JP2008122542A - Image forming method, liquid developing device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method, a liquid developing device and an image forming apparatus, which are friendly for the environment, and also, capable of firmly fixing toner particles to a recording medium while preventing deterioration in quality of the obtained image. <P>SOLUTION: The image forming method includes: by using a plurality of liquid developers having different colors, forming a plurality of single color images corresponding to the colors; transferring the plurality of single color image corresponding to the colors onto a recording medium and forming a non-fixed color image onto the recording medium; and fixing the non-fixed color image onto the recording medium. In the image forming method, each of the liquid developers includes an insulating liquid containing unsaturated fatty acid components and toner particles dispersed in the insulating liquid, and an oxidation polymerization accelerator that accelerates an oxidation polymerization reaction of the unsaturated fatty acid components during fixation is contained in the liquid developer forming the single color image that is positioned closest to the recording medium among the plurality of single color images forming the non-fixed color image. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming method, a liquid developing device, and an image forming apparatus.

Conventionally, as a method for forming an image on a recording medium, a method using a liquid developer in which toner particles are dispersed in an insulating liquid is known.
In this method using a liquid developer, toner particles are more effectively prevented from agglomerating than dry toner using toner in a dry state, so that fine toner particles can be used. As described above, those having a low softening point (low softening temperature) can be used. As a result, an image forming apparatus using a liquid developer has characteristics that fine line image reproducibility, gradation reproducibility, and color reproducibility can be obtained. .

As the insulating liquid used for the liquid developer, petroleum-based hydrocarbons, silicone oils, and the like are generally used because of their high chemical stability.
However, the method using a liquid developer has a problem that the insulating liquid adhering to the surface of the toner particles at the time of fixing permeates into the recording medium and reduces the fixing strength. In addition, there is also a problem that it becomes difficult to add information to the recording medium with a ballpoint pen or the like due to this soaking.

In order to solve such a problem, an attempt has been made to use naturally-derived fats and oils such as vegetable oil as an insulating liquid, and to utilize the oxidative polymerization reaction of the fats and oils for fixing (for example, see Patent Document 1). ).
However, in Patent Document 1, fixing properties are improved by using an oxidative polymerization accelerator such as a fatty acid metal salt that promotes oxidative polymerization. However, such an oxidative polymerization accelerator decreases the color of an obtained image. Therefore, it has been difficult to apply to color development.

JP 2000-162829 A

  An object of the present invention is to provide an image forming method, a liquid developing apparatus, and an image forming apparatus that are environmentally friendly and can firmly fix toner particles on a recording medium while preventing deterioration of the image quality of the obtained image. There is to do.

Such an object is achieved by the present invention described below.
The image forming method of the present invention is an image forming method for forming a color image on a recording medium using a liquid developer in which toner particles are dispersed in an insulating liquid containing an unsaturated fatty acid component.
A development step of forming a plurality of single color images corresponding to each color using a plurality of liquid developers having different colors;
Transferring a plurality of monochrome images corresponding to each color to the recording medium, and forming an unfixed color image formed by superimposing the plurality of monochrome images on the recording medium;
A fixing step of fixing the unfixed color image on the recording medium,
Of the plurality of monochrome images constituting the unfixed color image, only the liquid developer that forms a monochrome image located closest to the recording medium is subjected to an oxidation polymerization reaction of the unsaturated fatty acid component at the time of fixing. It includes an oxidative polymerization accelerator that promotes the polymerization.
Accordingly, it is possible to provide an image forming method that is friendly to the environment and can firmly fix the toner particles on the recording medium while preventing deterioration of the image quality of the obtained image.

The image forming method of the present invention is an image forming method for forming a color image on a recording medium using a liquid developer in which toner particles are dispersed in an insulating liquid containing an unsaturated fatty acid component.
A development step of forming a plurality of single color images corresponding to each color using a plurality of liquid developers having different colors;
Transferring a plurality of monochrome images corresponding to each color to the recording medium, and forming an unfixed color image formed by superimposing the plurality of monochrome images on the recording medium;
A fixing step of fixing the unfixed color image on the recording medium,
Accelerates the oxidative polymerization reaction of the unsaturated fatty acid component at the time of fixing to a liquid developer that forms a single color image located closest to the recording medium among the plurality of single color images constituting the unfixed color image It is characterized by containing the most oxidative polymerization accelerator.
Accordingly, it is possible to provide an image forming method that is friendly to the environment and can firmly fix the toner particles on the recording medium while preventing deterioration of the image quality of the obtained image.

In the image forming method of the present invention, the oxidative polymerization included in the liquid developer that forms a single color image located closest to the recording medium among the plurality of single color images constituting the unfixed color image. The content of the accelerator is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the insulating liquid.
As a result, the oxidation polymerization reaction of the insulating liquid can be more reliably advanced at the time of fixing while sufficiently preventing the oxidation polymerization reaction during storage of the liquid developer, etc. A reduction in image quality can be effectively prevented.
In the image forming method of the present invention, the liquid developer that forms a single color image positioned closest to the recording medium among the plurality of single color images constituting the unfixed color image is a single color corresponding to black. It is preferable to form an image.
As a result, it is possible to more effectively prevent a reduction in image quality of the obtained image.

In the image forming method of the present invention, the insulating liquid preferably contains an unsaturated fatty acid glyceride and a fatty acid monoester.
Thereby, the fixing strength of the toner particles can be increased, and fixing at a low temperature can be achieved.
In the image forming method of the present invention, the oxidative polymerization accelerator is preferably contained in the liquid developer in an encapsulated state.
As a result, the unintentional oxidative polymerization reaction of the unsaturated fatty acid component can be prevented, and at the time of fixing, the capsule is crushed by the pressure at the time of fixing and the oxidative polymerization reaction of the unsaturated fatty acid component is reliably advanced. be able to.

The liquid developing apparatus of the present invention is a liquid developing apparatus applied to the image forming method of the present invention,
A plurality of developing units that form the single-color image corresponding to each color using a plurality of liquid developers having different colors;
By transporting the recording medium, the plurality of single-color images formed by the plurality of developing units are sequentially transferred to the recording medium, and the unfixed color image formed by superimposing the transferred plurality of single-color images And a transfer portion formed on the recording medium.
Accordingly, it is possible to provide a liquid developing apparatus that is friendly to the environment and can firmly fix the toner particles on the recording medium while preventing deterioration of the image quality of the obtained image.

The liquid developing apparatus of the present invention is a liquid developing apparatus applied to the image forming method of the present invention,
A plurality of developing units that form a single color image corresponding to each color using a plurality of liquid developers having different colors;
An intermediate transfer unit that sequentially transfers a plurality of the single-color images formed by the plurality of developing units, and forms an intermediate transfer image formed by superimposing the transferred single-color images;
A secondary transfer unit that transfers the intermediate transfer image and transfers the transferred intermediate transfer image;
And a tertiary transfer unit that transfers the conveyed intermediate transfer image onto the recording medium and forms the unfixed color image on the recording medium.
Accordingly, it is possible to provide a liquid developing apparatus that is friendly to the environment and can firmly fix the toner particles on the recording medium while preventing deterioration of the image quality of the obtained image.
An image forming apparatus of the present invention includes the liquid developing device of the present invention and a fixing device that fixes the unfixed color image formed on the recording medium.
As a result, it is possible to provide an image forming apparatus that is friendly to the environment and can firmly fix the toner particles to the recording medium while preventing deterioration of the image quality of the obtained image.

Hereinafter, preferred embodiments of the image forming method, the liquid developing apparatus, and the image forming apparatus of the present invention will be described.
<First Embodiment of Image Forming Method>
First, a first embodiment of the image forming method of the present invention will be described.
The image forming method of this embodiment uses a plurality of liquid developers having different colors to develop a plurality of single color images corresponding to each color, and transfers a plurality of single color images corresponding to each color to a recording medium. And a transfer step of forming an unfixed color image formed by superimposing a plurality of single color images on the recording medium, and a fixing step of fixing the unfixed color image on the recording medium.
Further, in the image forming method of the present embodiment, the liquid developer is one in which toner particles are dispersed in an insulating liquid containing an unsaturated fatty acid component.

[Liquid developer]
First, the liquid developer applied to the image forming method (liquid developing apparatus, image forming apparatus) of the present invention will be described in detail.
1. Insulating Liquid First, the insulating liquid will be described.

The insulating liquid constituting the liquid developer used in the image forming method (liquid developing apparatus, image forming apparatus) of the present invention contains an unsaturated fatty acid component having an unsaturated bond.
This unsaturated fatty acid component is an environmentally friendly component. Accordingly, it is possible to reduce the load on the environment of the insulating liquid due to leakage of the insulating liquid to the outside of the liquid developing device and disposal of the used liquid developer. As a result, an environment-friendly image forming method can be provided.

The unsaturated fatty acid component is a component that undergoes oxidative polymerization by heating or the like during fixing. That is, the unsaturated fatty acid component is a component having a function of curing itself by oxidative polymerization and improving the fixing property of the toner particles. In particular, by using an oxidative polymerization accelerator described later, the oxidative polymerization reaction can be rapidly advanced, and the toner particles can be firmly fixed in a shorter time. Further, since the unsaturated fatty acid component is cured, the fixed toner image can be easily and reliably added with an aqueous ballpoint pen.
Further, since the unsaturated fatty acid component has a high affinity with the toner particles (resin material constituting the toner particles), the toner containing the unsaturated fatty acid component as the insulating liquid as in the present invention can be used as a toner. The dispersibility of the particles can be improved. As a result, it is possible to effectively prevent toner particles from being settled or aggregated during storage.

  Examples of unsaturated fatty acids constituting the unsaturated fatty acid component include monounsaturated fatty acids represented by oleic acid, palmitoleic acid, ricinoleic acid, etc., linoleic acid, α-linolenic acid, γ-linolenic acid, arachidonic acid , Polyunsaturated fatty acids typified by docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and the like, and one or more of these can be used.

Among the above-mentioned, it is preferable to use a polyunsaturated fatty acid component, and it is more preferable to use a polyunsaturated fatty acid component having a conjugated unsaturated bond (conjugated unsaturated fatty acid component). Thereby, the oxidative polymerization reaction can proceed more effectively.
As such a conjugated unsaturated fatty acid component, any component having a conjugated unsaturated bond may be used. For example, a synthesized one may be used, or one extracted directly from vegetable oil or the like. May be used, or those obtained by conjugating unsaturated fatty acid components may be used.

Unsaturated fatty acid components as described above are, for example, dehydrated castor oil, tung oil, safflower oil, linseed oil, sunflower oil, corn oil, cottonseed oil, soybean oil, sesame oil, corn oil, cannabis oil, evening primrose oil, blackcurrant oil, borage Oils (borage oil), oils derived from plants such as sardine oil, mackerel oil and herring oil, and oils derived from nature such as oils and fats derived from various animals.
Among the above-mentioned, dehydrated castor oil can be suitably used because it contains a large amount of conjugated linoleic acid component (conjugated unsaturated fatty acid component), and allows the oxidative polymerization reaction to proceed more effectively. As a result, the toner image can be fixed more firmly.

The ratio of the unsaturated fatty acid component to the total fatty acid component in the insulating liquid is not particularly limited, but is preferably 10 mol% or more, more preferably 20 mol% or more, and further preferably 20 to 90 mol%. preferable. Thereby, the oxidation polymerization reaction can be more effectively advanced during fixing.
Further, in the insulating liquid, the unsaturated fatty acid component may take any form. For example, in the insulating liquid, the unsaturated fatty acid component may exist as an unsaturated fatty acid (or a co-unsaturated fatty acid salt), or may be combined with other components to form a compound. Also good. Examples of such compounds include esters of unsaturated fatty acid components and alcohol components (polyhydric alcohol components), amides of unsaturated fatty acid components and amine components (polyhydric amine components), among others, Esters are preferred, and esters of glycerin and unsaturated fatty acid components (hereinafter also referred to as “unsaturated fatty acid glycerides”) are more preferred. The formation of the ester as described above in the insulating liquid makes the liquid developer excellent in storage stability and long-term stability, and more excellent in fixing properties of toner particles to the recording medium. Can be.

In addition, the insulating liquid may contain, for example, a saturated fatty acid component as shown below in addition to the components described above.
The saturated fatty acid component is a component having a function of keeping the chemical stability of the liquid developer high. Therefore, when a saturated fatty acid component is included in the insulating liquid, chemical change of the liquid developer can be effectively prevented, and as a result, the storage stability and long-term stability of the obtained liquid developer are higher. It can be.
Moreover, the saturated fatty acid component has a function of keeping electrical insulation and viscosity high. Therefore, when the insulating liquid contains a saturated fatty acid component, the electrical resistance of the liquid developer can be maintained at a higher level. Further, the transportability of the liquid developer becomes better due to an appropriate viscosity.

Examples of saturated fatty acids constituting such saturated fatty acid components include butyric acid (C4), caproic acid (C6), caprylic acid (C8), capric acid (C10), lauric acid (C12), and myristylic acid (C14). , Palmitic acid (C16), stearic acid (C18), arachidic acid (C20), behenic acid (C22), lignoceric acid (C24) and the like, and one or more selected from these are used in combination. be able to. Among the saturated fatty acids as described above, the number of carbon atoms in the molecule is preferably 6-22, more preferably 8-20, and even more preferably 10-18. . By including a saturated fatty acid component composed of such a saturated fatty acid, the effects as described above are exhibited more significantly.
The saturated fatty acid components as described above are, for example, natural oils and fats such as oils derived from plants such as palm oil (particularly palm kernel oil), coconut oil, and palm oil, and oils and fats derived from various animals (eg butter). Can be obtained efficiently.

  When the saturated fatty acid component is contained in the insulating liquid, the ratio of the saturated fatty acid component to the total fatty acid component in the insulating liquid is not particularly limited, but is preferably 0.5 to 40 mol%, More preferably, it is 30 mol%. As a result, the oxidative polymerization reaction can be more effectively advanced at the time of fixing while increasing the electrical insulation of the insulating liquid.

  As described above, when the insulating liquid includes an unsaturated fatty acid component and a saturated fatty acid component, the unsaturated fatty acid component and the saturated fatty acid component may take any form in the insulating liquid. For example, in an insulating liquid, an unsaturated fatty acid component and a saturated fatty acid component are each independently present as an unsaturated fatty acid (or unsaturated fatty acid salt) or a saturated fatty acid (or saturated fatty acid salt). It may be combined with other components to form a compound. Examples of such compounds include unsaturated fatty acid components, esters of saturated fatty acid components and alcohol components (polyhydric alcohol components), unsaturated fatty acid components, amides of saturated fatty acid components and amine components (polyhydric amine components). Among them, an ester is preferable, and an ester of glycerin with an unsaturated fatty acid component and a saturated fatty acid component (hereinafter also referred to as “glyceride”) is more preferable.

The insulating liquid may contain, for example, the following fatty acid monoesters in addition to the components described above.
The fatty acid monoester is an ester of a fatty acid and a monohydric alcohol.
Since the fatty acid monoester has a property of low molecular weight and low viscosity, it penetrates into the resin particles (toner particles) during the fixing process and exhibits a plastic effect. Due to this plastic effect, for example, when paper is used as the recording medium, the toner particles can easily enter the gaps between the paper fibers, so that the fixing strength of the toner particles can be increased and at a low temperature. Fixing can also be possible. In addition, since the toner particles enter the gaps between the fibers of the recording medium in this way, the resulting color image is smooth without any unevenness, and as a result, the gloss of the formed image is excellent. can do.

Further, due to such a plastic effect, the toner particles corresponding to each color are suitably mixed at the time of fixing, and an image having a desired color tone can be suitably formed.
In particular, when a polyester resin is used as the resin material constituting the toner particles, the plastic effect as described above is remarkably exhibited, the fixing strength of the toner particles can be made particularly high, and a particularly excellent color tone can be obtained. Color images can be formed.

In addition, since fatty acid monoester is a component that easily penetrates into the recording medium, the fatty acid monoester adhering to the vicinity of the surface of the toner particles quickly penetrates into the recording medium when the toner particles come into contact with the recording medium during fixing. To do. Along with the permeation of the fatty acid monoester, a part of the toner particles (resin material constituting the toner particles) melted by heat at the time of fixing penetrates into the inside of the recording medium, an anchor effect works, and the fixing strength is improved. . Further, along with the penetration of the fatty acid monoester, a part of the unsaturated fatty acid glyceride existing near the surface of the toner particles also penetrates, and the toner particles are fixed more firmly by oxidative polymerization in this state.
Furthermore, since this fatty acid monoester is an environmentally friendly component, it is possible to reduce the environmental impact of the insulating liquid due to leakage of the insulating liquid outside the image forming apparatus and disposal of the used liquid developer. it can. As a result, an environment-friendly image forming apparatus can be provided.

  The content of the fatty acid monoester in the insulating liquid is preferably 5 to 55 wt%, more preferably 10 to 50 wt%, and still more preferably 20 to 50 wt%. When the content of the fatty acid monoester is within the above range, the permeability of the insulating liquid into the recording medium can be made higher. In addition, the plastic effect as described above can be sufficiently exhibited. As a result, the toner particles can be fixed more firmly, and a color image having a particularly excellent color tone can be formed.

  Fatty acid monoesters that can be used in the liquid developer of the present invention are not particularly limited. For example, oleic acid, palmitoleic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, arachidonic acid, docosahexaenoic acid (DHA), Unsaturated fatty acid alkyl (methyl, ethyl, propyl, butyl, etc.) monoesters such as eicosapentaenoic acid (EPA), butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, mytilic acid, palmitic acid, stearin Alkyl (methyl, ethyl, propyl, butyl, etc.) monoesters of saturated fatty acids represented by acid, arachidic acid, behenic acid, lignoceric acid, etc. are mentioned, and one or more selected from these are combined Can be used.

  As the fatty acid monoester, an unsaturated fatty acid monoester having an unsaturated fatty acid component as described above in the fatty acid component is preferably used. The unsaturated fatty acid component is a component that can contribute to improving the fixability of toner particles to a recording medium. More specifically, the unsaturated fatty acid monoester is oxidatively polymerized at the time of fixing, so that the unsaturated fatty acid monoester itself is cured, and the fixing strength between the toner particles and the recording medium can be particularly improved. As a result, not only unsaturated fatty acid glycerides but also unsaturated fatty acid monoesters can contribute to oxidative polymerization, so that the anchor effect described above can be made particularly effective, and particularly excellent fixing strength can be obtained. it can.

The content of unsaturated fatty acid components in the total fatty acid components in the fatty acid monoester is preferably 50 mol% or more, and more preferably 60 mol% or more. As a result, the above-described effect becomes particularly reliable, and a particularly strong fixing strength can be obtained.
The fatty acid component of the fatty acid monoester is preferably mainly composed of unsaturated fatty acids, but may partially contain saturated fatty acids. Thereby, the preservability and long-term stability of the insulating liquid can be further improved.

  The fatty acid monoester is an ester of a fatty acid and a monohydric alcohol, and this alcohol is preferably an alkyl alcohol having 1 to 4 carbon atoms. Thereby, the chemical stability of the liquid developer is excellent, and the storage stability and long-term stability of the liquid developer are further improved. Further, the viscosity of the insulating liquid can be made favorable, and the penetration of the liquid developer into the recording medium can be made more suitable. Examples of such alcohol include methanol, ethanol, propanol, butanol, isobutanol and the like.

  Moreover, it is preferable that the fatty acid monoester which comprises an insulating liquid is produced | generated by transesterification with fatty acid glyceride and C1-C4 monohydric alcohol. Thereby, since the affinity between the fatty acid monoester and the fatty acid glyceride is further increased, the viscosity of the insulating liquid becomes suitable, and the penetration of the liquid developer into the recording medium is further improved. Thereby, the fixing strength of the toner particles on the recording medium is excellent, and the liquid developer suitable for high-speed image formation can be suitably applied.

  When the insulating liquid is composed of the unsaturated fatty acid glyceride and the fatty acid monoester as described above, the content of the unsaturated fatty acid glyceride in the insulating liquid is A [wt%], and the content of the fatty acid monoester is B When [wt%] is satisfied, it is preferable to satisfy the relationship of 0.1 ≦ A / B ≦ 9, more preferably to satisfy the relationship of 0.4 ≦ A / B ≦ 9. It is more preferable that the relationship of 6 ≦ A / B ≦ 9 is satisfied. By satisfying such a relationship, the viscosity of the insulating liquid can be made more appropriate, and the permeability of the insulating liquid into the recording medium can be made higher. As a result, the anchor effect due to the curing of the unsaturated fatty acid component as described above is more remarkably exhibited, and the fixing strength of the toner particles to the recording medium can be made particularly excellent. Further, the plastic effect can be made more prominent, and the gloss (gloss) of the formed image can be made particularly excellent.

Further, when the insulating liquid is composed of the unsaturated fatty acid glyceride and the fatty acid monoester as described above, the content of the unsaturated fatty acid glyceride in the insulating liquid is specifically 20 to 90 wt%. Is preferable, and it is more preferable that it is 40-90 wt%.
Further, when the insulating liquid is composed of the unsaturated fatty acid glyceride and the fatty acid monoester as described above, the content of the fatty acid monoester in the insulating liquid is specifically 10 to 80 wt%. Is preferable, and it is more preferable that it is 10 to 60 wt%.
Further, the liquid developer (insulating liquid) may contain an antioxidant having a function of preventing and suppressing oxidation of the insulating liquid. Thereby, unintentional oxidation of the unsaturated fatty acid component can be prevented.

  Examples of the antioxidant described above include vitamin E such as tocopherol, d-tocopherol, dl-α-tocopherol, acetic acid-α-tocopherol, dl-α-tocopherol acetate, tocopherol acetate, α-tocopherol, etc., dibutylhydroxy Examples include vitamin C such as toluene, butylhydroxyanisole, ascorbic acid, ascorbates, ascorbic acid stearate, green tea extract, fresh coffee extract, sesamol, sesaminol, etc., one or more of these Can be used in combination.

  Among the above, when vitamin E is used, the following effects are obtained. In other words, vitamin E is an environmentally friendly component and a component that has a small influence on a liquid developer caused by oxidation of itself. In particular, vitamin E can be suitably used as an antioxidant because of its high dispersibility in liquids (particularly glycerides) containing unsaturated fatty acid components as described above. Further, the combined use of vitamin E and glycerides as described above can further improve the affinity between the insulating liquid and the toner particles. As a result, the storage stability of the liquid developer, the fixability of the toner particles to the recording medium, and the like are particularly excellent.

  Moreover, among the above-mentioned, when vitamin C is used, the following effects are acquired. That is, like the above-mentioned vitamin E, vitamin C is an environmentally friendly component and a component that has a small influence on a liquid developer due to oxidation of itself. In addition, since vitamin C has a relatively low thermal decomposition temperature, it can sufficiently exhibit its function as an antioxidant during storage of a liquid developer (including idling of an image forming apparatus). At the same time, at the time of fixing, the function as an antioxidant can be reduced, and the oxidative polymerization reaction of the insulating liquid can proceed more reliably.

  The thermal decomposition temperature of the antioxidant is preferably not higher than the fixing temperature at the time of fixing. This effectively prevents deterioration of the insulating liquid during storage of the liquid developer, and at the time of fixing, thermally decomposes the antioxidant in the insulating liquid attached to the surface of the toner particles, The insulating liquid can be effectively cured (oxidative polymerization reaction), and the toner particles can be sufficiently fixed to the recording medium.

Specifically, the thermal decomposition temperature of the antioxidant is preferably 200 ° C. or lower, and more preferably 180 ° C. or lower. Thereby, it is possible to more effectively improve the fixing strength of the toner particles while sufficiently retaining the function as an antioxidant.
The electrical resistance of the insulating liquid as described above at room temperature (20 ° C.) is preferably 1 × 10 ⁹ Ωcm or more, more preferably 1 × 10 ¹¹ Ωcm or more, and 1 × 10 ¹³ Ωcm or more. More preferably.
The dielectric constant of the insulating liquid is preferably 3.5 or less.

2. Oxidation polymerization accelerator In the present embodiment, a liquid developer (hereinafter simply referred to as a liquid developer) that forms a monochrome image located on the side closest to the recording medium among a plurality of monochrome images constituting an unfixed color image formed on the recording medium. Only the first liquid developer) contains an oxidative polymerization accelerator (curing accelerator) that accelerates the oxidative polymerization reaction (curing reaction) of the unsaturated fatty acid component during fixing.

By the way, in general, the oxidation polymerization accelerator itself exhibits a color such as brown. Therefore, usually, when applied to color development, there is a problem that the color of the resulting image is lowered by the color exhibited by the oxidation polymerization accelerator.
On the other hand, in the case of this embodiment, since the single-color image near the surface layer of the unfixed toner image transferred to the recording medium does not contain the oxidation polymerization accelerator, the influence of the color of the oxidation polymerization accelerator is small. As a result, it is possible to prevent deterioration of the image quality of the obtained image.

Further, since the unfixed toner image is transferred so that the layer containing the oxidation polymerization accelerator (monochromatic image) and the recording medium are in contact with each other, the insulating liquid containing the oxidation polymerization accelerator soaks into the recording medium, and in this state Since the unsaturated fatty acid component is solidified by fixing, the anchor effect works and the toner particles can be firmly fixed.
The oxidative polymerization accelerator is not particularly limited. However, during storage (including idling of the image forming apparatus), the oxidative polymerization accelerator does not substantially contribute to the oxidative polymerization reaction of the unsaturated fatty acid component, and during fixing. It is preferable that it contributes to the oxidative polymerization (curing) reaction of the unsaturated fatty acid component.
Moreover, as an oxidative polymerization accelerator, for example, it has a function of accelerating the oxidative polymerization reaction (curing reaction) of the insulating liquid under heating conditions. A substance that does not have a function of promoting the reaction), that is, a substance having a relatively high activation energy in the oxidative polymerization reaction (curing reaction) of the unsaturated fatty acid component can be used.

Examples of such oxidative polymerization accelerators include fatty acid metal salts.
Examples of fatty acid metal salts include resin acid metal salts (for example, cobalt salts, manganese salts, lead salts, etc.), linolenic acid metal salts (for example, cobalt salts, manganese salts, lead salts, etc.), octylic acid metal salts (for example, , Cobalt salts, manganese salts, lead salts, zinc salts, calcium salts, etc.), naphthenic acid metal salts (for example, zinc salts, calcium salts, cobalt salts, etc.), etc. They can be used in combination.

  Further, the oxidative polymerization accelerator may be contained in the liquid developer in an encapsulated state. Thus, as described above, the oxidative polymerization accelerator does not substantially contribute to the oxidative polymerization reaction of the unsaturated fatty acid component at the time of idling of the image forming apparatus, and the oxidation of the unsaturated fatty acid component at the time of fixing. It can contribute to a polymerization (curing) reaction. In other words, the oxidative polymerization reaction during storage of the liquid developer is more reliably prevented, and at the time of fixing, the oxidative polymerization accelerator and the insulating liquid come into contact with each other by the capsule being crushed by the pressure during fixing. In addition, the oxidative polymerization reaction of the insulating liquid can be reliably advanced. Further, with such a configuration, the range of selection of the material for the oxidation polymerization accelerator is widened. In other words, even a highly reactive oxidative polymerization accelerator (an oxidative polymerization accelerator that contributes to the oxidative polymerization reaction of an insulating liquid at a relatively low temperature) can be suitably used, and toner particles are fixed on a recording medium. The strength can be made particularly excellent.

The encapsulation of the oxidation polymerization accelerator can be performed, for example, as follows.
First, an oxidation polymerization accelerator is prepared.
Next, the oxidative polymerization accelerator is dissolved in a solvent.
Such a solvent is not particularly limited as long as the oxidative polymerization accelerator is soluble, and examples thereof include inorganic solvents such as carbon disulfide and carbon tetrachloride, methyl ethyl ketone (MEK), and methyl isopropyl ketone (MIPK). , Ketone solvents such as 2-heptanone, alcohol solvents such as pentanol, n-hexanol, 1-octanol and 2-octanol, ether solvents such as diethyl ether and anisole, hexane, pentane, heptane, cyclohexane, octane, Aliphatic hydrocarbon solvents such as isoprene, aromatic hydrocarbon solvents such as toluene, xylene, benzene, ethylbenzene, and naphthalene, aromatic heterocyclic compounds solvents such as furan and thiophene, halogen compound solvents such as chloroform, acetic acid Ethyl, isopropyl acetate, isobutyl acetate, Examples include organic solvents such as ester solvents such as ethyl crylate, nitrile solvents such as acrylonitrile, nitro solvents such as nitromethane and nitroethane, and a mixture of one or more selected from these. be able to.

Next, a porous material such as hydrophilic silica, hydrophilic alumina, hydrophilic titanium oxide or the like is added to the obtained solution, and the solution is adsorbed on the porous material.
Next, the porous body on which the solution is adsorbed and a polyether such as polyethylene glycol or polypropylene glycol are mixed while heating.
The mixing ratio of the porous body and the polyether is preferably about 1: 0.5 to 1:10, more preferably about 1: 1 to 1: 5, by weight.
Moreover, it is preferable that the temperature at the time of mixing a porous body and polyether is 5-80 degreeC, and it is more preferable that it is 20-80 degreeC.

Next, after the obtained mixture is sufficiently dispersed in the petroleum-based hydrocarbon, it is cooled and the polyether is deposited on the surface of the porous body. As a result, a polyether film is formed on the surface of the porous body.
Then, the encapsulated oxidative polymerization accelerator is obtained by filtering to remove petroleum hydrocarbons.

  The content of the oxidative polymerization accelerator in the first liquid developer is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the insulating liquid, and 0.05 to 1 part by weight. More preferably, it is 0.1 to 0.8 part by weight. As a result, the oxidation polymerization reaction of the unsaturated fatty acid component can be progressed more reliably during fixing while sufficiently preventing the oxidation polymerization reaction during storage of the liquid developer, etc. It is possible to prevent the deterioration of the image quality due to.

3. Toner Particles Next, toner particles will be described.
(Constituent material of toner particles)
The toner particles (toner) include at least a binder resin (resin material).

(1) Resin material The toner constituting the liquid developer is composed of a material containing a resin material as a main component.
In the present invention, the resin (binder resin) is not particularly limited, and for example, polystyrene, poly-α-methylstyrene, chloropolystyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-butadiene copolymer. Polymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester -Styrene resin such as methacrylic acid ester copolymer, styrene-α-crawler methyl acrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, styrene-vinyl methyl ether copolymer, etc. Homopolymer or copolymer containing , Polyester resin, epoxy resin, urethane modified epoxy resin, silicone modified epoxy resin, vinyl chloride resin, rosin modified maleic acid resin, phenyl resin, polyethylene resin, polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene- Examples include an ethyl acrylate copolymer, a xylene resin, a polyvinyl butyral resin, a terpene resin, a phenol resin, an aliphatic or alicyclic hydrocarbon resin. One or more of these can be used in combination. Among these, when a polyester resin is used, the dispersibility of the toner particles in the liquid developer can be made particularly excellent. This is presumably because the affinity between the polyester resin and the vegetable oil is high.

  Although the softening temperature of resin (resin material) is not specifically limited, It is preferable that it is 50-130 degreeC, It is more preferable that it is 50-120 degreeC, It is further more preferable that it is 60-115 degreeC. In the present specification, the softening temperature is a measurement condition in a Koka type flow tester (manufactured by Shimadzu Corporation): temperature increase rate: 5 ° C./min, softening start temperature defined by a die hole diameter of 1.0 mm. Point to.

(2) Colorant The toner may contain a colorant. Examples of the colorant that can be used include pigments and dyes. Examples of such pigments and dyes include carbon black, spirit black, lamp black (CI No. 77266), magnetite, titanium black, chrome lead, cadmium yellow, mineral fast yellow, navel yellow, and naphthol yellow S. , Hansa Yellow G, Permanent Yellow NCG, Chrome Yellow, Benzidine Yellow, Quinoline Yellow, Tartrazine Lake, Red Mouth Lead, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Benzidine Orange G, Cadmium Red, Permanent Red 4R, Watching Red Calcium salt, eosin lake, brilliant carmine 3B, manganese purple, fast violet B, methyl violet lake, bitumen, cobalt blue, al Reblue Lake, Victoria Blue Lake, First Sky Blue, Indanthrene Blue BC, Ultramarine, Aniline Blue, Phthalocyanine Blue, Calco Oil Blue, Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Phthalocyanine Green, Final Yellow Green G, Rhodamine 6G, quinacridone, rose bengal (C.I. No. 45432), C.I. I. Direct Red 1, C.I. I. Direct Red 4, C.I. I. Acid Red 1, C.I. I. Basic Red 1, C.I. I. Modern Tread 30, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 184, C.I. I. Direct Blue 1, C.I. I. Direct Blue 2, C.I. I. Acid Blue 9, C.I. I. Acid Blue 15, C.I. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Modern Blue 7, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 5: 1, C.I. I. Direct Green 6, C.I. I. Basic Green 4, C.I. I. Basic Green 6, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 162, nigrosine dye (CI No. 50415B), metal complex dye, silica, aluminum oxide, magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, Examples thereof include metal oxides such as magnesium oxide, and magnetic materials containing magnetic metals such as Fe, Co, and Ni, and one or more of these can be used in combination.

(3) Other components The toner may contain components other than those described above. Examples of such components include waxes, charge control agents, magnetic powders, and the like.
Examples of the wax include hydrocarbon waxes such as ozokerite, cercin, paraffin wax, microwax, microcrystalline wax, petrolatum, Fischer-Tropsch wax, carnauba wax, rice wax, methyl laurate, methyl myristate, palmitic acid. Methyl, methyl stearate, butyl stearate, candelilla wax, cotton wax, wood wax, beeswax, lanolin, montan wax, fatty acid ester ester wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax Olefin wax such as 12-hydroxystearic acid amide, stearic acid amide, amide anhydride such as phthalic anhydride, Lauro , Ketone waxes such as stearone, ether waxes, and the like, can be used singly or in combination of two or more of them.

Examples of the charge control agent include benzoic acid metal salts, salicylic acid metal salts, alkyl salicylic acid metal salts, catechol metal salts, stearic acid metal salts, metal-containing bisazo dyes, nigrosine dyes, tetraphenylborate derivatives, Quaternary ammonium salts, alkylpyridinium salts, chlorinated polyesters, nitrofunnic acid and the like can be mentioned.
Examples of the magnetic powder include magnetite, maghemite, various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, magnesium oxide, and other metal oxides, and magnetic materials such as Fe, Co, and Ni. The thing etc. which were comprised with the magnetic material containing a metal are mentioned.
In addition to the materials described above, for example, zinc oxide, cerium oxide, silica, titanium oxide, iron oxide, fatty acid, fatty acid metal salt, and the like may be used as the constituent material (component) of the toner.

(Toner particle shape)
The average particle size of the toner particles composed of the above materials is preferably 0.1 to 5 μm, more preferably 0.1 to 4 μm, and further preferably 0.5 to 3 μm. preferable. When the average particle diameter of the toner particles is a value within the above range, the resolution of an image formed by the liquid developer (toner) can be made sufficiently high.
The content ratio of the toner particles in the liquid developer is preferably 10 to 60 wt%, and more preferably 10 to 30 wt%.

  The liquid developer as described above may be obtained by any method. For example, an associated particle is obtained by adding an electrolyte to a dispersion liquid (including an emulsion liquid) in which a toner material is dispersed in a dispersion medium. And the toner particles obtained by pulverizing the associated particles are dispersed in an insulating liquid. Further, it may be produced by dispersing toner particles obtained by pulverizing a toner material by a pulverization method in an insulating liquid. Also produced by a method for producing a liquid developer using a dispersion obtained by dispersing a toner material in a dispersion medium (for example, a method as described in JP-A-2006-178117). It may be.

  The image forming method according to the present embodiment is a method of forming an image using the liquid developer as described above, and using the plurality of liquid developers having different colors, a plurality of single color images corresponding to the respective colors are formed. Forming (developing process), transferring the plurality of single color images to a recording medium, forming an unfixed color image on the recording medium (transfer process), and fixing the unfixed color image on the recording medium (fixing) Step) method. Accordingly, it is possible to provide an image forming method that is friendly to the environment and can firmly fix the toner particles on the recording medium while preventing deterioration of the image quality of the obtained image.

<First Embodiment of Image Forming Apparatus (Liquid Developing Apparatus)>
Next, a first embodiment of the image forming apparatus (liquid developing apparatus) of the present invention will be described.
The image forming apparatus according to the first embodiment is applied to the image forming method according to the first embodiment, and forms a color image on a recording medium using the liquid developer as described above. Is.

FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention, FIG. 2 is a schematic diagram illustrating an example of a developing unit provided in the liquid developing apparatus of the present invention, and FIG. 3 is applied to the image forming apparatus of the present invention. It is sectional drawing which shows an example of the fixing device used. In FIG. 1, the arrows indicate the vertical direction.
As shown in FIG. 1, the image forming apparatus 1000 ′ includes a liquid developing device 10 ′ and a fixing device F40.

[Liquid developing device]
First, the liquid developing device 10 ′ will be described with reference to the attached drawings.
As shown in FIG. 1, the liquid developing device 10 ′ includes four developing units 15K, 15M, 15C, and 15Y, and a transfer unit (recording medium conveyance belt) 80 ′.
The developing units 15K, 15M, 15C, and 15Y are a black (K) liquid developer, a magenta (M) liquid developer, a cyan (C) liquid developer, and a yellow (Y) liquid developer, respectively. The latent image is developed to form a single color image corresponding to each color.

Since the developing units 15K, 15M, 15C, and 15Y have the same configuration, the developing unit 15K will be described below.
As shown in FIG. 1, the developing unit 15K includes a photoconductor 20K as an example of an image carrier, a charging unit 30K, an exposure unit 40K, a development unit 50K, and a primary unit along the rotation direction of the photoconductor 20K. The image forming apparatus includes a transfer unit 60K, a charge eliminating unit 73K, and a photoconductor cleaning unit 75K.

The photoconductor 20K has a cylindrical base material and a photosensitive layer formed on the outer peripheral surface thereof, and is rotatable about a central axis. In the present embodiment, as shown by an arrow in FIG. Rotate clockwise.
The charging unit 30K is a device for charging the photosensitive member 20K, and the exposure unit 40K is a device for forming a latent image on the charged photosensitive member 20K by irradiating a laser. The exposure unit 40K includes a semiconductor laser, a polygon mirror, an F-θ lens, and the like, and charges a modulated laser based on an image signal input from a host computer (not shown) such as a personal computer or a word processor. Irradiation is performed on the photoconductor 20K.
The developing unit 50K is a device for developing the latent image formed on the photoreceptor 20K using a black (K) liquid developer. Details of the developing unit 50K will be described later.

The transfer unit (recording medium conveyance belt) 80 ′ is an endless belt stretched around a plurality of support rollers, and has a function of conveying the recording medium 2.
Further, the transfer portion 80 ′ is rotationally driven while being in contact with the photoreceptors 20K, 20M, 20C, and 20Y.
The transfer unit 80 ′ is configured such that the recording medium 2 to be conveyed passes through a contact portion between the transfer unit 80 ′ and each photoconductor.

The monochromatic image formed by each developing unit is sequentially transferred to the recording medium 2 when passing through the contact portion with each photoconductor.
As described above, the liquid developing apparatus 10 ′ according to the present embodiment sequentially transfers the single color images formed by the developing units to the recording medium 2 conveyed through the transfer unit (conveying belt) 80 ′, thereby An unfixed color image formed by superimposing single color images is formed on the recording medium 2.
In the present embodiment, as shown in FIG. 1, black, magenta, cyan, and yellow single color images are sequentially transferred to the recording medium 2.
As described above, the unfixed color image 2a formed on the recording medium 2 is fixed to the recording medium 2 by the fixing device F40 described later.

The neutralization unit 73K is a device that removes residual charges on the photoconductor 20K after the intermediate transfer image is transferred onto the intermediate transfer unit 70 by the primary transfer unit 60K.
The photoconductor cleaning unit 75K has a rubber photoconductor cleaning blade 76K in contact with the surface of the photoconductor 20K, and after the developer image is transferred onto the intermediate transfer unit 70 by the primary transfer unit 60K, This is a device for removing the liquid developer remaining on the photoconductor 20K by scraping it off with the photoconductor cleaning blade 76K.

In the liquid developing device 10 ′ of the present embodiment, the oxidative polymerization accelerator as described above is applied only to the developing unit that first transfers the monochrome image to the recording medium 2, that is, the liquid developer accommodated in the developing unit 15K. It is included.
In other words, among the plurality of single color images constituting the unfixed color image, only the liquid developer (first liquid developer) that forms the single color image located closest to the recording medium is oxidized as described above. A polymerization accelerator is included.
By adopting such a configuration, since the oxidation polymerization accelerator is not included in the vicinity of the surface layer of the unfixed color image 2a transferred to the recording medium 2, the influence of the color of the oxidation polymerization accelerator is small. As a result, it is possible to prevent deterioration of the image quality of the obtained image.

Further, since the unfixed color image is transferred so that the layer containing the oxidation polymerization accelerator (monochromatic image) and the recording medium are in contact with each other, the insulating liquid containing the oxidation polymerization accelerator soaks into the recording medium. Since the unsaturated fatty acid component is solidified by fixing, the anchor effect works and the toner particles can be firmly fixed.
In the present embodiment, the developing unit that first transfers the monochrome image to the recording medium 2 is the developing unit 15K corresponding to black. That is, the oxidative polymerization accelerator as described above is contained in the liquid developer corresponding to black. By setting it as such a structure, the influence of the color of oxidation polymerization accelerator itself can be made small more effectively. As a result, it is possible to prevent the deterioration of the image quality of the obtained image more reliably.

Next, the developing units 50K, 50M, 50C, and 50Y will be described in detail with reference to the attached drawings. In the following description, the developing unit 50K will be typically described.
As shown in FIG. 2, the developing unit 50K includes a liquid developer storage unit 530, a liquid developer supply roller 550, a liquid raising roller 540, a regulating blade 560, a developing roller 510, and a developing roller cleaning unit 570. have.

The liquid developer storage unit 530 has a function of storing the liquid developer D for developing the latent image formed on the photoconductor 20K.
Further, as shown in FIG. 2, the liquid developer reservoir 530 of the developing unit 50K is provided with a reducing member 590 for reducing the oxidized unsaturated fatty acid component.
The reducing member 590 is disposed near the liquid surface of the liquid developer D so as to come into contact with the liquid developer D in the liquid developer reservoir 530.

Since the unsaturated fatty acid component in the liquid developer D stored in the liquid developer storage unit 530 is a component that undergoes oxidative polymerization, if the liquid is stored in the liquid developer storage unit 530 for a long time, the oxidation proceeds with time. May progress. As a result, the function as the insulating liquid is lowered, and the obtained image quality may be lowered. In particular, this tendency is relatively strong in a liquid developer containing an oxidative polymerization accelerator.
Thus, by installing the reducing member 590 for reducing the oxidized unsaturated fatty acid component in the liquid developer reservoir 530 as described above, it is possible to prevent the deterioration of the function of the insulating liquid over a long period of time. As a result, it is possible to more effectively prevent the deterioration of the image quality of the obtained image.

The reducing member 590 is mainly composed of zeolite.
Zeolite has a condensed aluminosilicate structure, and is a crystal in which SiO ₄ tetrahedrons or AlO ₄ tetrahedrons substituted with Al instead of Si share oxygen atoms and are bonded in a three-dimensional network. It is.
Zeolite has a cation exchange ability, and it is considered that the oxidized unsaturated fatty acid component is reduced by this ability.
The reducing member 590 is a porous body. Such a porous body can be obtained by sintering zeolite powder.

When the reducing member 590 is a porous body, the contact area with the liquid developer D increases, and the unsaturated fatty acid component can be reduced efficiently. Further, oxygen contained in the liquid developer 1 can be taken into the pores, and oxidation of the unsaturated fatty acid component contained in the liquid developer D can be effectively prevented.
The porosity of the reducing member 590 is about 50 to 80 vol%, and preferably about 70 to 80 vol%. Thereby, an unsaturated fatty acid component can be reduced more efficiently. In addition, oxygen contained in the liquid developer D can be more efficiently taken into the pores.
In addition, the reducing member 590 can be attached and detached, so that the reducing member having reduced reducing ability and adsorption ability can be replaced with a new one.

  In the illustrated configuration, such a reducing member 590 is provided only in the developing unit 50K (developing unit 15K) in which the magenta liquid developer is accommodated (stored). The developing units 50M, 50C, and 50Y (developing units 15M, 15C, and 15Y) other than the developing unit 50K may be provided. Thereby, the oxidative deterioration of the unsaturated fatty acid component in the developing unit other than the developing unit 15K can be prevented, and the deterioration of the image quality can be more effectively prevented.

The developer supply roller 550 has a function of supplying the liquid developer D to the developing roller 510.
Further, the developer supply roller 550 has a surface pressed against an elastic body layer described later of the developing roller 510 in order to appropriately transfer the liquid developer D on the developer supplying roller 550 to the developing roller 510. is doing. Further, the developer supply roller 550 can rotate around its central axis 550 a, and the central axis 550 a is below the rotation central axis of the developing roller 510. Further, the developer supply roller 550 rotates in a direction (clockwise in FIG. 2) opposite to the rotation direction of the developing roller 510 (counterclockwise in FIG. 2).

  Further, the liquid developer supply roller 550 is immersed in the liquid developer D accommodated in the liquid developer reservoir 530 with a part thereof exposed. Accordingly, when the liquid developer supply roller 550 rotates in such a situation, the liquid developer supply roller 550 enters the liquid developer D on the right side in FIG. 2 when viewed from the vertical plane A passing through the central axis of the liquid developer supply roller 550. Then, the liquid developer supply roller 550 advances from the liquid developer D on the left side in FIG.

The lifting roller 540 is configured such that, on the liquid surface of the liquid developer D, the liquid-side supply surface 580 on the side where the liquid developer-supply roller 550 rotates and enters the liquid developer D is the central axis of the liquid developer-supply roller 550. It has a function of making it higher than the horizontal plane B passing through 550a. The pumping roller 540 is a SUS roller and has a diameter of about 10 mm.
The pumping roller 540 has the liquid developer supply roller 550 arranged so that the axial direction of the central axis 540a is along the axial direction of the central axis 550a of the liquid developer supply roller 550 and when viewed from the vertical plane A described above. It is provided on the side that rotates and enters the liquid developer D (that is, the right side in FIG. 2 when viewed from the vertical plane A). Further, the central shaft 540 a of the liquid feeding roller 540 is positioned vertically below the central shaft 550 a of the liquid developer supply roller 550, and the upper end 540 b of the liquid lifting roller 540 is the liquid developer supply roller 550. It is located above the central axis 550a in the vertical direction. Further, the pumping roller 540 is separated from the liquid developer supply roller 550 with a width of about 2 mm.
Further, the pumping roller 540 is rotatable about its central axis 540a, and rotates in the same direction (clockwise in FIG. 2) as the rotation direction of the liquid developer supply roller 550 (clockwise in FIG. 2). The rotational speed of the pumping roller 540 is the same as the rotational speed of the liquid developer supply roller 550 and the linear speed.

The liquid raising roller 540 configured in this manner makes the entry side liquid level 580 higher than the horizontal plane B by rotating. For example, when the pumping roller 540 rotates while the entry side liquid level 580 is lower than the horizontal plane B, the rotation causes the liquid developer D around the pumping roller 540 to move, and the entry side The liquid level 580 becomes higher than the horizontal plane B.
The liquid lifting roller 540 has the above-described function, and moves the liquid developer D stored in the liquid developer reservoir 530 toward the liquid developer supply roller 550, so that the liquid developer D is transferred. It also has a function of supplying the liquid developer supply roller 550 and a function of stirring the liquid developer D in order to maintain the liquid developer D in an appropriate state.

  The regulating blade 560 contacts the surface of the liquid developer supply roller 550 and regulates the amount of the liquid developer D on the liquid developer supply roller 550. That is, the regulating blade 560 plays a role of scraping off excess liquid developer on the liquid developer supply roller 550 and measuring the liquid developer D on the liquid developer supply roller 550 supplied to the development roller 510. . The restriction blade 560 is made of urethane rubber as an elastic body, and is supported by a restriction blade support member 562 made of metal such as iron. Further, the regulation blade 560 is provided on the side where the liquid developer supply roller 550 rotates and advances from the liquid developer D when viewed from the vertical plane A (that is, the left side in FIG. 2 when viewed from the vertical plane A). It has been. The rubber hardness of the regulating blade 560 is about 62 degrees according to JIS-A, and the hardness (about 62 degrees) of the contact portion of the regulating blade 560 with the surface of the liquid developer supply roller 550 is about the development described later. The hardness of the elastic body layer of the roller 510 is lower than the hardness (about 85 degrees) of the pressure contact portion to the surface of the liquid developer supply roller 550.

  The developing roller 510 carries the liquid developer D and transports it to the developing position facing the photoconductor 20M in order to develop the latent image carried on the photoconductor 20K with the liquid developer D. The developing roller 510 includes a conductive elastic layer on the outer peripheral portion of an inner core made of metal such as iron, and has a diameter of about 20 mm. The elastic body layer has a two-layer structure. As the inner layer, urethane rubber having a rubber hardness of about 30 degrees JIS-A and a thickness of about 5 mm is used, and as the surface layer (outer layer), the rubber hardness is JIS. A urethane rubber having a thickness of about 30 μm at about 85 ° A is provided. The developing roller 510 is in pressure contact with the liquid developer supply roller 550 and the photoconductor 20M in a state of being elastically deformed with the surface layer serving as a pressure contact portion.

Further, the developing roller 510 can rotate around its central axis, and the central axis is below the rotational central axis of the photoconductor 20M. Further, the developing roller 510 rotates in a direction (counterclockwise in FIG. 2) opposite to the rotation direction of the photoconductor 20M (clockwise in FIG. 2). When developing the latent image formed on the photoconductor 20M, an electric field is formed between the developing roller 510 and the photoconductor 20M.
The developing roller cleaning unit 570 has a rubber developing roller cleaning blade 571 in contact with the surface of the developing roller 510, and the liquid developer remaining on the developing roller 510 after development is performed at the developing position. It is an apparatus for scraping and removing D by a developing roller cleaning blade 571.

In the developing unit 50 </ b> K configured as described above, the liquid lifting roller 540 rotates around its central axis 540 a, whereby the liquid developer D stored in the liquid developer storage unit 530 is transferred to the liquid developer supply roller 550. The liquid developer D is supplied to the liquid developer supply roller 550.
The liquid developer D reaches the contact position of the regulating blade 560 by the rotation of the liquid developer supply roller 550. Then, when passing through the contact position, the excess liquid developer D is scraped off by the regulating blade 560, and the amount of liquid developer D supplied to the developing roller 510 is measured.

  The liquid developer D held by the liquid developer supply roller 550 reaches the pressure contact position with the development roller 510 by further rotation of the liquid developer supply roller 550. The liquid developer D that has reached the pressure contact position is transferred from the liquid developer supply roller 550 to the development roller 510 by the action of pressure generated by the pressure contact between the liquid developer supply roller 550 and the development roller 510, and the development roller 510. A thin film of liquid developer D is formed thereon.

The thin film of the liquid developer D formed on the developing roller 510 in this way reaches the developing position (that is, the pressure contact position with the photosensitive member 20K) facing the photosensitive member 20K by the rotation of the developing roller 510. The latent image formed on the photoconductor 20K is subjected to development at a development position under an electric field of a predetermined magnitude. The liquid developer D on the developing roller 510 that has passed the developing position reaches the contact position of the developing roller cleaning blade 571 as the developing roller 510 further rotates. Then, when passing through the contact position, the liquid developer D adhering to the surface of the developing roller 510 is scraped off by the developing roller cleaning blade 571, and the liquid developer D scraped off is removed from the developing roller. The residual liquid developer is collected by the cleaning unit 570.
Note that the rotation of the liquid developer supply roller 550 is started in a state where the pumping roller 540 is rotating. In other words, the liquid developing device 10 ′ rotates the liquid developer supply roller 550 after rotating the pumping roller 540.

[Fixing device]
Next, the fixing device will be described.
The fixing device F40 fixes the color image 2a on the recording medium 2 having the unfixed color image 2a formed by the liquid developing device.
As shown in FIG. 3, the fixing device F40 includes a heat fixing roller F1, a pressure roller F2, a heat-resistant belt F3, a belt stretching member F4, a cleaning member F6, a frame F7, and a spring F9. is doing.

The heat fixing roller (fixing roller) F1 includes a roller base material F1b made of a pipe material, an elastic body F1c covering the outer periphery thereof, and a columnar halogen lamp F1a as a heating source inside the roller base material F1b. It can be rotated counterclockwise as indicated by an arrow in the figure.
The elastic body F1c of the heat fixing roller F1 includes a release layer F11c on its surface layer.
The release layer F11c has a function of preventing toner particles from adhering to the surface of the heat fixing roller F1 during fixing.
Examples of the material constituting the release layer F11c include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene / hexafluoropropylene copolymer (FEP). And fluorine rubber, silicone rubber and the like.

  Inside the heat fixing roller F1, two columnar halogen lamps F1a and F1a constituting a heating source are incorporated, and the heating elements of these columnar halogen lamps F1a and F1a are arranged at different positions. Yes. Then, by selectively lighting each columnar halogen lamp F1a, F1a, a fixing nip portion where a heat-resistant belt F3, which will be described later, is wound around the heat-fixing roller F1, and a belt stretching member F4, which will be described later, are attached to the heat-fixing roller F1. The temperature controller is easily performed under different conditions from the sliding contact portion, different conditions between the wide recording medium and the narrow recording medium, or the like.

The pressure roller F2 is arranged to face the heat fixing roller F1, and is configured to apply pressure to the recording medium 2 on which an unfixed color image is formed via a heat-resistant belt F3 described later. ing.
Further, the pressure roller F2 has a roller base material F2b made of a pipe material and an elastic body F2c covering the outer periphery thereof, and is rotatable in the clockwise direction indicated by an arrow in the drawing.
The aforementioned elastic body F1c of the heat fixing roller F1 and the elastic body F2c of the pressure roller F2 are subjected to substantially uniform elastic deformation to form a so-called horizontal nip. Further, since there is no difference in the conveyance speed of the heat-resistant belt F3 (described later) or the recording medium 2 with respect to the peripheral speed of the heat fixing roller F1, extremely stable image fixing is possible.

The heat-resistant belt F3 is an endless annular belt that is stretched around the outer periphery of the pressure roller F2 and the belt stretching member F4 and is movable, and is sandwiched between the heat fixing roller F1 and the pressure roller F2. is there.
The heat-resistant belt F3 has a thickness of 0.03 mm or more, and its front surface (the surface on which the recording medium 2 is in contact) is formed of PFA, and the rear surface (the pressure roller F2 and the belt stretching member F4 is in contact). The side surface is formed of a seamless tube having a two-layer structure formed of polyimide. The heat-resistant belt F3 is not limited to this, and can be formed of other materials such as a metal tube such as a stainless steel tube or a nickel electroformed tube, or a heat-resistant resin tube such as silicone.

The belt stretching member F4 is disposed upstream of the fixing nip portion between the heat fixing roller F1 and the pressure roller F2 in the recording medium 2 conveyance direction, and an arrow P centering on the rotation shaft F2a of the pressure roller F2. It is arranged so that it can swing in the direction.
The belt stretching member F4 is configured to stretch the heat-resistant belt F3 in the tangential direction of the heat fixing roller F1 in a state where the recording medium 2 does not pass through the fixing nip portion. If the fixing pressure is large at the initial position where the recording medium 2 enters the fixing nip portion, the entry may not be smoothly performed and the recording medium 2 may be fixed with the leading end of the recording medium folded. By adopting a configuration in which F3 is stretched in the tangential direction of the heat fixing roller F1, an inlet port of the recording medium 2 where the recording medium 2 smoothly enters can be formed, and the stable fixing nip portion of the recording medium 2 can be formed. Can enter.

The belt stretching member F4 is inserted into the inner periphery of the heat-resistant belt F3 and cooperates with the pressure roller F2 to apply a tension f to the heat-resistant belt F3 (the heat-resistant belt F3 is a belt). Sliding on the tension member F4). The belt stretching member F4 is disposed at a position where the heat-resistant belt F3 is wound around the heat fixing roller F1 side from the pressing portion tangent L between the heat fixing roller F1 and the pressure roller F2 to form a nip. The protruding wall F4a protrudes from one end or both ends of the belt stretching member F4 in the axial direction. The protruding wall F4a is formed by the heat-resistant belt F3 when the heat-resistant belt F3 approaches one of the axial ends. The contact to the end of the heat-resistant belt F3 is regulated by contacting the wall F4a. A spring F9 is contracted between the end of the protruding wall F4a opposite to the heat fixing roller F1 and the frame, and the protruding wall F4a of the belt stretching member F4 is lightly pressed by the heat fixing roller F1, so that the belt tension is increased. The frame member F4 is positioned in sliding contact with the heat fixing roller F1.
The position where the belt stretching member F4 is lightly pressed against the heat fixing roller F1 is the nip initial position, and the position where the pressure roller F2 is pressed against the heat fixing roller F1 is the nip end position.

  In the fixing device F40, the recording medium 2 on which an unfixed color image 2a is formed using an image forming apparatus as described later enters the fixing nip portion from the initial nip position and enters the heat-resistant belt F3 and the heat fixing roller F1. And the unfixed color image 2a formed on the recording medium 2 is fixed, and then the tangent line of the pressing portion of the pressure roller F2 to the heat fixing roller F1. It is discharged in the direction L.

The cleaning member F6 is disposed between the pressure roller F2 and the belt stretching member F4.
The cleaning member F6 is in slidable contact with the inner peripheral surface of the heat-resistant belt F3 and cleans foreign matter, wear powder, and the like on the inner peripheral surface of the heat-resistant belt F3. In this way, by cleaning the foreign matter, wear powder, and the like, the heat-resistant belt F3 is refreshed, and the above-described instability factor of the friction coefficient is removed. Further, the belt stretching member F4 is provided with a recess F4f, and is configured to store foreign matter, abrasion powder, or the like removed from the heat-resistant belt F3.

  Further, the fixing device F40 has a removing blade (removing means) F12 for removing the insulating liquid adhering (remaining) on the surface of the heat fixing roller F1 after fixing the color image 2a on the recording medium 2. . The oxidative polymerization accelerator removing blade F12 can remove the insulating liquid and simultaneously remove the toner transferred onto the heat fixing roller F1 at the time of fixing.

  In order to stably drive the heat-resistant belt F3 by the pressure roller F2 and the belt stretching member F4 and stably drive the pressure roller F2, the friction coefficient between the pressure roller F2 and the heat-resistant belt F3 is determined by the belt tension. It is good to set larger than the friction coefficient of the frame member F4 and the heat-resistant belt F3. However, the friction coefficient is such that foreign matter enters between the heat-resistant belt F3 and the pressure roller F2 or between the heat-resistant belt F3 and the belt stretching member F4, or the heat-resistant belt F3, the pressure roller F2, and the belt stretching member. It may become unstable due to wear of the contact portion with F4.

Therefore, the belt tension member F4 and the heat-resistant belt F3 have a winding angle smaller than the winding angle of the pressure roller F2 and the heat-resistant belt F3, and the diameter of the belt stretching member F4 is smaller than the diameter of the pressure roller F2. Set as follows. As a result, the length that the heat-resistant belt F3 slides on the belt stretching member F4 is shortened, which can be avoided from instability factors such as changes with time and disturbances, and the heat-resistant belt F3 is driven stably by the pressure roller F2. Will be able to.
The fixing temperature when fixing an unfixed color image is preferably 80 to 200 ° C, and more preferably 80 to 180 ° C. With such a fixing temperature, the oxidative polymerization reaction of the unsaturated fatty acid component can proceed more effectively, and the fixing strength of the toner particles can be improved more effectively.

<Second Embodiment of Image Forming Apparatus (Liquid Developing Apparatus)>
Next, a second embodiment of the image forming apparatus (liquid developing apparatus) of the present invention will be described. In the following description, parts different from those of the first embodiment of the image forming apparatus (liquid developing apparatus) of the present invention described above will be mainly described, and description of similar parts will be omitted.
The image forming apparatus (liquid developing apparatus) according to the second embodiment is applied to the above-described image forming method according to the first embodiment, and a recording medium using the liquid developer as described above. A color image is formed thereon.
FIG. 4 is a schematic view showing another example of the image forming apparatus of the present invention.
As shown in FIG. 4, the image forming apparatus 1000 ″ includes a liquid developing device 10 ″ and a fixing device F40.

[Liquid developing device]
First, the liquid developing apparatus 10 ″ will be described with reference to the attached drawings.
As shown in FIG. 4, the liquid developing apparatus 10 ″ includes four developing units 15K, 15M, 15C, and 15Y, an intermediate transfer unit 70, a secondary transfer unit (secondary transfer unit) 80 ″, and a tertiary transfer. Unit (tertiary transfer portion) 90.

The developing units 15K, 15M, 15C, and 15Y have the same configuration as that of the first embodiment described above.
The intermediate transfer unit 70 is an endless belt stretched around a plurality of support rollers, and rotates while being in contact with the photoconductors 20K, 20M, 20C, and 20Y.
The single color images corresponding to the respective colors formed in the developing units are sequentially transferred to the intermediate transfer unit 70 described later by the primary transfer units 60K, 60M, 60C, and 60Y, and the single color images corresponding to the respective colors are superimposed to form a full color. A developer image (intermediate transfer image) is formed.
The intermediate transfer image formed on the intermediate transfer portion 70 is transferred to a secondary transfer unit (secondary transfer portion) 80 ″ described later.

The secondary transfer unit (secondary transfer unit) 80 ″ rotates in the opposite direction to the intermediate transfer unit 70 while contacting the intermediate transfer unit 70. An intermediate transfer image is transferred.
The secondary transfer unit 80 ″ has a function of transporting the transferred intermediate transfer image and transferring the transported intermediate transfer image to a later-described tertiary transfer unit (tertiary transfer unit) 90.

The tertiary transfer unit (tertiary transfer unit) 90 transfers the intermediate transfer image transferred by the secondary transfer unit 80 ″ to the recording medium 2 such as paper, film, cloth, etc., and unfixed color on the recording medium 2 It has a function of forming the image 2a.
The unfixed color image 2a transferred onto the recording medium 2 by the tertiary transfer unit 90 is sent to a fixing device F40, which will be described later, and fixed.

In the liquid developing apparatus 10 ″ of the present embodiment, the oxidative polymerization acceleration described above is applied only to the developing unit that first transfers the monochromatic image to the intermediate transfer unit 70, that is, the liquid developer contained in the developing unit 15K. Contains the agent.
In other words, among the plurality of single color images constituting the unfixed color image, only the liquid developer (first liquid developer) that forms the single color image located closest to the recording medium is oxidized as described above. A polymerization accelerator is included.

By adopting such a configuration, since the oxidation polymerization accelerator is not included in the vicinity of the surface layer of the unfixed toner image 2a transferred to the recording medium 2, the influence of the color of the oxidation polymerization accelerator is small. As a result, it is possible to prevent deterioration of the image quality of the obtained image.
Further, since the unfixed toner image is transferred so that the layer containing the oxidation polymerization accelerator (monochromatic image) and the recording medium are in contact with each other, the insulating liquid containing the oxidation polymerization accelerator soaks into the recording medium, and in this state Since the unsaturated fatty acid component is solidified by fixing, the anchor effect works and the toner particles can be firmly fixed.

<Second Embodiment of Image Forming Method>
Next, a second embodiment of the image forming method of the present invention will be described. In the following description, parts different from those of the first embodiment of the image forming method of the present invention described above will be mainly described, and description of similar parts will be omitted.
In this embodiment, a liquid developer (first liquid developer) that forms a single color image located on the side closest to the recording medium among a plurality of single color images constituting an unfixed color image formed on the recording medium. ) Is different from the above-described first embodiment of the image forming method of the present invention in that it includes an oxidative polymerization accelerator as described above, and the other configurations are the same. .

In other words, in this embodiment, the content of the oxidative polymerization accelerator in the first liquid developer is larger than the content of the oxidative polymerization accelerator in the liquid developer other than the first liquid developer. It is characterized by a point.
By adopting such a configuration, it is possible to firmly fix the toner particles on the recording medium while preventing deterioration of the image quality of the obtained image. This is considered to be due to the following reasons.

That is, the monochromatic image near the surface layer of the unfixed toner image transferred to the recording medium has a smaller content of the oxidative polymerization accelerator than the monochromatic image composed of the first liquid developer, and therefore promotes oxidative polymerization. The influence of the color of the agent can be made small, and as a result, deterioration of the image quality of the obtained image can be prevented.
In addition, since the unfixed toner image is transferred so that the layer containing the most oxidative polymerization accelerator (monochromatic image) and the recording medium are in contact with each other, the toner particles can be firmly fixed.

  The content of the oxidation polymerization accelerator in the first liquid developer is preferably 0.01 to 2 parts by weight with respect to 100 parts by weight of the insulating liquid, as in the first embodiment described above. The amount is more preferably 0.05 to 1 part by weight, and still more preferably 0.1 to 0.8 part by weight. As a result, the oxidation polymerization reaction of the insulating liquid can be more reliably advanced at the time of fixing while sufficiently preventing the oxidation polymerization reaction during storage of the liquid developer, etc. A reduction in image quality can be effectively prevented.

  The content of the oxidative polymerization accelerator in the liquid developer other than the first liquid developer varies depending on the corresponding color. For example, when the first liquid developer is a liquid developer corresponding to black. The content of the oxidative polymerization accelerator in the liquid developer corresponding to magenta is preferably 1.5 parts by weight or less with respect to 100 parts by weight of the insulating liquid, and 0.7 parts by weight or less. Is more preferable. Thereby, the influence of the color of the oxidative polymerization accelerator on the image quality can be made sufficiently small.

When the first liquid developer is a liquid developer corresponding to black, the content of the oxidative polymerization accelerator in the liquid developer corresponding to yellow is 0. 0 parts by weight with respect to 100 parts by weight of the insulating liquid. The amount is preferably 15 parts by weight or less, and more preferably 0.05 parts by weight or less. Thereby, the influence of the color of the oxidative polymerization accelerator on the image quality can be made sufficiently small.
When the first liquid developer is a liquid developer corresponding to black, the content of the oxidative polymerization accelerator in the liquid developer corresponding to cyan is 0. 0 parts by weight with respect to 100 parts by weight of the insulating liquid. The amount is preferably 6 parts by weight or less, and more preferably 0.4 parts by weight or less. Thereby, the influence of the color of the oxidative polymerization accelerator on the image quality can be made sufficiently small.

<Third Embodiment of Image Forming Apparatus (Liquid Developing Apparatus)>
Next, a third embodiment of the image forming apparatus (liquid developing apparatus) of the present invention will be described. In the following description, parts different from those of the first embodiment of the image forming apparatus (liquid developing apparatus) of the present invention described above will be mainly described, and description of similar parts will be omitted.
The image forming apparatus (liquid developing apparatus) according to the third embodiment is applied to the above-described image forming method according to the second embodiment, and a recording medium using the liquid developer as described above. A color image is formed thereon.
Similar to the image forming apparatus according to the first embodiment described above, the image forming apparatus 1000 ′ according to the present embodiment includes a liquid developing device 10 ′ and a fixing device F40.

  In the image forming apparatus 1000 ′ (liquid developing apparatus 10 ′) of the present embodiment, the liquid developer contained in the developing unit that first transfers the single color image to the recording medium 2, that is, the developing unit 15K is described above. The image forming apparatus according to the first embodiment is different from the image forming apparatus (liquid developing apparatus) according to the first embodiment described above in that the oxidative polymerization accelerator is contained in the largest amount. The configuration is the same as that of the apparatus (liquid developing apparatus).

In other words, among the plurality of single-color images constituting the unfixed color image, the above-described oxidation polymerization is performed on the liquid developer (first liquid developer) that forms a single-color image located on the side closest to the recording medium. Contains the most accelerators.
Furthermore, in other words, the content of the oxidative polymerization accelerator in the liquid developer in the developing unit that first transfers the monochromatic image to the recording medium 2 is such that the oxidative polymerization accelerator in the liquid developer in the other developing unit. It is characterized in that it is more than the content of.

With this configuration, the monochromatic image near the surface layer of the unfixed toner image transferred to the recording medium has a content of the oxidation polymerization accelerator as compared with the monochromatic image composed of the first liquid developer. And the influence of the color of the oxidative polymerization accelerator can be reduced, and as a result, deterioration of the image quality of the obtained image can be prevented.
In addition, since the unfixed toner image is transferred so that the layer containing the most oxidative polymerization accelerator (monochromatic image) and the recording medium are in contact with each other, the toner particles can be firmly fixed.
The content of the oxidation polymerization accelerator is the same as that described in the second embodiment of the image forming method described above.

<Fourth Embodiment of Image Forming Apparatus (Liquid Developing Apparatus)>
Next, a fourth embodiment of the image forming apparatus (liquid developing device) of the present invention will be described. In the following description, parts different from those in the second embodiment of the image forming apparatus (liquid developing apparatus) of the present invention described above will be mainly described, and description of similar parts will be omitted.
The image forming apparatus (liquid developing apparatus) according to the fourth embodiment is applied to the image forming method according to the second embodiment described above, and uses a liquid developer as described above to record a recording medium. A color image is formed thereon.
Similar to the image forming apparatus according to the second embodiment, the image forming apparatus 1000 ″ according to the present embodiment includes the liquid developing device 10 ″ and the fixing device F40.

  In the image forming apparatus 1000 ″ (liquid developing apparatus 10 ″) of the present embodiment, the liquid developer accommodated in the developing unit that first transfers the monochrome image to the intermediate transfer unit 70, that is, the developing unit 15K, is described above. It differs from the image forming apparatus (liquid developing apparatus) according to the first embodiment described above in that it contains the most oxidative polymerization accelerator as described above, and the image according to the first embodiment described above other than that. The configuration is the same as that of the forming apparatus (liquid developing apparatus).

In other words, among the plurality of single-color images constituting the unfixed color image, the above-described oxidation polymerization is performed on the liquid developer (first liquid developer) that forms a single-color image located on the side closest to the recording medium. Contains the most accelerators.
Furthermore, in other words, the content of the oxidative polymerization accelerator in the liquid developer in the developing unit that first transfers the single color image to the intermediate transfer unit 70 is determined so that the oxidative polymerization promotion in the liquid developer in the other developing unit. It is characterized in that it is more than the content of the agent.

With this configuration, the monochromatic image near the surface layer of the unfixed toner image transferred to the recording medium has a content of the oxidation polymerization accelerator as compared with the monochromatic image composed of the first liquid developer. And the influence of the color of the oxidative polymerization accelerator can be reduced, and as a result, deterioration of the image quality of the obtained image can be prevented.
In addition, since the unfixed toner image is transferred so that the layer containing the most oxidative polymerization accelerator (monochromatic image) and the recording medium are in contact with each other, the toner particles can be firmly fixed.
The content of the oxidative polymerization accelerator is the same as that described in the second embodiment of the image forming method described above.

As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to these.
For example, in the image forming method of the present invention, an optional process can be added as necessary.
In addition, each unit constituting the liquid developing device and the image forming apparatus of the present invention can be replaced with an arbitrary one that exhibits the same function, or another configuration can be added.

In the above-described embodiment, the case where four color liquid developers of magenta, yellow, cyan, and black are used for image formation has been described. However, the present invention is not limited to this, and five color liquid developers are used. Alternatively, a liquid developer having six or more colors may be used. For example, liquid developers having colors similar to magenta, yellow, and cyan may be added.
Further, the liquid developing device and the image forming apparatus of the present invention are not limited to those having the configuration shown in the drawing.
In the above-described embodiment, the configuration in which the developing unit that transfers the single color image to the recording medium (intermediate transfer unit) contains the liquid developer corresponding to black has been described. The liquid developer corresponding to yellow, cyan may be accommodated.

The fixing device applied to the image forming apparatus of the present invention is not limited to the above-described embodiment, and each part constituting the fixing device is replaced with an arbitrary one that exhibits the same function, or other configuration. Can also be added.
In the above-described embodiment, the case where heat is applied during fixing has been described. However, the present invention is not limited to this. For example, ultraviolet rays may be irradiated.
In the above-described embodiment, the heating is described from the fixing roller side. However, the heating may be performed from the pressure roller side.

<< 1 >> Production of Liquid Developer <Black Liquid Developer D-1>
[Preparation of insulating liquid]
A liquid containing an unsaturated fatty acid glyceride and a liquid containing a fatty acid monoester used as an insulating liquid were prepared as follows.

(Preparation of liquid containing unsaturated fatty acid glycerides)
First, crude soybean oil was purified as follows to obtain purified soybean oil.
First, crude soybean oil was roughly purified by a low temperature crystallization method using methanol, diethyl ether, petroleum ether, acetone or the like as a solvent.
Next, 300 parts by volume of roughly refined crude soybean oil (first roughly refined oil) was put into the flask, and then 100 parts by volume of boiled water was poured into the flask, and the flask was stoppered.

Next, the flask was shaken, and the above-described crude soybean oil (first crudely refined oil) and boiled water were mixed.
Next, the flask was allowed to stand until the mixed liquid in the flask was separated into three layers.
After complete separation was confirmed, the flask was transferred to a freezer and left for 24 hours.
Thereafter, the components that were not frozen were transferred to another flask.
The same operation as described above was repeated for the unfrozen component, and the obtained non-frozen component was taken out to obtain a crude oil (second crude oil).

Next, in the flask, the crude oil and fat (second crude oil) obtained as described above: 100 parts by volume and active clay mainly composed of hydrous aluminum silicate: 35 parts by volume were mixed. Stir.
Next, the obtained mixture was stored under pressure (0.18 MPa) for 48 hours to completely precipitate the activated clay.
Thereafter, the precipitate was removed to obtain refined soybean oil (hereinafter simply referred to as soybean oil). In addition, the unsaturated fatty acid glyceride which has linoleic acid as a main component was contained in soybean oil, and the unsaturated fatty acid glyceride in soybean oil was 98 wt%. Moreover, the linoleic acid component was 53 mol% of the total fatty acid components.

(Preparation of liquid containing fatty acid monoester)
Next, a transesterification reaction between a part of the soybean oil and methanol was performed, and glycerin generated by this reaction was removed to obtain a liquid mainly composed of fatty acid monoesters. Further, by purifying this liquid, soybean oil fatty acid methyl ester having a fatty acid monoester content of 99.9 wt% or more was obtained. Fatty acid monoesters thus obtained are mainly unsaturated fatty acid monoesters such as methyl oleate, methyl linoleate and methyl α-linolenate, and saturated fatty acid monoesters such as methyl palmitate and methyl stearate. Was mainly composed.

[Preparation of toner particles]
(Preparation of colorant master solution)
First, a mixture (mass ratio 50:50) of a polyester resin (melt viscosity: 125 ° C., Tg: 60.5 ° C., acid value: 7.7) and carbon black as a colorant was prepared. These components were mixed using a 20 L type Henschel mixer to obtain a raw material for toner production.

Next, this raw material (mixture) was kneaded using a twin-screw kneading extruder. The kneaded product extruded from the extrusion port of the biaxial kneading extruder was cooled.
The kneaded product cooled as described above was coarsely pulverized to obtain a powder having an average particle size of 1.0 mm or less. A hammer mill was used for coarse pulverization of the kneaded product.
Methyl ethyl ketone was added to the obtained powder of the kneaded material so that the solid content was 30 wt%, and wet-dispersed with an Eiger motor mill (manufactured by Eiger, USA: M-1000) to prepare a colorant master solution.

(Preparation of resin solution)
200 parts by weight of methyl ethyl ketone and 73 parts by weight of the polyester resin were added to 33 parts by weight of the colorant master solution, and the mixture was mixed with an Eiger motor mill (manufactured by Eiger, USA: M-1000) to prepare a resin solution. In this solution, the pigment was uniformly finely dispersed.

(Preparation of aqueous emulsion)
500 parts by weight of the above resin liquid and 45.5 parts by weight of methyl ethyl ketone were placed in a cylindrical 2 L separable flask having a Max blend stirring blade, and the solid content of the resin liquid was 55%.
Next, 11.7 ammonia water: 41.7 parts by weight (the molar equivalent ratio with respect to the total amount of carboxyl groups of the polyester resin is 1.1) is added to the resin liquid in the flask, and three-one motor (manufactured by Shinto Kagaku Co., Ltd.) is used. The rotation speed of the stirring blade was set to 210 rpm (peripheral speed of stirring blade: 0.71 m / s), and the mixture was sufficiently stirred, and then 133 parts by weight of deionized water was added while maintaining stirring. While adjusting the temperature of the solution in the flask to 25 ° C. and continuing stirring, 133 parts by weight of deionized water was dropped into the resin liquid to cause phase inversion emulsification, and the dispersoid containing the resin material was dispersed. An aqueous emulsion was obtained.

(Production of associated particles by association)
Next, while continuing stirring in the flask, 285 parts by weight of deionized water was added to the aqueous emulsion so that the total amount of 1N ammonia water and water was 593 parts by weight. Subsequently, 2.6 parts by weight of Emul 0 (manufactured by Kao Corporation), which is an anionic emulsifier, was diluted to 30 parts by weight of deionized water and added to the aqueous emulsion.

Thereafter, while maintaining the temperature of the aqueous emulsion at 25 ° C., the rotation speed of stirring was 150 rpm (peripheral speed of stirring blade: 0.54 m / s), and 3.5% ammonium sulfate aqueous solution: 300 parts by weight was dropped. The particle size of the dispersoid aggregate was 3.5 μm. After dropping, stirring was continued until the particle size of the dispersoid aggregates grew to 5.0 μm, and the association operation was completed.
The resulting aggregate dispersion was dried by distilling off the organic solvent under reduced pressure to obtain associated particles.

[Preparation of liquid developer]
Associating particles obtained by the above method: 40 parts by weight, soybean oil fatty acid methyl ester: 80 parts by weight, polyamine aliphatic polycondensate (manufactured by Nippon Lubrizol, trade name “Solsperse 13940”): 1 part by weight of ceramic The product was placed in a pot (internal volume 600 ml), and zirconia balls (ball diameter: 1 mm) were further placed in a ceramic pot so that the volume filling rate was 25%. Crushing was performed for 120 hours at a rotational speed of 210 rpm (1 / min) in a desktop pot mill, and the dispersion in the pot was separated from the zirconia balls and taken out to obtain a toner particle dispersion.
Thereafter, 120 parts by weight of purified soybean oil, 0.5 parts by weight of zinc stearate (manufactured by NOF Corporation) as a charge control agent, and encapsulation as an oxidative polymerization accelerator are added to the obtained toner particle dispersion. Coated naphthenate: 0.5 parts by weight (addition amount as pure naphthenate) was further pulverized for 24 hours to obtain a liquid developer D-1.

In the obtained liquid developer D-1, the average particle size (volume-based average particle size) of the toner particles was 1.9 μm, and the standard deviation of the particle size between the toner particles was 0.54 μm.
The average particle size and particle size distribution of the toner particles were measured with a Mastersizer 2000 particle analyzer (manufactured by Malvern Instruments Ltd.).

Moreover, encapsulation of cobalt naphthenate was performed as follows.
First, 10 g of cobalt naphthenate was dissolved in 15 ml of acetone, and the resulting solution was adsorbed on porous hydrophilic silica gel to obtain a core material.
Next, 10 g of the obtained core material and 20 g of polyethylene glycol (PEG) were heated and mixed to obtain a mixture.
Next, this mixture was put in 400 ml of AF6 solvent manufactured by Mitsubishi Oil Corporation, and sufficiently dispersed with a homomixer, and then slowly cooled to deposit PEG.
Thereafter, the solvent was removed by filtration to obtain encapsulated cobalt naphthenate.

<Magenta Liquid Developer D-2>
Except for using magenta pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Red 122) as a colorant and setting the content of the oxidation polymerization accelerator to 0.15 parts by weight with respect to 100 parts by weight of the insulating liquid A liquid developer D-2 was produced in the same manner as the liquid developer D-1.
<Cyan Liquid Developer D-3>
A cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) was used as the colorant, and the content of the oxidation polymerization accelerator was 0.1 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer D-3 was produced in the same manner as the liquid developer D-1.
<Yellow liquid developer D-4>
Except for using a yellow pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow 93) as a colorant and setting the content of the oxidation polymerization accelerator to 0.01 parts by weight with respect to 100 parts by weight of the insulating liquid, A liquid developer D-4 was produced in the same manner as the liquid developer D-1.

<Black liquid developer E-1>
A liquid developer E-1 was produced in the same manner as the liquid developer D-1, except that the oxidation polymerization accelerator was not added.
<Magenta Liquid Developer E-2>
The liquid developer E-2 was the same as the liquid developer D-1, except that a magenta pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Red 122) was used as the colorant, and no oxidation polymerization accelerator was added. Manufactured.

<Cyan Liquid Developer E-3>
A liquid developer E was used in the same manner as the liquid developer D-1, except that a cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) was used as the colorant and no oxidation polymerization accelerator was added. -3 was produced.
<Yellow liquid developer E-4>
The liquid developer E-4 was the same as the liquid developer D-1 except that a yellow pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow 93) was used as the colorant, and no oxidation polymerization accelerator was added. Manufactured.

<Black liquid developer F-1>
A liquid developer F-1 was produced in the same manner as the liquid developer D-1, except that the content of the oxidation polymerization accelerator was 2 parts by weight with respect to 100 parts by weight of the insulating liquid.
<Magenta Liquid Developer F-2>
The liquid development described above, except that a magenta pigment (Pigment Red 122, manufactured by Dainichi Seika Co., Ltd.) is used as the colorant, and the content of the oxidation polymerization accelerator is 1 part by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer F-2 was produced in the same manner as Agent D-1.

<Cyan Liquid Developer F-3>
A cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) was used as the colorant, and the content of the oxidation polymerization accelerator was 0.6 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer F-3 was produced in the same manner as the liquid developer D-1.
<Yellow liquid developer F-4>
Except for using a yellow pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow 93) as a colorant and setting the content of the oxidative polymerization accelerator to 0.2 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer F-4 was produced in the same manner as the liquid developer D-1.
<Black liquid developer G-1>
A liquid developer G-1 was produced in the same manner as the liquid developer D-1, except that the content of the oxidative polymerization accelerator was 0.5 parts by weight with respect to 100 parts by weight of the insulating liquid.
<Magenta Liquid Developer G-2>
Except for using magenta pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Red 122) as a colorant and setting the content of the oxidation polymerization accelerator to 0.2 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer G-2 was produced in the same manner as the liquid developer D-1.

<Cyan Liquid Developer G-3>
A cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) was used as the colorant, and the content of the oxidation polymerization accelerator was 0.1 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer G-3 was produced in the same manner as the liquid developer D-1.
<Yellow liquid developer G-4>
Except that a yellow pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow 93) was used as a colorant, and the content of the oxidation polymerization accelerator was 0.04 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer G-4 was produced in the same manner as the liquid developer D-1.

<Black liquid developer H-1>
A liquid developer H-1 was produced in the same manner as the liquid developer D-1, except that the content of the oxidative polymerization accelerator was 0.1 parts by weight with respect to 100 parts by weight of the insulating liquid.
<Magenta Liquid Developer H-2>
Except for using magenta pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Red 122) as a colorant, the content of the oxidation polymerization accelerator is 0.01 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer H-2 was produced in the same manner as the liquid developer D-1.

<Cyan Liquid Developer H-3>
A cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) was used as the colorant, and the content of the oxidation polymerization accelerator was 0.005 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer H-3 was produced in the same manner as the liquid developer D-1.
<Yellow liquid developer H-4>
Except for using a yellow pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Yellow 93) as a colorant and changing the content of the oxidation polymerization accelerator to 0.005 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer H-4 was produced in the same manner as the liquid developer D-1.

<Black liquid developer I-1>
A liquid developer I-1 was produced in the same manner as the liquid developer D-1, except that encapsulated manganese naphthenate was used as the oxidative polymerization accelerator.
<Magenta Liquid Developer I-2>
A liquid developer I-1 was produced in the same manner as the liquid developer D-2 except that encapsulated manganese naphthenate was used as the oxidative polymerization accelerator.

<Cyan Liquid Developer I-3>
A liquid developer I-1 was produced in the same manner as the liquid developer D-3 except that encapsulated manganese naphthenate was used as the oxidative polymerization accelerator.
<Yellow liquid developer I-4>
A liquid developer I-1 was produced in the same manner as the liquid developer D-4 except that encapsulated manganese naphthenate was used as the oxidative polymerization accelerator.

<Black liquid developer J-1>
A liquid developer J-1 was produced in the same manner as the liquid developer D-1, except that encapsulated manganese octylate was used as the oxidative polymerization accelerator.
<Magenta Liquid Developer J-2>
A liquid developer J-1 was produced in the same manner as the liquid developer D-2 except that encapsulated manganese octylate was used as the oxidative polymerization accelerator.

<Cyan Liquid Developer J-3>
A liquid developer J-1 was produced in the same manner as the liquid developer D-3 except that encapsulated manganese octylate was used as the oxidative polymerization accelerator.
<Yellow liquid developer J-4>
A liquid developer J-1 was produced in the same manner as the liquid developer D-4 except that encapsulated manganese octylate was used as the oxidative polymerization accelerator.

<Black liquid developer K-1>
A liquid developer K-1 was produced in the same manner as the liquid developer D-1, except that the content of the oxidation polymerization accelerator was 1 part by weight with respect to 100 parts by weight of the insulating liquid.
<Magenta Liquid Developer K-2>
The liquid development described above except that a magenta pigment (Dainipei Seika Co., Ltd., Pigment Red 122) is used as the colorant and the content of the oxidation polymerization accelerator is 2 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer K-2 was produced in the same manner as Agent D-1.

<Cyan Liquid Developer K-3>
Except for using a cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) as the colorant and setting the content of the oxidation polymerization accelerator to 2 parts by weight with respect to 100 parts by weight of the insulating liquid, A liquid developer K-3 was produced in the same manner as the liquid developer D-1.
<Yellow liquid developer K-4>
The liquid development was performed except that a yellow pigment (Dainipei Seika Co., Ltd., Pigment Yellow 93) was used as the colorant and the content of the oxidation polymerization accelerator was 2 parts by weight with respect to 100 parts by weight of the insulating liquid. A liquid developer K-4 was produced in the same manner as Agent D-1.

<< 2 >> Image Formation (Example 1)
Liquid developers D-1, E-2, E-3, and E-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 2)
Liquid developers F-1, E-2, E-3, and E-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 3)
Liquid developers G-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

Example 4
Liquid developers H-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 5)
Liquid developers I-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 6)
Liquid developers J-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image having a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and thereafter, fixing was performed using a fixing device as shown in FIG.

(Example 7)
Liquid developers K-3, E-2, E-1, and E-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 8)
Liquid developers D-1, E-2, E-3, and E-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image having a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and thereafter, fixing was performed using a fixing device as shown in FIG.

Example 9
Liquid developers F-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image having a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and thereafter, fixing was performed using a fixing device as shown in FIG.

(Example 10)
Liquid developers G-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image having a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and thereafter, fixing was performed using a fixing device as shown in FIG.

(Example 11)
Liquid developers H-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 12)
Liquid developers I-1, E-2, E-3, and E-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image having a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and thereafter, fixing was performed using a fixing device as shown in FIG.

(Example 13)
Liquid developers J-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 14)
Liquid developers K-3, E-2, E-1, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 15)
Liquid developers D-1, D-2, D-3, and D-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 16)
Liquid developers F-1, F-2, F-3, and F-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 17)
Liquid developers G-1, G-2, G-3, and G-4 are respectively added to the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 18)
Liquid developers H-1, H-2, H-3, and H-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 19)
Liquid developers I-1, I-2, I-3, and I-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 20)
Liquid developers J-1, J-2, J-3, and J-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 21)
Liquid developers D-3, D-2, H-1, and D-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 22)
Liquid developers D-1, D-2, D-3, and D-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 23)
Liquid developers F-1, F-2, F-3, and F-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 24)
Liquid developers G-1, G-2, G-3, and G-4 are respectively added to the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 25)
Liquid developers H-1, H-2, H-3, and H-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 26)
Liquid developers I-1, I-2, I-3, and I-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 27)
Liquid developers J-1, J-2, J-3, and J-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Example 28)
Liquid developers D-3, D-2, H-1, and D-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Comparative Example 1)
Liquid developers E-1, E-2, E-3, and E-4 are charged into the developing sections 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Comparative Example 2)
Liquid developers E-1, E-2, E-3, and E-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Comparative Example 3)
Liquid developers K-1, K-2, K-3, and K-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ′ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.

(Comparative Example 4)
Liquid developers K-1, K-2, K-3, and K-4 are charged into the developing units 15K, 15M, 15C, and 15Y of the liquid developing apparatus 10 ″ as shown in FIG. Then, an unfixed toner image of a predetermined pattern was formed on a recording medium (Fuji Xerox Office Supply, J paper), and then fixing was performed using a fixing device as shown in FIG.
Table 1 shows the figure of the applied liquid developing device, the color of the liquid developer introduced into each developing unit, and the content of the oxidation polymerization accelerator with respect to 100 parts by weight of the insulating liquid for each of the above Examples and Comparative Examples. Indicated.

<< 3 >> Evaluation (3-1) Fixing Strength Eraser (LION 261-11, made by Lion Business Machine Co., Ltd.) erases the fixing toner image on the recording medium obtained in each of the above Examples and Comparative Examples. By rubbing three times with a pressing load of 1.5 kgf, the residual ratio of image density was measured by “X-Rite model 404” manufactured by X-Rite Inc, and evaluated according to the following five-stage criteria.
A: Image density residual ratio is 95% or more.
A: Image density residual ratio is 90% or more and less than 95%.
○: Image density remaining rate is 80% or more and less than 90%.
Δ: Image density remaining rate is 70% or more and less than 80%.
X: Image density remaining rate is less than 70%.

(3-2) Evaluation of image quality (color) When magenta, yellow, cyan mixed color patch and black patch after fixing are measured with X-Rite 968, and no oxidation polymerization accelerator is added (Comparative Example) The color reproducibility for the fixing patch of 1) was evaluated according to the following criteria.
A: No difference from the original (ΔE ≦ 2)
○: Almost no difference from the original (2 <ΔE ≦ 3)
Δ: Slightly different from the original color (3 <ΔE <5)
×: greatly different from the original color (ΔE ≧ 5)
These results are shown in Table 2.

  As is clear from Table 2, in each of the examples, both the fixing strength and the image quality were excellent. On the other hand, in each comparative example, a satisfactory result was not obtained.

It is a figure which shows an example of the image forming apparatus of this invention. FIG. 3 is a schematic diagram illustrating an example of a developing unit provided in the liquid developing device of the present invention. 1 is a cross-sectional view illustrating an example of a fixing device applied to an image forming apparatus of the present invention. It is a figure which shows another example of the image forming apparatus of this invention.

Explanation of symbols

  1000 ', 1000 "... image forming apparatus 2 ... recording medium 2a ... toner image 10', 10" ... liquid developing device 15Y, 15M, 15C, 15K ... developing unit 20Y, 20M, 20C, 20K ... photosensitive member 30Y, 30M, 30C, 30K ... Charging unit 40Y, 40M, 40C, 40K ... Exposure unit 50Y, 50M, 50C, 50K ... Developing unit 60Y, 60M, 60C, 60K ... Primary transfer unit 70 ... Intermediate transfer unit 73Y, 73M, 73C, 73K ... Static elimination unit 75Y, 75M, 75C, 75K ... Photoconductor cleaning unit 76Y, 76M, 76C, 76K ... Photoconductor cleaning blade 80 '... Transfer section (recording medium transport belt) 80 "... Secondary transfer unit (secondary transfer section) 90 ... Tertiary transfer unit (tertiary transfer unit) 510 ... Current Image roller 530... Developer storage unit 540... Lifting roller 540 a... Central shaft 540 b .. Upper end 550. Developer supply roller 550 a .. Center shaft 550 b. ... Developing roller cleaning blade 580 ... Entry side liquid level 590 ... Reducing member F40 ... Fixing device F1 ... Heat fixing roller (heating roller) F1a ... Column halogen lamp F1b ... Roller base material F1c ... Elastic body F11c ... Releasing layer F12 ... Removal Blade F2 ... Pressure roller F2a ... Rotary shaft F2b ... Roller base material F2c ... Elastic body F3 ... Heat-resistant belt F4 ... Belt tension member F4a ... Projection wall F4f ... Concavity F6 ... Cleaning member F7 ... Frame F9 ... Spring

Claims (9)

An image forming method for forming a color image on a recording medium using a liquid developer in which toner particles are dispersed in an insulating liquid containing an unsaturated fatty acid component,
A development step of forming a plurality of single color images corresponding to each color using a plurality of liquid developers having different colors;
Transferring a plurality of monochrome images corresponding to each color to the recording medium, and forming an unfixed color image formed by superimposing the plurality of monochrome images on the recording medium;
A fixing step of fixing the unfixed color image on the recording medium,
Of the plurality of single color images constituting the unfixed color image, only the liquid developer that forms a single color image located closest to the recording medium is subjected to an oxidative polymerization reaction of the unsaturated fatty acid component at the time of fixing. An image forming method comprising an oxidative polymerization accelerator for promoting. An image forming method for forming a color image on a recording medium using a liquid developer in which toner particles are dispersed in an insulating liquid containing an unsaturated fatty acid component,
A development step of forming a plurality of single color images corresponding to each color using a plurality of liquid developers having different colors;
Transferring a plurality of monochrome images corresponding to each color to the recording medium, and forming an unfixed color image formed by superimposing the plurality of monochrome images on the recording medium;
A fixing step of fixing the unfixed color image on the recording medium,
Accelerates the oxidative polymerization reaction of the unsaturated fatty acid component at the time of fixing to a liquid developer that forms a single color image located closest to the recording medium among the plurality of single color images constituting the unfixed color image An image forming method characterized in that it contains the most oxidative polymerization accelerator.   Among the plurality of single color images constituting the unfixed color image, the content of the oxidative polymerization accelerator contained in the liquid developer that forms a single color image located closest to the recording medium is The image forming method according to claim 1, wherein the amount is 0.01 to 2 parts by weight with respect to 100 parts by weight of the ionic liquid.   2. The liquid developer that forms a single color image located closest to the recording medium among the plurality of single color images constituting the unfixed color image forms a single color image corresponding to black. 4. The image forming method according to any one of 3 above.   The image forming method according to claim 1, wherein the insulating liquid contains an unsaturated fatty acid glyceride and a fatty acid monoester.   6. The image forming method according to claim 1, wherein the oxidative polymerization accelerator is contained in the liquid developer in an encapsulated state. A liquid developing device applied to the image forming method according to claim 1,
A plurality of developing units that form the single-color image corresponding to each color using a plurality of liquid developers having different colors;
By transporting the recording medium, the plurality of monochrome images formed by the plurality of developing units are sequentially transferred to the recording medium, and the unfixed color image formed by superimposing the transferred plurality of monochrome images And a transfer unit formed on the recording medium. A liquid developing device applied to the image forming method according to claim 1,
A plurality of developing units that form a single color image corresponding to each color using a plurality of liquid developers having different colors;
An intermediate transfer unit that sequentially transfers a plurality of the single-color images formed by the plurality of developing units, and forms an intermediate transfer image formed by superimposing the transferred single-color images;
A secondary transfer unit that transfers the intermediate transfer image and transfers the transferred intermediate transfer image;
A liquid developing apparatus, comprising: a tertiary transfer unit that transfers the conveyed intermediate transfer image onto the recording medium and forms the unfixed color image on the recording medium.   9. An image forming apparatus comprising: the liquid developing device according to claim 7; and a fixing device that fixes the unfixed color image formed on the recording medium.

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