Patent Application
20160129717
1. Field of the Invention
The present application relates to an intermediate transfer member and an image forming method.
2. Description of the Related Art
A variety of printed articles are produced in smaller lots in shorter delivery times. An ink jet recording method and apparatuses using the same are expected to be a suitable technique for responding to such market demands. In the ink jet recording method, however, the ink jet recording head (hereinafter referred to as recording head) may be broken by contact with the recording medium, or may be degraded in ejection stability due to paper dust or the like produced from the recording medium. In order to overcome these problems, there have been devised a variety of transfer ink jet recording methods that are performed by forming an intermediate image on an intermediate transfer member with a recording head, and transferring the intermediate image to a desired recording medium to form a final image. Japanese Patent Laid-Open No. 59-225958 discloses an ink jet printer that forms an intermediate image on a drum with a dye ink and then transfers the intermediate image to a recording medium.
It is desired from the viewpoint of image transfer efficiency that the intermediate transfer member used in such a transfer ink jet recording method have a surface having a low surface free energy. Unfortunately, if an intermediate image is formed on a surface having a low surface free energy, ink dots are attracted or mixed to each other by surface tension. This can cause the degradation of image quality. There have been devised many methods of applying a treatment liquid for reducing the fluidity of ink onto the intermediate transfer member before forming an intermediate image. In these methods, the treatment liquid previously applied to the surface of the intermediate transfer member reacts with the ink to reduce the fluidity of the ink, thereby keeping the resulting intermediate image in a good condition. Even if such a technique is used, however, an intermediate transfer member having a low surface energy is likely to reject the treatment liquid or cause similar phenomena, consequently degrading the quality of the subsequently formed intermediate image. In general, this tends to occur more frequently when the intermediate transfer member has a smooth surface with a small surface roughness. Accordingly, Japanese Patent Laid-Open No. 2009-078391 discloses that such a phenomenon is prevented by forming a fine uneven pattern in the surface of the intermediate transfer member.
According to an aspect of the disclosure, there is provided an intermediate transfer member used in an image forming method including applying a treatment liquid onto an intermediate transfer member, forming an intermediate image by applying an ink onto the intermediate transfer member coated with the treatment liquid so as to form dots having an average diameter of R, and transferring the intermediate image to a recording medium. The intermediate transfer member includes a surface capable of receiving the treatment liquid and the ink. The surface has a plurality of discrete recessed portions, each allowing a circle having a diameter of less than R to be present therein when viewed from above. The surface has a projected area S1 and an actual surface area S2 satisfying the relationship 1.1≦S2/S1≦5.
According to another aspect of the disclosure, an image forming method is provided which includes applying a treatment liquid onto the above-described intermediate transfer member, forming an intermediate image by applying an ink onto the intermediate transfer member coated with the treatment liquid so as to form dots having an average diameter of R, and transferring the intermediate image to a recording medium.
The intermediate transfer member and the image forming method can suppress the degradation of intermediate image quality resulting from the expansion of a defect in the coating of the treatment liquid and thus can enable high-quality images to be formed.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Even in the case of using an intermediate transfer member having a surface in which a fine uneven pattern is formed as disclosed in Japanese Patent Laid-Open No. 2009-078391, if the uneven pattern has a defect therein or foreign matter such as dust is deposited, the treatment liquid can be rejected from such a portion. Also, if the coating of the treatment liquid spread over the surface of the intermediate transfer member has a defect caused by such rejection, the three-phase contact line (the boundary of intermediate transfer member, treatment liquid, and air) is formed in the defect of the coating, and the boundary can migrate due to the surface tension of the treatment liquid. In this instance, the defect in the coating expands gradually (the exposed portion of the surface of the intermediate transfer member becomes larger) with time. In the exposed portion of the surface of the intermediate transfer member, the treatment liquid does not come into contact with the ink applied to the surface in a subsequent step, and therefore cannot reduce the fluidity of the ink. Consequently, the quality of the resulting intermediate image is degraded.
Accordingly, the present disclosure provides an intermediate transfer member that can suppress the degradation of intermediate image quality resulting from the expansion of a defect in the coating of the treatment liquid and thus can enable high-quality images to be formed, and an image forming method using the intermediate transfer member.
In the image forming method disclosed herein, a treatment liquid is applied onto an intermediate transfer member, and then, an intermediate image is formed by applying an ink onto the intermediate transfer member coated with the treatment liquid so as to form dots having an average diameter of R. Subsequently, the intermediate image is transferred to a recording medium. The surface of the intermediate transfer member that will receive the treatment liquid and the ink has a plurality of discrete recessed portions therein. Each of the recessed portions allows a circle having a diameter of less than R to be present therein when viewed from above. The projected area S1 and actual surface area S2 of the intermediate transfer member satisfy the relationship 1.1≦S2/S1≦5.
The intermediate transfer member disclosed herein is intended for use in the above-described image forming method. Exemplary embodiments of the image forming method and the intermediate transfer member will now be described.
The image forming method disclosed herein will be roughly illustrated below with reference to
In the following step, an intermediate image 105 is formed by selectively applying an image-forming ink to the surface of the intermediate transfer member 101 coated with the treatment liquid 102, using an ink jet recording head 104. In this operation, the ink is applied so as to form dots having a predetermined average diameter R. The average diameter R is desirably, but not limited to, 1 μm or more from the viewpoint of allowing the ink jet recording head to be controlled so as to accurately apply ink to appropriate positions. The ink applied to the intermediate transfer member 101 comes into contact with the treatment liquid 102 at the surface of the intermediate transfer member 101, thereby bringing about a chemical and/or physical reaction to reduce the fluidity thereof. Consequently, the phenomenon of attracting ink dots each other or mixing ink dots with each other can be reduced.
In the next step, the liquid component is removed from the intermediate image formed on the intermediate transfer member 101. This step prevents an excess of the liquid component in the intermediate image from coming out or overflowing during transfer and thus prevents messy images and transfer failure. For removing the liquid component from the intermediate image, any of the known methods may be used. For example, the liquid component may be removed by heating the intermediate image, blowing low-humidity air on the intermediate image, reducing pressure, bringing an absorber into contact with the intermediate image, or a combination of these methods. Natural drying may also be performed. The image forming apparatus shown in
Subsequently, in the next step, a recording medium 109 is pressed against the intermediate transfer member 101 to transfer the intermediate image to the recording medium 109. In the image forming apparatus shown in
If the intermediate transfer member is consecutively and repeatedly used from the viewpoint of productivity, the surface of the intermediate transfer member 101 may be cleaned to restore it before subsequent use. For cleaning for restoring, any of the known methods may be suitably used. For example, the surface of the intermediate transfer member may be cleaned by being showered with a cleaning liquid, being wiped with a wet Molton roller in contact therewith, or being brought into contact with the surface of a cleaning liquid. Alternatively, a wiper blade may be used for removing a residue, or an energy may be applied. Any method is useful. Some of these techniques may be combined. The image forming apparatus shown in
The image data transmitted from the image supplying device are thus processed, and the process of image forming is completed. The recording medium to which the image has been transferred may be pressed with a fixing roller to increase the smoothness of the surface in an additional step. The fixing roller may be heated to impart a fastness to the resulting image.
The main members and materials used in the image forming method of the present embodiment will now be described in detail.
The surface 202 used herein refers to the faces in the recessed portions at the level of 10% or less of the depth D of the recessed portions and the surface between the recessed portions.
In plan view, the opening 203 of each recessed portion allows an imaginary circle having a diameter of less than the average diameter R of the ink to be present therein, and the surface of the intermediate transfer member has a projected area S1 and an actual surface area S2 satisfying the relationship 1.1≦S2/S1≦5. If the coating film of the treatment liquid applied on the intermediate transfer member has a defect, the intermediate transfer member 101 having such recessed portions therein suppresses the expansion of the defect. The reason of this will be described below.
(1) The projection area S1 and actual surface area S2 of the intermediate transfer member satisfy the relationship 1.1≦S2/S1≦5. When this relationship holds true, the surface roughness of the intermediate transfer member can be appropriate and allows the treatment liquid to spread to form a coating film over the surface of the intermediate member.
(2) If the coating film of the treatment liquid has a defect, the three-phase contact line (the boundary of intermediate transfer member, treatment liquid, and air) is formed in the defect of the coating film. The boundary can migrate due to the surface tension of the treatment liquid, and thus the defect can expand. This is more likely to occur particularly on the surface of an intermediate transfer member made of a material having a low surface free energy. Such a surface tends to repel the treatment liquid. If a solid surface has a small step or the like, however, an edge of the step can pin (fix) the migrating three-phase contact line. In the intermediate transfer member 200 of the embodiments described herein, accordingly, an edge of the opening 203 of the recessed portion 201 pins the three-phase contact line even though a defect is formed in the coating film of the treatment liquid within any one of the recessed portions 201. Since the defect formed in the coating film within a recessed portion 201 is surrounded by the wall defining the opening 203, the expansion of the defect is stopped when the defect has reached the wall of the opening 203.
In the embodiments disclosed herein, in addition, the ink is applied so as to form dots having an average diameter of R, and the opening (defined by the shape of the recessed portion viewed from above) of the recessed portions allows an imaginary circle having a diameter of less than R to be present therein. Consequently, the treatment liquid and the ink can be brought into contact with each other effectively, thus helping the formation of a high-quality intermediate image. If the imaginary circle allowed to be present within the opening 203 of the recessed portion has a diameter more than or equal to R, the intermediate transfer member will be exposed with an area larger than the ink dot size, even if the migration of the three-phase contact line is stopped at the edge of the opening 203. When ink dots are applied in a subsequent step, therefore, the ink dot deposited on the exposed region of the intermediate transfer member does not come into contact with the treatment liquid, and consequently, the resulting image does not have satisfactory quality.
The shape of the opening 203 of the recessed portion 201 may be in any shape, such as a circular, a polygonal, or a grip shape, and is not particularly limited. Although the section of the recessed portion 201 taken along the thickness direction of the intermediate transfer member may be rectangular, triangular, or domed, and may be in any shape, the depth D of the recessed portion 201 desirably satisfies 0.05 μm≦D≦5.0 μm. Recessed portions 201 having a depth D of 0.05 μm or more can hold the treatment liquid therein effectively and allow the treatment liquid to spread efficiently over the surface of the intermediate transfer member so as to form a coating film. Recessed portions 201 having a depth D of 5.0 μm or less allow the treatment liquid and ink having penetrated thereinto to be transferred effectively to a recording medium, thus contributing to improving image transfer efficiency. The depth D of a recessed portion 201 refers to the length from the surface of the intermediate transfer member adjacent to the recessed portion 201 to the position having the largest depth of the recessed portion 201. The intermediate transfer member satisfies the relationship 1.1≦S2/S1≦5. When S2/S1 is in this range, the intermediate transfer member allows the treatment liquid to spread over the surface thereof to form a coating film of the treatment liquid. Advantageously, the projected area S1 and the actual surface area S2 satisfy the relationship 1.1≦S2/S1≦2.1, desirably 1.15≦S2/S1≦1.8.
In the recessed portion 201, protruding members having various shapes may be arranged on the bottom or the side wall. For example, protruding portions extending to the level of the height of the opening 203 of the recessed portion 201 may be formed from the bottom of the recessed portion 201 in the opening 203 so that the upper end surfaces of the protruding portions 203 are arranged in an island manner in the opening 203, as shown in
In this instance, each portion surrounded by straight solid lines in plan view (in
The opening 203 of each recessed portion 201 separated from each other by the protruding portion, that is, each discrete recessed portion, desirably has an area (in plan view) of 2 μm2 or more. In the case shown in
The support member of the intermediate transfer member is required to have a strength to some extent from the viewpoint of conveyance accuracy and durability. Suitable materials of the support member include metals, ceramics and resins. Among these materials, advantageous are aluminum, iron, stainless steel, acetal resin, epoxy resin, polyimide, polyethylene, polyethylene terephthalate, nylon, polyurethane, silica ceramics, and alumina ceramics. These materials are suitable in view of the rigidity of the support member against pressure applied for transfer and the dimensional accuracy, and suitable to reduce the inertia in operation to improve control response. Two or more of these materials may be used in combination. The surface member of the intermediate transfer member may be made of a rubber elastic material, such as rubber or elastomer. These materials allow the surface of the intermediate transfer member to be elastically deformed by the pressure applied for transfer, and allows intermediate images to be transferred to the surface of various types of recording media. Also, from the viewpoint of the efficiency of image transfer from the intermediate transfer member to the recording medium, the material of the surface member desirably has a low surface free energy. Accordingly, the surface member (surface of the intermediate transfer member) may be formed of a compound having a dimethylsiloxane structure or a fluoroalkyl structure. Silicone rubber and fluorocarbon rubber can be an example of such an advantageous material. Alternatively, the surface member may be formed by forming some layers of different materials. For example, the surface made of a rubber may be coated with a material having a low surface free energy. More specifically, a urethane rubber member may be coated with a condensed material produced by condensation of a hydrolyzable organic silicon compound.
For forming fine recessed portions in the surface of the intermediate transfer member, sand blast, cutting, or press forming such as nanoimprinting may be applied. In particular, nanoimprinting enables the formation of uniform grooves having dimensions of the order of sub-micron to nanometers in a wide area, and is therefore advantageous. In a nanoimprinting process, desired recessed portions can be formed by pressing using a mold having a desired negative pattern of grooves having dimensions of the order of sub-micron to nanometers. For forming the mold, photolithography or etching is advantageous from the viewpoint of accuracy and facilitating the manufacturing process. In these techniques, the process conditions can be appropriately set according to the shape and dimensions of the recessed portion.
The treatment liquid is intended to reduce the fluidity of the ink and may contain a substance for increasing the viscosity of the ink (hereinafter referred to as ink viscosity-increasing component) selected from known materials including, but not limited to, polyvalent metal ions, organic acids, cationic polymers, and porous particles without particular limitation. The ink viscosity-increasing component chemically reacts with or physically adsorbs to the coloring material or resin in the ink, thereby increasing the viscosity of the ink as a whole or forming an aggregate of some of the ink constituents. Thus, the viscosity of the ink is increased. Polyvalent metal ions and organic acids are particularly advantageous as the ink viscosity-increasing component. One or more of these ink viscosity-increasing components may be used in combination. The content of the ink viscosity-increasing component in the treatment liquid is desirably 5% by mass or more relative to the total mass of the treatment liquid.
More specifically, metal ions that can be used as the ink viscosity-increasing component include divalent metal ions and trivalent metal ions. Examples of divalent metal ions include Ca2+, cu2+, Ni2+, Mg2+, Sr2+, Ba2+, and Zn2+. Examples of trivalent metal ions include Fe3+, Cr3+, Y3+, and Al3+.
Examples of organic acids that can be used as the ink viscosity-increasing 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, pyrrolidonecarboxylic acid, pyronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumalic acid, thiophenecarboxylic acid, oxysuccinic acid, and dioxysuccinic acid.
The treatment liquid may contain an appropriate amount of water or organic solvent. The water is desirably deionized by, for example, ion exchange. The organic solvent that may be used in the treatment liquid is not particularly limited, and can be selected from known organic solvents. The treatment liquid may contain a resin. The addition of an appropriate resin to the treatment liquid is advantageous for increasing the adhesion of the transferred intermediate transfer member to the recording medium and for increasing the mechanical strength of the final image. Any resin may be added without particular limitation as long as it can coexist with the ink viscosity-increasing component. The treatment liquid may further contain a surfactant or a viscosity modifier to control the surface tension or the viscosity, if necessary. Any substance may be added without particular limitation as long as it can coexist with the ink viscosity-increasing component. For example, the surfactant may be selected from among cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants, fluorochemical surfactants, and silicone surfactants. A mixture of two or more of these surfactants may be used. If the surface of the intermediate transfer member is made of a material having a low surface free energy such as fluorocarbon or silicone, a treatment liquid containing a fluorochemical or silicone surfactant is effective and advantageous in terms of transferability. The content of such a surfactant may be 0.1% by mass or more relative to the total mass of the treatment liquid from the viewpoint of sufficiently reducing the surface tension of the treatment liquid so that it can be retained in the recessed portions 101B of the intermediate transfer member 101. The treatment liquid may further contain fine particles. The fine particles may be, but are not limited to, resin particles or inorganic particles. The content of the fine particles may be 5% by mass or more relative to the total mass of the treatment liquid. Advantageously, the fine particles have a particle size allowing the particles to enter the recessed portions in the surface of the intermediate transfer member.
The viscosity of the treatment liquid is desirably 500 Pa·s or less. A treatment liquid having a viscosity of 500 Pa·s or less can easily fill the recessed portions and uniformly spread over a surface. The surface tension of the treatment liquid is desirably 40 mN/m or less. A treatment liquid having a surface tension of 40 mN/m or less can easily spread over a surface.
The ink may contain at least one of pigments and dyes as a coloring material. The coloring material can be selected from among the dyes and pigments generally used in inks without particular limitation, and a desired amount of the selected material can be used. For example, for an ink jet ink, a known dye, carbon black, an organic pigment, or the like may be used as the coloring material. A solution or dispersion of a dye and/or a pigment may be used as the ink. Pigments are advantageous as the coloring material in terms of the fastness and quality of printed articles. If a pigment is used, a known inorganic or organic pigment may be used without particular limitation. More specifically, pigments designated by color index (C.I.) numbers can be used. A carbon black may be used as a black pigment. The pigment content in the ink may be in the range of 0.5% by mass to 15.0% by mass, such as in the range of 1.0% by mass to 10.0% by mass, relative to the total mass of the ink.
A pigment dispersant may be used for dispersing the pigment. The pigment dispersant can be selected from among known materials used in the ink jet recording method. Among the known pigment dispersants, advantageous is a water-soluble dispersant having a molecular structure having both a hydrophilic site and a hydrophobic site. In particular, there may be used a pigment dispersant containing a resin produced by copolymerizing at least a hydrophilic monomer and a hydrophobic monomer. The monomers are not particularly limited, and any known monomers can be used. Examples of the hydrophobic monomer include styrene, styrene derivatives, alkyl (meth)acrylates, and benzyl (meth)acrylate. Examples of the hydrophilic monomer include acrylic acid, methacrylic acid, and maleic acid. The dispersant may have an acid value in the range of 50 mg KOH/g to 550 mg KOH/g. The weight average molecular weight of the dispersant may be in the range of 1,000 to 50,000. The mass ratio of the pigment to the dispersant may be in the range of 1:0.1 to 1:3. Instead of using a dispersant, a self-dispersible pigment that has been surface-modified so as to be dispersible may be used.
The ink may further contain fine particles not containing a coloring material. Since some types of resin fine particles have the effect of improving image quality and adhesion, resin fine particles are advantageous. The material of the resin fine particles can be selected from among known resins without particular limitation. Exemplary materials of the resin fine particles include homopolymers or copolymers, such as polyolefin, polystyrene, polyurethane, polyester, polyether, polyurea, polyamide, polyvinyl alcohol, poly(meth)acrylic acids and salts thereof, polyalkyl (meth)acrylates, and polydiens. The weight average molecular weight of the resin fine particles may be in the range of 1,000 to 2,000,000. The content of the resin fine particles in the ink may be in the range of 1% by mass to 50% by mass, such as in the range of 2% by mass to 40% by mass, relative to the total mass of the ink. The ink may be used in the form of a resin fine particle dispersion in which resin fine particles are dispersed. The resin fine particles may be dispersed by any process. For example, particles of a homopolymer or copolymer of one or more monomers having a dissociable group are dispersed, and a thus prepared dispersion of self-dispersible resin particles is advantageously used. Exemplary dissociable groups include carboxy, sulfo and phosphate groups, and monomers having such a dissociable group include acrylic acid and methacrylic acid. Alternatively, an emulsifier-dispersed resin particle dispersion may be used which is prepared by dispersing resin fine particles with an emulsifier. A known surfactant may be used as the emulsifier irrespective of whether the resin particles have a low molecular weight or a high molecular weight. A nonionic surfactant or a surfactant having the same polarity as the resin fine particles is advantageous as the surfactant. The resin particles in the resin fine particle dispersion may have a particle size in the range of 10 nm to 1000 nm, such as 100 nm to 500 nm. For preparing the resin fine particle dispersion, some additives may be added to stabilize the dispersion. Examples of the 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. The surfactant may be Acetylenol EH (produced by Kawaken Fine Chemicals). The surfactant content in the ink may be in the range of 0.01% by mass to 5.0% by mass relative to the total mass of the ink. The ink may also contain water and/or a water-soluble organic solvent as the solvent. The water is desirably deionized by ion exchange. The water content in the ink can be in the range of 30% by mass to 97% by mass relative to the total mass of the ink. The water-soluble organic solvent is not particularly limited and any known organic solvent may be used. Examples of the water-soluble organic solvent include glycerin, diethylene glycol, polyethylene glycol, and 2-pyrrolidone. The content of the water-soluble organic solvent in the ink may be in the range of 3% by mass to 70% by mass relative to the total mass of the ink. The ink used in the present embodiment may further contain other additives, such as a pH adjuster, a rust preventive, a preservative, a fungicide, an antioxidant, an antireductant, a water-soluble resin and its neutralizer, and a viscosity modifier, as needed.
The image forming method and intermediate transfer member according to an embodiment of the disclosure will be further described with reference to Examples. The scope of the disclosure is not limited to the following Examples. In the following description, “part(s)” and “%” are on a mass basis unless otherwise specified.
One of the intermediate transfer members used in the Examples and Comparative Examples was prepared as below. First, a silicon substrate was formed into a mold for forming the intermediate transfer member by photolithography and etching. Subsequently, the mold was dipped in a release agent Durasurf HD-1101 TH (product name) produced by Harves. Then, the mold was allowed to stand at room temperature for 24 hours and rinsed with Novec HFE-7100 (product name) produced by 3M to remove the excess release agent. Subsequently, a silicone rubber SIM-260 (product name) produced by Shin-Etsu Chemical, which is a compound having a dimethylsiloxane structure and a curing agent CAT-260 (product name) by Shin-Etsu Chemical were mixed and kneaded in a mass ratio of 10 to 1, and the mixture was applied to a polyimide film to form a silicone rubber layer. Then, the silicon mold was pressed against the silicone rubber and heated at 150° C. for 30 minutes to cure the silicone rubber. Then, the mold was removed to yield an intermediate transfer member having small recessed portions in the surface thereof.
The surface and section of the resulting intermediate transfer member were observed through a scanning electron microscope and an atomic force microscope for measuring the shape and dimensions of the recessed portions. The section of the intermediate transfer member was formed by cutting the intermediate transfer member. As a result, it was found that recessed portions were formed in a grid manner throughout the surface as shown in
Two mixtures were prepared according to the compositions shown in Table 2. Then, the two mixtures were each heated in an oven at 50° C. for 24 hours to remove water, thus yielding treatment liquids A and B from which water was removed.
Inks were prepared according to the compositions shown in Table 3.
The following steps (a) to (c) for forming images were performed, using the above-prepared intermediate transfer members, treatment liquids for reducing ink fluidity, and inks.
(a) Step of Applying Treatment Liquid onto Intermediate Transfer Member
The treatment liquid was applied to the surface of the intermediate transfer member with a roll coater. The treatment liquid was applied at a rate of 1.0 g/m2.
Using an ink jet recording apparatus (nozzle density: 1200 dpi; ejection amount: 4.8 pL; driving frequency: 12 kHz), a mirror-reverse characters (intermediate image) were formed by applying inks onto the intermediate transfer member coated with the treatment liquid. The average diameter R of the ink dots applied on the intermediate transfer member was measured through an optical microscope, and it was 30 μm. The average diameter R of the ink dots was calculated by averaging the measured diameters of the ink dots at 25 points randomly selected from a square region of 500 μm on a side observed through the optical microscope.
The liquid component in the intermediate image was reduced by blowing hot air from a dryer on the intermediate image on the intermediate transfer member. Then, the intermediate transfer member was heated to 70° C. on a hot plate, and the intermediate image on the intermediate transfer member and a recording medium were pressed on each other at 1.0 MPa with a pressure roller. The recording medium was Aurora Coat manufactured by Nippon Paper Industries.
The intermediate transfer members and the treatment liquids were combined as shown in Table 4. The resulting images were evaluated as below. The evaluation results are shown in Table 4.
The surface of each intermediate transfer member subjected to Step (a) was observed through an optical microscope. The area of the portions of the intermediate transfer member exposed by repelling of the treatment liquid and allowing a circle with a diameter of 30 μm or more to be present therein was measured, and the percentage of this area to the projected area of the intermediate transfer member was calculated.
Images obtained through Step (c) were evaluated according to the following criteria.
Good: Color unevenness resulting from unintended migration of ink dots or attraction among ink dots was hardly observed.
Bad: A large amount of color unevenness resulting from unintended migration of ink dots or attraction among ink dots was observed.
The results clearly show that an embodiment of the disclosure enables the formation of high-quality images having little color unevenness.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2014-226065, filed Nov. 6, 2014, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-226065 | Nov 2014 | JP | national |
