JP2015205398A - Intermediate transfer body, image recording device and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate transfer body, an image recording device and an image recording method which is excellent in transfer performance and image quality of an intermediate image and improves durability of the intermediate transfer body.SOLUTION: An image recording method includes: a process of applying ink onto an intermediate transfer body having grooves formed by using a mold having protrusions of which a height d[μm] and a width w[μm] satisfy d/w≤0.7 and 0.01≤d≤1.0 to form an intermediate image; and a process of transferring the intermediate image to a recording medium on the intermediate transfer body such that, when a compression modulus of the surface of the intermediate transfer body is E[MPa] and a pressure upon transfer is P[MPa], 1≤P and 1≤E/P≤8 are satisfied.

Description

  The present invention relates to an intermediate transfer member, an image recording apparatus, and an image recording method.

  2. Description of the Related Art In recent years, an inkjet image recording method and an image recording apparatus using the same have attracted attention as a suitable technique for meeting market demands such as a reduction in the number of lots of printed products and a short delivery time. However, in this method, the recording head may be damaged due to contact between the recording medium and the recording head, or the ejection stability of the recording head may be reduced due to paper dust or the like. In order to avoid such problems, there has been proposed a method (transfer type inkjet method) in which an intermediate image is formed on an intermediate transfer member by a recording head and then transferred to a desired recording medium to form a final image. Yes. Patent Document 1 proposes an image recording apparatus that forms an intermediate image with dye ink on an intermediate transfer member and transfers the intermediate image to a recording medium.

  In order to increase the transfer efficiency of the intermediate image from the intermediate transfer member to the recording medium, it is desirable that the surface of the intermediate transfer member has a low surface free energy. However, when an intermediate image is formed on an intermediate transfer member having a low surface free energy, a phenomenon in which adjacent ink dots are attracted or mixed due to the surface tension of the ink may occur, resulting in a reduction in image quality. In general, the deterioration of the quality of the intermediate image is more likely to occur as the surface roughness of the intermediate transfer member is smaller and smoother. For this reason, Patent Document 2, Patent Document 3, and Patent Document 4 propose to prevent the above-described phenomenon by using an intermediate transfer body having an uneven shape such as a fine groove formed on the surface.

JP 59-225958 A Japanese Patent Laid-Open No. 7-017030 JP 2009-078391 A JP 2010-069796 A

  In the transfer ink jet system as described above, it is desirable to repeatedly use an intermediate transfer member from the viewpoint of cost and the like, but in this case, durability of the intermediate transfer member becomes a problem.

  That is, in the case of the transfer type ink jet system as described above, the intermediate image is easily transferred to the recording medium and the image quality on the recording medium is improved. In particular, in order to improve productivity, higher pressure is required when transferring an intermediate image to a recording medium at a high speed or when transferring an intermediate image to a recording medium having various thicknesses and surface roughnesses. In this case, if the pressure bonding of the intermediate transfer member to the recording medium is repeated with a high pressure, the side walls of the fine uneven portions on the surface of the intermediate transfer member may contact and adhere to each other, and the uneven shape may be deformed. As a result, the surface characteristics of the intermediate transfer member are not maintained, and unintentional repelling or drawing of ink or processing liquid occurs on the intermediate transfer member, thereby degrading the quality of the intermediate image.

  Therefore, Patent Documents 3 and 4 describe an image forming method in which a concavo-convex shape is formed on the surface of the intermediate transfer member every time before forming an intermediate image on the intermediate transfer member. However, in these methods, the process of treating the surface of the intermediate transfer member becomes complicated and the image quality of the obtained image may be insufficient.

One embodiment is:
An intermediate having a groove formed on the surface using a mold having a convex portion with a height d [μm] and a width w [μm] satisfying d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0. Forming an intermediate image by applying ink on the transfer member;
On the intermediate transfer member, the compression elastic modulus E [MPa] of the surface of the intermediate transfer member is set to P [MPa], and 1 ≦ P and 1 ≦ E / P ≦ 8 are satisfied. Transferring the intermediate image to a recording medium;
It is related with the image recording method characterized by having.

Other embodiments are:
It has a groove formed on the surface using a mold having a convex portion whose height d [μm] and width w [μm] satisfy d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0. The present invention relates to an intermediate transfer member characterized by

  The transferability and image quality of the intermediate image are excellent, and the durability of the intermediate transfer member can be improved.

It is a schematic diagram showing an image recording device. It is a schematic diagram showing the metal mold | die for forming a groove | channel on the surface of an intermediate transfer body.

1. Image Recording Device FIG. 1 is a schematic diagram showing a schematic configuration of an image recording device according to an embodiment. In FIG. 1, the intermediate transfer member has a rotatable drum-shaped support member 12 and a surface layer member 11 disposed on the outer peripheral surface thereof. The support member 12 is driven to rotate in the direction of the arrow about the shaft 13, and each mechanism disposed in the periphery operates in synchronization with the rotation.

  In the image recording apparatus of FIG. 1, image recording is performed as follows. First, the processing liquid is applied onto the surface of the intermediate transfer member from the processing liquid applying unit 14 that can apply the processing liquid. Next, when image data is transmitted from an image supply device (not shown) and recording is instructed, the image recording is performed on the image data by the ink jet recording head (ink applying means capable of applying ink) 15. The required image processing is performed. Then, the support member 12 rotates, and ink for image recording is selectively applied to the surface of the intermediate transfer member using the ink jet recording head 15 to form an intermediate image. In the apparatus illustrated in FIG. 1, a blower 16 and a heater 17 that performs heating from the back side of the intermediate transfer member are arranged. The blower 16 and the heater 17 can remove the liquid component in the intermediate image. As the next step, a recording medium 18 is passed between the pressure roller (transfer means) 19 and the intermediate transfer member, and at this time, the intermediate transfer member 11 is pressed against the intermediate transfer member 11 with a desired pressure to record an intermediate image. Transfer to the medium 18.

  The pressure during the transfer is P [MPa], and the compression elastic modulus of the surface of the intermediate transfer member is E [MPa]. At this time, these values are set so as to satisfy the relationship of 1 ≦ P and 1 ≦ E / P ≦ 8 in order to uniformly press the intermediate image on the intermediate transfer body 11 on the surface of the recording medium 18. According to this setting, a high-quality transfer image is obtained even when the transfer speed of the intermediate image to the recording medium is high or when the intermediate image is transferred to a recording medium having various thicknesses and surface roughnesses. be able to. When P is less than 1 MPa or E / P exceeds 8, the surface layer member of the intermediate transfer member cannot be elastically deformed enough to be pressed against the surface of the recording medium 18 at the time of transfer. The image may not be transferred sufficiently. Further, E / P needs to be 1 or more so that the intermediate transfer member does not break due to plastic deformation during transfer. The compression elastic modulus E [MPa] on the surface of the intermediate transfer member can be measured with a microhardness tester, Fischerscope HM2000 (trade name) manufactured by Fischer Instruments. At this time, the measurement conditions are a probe indentation speed of 10 μm / sec and an indentation depth of 1/10 of the thickness of the surface member.

In the apparatus shown in FIG. 1, the surface of the intermediate transfer member is cleaned by the cleaning unit 20 before the next intermediate image is formed. As the cleaning means 20, any of various methods conventionally used can be suitably applied. For example, any of the following methods can be suitably used.
A method of applying a cleaning liquid to the surface of the intermediate transfer member in a shower form.
A method in which a wet Molton roller is wiped by contacting the surface of the intermediate transfer member.
A method in which the surface of the intermediate transfer member is brought into contact with the cleaning liquid surface.
-A method of scraping the surface of the intermediate transfer member with a wiper blade.
A method of applying various kinds of energy to the surface of the intermediate transfer member.
A method of combining a plurality of these is also suitable.

  The material constituting the support member 12 of the intermediate transfer member is not particularly limited. For example, a drum made of a lightweight metal such as an aluminum alloy is preferable for reasons such as rigidity and dimensional accuracy that can withstand pressurization during transfer, as well as reducing rotational inertia and improving control responsiveness. Further, the shape of the support member may be any shape as long as the surface layer member can come into contact with the recording medium 18, and for example, a roller shape or a belt shape according to the form of the image recording apparatus to be applied or the transfer mode to the recording medium. These can be preferably used. In particular, when the drum-shaped support member or the belt-shaped endless web-structured support member shown in FIG. 1 is used, it becomes easy to repeatedly use the same intermediate transfer body. A member can be used conveniently.

  The material of the surface layer member of the intermediate transfer member is 1 ≦ P and 1 ≦ E / P ≦ 8 when the compression elastic modulus E [MPa] of the surface of the intermediate transfer member is P [MPa]. There is no particular limitation as long as it satisfies the requirements. Preferably, a rubber elastic body is desirable because it can be elastically deformed by the pressure at the time of transfer so that intermediate images can be uniformly pressed onto the surface of various recording media, and further, damage such as cracks and chippings is unlikely to occur in grooves on the surface. . Specifically, various rubber materials and elastomer materials can be preferably used. For example, polybutadiene rubber, nitrile rubber, chloroprene rubber, silicone rubber, fluorine rubber, urethane rubber, styrene elastomer, olefin elastomer, vinyl chloride elastomer, ester elastomer, amide elastomer and the like are suitable. . In particular, nitrile butadiene rubber, silicone rubber, fluorine rubber, and urethane rubber can be used very suitably from the viewpoint of durability, heat resistance, and the like. These materials may be used alone or may be used by laminating a plurality of materials. The thickness of the surface layer member is desirably 10 μm to 1000 μm. If it is thinner than this, it is impossible to uniformly press the recording medium, and if it is thicker than this, the amount of deformation of the surface layer member at the time of pressing increases, so that the image quality may deteriorate in any case. Further, in terms of the efficiency of image transfer from the intermediate transfer member to the recording medium, it is desirable that the surface of the intermediate transfer member has a property that the intermediate image can be easily peeled off.

  The intermediate transfer member was produced from a mold having a convex portion with a height d [μm] and a width w [μm] satisfying d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0 on the surface thereof. Has a groove. The convex portion formed on the mold surface has a reverse shape of a groove provided on the surface of the intermediate transfer member. That is, by pressing the convex portion of the mold onto the surface of the intermediate transfer member, a groove in which the shape of the convex portion is transferred is formed on the surface of the intermediate transfer member. Thereby, even if the transfer pressure P is applied to the intermediate transfer body 11 repeatedly, the side walls of the grooves formed on the surface of the intermediate transfer body 11 or the side walls and the bottom face contact and adhere to each other, and the grooves are blocked. There is no deformation. As a result, the surface characteristics of the intermediate transfer member 11 can be maintained without being damaged. Further, the intermediate transfer member has a groove on the surface on which the intermediate image is formed, and the phenomenon that ink dots applied on the intermediate transfer member are attracted to each other or mixed is reduced. Further, as will be described later, even when the processing liquid is applied on the intermediate transfer member in advance before applying the ink, the phenomenon that the processing liquid is repelled by the grooves on the surface of the intermediate transfer member is reduced, and the image quality is good. Is retained.

  There is no particular limitation on the shape of the groove as viewed from the surface of the intermediate transfer member and the direction in which the groove extends. For example, the groove may be a straight line, a curve, a zigzag shape, or the like, and a plurality of grooves may intersect. Cross-sectional shape of the groove (that is, the shape of the cross section appearing on the plane perpendicular to the plane and intersecting the direction of the groove (longitudinal direction of the groove when the surface on which the groove of the intermediate transfer member is provided is flat) ) Is not particularly limited. The cross-sectional shape of the groove can be selected from a rectangular shape, a trapezoid shape, a substantially rectangular shape obtained by deforming these, a substantially trapezoid shape, and the like. The convex part on the mold side for forming the groove only needs to have an inverted shape with respect to the target groove. The cross-sectional shape of the groove, and the width and depth of the cross-sectional shape are defined by the width w and height d in the cross-section of the convex portion on the mold side corresponding to the cross-sectional shape of the groove. The width w of the convex portion is the distance between the opposing side surfaces appearing in the cross section of the convex portion described above, that is, the distance between the side surfaces in the direction parallel to the mold surface. When the width of the convex section changes in the height direction of the convex section, the distance at the narrowest position between the opposing side surfaces is defined as the width w. The height d of the convex portion is a distance from the mold surface in the convex section to the highest position in the upper portion of the convex section. The width w when the convex portion extends in a curved line is defined as the shortest distance among the distances between the side surfaces in the direction intersecting the direction in which the convex portion extends. The width w and height d of the convex portion can be measured by surface observation with a scanning electron microscope.

  As a means for forming grooves on the surface of the intermediate transfer member, nano-imprinting and press molding are suitable because a uniform groove shape with sub-micron to nanometer level dimensions can be formed relatively easily over a wide area. In particular, a mold having a convex pattern which is a groove-shaped negative pattern having a dimension of a desired submicron to nanometer level is suitable. A mold having these convex portions can be easily and accurately manufactured using photolithography and etching. The convex portion of the mold corresponds to the groove of the intermediate transfer member, and a groove having a shape corresponding to the convex portion is formed on the surface of the intermediate transfer member by pressing the convex portion against the surface of the intermediate transfer member. .

  2A to 2C are schematic views showing a part of the surface of a mold for forming grooves on the surface of the intermediate transfer member, and FIG. 2D is a view inside FIG. It is a schematic diagram which shows the AA 'cross section. 2A and 2D, the height is d [μm], the width is w [μm], and a plurality of convex portions 21 extending linearly in a certain direction are arranged in parallel at a certain interval. FIG. 4 is a view showing a mold having a substantially rectangular cross-sectional shape orthogonal to the extending direction of each convex portion. FIG. 2B shows a mold in which a plurality of protrusions extending in parallel in a straight line in the horizontal direction and a plurality of protrusions extending in parallel in a straight line in the vertical direction are arranged orthogonal to each other. FIG. 2C is a view showing a mold having a convex portion 21 extending in a curved shape. When a mold having these convex portions 21 is used, an intermediate transfer member having grooves on the surface having a shape corresponding to the shape of the convex portions 21 is formed. The shape of the convex portion 21 of the mold is not limited to that shown in FIG. 2, and there is no particular limitation on the shape and direction of the convex portion viewed from the surface of the intermediate transfer member. The convex portion may be, for example, a straight line, a curved line, a zigzag shape, or the like, and a plurality of convex portions may intersect.

In general, when the contact angle between a smooth solid surface and a droplet is θ, the surface tension of the liquid is γ _L , the surface tension of the solid is γ _S , and the surface tension of the solid-liquid interface is γ _LS. The following Young's equation holds.
γ _S = γ _SL + γ _L cos θ
A Wenzel model is known as a model representing the relationship between surface roughness and wettability. When the uneven shape is formed on the solid surface, the contact area of the solid-liquid interface increases with the formed uneven surface. Assuming that the projected surface area in the vertical direction of the solid surface is S1, the actual surface area is S2, and r = S1 / S2, the apparent contact angle θ ′ on the roughened surface is expressed as follows.
cos θ ′ = r · cos θ = r (γ _S −γ _SL ) / γ _L
The contact angle θ ′ is preferably 20 ° or less in order to reduce unintentional attracting and mixing between the inks and the processing liquids on the intermediate transfer body and stably spread the ink. The following is more preferable. Therefore, in order to deal with inks and processing liquids having various physical properties, the projected surface area in the direction perpendicular to the plane when the surface of the intermediate transfer body on which the grooves are arranged is planar is S1, and the actual surface area is S2. In this case, 1.25 <S2 / S1 is preferable.

  The height d of the convex portion of the mold for forming the groove on the surface of the intermediate transfer member is preferably 0.01 μm or more and 1.0 μm or less. When d is 0.01 μm or more, the effect of reducing the apparent contact angle θ ′ is increased. Moreover, if d is 1.0 μm or less, bubbles or the like hardly enter the groove, and the entire inside of the groove can be effectively wetted with ink or processing liquid. d is more preferably 0.1 μm or more and 1.0 μm or less.

  S2 / S1 is a method for adsorbing molecules with a known adsorption area on the surface and obtaining a surface area from the amount (BET method, etc.), scanning probe microscope (SPM), confocal laser microscope, scanning optical interferometer Measurement is possible by using a device capable of acquiring three-dimensional measurement information such as.

2. Image Recording Method The image recording method of the present embodiment includes a step of forming an intermediate image by applying ink on the intermediate transfer member, and a step of transferring the intermediate image on the intermediate transfer member to a recording medium. In the intermediate image forming process, the height d [μm] and the width w [μm] are formed using a mold having convex portions that satisfy d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0. An intermediate image is formed by applying ink onto an intermediate transfer member having a groove on the surface. In the transfer step, when the compression elastic modulus E [MPa] of the surface of the intermediate transfer member is P [MPa], the intermediate transfer member satisfies 1 ≦ P and 1 ≦ E / P ≦ 8. The upper intermediate image is transferred to a recording medium.

  As described above, the intermediate transfer member has a groove formed on the surface thereof using a mold having a convex portion satisfying d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0. Thereby, even if the transfer pressure P is applied to the intermediate transfer body 11 repeatedly, the side walls of the grooves formed on the surface of the intermediate transfer body 11 or the side walls and the bottom face contact and adhere to each other, and the grooves are blocked. There is no deformation. As a result, the surface characteristics of the intermediate transfer member 11 can be maintained without being damaged. In addition, the phenomenon that ink dots applied on the surface of the intermediate transfer member are attracted or mixed together is reduced. Further, as will be described later, even when the processing liquid is applied on the intermediate transfer member in advance before applying the ink, the phenomenon that the processing liquid is repelled by the grooves on the surface of the intermediate transfer member is reduced, and the image quality is good. Is retained.

  Further, when the intermediate image is transferred using the intermediate transfer member according to the present embodiment, when 1 ≦ P and 1 ≦ E / P ≦ 8 are satisfied, the intermediate image on the intermediate transfer member 11 is uniformly formed on the surface of the recording medium 18. Can be crimped to. In particular, a high-quality transfer image can be obtained even when the transfer speed of the intermediate image to the recording medium is high or when the intermediate image is transferred to a recording medium having various thicknesses and surface roughnesses. When P is less than 1 MPa or E / P exceeds 8, the surface layer member of the intermediate transfer member cannot be elastically deformed enough to be pressed against the surface of the recording medium 18 at the time of transfer. The image is not fully transferred. Further, E / P needs to be 1 or more so that the intermediate transfer member does not cause plastic deformation and breakage during transfer. Note that the pressure P at the time of transfer can be measured using pressure sensitive paper or a surface pressure sensor.

Further, the image recording method of the present embodiment may include the following steps in addition to the above steps.
・ Process to apply treatment liquid onto the intermediate transfer body before applying ink ・ Process to reduce the liquid content in the intermediate image ・ Process to fix the image on the recording medium The materials to be described will be described in detail.

(Processing liquid application process)
Before the step of applying ink, a step of applying a treatment liquid for reducing the fluidity of the ink on the intermediate transfer member may be provided. In this way, the treatment liquid applied on the intermediate transfer member reacts with the ink to reduce the fluidity of the ink. As a result, the ink applied to the surface of the intermediate transfer member does not flow, and the intermediate image can be favorably held on the intermediate transfer member. Any conventionally used technique such as a spray coater or a bar coater can be suitably used as the treatment liquid application means capable of applying the treatment liquid. From the viewpoint of control of the coating amount and productivity, a roll coater type coating apparatus is particularly preferably used. For the same reason, a recording head that discharges a treatment liquid for reducing the fluidity of ink by an ink jet method can also be used very suitably.

(Processing liquid)
The treatment liquid contains an ink thickening component that reduces the fluidity of a part of the ink and / or ink composition. Here, increasing the viscosity of the ink means that the color material or resin that is part of the ink reacts chemically with the ink viscosity increasing component, or is physically adsorbed to the viscosity of the entire ink. The case where an increase is recognized In addition to this, it also includes the case where the viscosity of the ink is locally increased by agglomeration of a part of the ink composition such as a coloring material. The concentration of the ink thickening component in the treatment liquid may be selected according to the type of the ink thickening component, the application condition to the intermediate transfer member, the type of ink, and the like.

  As the ink thickening component, conventionally known materials such as polyvalent metal ions, organic acids, cationic polymers, and porous fine particles can be used without particular limitation. Of these, polyvalent metal ions and organic acids are particularly preferred. It is also preferable to contain a plurality of types of ink thickening components. The content of the ink viscosity increasing component in the treatment liquid is preferably 5% by mass or more based on the total mass of the treatment liquid.

Specific examples of metal ions that can be used as the ink thickening component include divalent and trivalent metal ions. Examples of divalent metal ions include Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ , Sr ²⁺ , Ba ^2+, and Zn ²⁺ , and examples of trivalent metal ions include Fe ³⁺ , Cr ³⁺ , Y ^3+, and Al ^3+. be able to.

  Examples of organic acids that can be used as the ink thickening component include oxalic acid, polyacrylic acid, formic acid, acetic acid, propionic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, levulinic acid, succinic acid, Glutaric acid, glutamic acid, fumaric acid, citric acid, tartaric acid, lactic acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, oxysuccinic acid, dioxysuccinic acid Etc.

  The treatment liquid may contain an appropriate amount of water or an organic solvent. The water used in this case is preferably water deionized by ion exchange or the like. Moreover, it does not specifically limit as an organic solvent which can be used for a process liquid, All can use a well-known organic solvent. Various resins can also be added to the treatment liquid. By adding an appropriate resin, it is possible to improve the adhesion of the intermediate image to the recording medium at the time of transfer, and to increase the mechanical strength of the final image, and the use of the resin is preferable. The material used for the resin is not particularly limited as long as it can coexist with the ink thickening component. Moreover, a surface active agent and a viscosity modifier can be added to a process liquid, and the surface tension and viscosity can be adjusted suitably and used. The material used for these is not particularly limited as long as it can coexist with the ink thickening component. Specific examples of the surfactant used include acetylenol E100 (manufactured by Kawaken Fine Chemical Co., Ltd.).

(Intermediate image formation process)
In the intermediate image forming step, an intermediate image is formed by selectively applying ink onto the intermediate transfer member. Here, in the present specification, when the treatment liquid is not applied to the intermediate transfer member, an image formed on the intermediate transfer member with ink and finally transferred to the recording medium in the transfer step is referred to as an “intermediate image”. Call it. In addition, when applying the treatment liquid onto the intermediate transfer body, an image formed on the intermediate transfer body by contact between the treatment liquid and ink and finally transferred to the recording medium in the transfer step is referred to as “intermediate image”. "

  The method for applying ink is not particularly limited, but it is preferable to use an ink jet method. Examples of the ink jet device for the ink jet system include a mode in which ink is ejected by causing film boiling in the ink by an electro-thermal converter and forming bubbles. In addition, a mode in which ink is ejected by an electro-mechanical converter, a mode in which ink is ejected using static electricity, and the like can be given. As described above, any of various inkjet devices proposed in the inkjet liquid ejection technique can be used. Among these, particularly from the viewpoint of high-speed and high-density printing, those utilizing an electro-thermal converter can be suitably used.

  Moreover, there is no restriction | limiting in particular as a form of the whole inkjet device. For example, a so-called shuttle-type inkjet head that performs recording while scanning the head perpendicular to the traveling direction of the intermediate transfer member can be used. It is also possible to use a so-called line head type ink jet head in which ink discharge ports are arranged in a line substantially perpendicular to the traveling direction of the intermediate transfer member (that is, substantially parallel to the axial direction in the case of a drum shape).

(ink)
Below, each component which can be contained in an ink is demonstrated in detail.
The ink can contain at least one of a pigment and a dye as a coloring material. The dye and the pigment are not particularly limited, and can be selected from those that can be used as a color material for the ink, and the necessary amount thereof can be used. For example, a known dye, carbon black, organic pigment, or the like can be used as an ink for ink jet. In addition, an ink in which a dye and / or pigment is dissolved and / or dispersed in a liquid medium can be used. Among these, various pigments are suitable because they are characterized by durability and quality of printed matter. It does not specifically limit as a pigment, A well-known inorganic pigment and organic pigment can be used. Specifically, C.I. I. A pigment represented by a (color index) number can be used. Moreover, it is also preferable to use carbon black as a black pigment. The content of the pigment in the ink is preferably 0.5% by mass or more and 15.0% by mass or less, and more preferably 1.0% by mass or more and 10.0% by mass or less with respect to the total mass of the ink. .

  Moreover, as the dispersant for dispersing the pigment, any of those used in conventionally known ink jet recording can be used. Among these, it is preferable to use a water-soluble dispersant having both a hydrophilic part and a hydrophobic part in the molecular structure. In particular, a dispersant composed of a resin obtained by copolymerizing at least a hydrophilic monomer and a hydrophobic monomer can be preferably used. There is no restriction | limiting in particular about each monomer used here, A conventionally well-known thing can be used conveniently. Specifically, styrene, a styrene derivative, alkyl (meth) acrylate, benzyl (meth) acrylate, etc. can be mentioned as a hydrophobic monomer. Examples of the hydrophilic monomer include acrylic acid, methacrylic acid, maleic acid and the like. The acid value of the dispersant is preferably 50 mgKOH / g or more and 550 mgKOH / g or less. Moreover, it is preferable that the weight average molecular weights of a dispersing agent are 1000 or more and 50000 or less. The mass ratio of pigment to dispersant is preferably in the range of 1: 0.1 to 1: 3.

  It is also preferable to use a so-called self-dispersing pigment that does not use a dispersing agent and that can be dispersed by surface modification of the pigment itself. The ink can contain various fine particles having no color material. Among these, resin particles are preferable because they may be effective in improving image quality and fixability. The material of the resin particles is not particularly limited, and a known resin can be appropriately used. Specifically, homopolymers such as polyolefin, polystyrene, polyurethane, polyester, polyether, polyurea, polyamide, polyvinyl alcohol, poly (meth) acrylic acid and salts thereof, poly (meth) acrylate alkyl, polydiene, or the like A copolymer obtained by combining a plurality of these may be used. The weight average molecular weight of the resin constituting the resin particles is preferably in the range of 1,000 to 2,000,000. Further, the amount of the resin particles in the ink is preferably 1% by mass or more and 50% by mass or less, and more preferably 2% by mass or more and 40% by mass or less with respect to the total mass of the ink.

  Further, it is preferably used as a resin particle dispersion in which resin particles are dispersed in a liquid. There is no particular limitation on the method of dispersing the resin particles, but a so-called self-dispersing resin particle dispersion in which a monomer having a dissociable group is homopolymerized or dispersed using a copolymerized resin is suitable. It is. Here, examples of the dissociable group include a carboxyl group, a sulfonic acid group, and a phosphoric acid group, and examples of the monomer having the dissociable group include acrylic acid and methacrylic acid.

  A so-called emulsification-dispersed resin particle dispersion in which resin particles are dispersed with an emulsifier can also be suitably used. As the emulsifier here, a known surfactant can be suitably used regardless of low molecular weight or high molecular weight. The surfactant is preferably nonionic or has the same charge as the resin particles. The resin particle dispersion desirably has a dispersed particle diameter of 10 nm to 1000 nm, and more preferably 100 nm to 500 nm.

Moreover, when preparing a resin particle dispersion, it is also preferable to add various additives for stabilization. Examples of suitable additives include n-hexadecane, dodecyl methacrylate, stearyl methacrylate, chlorobenzene, dodecyl mercaptan, olive oil, blue dye (Blue 70), and polymethyl methacrylate.
The ink may contain a surfactant. Specific examples of the surfactant include acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.). The amount of the surfactant in the ink is preferably 0.01% by mass or more and 5.0% by mass or less with respect to the total mass of the ink.

The ink can contain water and / or a water-soluble organic solvent as a solvent. The water is preferably water deionized by ion exchange or the like. Further, the water content in the ink is preferably 30% by mass or more and 97% by mass or less with respect to the total mass of the ink. The kind of water-soluble organic solvent is not particularly limited, and any known organic solvent can be used. Specific examples include glycerin, diethylene glycol, polyethylene glycol, and 2-pyrrolidone. The content of the water-soluble organic solvent in the ink is preferably 3% by mass or more and 70% by mass or less with respect to the total mass of the ink.
In addition to the above components, the ink that can be used in the present embodiment includes a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, an anti-reduction agent, a water-soluble resin, and the like as necessary. You may contain various additives, such as a compatibilizer and a viscosity modifier.

(Liquid reduction process)
It is preferable to provide a step of reducing the liquid content from the intermediate image on the intermediate transfer member before the step of transferring the intermediate image on the intermediate transfer member to the recording medium. If the liquid content in the intermediate image on the intermediate transfer member is excessive, excess liquid may overflow or overflow in the transfer process, which may cause image distortion or transfer failure. Therefore, the above phenomenon can be prevented by providing the liquid reducing step. Any of various methods that have been used from the past can be suitably applied as the method for removing the liquid component. Specifically, any of a heating method, a method of blowing low-humidity air, a method of reducing pressure, a method of bringing an absorber into contact with each other, or a method of combining them can be suitably used. It is also possible to carry out by natural drying.

(Fixing process)
As an additional step, after the transfer, the recording medium on which the image has been recorded may be pressed with a fixing roller to improve the surface smoothness. At this time, the fixing roller may be heated to give the image robustness.

  Next, the present invention will be described more specifically with reference to examples of the image recording method and the like according to the present invention. The present invention is not limited by the following examples unless it exceeds the gist. In the text, “parts” and “%” are based on mass unless otherwise specified.

Example 1
[Preparation of intermediate transfer member]
First, an i-line positive resist PFI-38A8 (trade name) manufactured by Sumitomo Chemical Co., Ltd. was applied to a silicon substrate by spin coating, and heated at 90 ° C. for 60 seconds using a hot plate. The film thickness of the resist after heating was 1 μm. Subsequently, it exposed to the stripe pattern of the desired convex part width | variety using Canon i line | wire stepper FPA-3000i5 + (brand name). Next, it was again heated on a hot plate at 110 ° C. for 90 seconds, and developed with a 2.38 wt% aqueous solution of tetramethylammonium hydroxide. Next, etching was performed using the resist pattern as a mask using an etching apparatus AMS200 (trade name) manufactured by ALCATEL until the desired depth was reached. Next, the resist was peeled off to complete a mold for forming grooves on the surface of the intermediate transfer member. When the surface of the completed mold was observed with a scanning electron microscope, linear protrusions were formed in parallel on the entire surface at a pitch of 1.5 μm. Each convex portion had a width w = 0.75 μm and a height d = 0.5 μm. Next, the mold was dipped in a release agent Durasurf HD-1101TH (trade name) manufactured by Harves. And after leaving still at room temperature for 24 hours, it rinsed with Sumitomo 3M Novec HFE-7100 (brand name), and the excess mold release agent was removed.

  Next, silicone rubber SIM-260 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. and a curing agent CAT-260 (trade name) were kneaded at a ratio of 10: 1 and coated on a polyimide film. Then, the mold produced as described above is pressed onto silicone rubber, heated at 150 ° C. for 30 minutes to cure the silicone rubber, the mold is removed, and an intermediate transfer having a minute groove shape on the surface. Completed the body. The compression modulus of the completed intermediate transfer member was measured with a microhardness tester Fischerscope HM2000 (trade name) manufactured by Fischer Instruments (probe pushing speed 10 μm / sec, pushing depth 10 μm). As a result, the compression elastic modulus was 6.2 MPa. S2 / S1 was also measured as described above.

[Image formation]
Using the intermediate transfer member produced as described above, the following image recording steps (a) to (d) were repeated 100 times.
(A) A step of applying a treatment liquid for reducing the fluidity of the ink on the intermediate transfer member. The surface of the intermediate transfer member produced as described above is composed of the following composition using a roll coater. A treatment liquid that reduces the fluidity of the ink was applied.
・ Glutaric acid: 10%
・ Surfactant (Acetyleneol EH manufactured by Kawaken Fine Chemical Co., Ltd.): 1%
・ Diethylene glycol: 30%
・ Pure water: 59%
(B) Step of forming an intermediate image on the intermediate transfer member In the ink jet recording apparatus (nozzle arrangement density 1200 dpi, discharge amount 4.8 pl, drive frequency 12 kHz), a mirror is formed on the intermediate transfer member coated with the treatment liquid. An inverted character image (intermediate image) was formed. Here, inks having the following prescription (four color inks each containing a color pigment as a coloring material) were used.

(Ink formulation)
Each of the following pigments: 3 parts Black: Carbon black (Mitsubishi Chemical: MCF88)
Cyan: Pigment Blue 15
Magenta: Pigment Red 7
Yellow: Pigment Yellow 74
・ Styrene-acrylic acid-ethyl acrylate copolymer: 1 part ・ Glycerin: 10 parts ・ Ethylene glycol: 5 parts ・ Surfactant: 1 part (manufactured by Kawaken Fine Chemicals: Acetylenol EH)
・ Ion-exchanged water: 80 parts (c) Step of reducing the liquid content from the intermediate image on the intermediate transfer body Applying warm air to the intermediate image on the intermediate transfer body using a dryer to reduce the liquid content of the intermediate image went.
(D) Step of transferring intermediate image to recording medium The intermediate transfer member is heated to 70 ° C., and the intermediate image on the intermediate transfer member and the recording medium are pressurized to 1.0 MPa with a pressure roller to record the intermediate image. Transferred to the medium. Aurora coated paper made by Nippon Paper Industries was used as the recording medium.

(Example 2)
The same procedure as in Example 1 was performed except that the pressure in the step (d) of transferring the intermediate image to the recording medium was 5.0 MPa.

(Example 3)
Example: Except that linear protrusions are formed in parallel with a pitch of 3.0 μm on the entire surface of the mold, and each protrusion has a width w = 1.5 μm and a height d = 0.5 μm. 1 was performed.

Example 4
An intermediate transfer member was produced in the same manner as in Example 1 except that silicone rubber SIM-240 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. and curing agent CAT-240 (trade name) were used as the silicone rubber and the curing agent. Further, the compression elastic modulus of the completed intermediate transfer member was measured with a microhardness tester Fischerscope HM2000 (trade name) manufactured by Fischer Instruments (probe pushing speed 10 μm / sec, pushing depth 10 μm). As a result, the compression elastic modulus was 1.5 MPa.

(Comparative Example 1)
Image recording was performed in the same manner as in Example 1 except that the pressure in the step (d) of transferring the intermediate image to the recording medium was 0.7 MPa.

(Comparative Example 2)
Example: Except that linear protrusions are formed in parallel at a pitch of 2.0 μm on the entire surface of the mold, and each protrusion has a width w = 1.0 μm and a height d = 1.0 μm. Image recording was performed in the same manner as in Example 1.

(Comparative Example 3)
Silicone rubber SIM-240 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd. and curing agent CAT-240 (trade name) are used as the silicone rubber and the curing agent, and the pressure in the process of transferring the intermediate image to the recording medium in (d) is 3 0.0 MPa. Other than this, image recording was performed in the same manner as in Example 1. The compression modulus of the completed intermediate transfer member was measured (probe indentation speed 10 μm / sec, indentation depth 10 μm) with a microhardness tester Fischerscope HM2000 (trade name) manufactured by Fisher Instruments. As a result, the compression elastic modulus was 1.5 MPa.

(Comparative Example 4)
Example: Except that linear protrusions are formed in parallel at a pitch of 6.6 μm on the entire surface of the manufactured mold, and each protrusion has a width w = 3.3 μm and a height d = 2.1 μm. Image recording was performed in the same manner as in Example 1.
The image formed on the recording medium as described above was evaluated as follows.

1. Evaluation of image quality Images on the recording medium formed in the first and 100th image recording steps were evaluated according to the following criteria.
○: Deformation of the image shape due to a phenomenon such as ink dots attracting each other is hardly observed. X: Deformation of the image shape due to a phenomenon such as ink dots attracting each other is observed.

2. Evaluation of transferability Images on the recording medium formed in the first and 100th image recording steps were evaluated according to the following criteria.
○: Almost no white portion due to transfer failure is observed in the image.
×: White spots due to transfer defects are observed in the image.

3. Evaluation of Durability of Intermediate Transfer Member A fine groove shape on the surface of the intermediate transfer member after 100 times of the image recording process was observed with a scanning electron microscope and evaluated according to the following criteria.
○: There are less than 5 grooves that are significantly deformed in an arbitrary observation range of 100 μm × 100 μm.
X: There are 5 or more significantly deformed grooves in an arbitrary observation range of 100 μm × 100 μm.
Table 1 shows the characteristic values and evaluation results of each example.

  As is apparent from the results in Table 1, according to the present invention, the surface characteristics of the intermediate transfer member are maintained even when the transfer process is repeated at a high pressure, and a high-quality image can be obtained.

DESCRIPTION OF SYMBOLS 11 Surface layer member 12 Support member 13 Shaft 14 Process liquid provision means 15 Inkjet recording head 16 Blower 17 Heater 18 Recording medium 19 Pressure roller 20 Cleaning means

Claims (7)

An intermediate having a groove formed on the surface using a mold having a convex portion with a height d [μm] and a width w [μm] satisfying d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0. Forming an intermediate image by applying ink on the transfer member;
On the intermediate transfer member, the compression elastic modulus E [MPa] of the surface of the intermediate transfer member is set to P [MPa], and 1 ≦ P and 1 ≦ E / P ≦ 8 are satisfied. Transferring the intermediate image to a recording medium;
An image recording method comprising:   2. The image recording method according to claim 1, wherein S1 is a projected surface area in the vertical direction of the surface of the intermediate transfer member and S2 is an actual surface area of the intermediate transfer member, and 1.25 <S2 / S1. Prior to the step of forming the intermediate image,
3. The image recording method according to claim 1, further comprising a step of applying a treatment liquid onto the intermediate transfer member.   It has a groove formed on the surface using a mold having a convex portion whose height d [μm] and width w [μm] satisfy d / w ≦ 0.7 and 0.01 ≦ d ≦ 1.0. An intermediate transfer member characterized by   The intermediate transfer member according to claim 4, wherein S1 is a projected surface area in the vertical direction of the surface of the intermediate transfer member and S2 is an actual surface area of the intermediate transfer member, and 1.25 <S2 / S1. The intermediate transfer member according to claim 4 or 5,
Ink application means capable of applying ink to the surface of the intermediate transfer member;
1 ≦ P and 1 ≦ E / P ≦ where the compression elastic modulus of the surface of the intermediate transfer member is E [MPa] and the pressure during transfer is P [MPa] in contact with the surface of the intermediate transfer member. Transfer means capable of pressurizing the surface of the intermediate transfer member so as to satisfy 8;
An image recording apparatus comprising:   The image recording apparatus according to claim 6, further comprising a processing liquid applying unit capable of applying a processing liquid to a surface of the intermediate transfer member.

Images