by an air classifier, and the base particle A2 having a volume average particle diameter of 6.5 μm, a shape factor SF1 of 104, and a particle size distribution GSD of 1.3. Got.

  Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particle A2 and stirring and mixing (about 30 seconds in a sample mill), the mother particle A2 is mixed with silica. The ink receiving particles A2 to which particles were externally added were prepared.

-Ink-receptive particles A3-
・ To 100 parts of styrene / nbutyl methacrylate / acrylic acid copolymer (Mw = 40000, polar monomer ratio 45 mol%, partially neutralized with sodium hydroxide), water / IPA solution (based on 80 parts by weight of water, A resin emulsion liquid emulsified in isopropyl alcohol (IPA) 20 parts by weight) was prepared.
The prepared resin emulsion liquid was supplied to a spray drying apparatus (manufactured by BUCHI, mini spray dryer B290 type) and spray-dried.
The spray drying conditions were as follows: the spray gun diameter used was 0.7 mm, the inlet temperature was 150 ° C., the aspirator setting was 100%, the pump setting was 20%, and the spray flow was 35 mm.
Furthermore, classification was performed on an airflow classifier to obtain mother particles A3 having a volume average particle diameter of 7 μm, a shape factor SF1 of 115, and a particle size distribution GSD of 1.35.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particles A3 and stirring and mixing (about 30 seconds in a sample mill), the mother particles A3 are mixed with silica. The ink receiving particles A3 to which the particles were externally added were prepared.

-Ink-receptive particles A4-
The ink-receptive particles A3 were spray-dried with a spray-drying apparatus, and then rotated with a hybridization system (Nara Machinery Co., Ltd., NHS-0 type) at a rotational speed of 12000 rpm and a processing time of 3 min. And further subjected to a classification process by an air classifier to obtain mother particles A4 having a volume average particle diameter of 7 μm, a shape factor SF1 of 102, and a particle size distribution GSD of 1.25.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particle A4 and stirring and mixing (about 30 seconds in a sample mill), the mother particle A4 is mixed with silica. The ink receiving particles A4 to which particles were externally added were prepared.

-Ink-receptive particles A5-
-To 100 parts of styrene / n-butyl methacrylate / acrylic acid copolymer (Mw = 40000, polar monomer ratio 45 mol%, partially neutralized with sodium hydroxide), water / IPA solution (based on 75 parts by weight of water, A resin emulsion liquid emulsified in isopropyl alcohol (IPA) 25 parts by weight) was prepared.
The prepared resin emulsion liquid is supplied to a spray drying apparatus (manufactured by BUCHI, mini spray dryer B290 type) and spray-dried, whereby a volume average particle diameter 7.5 μm, a shape factor SF1 is 128, and a particle size distribution GSD is It was 1.55, and mother particle A5 having a composite particle structure (result of observation with an electron microscope) was obtained.
The spray drying conditions were as follows: the spray gun diameter used was 0.7 mm, the inlet temperature was 150 ° C., the aspirator setting was 100%, the pump setting was 25%, and the spray flow was 35 mm.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particles A5 and stirring and mixing (about 30 seconds in a sample mill), the mother particles A5 are mixed with silica. Ink-receptive particles A5 with externally added particles were prepared.

-Ink-receptive particles A6-
The ink-receptive particles A5 are spray-dried by a spray-drying device, and further subjected to a classification process by an airflow classifier, and a mother whose volume average particle size is 7 μm, shape factor SF1 is 130, and particle size distribution GSD is 1.3. Particle A6 was obtained.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particles A6 and stirring and mixing (about 30 seconds in a sample mill), the mother particles A6 are mixed with silica. Ink-receptive particles A6 with externally added particles were prepared.

-Ink receiving particles A7-
-To 100 parts of styrene / n-butyl methacrylate / acrylic acid copolymer (Mw = 40000, polar monomer ratio 45 mol%, partially neutralized with sodium hydroxide), water / IPA solution (with respect to 90 parts by weight of water, A resin solution dissolved in 10 parts by weight of isopropyl alcohol (IPA) was prepared.
The prepared resin solution was freeze-dried. This freeze-drying treatment was performed by pre-freezing at −30 ° C. for 1 hour using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., FDU-1200, PFR-1000), under 5 × 10 ⁻⁴ Torr, −40 ° C. , By drying for 6 hours.
The resin solid obtained by freeze-drying the resin solution was pulverized using a jet mill, and then rotated with a hybridization system (Nara Machinery Co., Ltd., NHS-0 type) at a rotational speed of 12000 rpm and a processing time of 2 min. . And then applied to an airflow classifier to obtain a base particle A7 having a volume average particle diameter of 8 μm, a shape factor SF1 of 138, and a particle size distribution GSD of 1.4.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particles A7 and stirring and mixing (about 30 seconds in a sample mill), the mother particles A7 are mixed with silica. Ink-receptive particles A7 with externally added particles were prepared.

-Ink-receptive particles A8-
-To 100 parts of styrene / n-butyl methacrylate / acrylic acid copolymer (Mw = 40000, polar monomer ratio 45 mol%, partially neutralized with sodium hydroxide), water / IPA solution (based on 75 parts by weight of water, A resin emulsion liquid emulsified in isopropyl alcohol (IPA) 25 parts by weight) was prepared.
The prepared resin emulsion solution was freeze-dried. This freeze-drying treatment was performed by pre-freezing at −30 ° C. for 1 hour using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., FDU-1200, PFR-1000), under 5 × 10 ⁻⁴ Torr, −40 ° C. , By drying for 6 hours.
The resin solid obtained by freeze-drying the resin solution was pulverized using a jet mill, and then rotated at 12000 rpm with a hybridization system (Nara Machinery Co., Ltd., NHS-0 type) for 1 min. . To obtain mother particles A8 having a volume average particle diameter of 16 μm, a shape factor SF1 of 146, and a particle size distribution GSD of 1.7.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to the mother particles A8 and stirring and mixing (about 30 seconds in a sample mill), silica particles are added to the mother particles A8. Ink-receptive particles A8 with externally added particles were prepared.

-Ink-receptive particles A9-
-To 100 parts of styrene / nbutyl methacrylate / acrylic acid copolymer (Mw = 40000, polar monomer ratio 45 mol%, partially neutralized with sodium hydroxide), water / IPA solution (with respect to 50 parts by weight of water, A resin solution dissolved in isopropyl alcohol (IPA) 50 parts by weight) was prepared.
The prepared resin solution is supplied to a spray drying apparatus (manufactured by BUCHI, mini spray dryer B290 type) and spray-dried, so that the volume average particle diameter is 12 μm, the shape factor SF1 is 100, and the particle size distribution GSD is 1.55. Mother particle A9 was obtained.
The spray drying conditions were as follows: the spray gun diameter used was 0.7 mm, the inlet temperature was 150 ° C., the aspirator setting was 100%, the pump setting was 25%, and the spray flow was 40 mm.
Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size≈40 nm)) to the mother particles A9 and stirring and mixing (about 30 seconds in a sample mill), the mother particles A9 are mixed with silica. Ink-receptive particles A9 with externally added particles were prepared.

-Ink receiving particles B1-
The resin solution prepared with the ink receiving particles A1 was freeze-dried.
This freeze-drying treatment was performed by pre-freezing at −30 ° C. for 1 hour using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., FDU-1200, PFR-1000), under 5 × 10 ⁻⁴ Torr, −40 ° C. , By drying for 6 hours.

  The resin solid substance obtained by freeze-drying the resin solution was pulverized with a jet mill and further classified with an airflow classifier. Thereby, mother particle B1 was obtained. The volume average particle diameter of the ink receiving particles B1 is 7.5 μm, the shape factor SF1 is 148, and the particle size distribution GSD is 1.6. When observed with an electron microscope, the ink receiving particles B1 are plate-like irregular particles. Was observed.

  Further, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size≈40 nm)) to this base particle B1 and stirring and mixing (about 30 seconds in a sample mill), silica particles are added to the base particle B1. The ink receiving particles B1 to which particles were externally added were prepared.

-Ink receiving particles B2-
The resin solution prepared with the ink receiving particles A5 was lyophilized.
This freeze-drying treatment was performed by pre-freezing at −30 ° C. for 1 hour using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., FDU-1200, PFR-1000), under 5 × 10 ⁻⁴ Torr, −40 ° C. , By drying for 6 hours.
The resin solid obtained by freeze-drying the resin solution was pulverized with a jet mill and further classified with an airflow classifier. Thereby, mother particle B2 was obtained. The volume average particle diameter of the ink receiving particles B2 is 13.5 μm, the shape factor SF1 is 155, and the particle size distribution GSD is 1.8. When observed with an electron microscope, the ink receiving particles B2 are plate-like irregular particles. Was observed.
Furthermore, by adding 2 parts by weight of surface-hydrophobic-treated silica particles (Aerosil OX50 (volume average particle size ≈40 nm)) to this base particle B2 and stirring and mixing (about 30 seconds in a sample mill), silica particles are added to the base particle B2. The ink receiving particles B2 to which particles were externally added were prepared.

  The adjusted mother particles and ink receiving particles are shown in Table 1 below.

As the ink, the following ink was used.
-Ink-
Carbon black (CB): 5 parts by mass Styrene / n-butyl methacrylate / methacrylic acid: 1.5 parts by mass Glycerin: 20 parts by mass Triethylene glycol: 5 parts by mass Diethylene glycol monobutyl ether: 2 parts by mass E1010 (manufactured by Nissin Chemical Co., Ltd.): 1.5 parts by mass / water: remainder The above materials were mixed to obtain a liquid. The surface tension of this liquid was 32.5 mN / m.

(Example 1 to Example 9, Comparative Example 1 to Comparative Example 2)
The above-described embodiment to which the ink receiving particles A1 to A9 and the ink receiving particles B1 to B2 shown in Table 1 are applied and a recording apparatus having the same configuration except that the density increasing device is not provided (FIGS. 1 to 1). See 3 (however, the recording head was black only), and image formation was performed and the following evaluation was performed.
In Examples 1 to 9, ink receiving particles A1 to ink receiving particles A9 were used. In Comparative Examples 1 and 2, ink receiving particles B1 to ink receiving particles B2 were used.
The evaluation results are shown in Table 2.

(Example 10)
As shown in FIG. 1, evaluation was performed in the same manner as in Example 1 except that a recording apparatus provided with a density increasing apparatus was used as the recording apparatus. The evaluation results are shown in Table 2.

  As the density increasing device, a device in which an ultrasonic vibrator capable of outputting in the range of 1 kHz or more and 200 kHz or less is incorporated in the housing, so that the negative charging polarity is the same as that of the ink receiving particles. A negative voltage was applied.

(Comparative Example 3)
As shown in FIG. 1, evaluation was performed in the same manner as in Comparative Example 2 except that a recording apparatus provided with the same density increasing apparatus as in Example 10 was used as the recording apparatus. The evaluation results are shown in Table 2.

  In Examples 1 to 10 and Comparative Examples 1 to 3, OK topcoat N paper (manufactured by Oji Paper Co., Ltd.) was used as the recording medium. The ink-receptive particles and ink used were adjusted as described above.

(Evaluation)
-Drying time-
The drying time was evaluated as follows.
Using the above evaluation apparatus, the layer thickness of the release layer on the intermediate transfer member (the coating amount of the release agent) is 1 μm, and it varies depending on the particles, but depends on the ink receiving particles on the intermediate transfer member. The particles were dispersed so that the layer thickness of the particle layer (the amount of ink receiving particles supplied) was 20 to 40 μm and the amount of ink receiving particles sprayed was 7 to 10 g / m ² . A solid image was formed by ejecting ink such that the ink ejection amount was 4.5 g / m ² . The recording medium is placed in an ink-applied area of the ink-applied particle layer on the intermediate transfer member, and silicone rubber is placed on the surface of the metal cylindrical core metal through the recording medium. The roller (φ2.5 cm) pressed is applied with a load of 2 × 10 ⁴ Pa for 0.5 seconds, and after the ink is ejected (applied) to the particle layer, the ink is not transferred to the recording medium side. The time required was measured as the drying time. The evaluation criteria are shown below.

G0: Drying time is less than 0.3 seconds G1: Drying time is 0.3 seconds or more and less than 1 second G2: Drying time is 1 second or more and less than 3 seconds G3: Drying time is 3 seconds or more

-Density unevenness-
Density unevenness was evaluated as follows. Using the above evaluation apparatus, the layer thickness of the release layer on the intermediate transfer member (the coating amount of the release agent) is 1 μm, and it varies depending on the particles, but depends on the ink receiving particles on the intermediate transfer member. the thickness of the particle layer (the supply amount of ink receptive particles), 20 to 40 [mu] m, scattering amount is 7~10g / ^{m 2} of the ink receptive particles, the discharge amount of ink so that 4.5 g / ^{m 2} Ink was ejected to form a solid image on a recording medium.
For the solid image on the recording medium on which the solid image was formed, the optical density was measured at any five points on the solid image using an optical densitometer (X-Rite Mode 404 (manufactured by X-Rite)), The standard deviation of image density was determined. The evaluation criteria are shown below.

G0: Standard deviation is 0.03 or less G1: Standard deviation is a value exceeding 0.03 and 0.07 or less G2: Standard deviation is a value exceeding 0.07

-Image defects-
Image defects were evaluated as follows. Using the evaluation apparatus described above, the layer thickness of the release layer (release amount of the release agent) by the release agent on the intermediate transfer member is 1 μm, and the layer thickness of the particle layer by the ink receiving particles on the intermediate transfer member (ink) Receiving particle supply amount) is 20 to 40 μm, ink receiving particle spraying amount is 7 to 10 g / m ² , and ink discharge amount is 1200 × 1200 dpi (dpi: number of dots per inch). Thus, a linear image was formed with 2 pL per pixel.
With respect to the image on the line on the recording medium on which the linear image was formed, the presence or absence of image quality defects was determined for both the visual observation and the enlarged image with a microscope (magnification 1000 times). The evaluation criteria are shown below.

G0: Image quality defects are not observed for both the visual and enlarged images.
G1: In the enlarged image, a part of the linear image is missing, but cannot be determined visually.
G2: In the enlarged image, the line image is missing, and a part of the image can be identified visually.
G3: The same image quality defect is seen both in the enlarged image and in the visual inspection.

-Bleeding-
Bleeding was evaluated as follows. A 1-dot line pattern was printed, and sensory evaluation was performed with reference to a limit sample in which the degree of bleeding of the line was determined in advance.
The evaluation criteria are as follows.

G0: Even if an image portion is confirmed as an enlarged image, bleeding is not confirmed.
G1: When an image portion is confirmed as an enlarged image, bleeding can be confirmed, but it cannot be visually determined, and is within an allowable range. G2: Bleeding is visually recognized in the image portion, but within the allowable range. G3: The blur is visually recognized in the image part, and the degree is severe, and is outside the allowable range

From the above results, it can be seen that the present example is superior in drying time, bleeding, image unevenness and gloss unevenness as compared with the comparative example. Moreover, in the Example, the evaluation result that the drying time tends to be longer as the shape factor of the mother particle is closer to 100 was obtained.
Furthermore, from the comparison results between Examples 1 to 9 and Example 10 and the comparison results between Comparative Example 1 and Comparative Example 2 and Comparative Example 3, the image quality is better when the configuration is provided with a density increasing device in the evaluation device. The evaluation result that it was good was obtained.

It is a block diagram which shows the recording device which concerns on this embodiment. FIG. 2 is a configuration diagram illustrating a main part of a recording apparatus according to an embodiment. (A) and (B) are a top view and a cross-sectional view schematically showing a state in which the ink receiving particles according to this embodiment are supplied in a layer form to the intermediate transfer member. (A) (B) It is sectional drawing which shows typically each of the state by which the ink receptive particle which concerns on this embodiment was supplied in layer form on the intermediate transfer body, and the state transcribe | transferred on the recording medium. It is a schematic diagram which shows an example of the ink receptive particle which concerns on this embodiment. It is a schematic diagram which shows an example of the ink receptive particle which concerns on this embodiment. (A) and (B) are a top view and a cross-sectional view schematically showing a state in which ink receiving particles according to a conventional method are supplied in a layer form to an intermediate transfer member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Recording apparatus 12 Intermediate transfer body 15 Density increase apparatus 16 Ink receiving particle 18 Particle supply apparatus 20 Inkjet recording head 20K Inkjet recording head 20C Inkjet recording head 20M Inkjet recording head 20Y Inkjet recording head 22 Transfer fixing apparatus

Claims (7)

Ink-receptive particles that receive ink and have a shape factor SF1 of 146 or less.   2. The ink receiving particles according to claim 1, wherein the shape factor SF1 is larger than 100.   The ink receiving particles according to claim 1 or 2, wherein the particle size distribution GSD is 1.6 or less. An intermediate transfer member;
Supply means for supplying ink-receptive particles having a shape factor SF1 of 146 or less and receiving ink in layers on the intermediate transfer member;
An ink applying means for applying ink to the layer of the ink receiving particles supplied on the intermediate transfer member;
Transfer means for transferring the layer of ink receiving particles to a recording medium;
Fixing means for fixing the layer of the ink receiving particles transferred to the recording medium;
A recording apparatus comprising:   5. The recording apparatus according to claim 4, further comprising particle density increasing means for increasing a particle density in the layer of the ink receiving particles supplied onto the intermediate transfer member.   The recording apparatus according to claim 5, wherein the particle density increasing unit increases the particle density by applying vibration to the layer of the ink receiving particles supplied onto the intermediate transfer member. Supply means for supplying ink receiving particles having a shape factor SF1 of 146 or less and receiving ink in a layered manner on a recording medium;
An ink applying means for applying ink to the layer of the ink receiving particles supplied on the recording medium;
Fixing means for fixing the layer of the ink receiving particles on the recording medium;
A recording apparatus comprising: