JP2008185704A - Fixing method and unit, image forming method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to apply small amount of the fixing solution to the medium up to a point that paper holding the resin particles does not produce the feeling that the solution is still remaining on the paper after fixing the images by quickly fixing the resin particles to the medium after supplying the fixing solution without disturbing the resin containing toner particles on the medium. <P>SOLUTION: The fixing method has a process of producing a foamed fixing solution containing a softener to soften the resin by at least partly melting or swelling it, a process of static charging the resin particles containing a resin, and a process of supplying the foamed fixing solution around the surface of the resin particle layer consisting of static charged resin particles on the medium. The foamed fixing solution supplied around the surface of the resin particle layer is attracted by the charged resin particles and is foam-broken when entering between the particles, and the defoamed fixing solution infiltrates into the resin particles. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing method, a fixing device, an image forming method, and an image forming device, and more particularly to a fixing device that promotes bubble breakage of a foam-like fixing solution that fixes resin-containing fine particles on a medium.

  An image forming apparatus such as a printer, a facsimile, and a copying apparatus is an apparatus that forms an image including characters and symbols on a recording medium such as paper, cloth, and an OHP sheet based on image information. In particular, electrophotographic image forming apparatuses are widely used in offices because they can form high-definition images on plain paper at high speed. In such an electrophotographic image forming apparatus, a heat fixing method is widely used in which toner on a recording medium is heated and melted, and the molten toner is pressurized to fix the toner on the recording medium. Yes. This thermal fixing method is preferably used because it can provide a high fixing speed and high fixed image quality.

  However, about half or more of the power consumption in such an electrophotographic image forming apparatus is consumed in heating the toner in the heat fixing method. On the other hand, a low power consumption (energy saving) fixing device is desired from the viewpoint of countermeasures for environmental problems in recent years. That is, there is a demand for a fixing method in which the temperature for heating the toner for fixing the toner is extremely lowered than before, or the toner does not need to be heated. In particular, the non-heat fixing method in which the toner is fixed to the recording medium without heating the toner at all is ideal in terms of low power consumption.

  As such a non-heat fixing method, for example, an oil-in-water type fixing agent in which a toner can be dissolved or swelled and an organic compound insoluble or hardly soluble in water is dispersed and mixed in water is used. Patent Document 1 proposes a toner wet fixing method in which a toner is dissolved or swollen by spraying or dripping from the surface of the fixing object disposed at the position, and then the fixing object is dried.

  However, in the wet fixing method disclosed in Patent Document 1, an oil-in-water type fixing agent in which an organic compound insoluble or hardly soluble in water is dispersed and mixed in water is used. When applied to the recording medium, the recording medium such as transfer paper (non-fixed material) absorbs moisture of the fixing agent, and the recording medium is wrinkled and curled. This significantly impairs the stable and high-speed conveyance of the recording medium required for the image forming apparatus. Therefore, if water is removed from the fixing agent applied to the recording medium by evaporating a large amount of water contained in the fixing agent using a drying device, the power consumption of the image forming apparatus using the thermal fixing method is reduced. You will need comparable power.

In addition, several oil-based fixing solutions in which a material that dissolves or swells toner is dissolved in an oil-based solvent have been proposed as fixing solutions that do not repel water-repellent unfixed toner. As one example, for example, in Patent Document 2, an aliphatic dibasic acid ester or the like containing a material that dissolves or swells a resin component constituting a toner as a diluent (solvent) is diluted with nonvolatile dimethyl silicone. Fixing solutions (dissolved) have been proposed. In Patent Document 3, toner is used as a fixing solution that can be used in a fixing method in which an unfixed image formed by an electrostatic method can be clearly and easily fixed on an image receiving sheet without disturbing the image. A solution for fixing an unfixed toner image in a compatible state, in which 8 to 120 parts by volume of a silicone oil is mixed with 100 volumes of a solvent that is dissolved and compatible with the silicone oil, has been proposed. Such an oil-based fixing solution contains an oil-based solvent having a high affinity with the water-repellent-treated unfixed toner, so that the toner is dissolved or swollen without repelling the water-repellent-treated unfixed toner, The toner can be fixed on the recording medium.
Japanese Patent No. 3,290,513 JP 2004-109749 A JP 59-119364 A JP 2004-109747 A

  However, in any of the above patent documents, the liquid is applied to the unfixed toner layer. However, as shown in FIGS. 12A and 12B, recording is performed using the application roller 1 as a contact applying unit. In the configuration in which the fixing solution is applied to the unfixed toner layer 3 on the medium 2, the thickness of the fixing solution layer 4 on the coating roller 1 is thinner than that of the unfixed toner layer 3 in order to apply a small amount of the fixing solution to the recording medium 2. In this case, unfixed toner particles are pulled by the surface tension generated by the liquid film of the fixing liquid on the surface of the application roller 1 at a position where the application roller 1 is peeled from the recording medium 2, and the toner particles are offset on the surface of the application roller 1. Then, the image on the recording medium 2 is greatly disturbed. Conversely, as shown in FIG. 13, when the thickness of the fixing liquid layer 4 on the application roller 1 is sufficiently thicker than that of the unfixed toner layer 3, the amount of liquid is large at the position where the application roller 1 peels from the recording medium 2. Therefore, the surface tension due to the liquid film on the surface of the coating roller 1 is less likely to act directly on the toner particles, and the toner is not offset on the roller side. However, since a large amount of fixing liquid is applied to the paper surface, the toner particles are excessively fixed. The liquid is caused to flow on the recording medium 2 to cause deterioration of image quality, and the drying time becomes long, resulting in a problem in fixing response. In addition, a noticeable residual liquid feeling (a wet feeling when the paper is touched by hand) occurs on the paper. In addition, when the fixing solution contains water, when the amount of application to a medium containing cellulose such as paper is large, the recording medium such as paper is significantly curled, and the recording medium such as paper in the apparatus in an image forming apparatus or the like There is a risk of paper jams during transport. Therefore, in such a configuration in which the roller is applied with the fixing liquid, the fixing responsiveness is improved, the residual liquid feeling is reduced, and a small amount of the fixing liquid is applied to the toner layer on the paper to prevent the curling and the toner offset is prevented from being applied to the fixing roller. It is extremely difficult to do. Even when a die coating unit, a blade coating unit, or a wire bar coating unit is used as the contact coating unit, the toner is offset to the contact coating unit by surface tension when the amount of the fixing solution becomes small.

  As described above, in the conventional fixing solution formulation, the contact coating means can achieve both the application of a small amount of the fixing solution to the toner layer on the paper and the uniform application of the toner image without any disturbance in order to improve the fixing responsiveness. Is extremely difficult.

  The present invention is for solving these problems, and does not disturb resin fine particles containing a resin such as toner on a medium such as paper and supplies a fixing solution to the medium to which the resin fine particles are adhered. Alternatively, after the application, the resin fine particles are quickly fixed on the medium, and the resin fine particle fixer capable of being applied in a minute amount so as not to cause a residual liquid feeling on the medium, and a fixing method and a fixing device using the fixer An object of the present invention is to provide an image forming method and an image forming apparatus.

  In order to solve the above-mentioned problems, the fixing method of the present invention is to generate a foam-like fixing solution that forms a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least part of the resin. A charging step for charging resin fine particles containing a resin, and a fixing solution supply step for supplying a foamy fixing solution to the vicinity of the surface of the resin fine particle layer on the medium made of charged resin fine particles. Yes. According to the fixing method of the present invention, the foam-like fixing solution supplied in the vicinity of the surface of the resin fine particle layer is attracted to the charged resin fine particles and enters between the particles of the resin fine particles to break up and liquefy. However, the liquefied fixing solution is characterized by penetrating the resin fine particle layer. Therefore, without changing the shape and composition of the oil fine particles, after the foam-like fixer is supplied near the surface of the resin fine particle layer, it is attracted to the charged resin fine particles based on the electrowetting principle, and the resin fine particles The fixing solution penetrates into the resin fine particle layer by entering, quickly breaking and liquefying, and the fixing responsiveness can be improved.

  In addition, the fixing method of the present invention includes a foamy fixing solution generation step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin, and a hydrophilic resin. A fixing solution applying step for applying a foamy fixing solution to a resin fine particle layer on a medium composed of resin fine particles containing. According to the fixing method of the present invention, the foam-like fixing solution applied to the resin fine particle layer expands by contacting the hydrophilic resin, breaks and liquefies, and the liquefied fixing solution becomes the resin. It is characterized by penetrating into the fine particle layer. Therefore, when the foam-like fixing solution comes into contact with the hydrophilic resin, the wettability between the resin fine particles and the fixing solution increases, and the foam-like fixing solution breaks down and liquefies, so that the fixing solution is transferred to the resin fine particle layer. Penetration and fixing response can be improved.

  Furthermore, the resin fine particles are formed by locally attaching a hydrophobic resin to the surface of the hydrophilic resin.

  Further, the fixing method of the present invention includes a foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin, and a uniform particle size. In the resin fine particle layer on the medium, the resin fine particle layer on the medium in which the second resin fine particles containing the sharp protrusion-shaped resin are mixed into a part of the resin fine particle layer on the medium composed of the first resin fine particles containing the resin. A fixing solution applying step for applying the fixing solution. According to the fixing method of the present invention, the foam-like fixing solution applied to the resin fine particle layer breaks and liquefies by the sharp protrusion shape of the second resin fine particles, and the liquefied fixing solution becomes the resin fine particles. It is characterized by penetrating the layer. Therefore, the foam-breaking property of the foam-like fixing solution is promoted, and the foam-like fixing solution breaks and liquefies, whereby the fixing solution penetrates into the resin fine particle layer, and the fixing responsiveness can be improved.

  Further, the fixing solution preferably contains water and a fatty acid salt.

  In addition, a fixing device according to another invention includes a foam-like fixing solution generating unit that generates a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin, and a resin. Charging means for charging the contained resin fine particles, and fixing solution supply means for supplying a foamy fixing solution to the vicinity of the surface of the resin fine particle layer on the medium made of charged resin fine particles. In the fixing device of the present invention, the foam-like fixing liquid supplied near the surface of the resin fine particle layer by the fixing liquid supply means is attracted to the resin fine particles charged by the charging means, and is between the resin fine particles. It enters and breaks bubbles to liquefy, and the liquefied fixing solution penetrates into the resin fine particle layer. Therefore, without changing the shape and composition of the oil fine particles, after the foam-like fixer is supplied near the surface of the resin fine particle layer, it is attracted to the charged resin fine particles based on the electrowetting principle, and the resin fine particles The fixing solution penetrates into the resin fine particle layer by entering, quickly breaking and liquefying, and the fixing responsiveness can be improved.

  Further, the fixing device according to another invention includes a foam-like fixing solution generating means for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin, and a hydrophilic property. And a fixing solution applying means for applying a foamy fixing solution to the resin fine particle layer on the medium made of resin fine particles containing the above resin. In the fixing device of the present invention, the foamy fixing solution applied to the resin fine particle layer by the fixing solution applying means expands by contacting the hydrophilic resin, breaks up bubbles, liquefies, and is liquefied. The liquid penetrates into the resin fine particle layer. Therefore, when the foam-like fixing solution comes into contact with the hydrophilic resin, the wettability between the resin fine particles and the fixing solution increases, and the foam-like fixing solution breaks down and liquefies, so that the fixing solution is transferred to the resin fine particle layer. Penetration and fixing response can be improved.

  In addition, the fixing device according to another invention includes a foam-like fixing solution generating means for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin, and a particle size In the resin fine particle layer on the medium, a part of the resin fine particle layer on the medium composed of the first resin fine particles containing a uniform resin is mixed with the second resin fine particle containing the resin having a sharp protrusion shape. A fixing solution applying means for applying a fixing solution in the form of a liquid. In the present invention, the foam-like fixing solution applied to the resin fine particle layer by the fixing solution applying means breaks up and liquefies by the sharp protrusion shape of the second resin fine particles, and the liquefied fixing solution is a resin. It penetrates into the fine particle layer. Therefore, the foam-breaking property of the foam-like fixing solution is promoted, and the foam-like fixing solution breaks and liquefies, whereby the fixing solution penetrates into the resin fine particle layer, and the fixing responsiveness can be improved.

  Furthermore, an image forming method as another invention includes an image forming step of forming an unfixed toner image on a medium by performing an electrostatic recording process with a developer containing resin fine particles containing a resin and a colorant, and at least a resin Charge the resin fine particles of the unfixed toner image formed in the foam fixing solution generation process, which forms a fixing liquid containing a softening agent that softens the resin by dissolving or swelling a part, and the image forming process And a fixing solution for supplying a foamy fixing solution to a resin fine particle layer on the medium composed of resin fine particles charged in the charging step to fix an unfixed toner image on the medium to form an image on the medium. And a supply step. Therefore, without disturbing resin fine particles containing resin such as toner on a medium such as paper, and after supplying the fixing liquid to the medium to which the resin fine particles are attached, the resin fine particles are quickly fixed to the medium, Further, it is possible to apply a trace amount so as not to cause a residual liquid feeling on the medium, non-heat fixing, low power consumption, and an image forming method excellent in fixing responsiveness can be provided.

  An image forming method according to another invention includes an image forming step of forming an unfixed toner image on a medium by performing an electrostatic recording process with a developer containing resin fine particles containing a hydrophilic resin and a colorant, A foam-like fixer generating step for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least part of the resin, and a foam-like form in the resin fine-particle layer on the medium composed of resin fine-particles And a fixing solution applying step of fixing the unfixed toner image onto the medium to form an image on the medium. Therefore, without disturbing resin fine particles containing resin such as toner on a medium such as paper, and after supplying the fixing liquid to the medium to which the resin fine particles are attached, the resin fine particles are quickly fixed to the medium, Further, it is possible to apply a trace amount so as not to cause a residual liquid feeling on the medium, non-heat fixing, low power consumption, and an image forming method excellent in fixing responsiveness can be provided.

  Further, according to another image forming method of the present invention, there is provided a second developer containing a sharp protrusion-shaped resin in a part of a developer composed of a first resin fine particle containing a resin having a uniform particle diameter and a colorant. An image forming process for forming an unfixed toner image on a medium by mixing resin fine particles and performing an electrostatic recording process with a developer, and a softening agent for softening the resin by dissolving or swelling at least a part of the resin A foam-like fixer generating step for generating a fixer in the form of foam, and fixing the unfixed toner image on the medium by applying a foam-like fixer to the resin fine particle layer on the medium composed of the first and second resin fine particles. And a fixing solution applying step for forming an image on the medium. Therefore, the foam breaking property can be improved without changing the composition constituting the toner, and the production cost of the toner can be suppressed.

  An image forming apparatus according to another invention includes an image forming unit that forms an unfixed toner image on a medium by performing an electrostatic recording process with a developer including resin fine particles containing a resin and a colorant, and at least a resin. Charges the fine resin particles of the unfixed toner image formed by the foam-forming fixing solution generating means for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling a part thereof, and the image forming means. And a fixing solution for supplying a foamy fixing solution to a resin fine particle layer on a medium composed of resin fine particles charged by the charging device to fix an unfixed toner image on the medium to form an image on the medium. And a supply means. Therefore, without disturbing resin fine particles containing resin such as toner on a medium such as paper, and after supplying the fixing liquid to the medium to which the resin fine particles are attached, the resin fine particles are quickly fixed to the medium, Further, it is possible to apply a trace amount so that a residual liquid feeling does not occur on the medium, non-heat fixing, low power consumption, and an image forming apparatus excellent in fixing responsiveness can be provided.

  Furthermore, an image forming apparatus according to another invention includes an image forming unit that forms an unfixed toner image on a medium by performing an electrostatic recording process with a developer including resin fine particles containing a hydrophilic resin and a colorant. Foam fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin, and a resin fine particle layer on a medium composed of resin fine particles. And a fixing solution applying means for applying the fixing solution to fix the unfixed toner image on the medium to form an image on the medium. Therefore, without disturbing resin fine particles containing resin such as toner on a medium such as paper, and after supplying the fixing liquid to the medium to which the resin fine particles are attached, the resin fine particles are quickly fixed to the medium, Further, it is possible to apply a trace amount so that a residual liquid feeling does not occur on the medium, non-heat fixing, low power consumption, and an image forming apparatus excellent in fixing responsiveness can be provided.

  According to another aspect of the present invention, there is provided an image forming apparatus according to a second aspect of the invention, wherein a part of a developer composed of a first resin fine particle containing a resin having a uniform particle diameter and a colorant contains a sharp protrusion-shaped resin. Image forming means for forming an unfixed toner image on a medium by mixing resin fine particles and performing an electrostatic recording process with a developer, and a softening agent for softening the resin by dissolving or swelling at least part of the resin Fixing the unfixed toner image on the medium by applying a foam-like fixing liquid to the foam fine-fixing liquid generating means for generating the fixing liquid in the form of foam and the resin fine particle layer on the medium composed of the first and second resin fine particles. And a fixing solution applying means for forming an image on the medium. Accordingly, it is possible to provide an image forming apparatus that can improve the bubble-breaking property without changing the composition of the toner, is a non-heat fixing method, can reduce power consumption, and has excellent fixing response.

  According to the fixing method of the present invention, by using a foam-like fixing solution, the foam-like fixing solution is supplied to the foam-like fixing solution supplying means or the foam-like fixing solution-providing means when the foam-like fixing solution is supplied or applied to the resin fine particle layer. The offset of resin fine particles can be prevented, and a small amount of fixing solution can be realized. At the same time, bubbles can be liquefied immediately when a foam-like fixing solution is applied to the resin fine particle layer, thereby shortening the liquid penetration time into the toner layer. Fixing responsiveness can be improved.

  First, the principle of the present invention will be outlined. In the present invention, as shown in FIG. 1, the fixing liquid is a foamed fixing liquid 14 composed of foam, whereby the density of the fixing liquid can be reduced and the application roller. It has been found that the fixing liquid layer on the surface 11 can be thickened, and further, the influence of the surface tension of the fixing liquid can be suppressed, so that the offset of the resin fine particles to the coating roller 11 can be prevented. Further, when the size of the resin fine particles is about 5 μm to 10 μm, in order to apply the foam fixing solution 14 to the resin fine particle layer 13 without disturbing the fine particle layer, the bubble diameter range of the foam fixing solution is 5 μm to 50 μm. It turns out that a degree is necessary. As shown in FIG. 2, the foam-like fixing solution 20 composed of the bubbles 22 includes a liquid film boundary (hereinafter referred to as a plateau boundary) 21 that divides each of the bubbles 22. In FIG. 1, bubbles smaller than resin fine particles (about 5 μm) are also described. However, bubbles having a larger bubble particle size than resin fine particles contribute to the above effect.

  By the way, as a result of examining the fixing with the foam fixing solution based on the principle of the present invention as described above, as shown in FIG. 1, the use of the foam fixing solution can prevent the resin fine particles from being offset on the coating roller. If the foam is kept stable without breaking, the foam film remains on the resin fine particles, and the fixing liquid cannot penetrate into the resin fine particle layer 13 and may cause fixing failure. Therefore, as shown in FIG. 3, when the foam-like fixing solution 14 comes into contact with the surface of the resin fine particle layer 13 or immediately after the bubble breakage, the liquefied fixing solution easily penetrates into the resin fine particle layer 13. As a result, the fixing response is improved. Thus, it was found that the foam breaking property at the time of applying the foamy fixing solution to the resin fine particle layer affects the fixing responsiveness and stability.

  The present invention pays attention to such points, and applies a foamy fixer containing a softening agent that softens fine particles containing resin by dissolving or swelling at least a part of the resin to the fine resin particles on the medium. Then, in the fixing method for fixing the resin fine particles to the medium, the resin fine particles have an action of promoting bubble breakage, and the fixing solution is broken by foaming immediately after or immediately after the foamy fixer is applied to the resin fine particles. The solution is liquefied so that the fixer quickly penetrates into the resin fine particle layer. The bubble breakage is caused by the fact that the liquid in the plateau boundary moves for some reason, a part of the plateau boundary becomes extremely thin, and the boundary strength is maintained, so that the boundary is destroyed.

  FIG. 4 is an enlarged conceptual diagram when the foamy fixing solution is applied to the surface of the resin fine particle layer. In the figure, the same reference numerals as those in FIG. 2 denote the same components. The size of the bubbles 22 is preferably larger than the size of the resin fine particles 23 in order to prevent surface tension from acting on the resin fine particles 23, and the bulk density of the foam-like fixing liquid is preferably as small as possible. For this reason, it is desirable that the plateau boundary 21 (the liquid film portion at the boundary between the bubbles) is smaller than the diameter of the resin fine particles 23. In this configuration, the bubble 22 bursting (bubble breaking) means that the thickness of a part of the plateau boundary 21 is reduced by evaporating or moving the fixing liquid held on the plateau boundary 21 and the liquid film is retained. It means a phenomenon that the plateau boundary 21 is destroyed when it becomes impossible.

  In other words, the fact that the resin fine particles in the present invention have a function of easily defoaming means that the liquid in the plateau boundary easily moves to the surface of the resin fine particles when the foamy fixing solution contacts the resin fine particles. Means that

  In the present invention, the fixing solution contains water as a base material. In order to reach the surface of the resin fine particles where the fixer easily moves, the surface of the resin fine particles is generally made hydrophilic. However, when the surface of the resin fine particles is always hydrophilic, there is a problem due to the influence of environmental humidity. For example, when the resin fine particles are toner for electrophotographic recording, if the toner is hydrophilic, the amount of charge varies due to the influence of environmental humidity, and an abnormal image is likely to occur. For this reason, the surface of the toner is hydrophobically treated so as not to be affected by humidity.

  Therefore, in the present invention, in order to prevent the resin fine particles such as toner from being affected by the environmental humidity, it is essential that the resin surface has a certain degree of hydrophobicity, and the fixing liquid moves to the surface of the resin fine particles. The resin fine particles having a difficult surface have an effect that the liquid in the plateau boundary easily moves to the surface of the resin fine particles when the foamy fixing solution is applied.

  FIG. 5 is a schematic view showing a state of fixing by the fixing device according to the first embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 4 denote the same components. In the fixing device of the present embodiment shown in the figure, the resin fine particles 23 are charged in advance by a charging means (not shown) before the foamy fixing solution is applied. In the figure, it is positively charged. Then, as shown in FIG. 5A, the fixing liquid in the plateau boundary expands and moves to the surface of the resin fine particles 23 by the action of electro wetting. Induced by the charge of the resin fine particles 23, the plateau boundary 21 of the foam-like fixer is negatively charged. When the bubble 22 comes into contact with the toner in this state, as shown in FIG. 5B, the wettability of the surface of the resin fine particles 23 increases in a state where a strong electric field is applied according to the principle of electro wetting. The liquid in the plateau boundary expands and gets wet on the surface of the resin fine particles 23, and a part of the liquid film on the plateau boundary 21 becomes extremely thin, causing bubble breakage. In this way, as shown in FIG. 5C, the fixer 24 that has broken and liquefied penetrates into the resin fine particles 23.

  Next, FIG. 6 is a schematic view showing a state of fixing by the fixing device according to the second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 5 denote the same components. In FIG. 6A, the resin fine particles 23 such as toner are desirably hydrophobic so that the surface of the toner is less susceptible to the influence of environmental humidity, but it is not necessary to be hydrophobic as it repels water. . Therefore, the resin fine particles 23 are made hydrophilic, and hydrophobic fine particles 25 having a diameter one order of magnitude smaller than the particle size of the resin fine particles 23 are attached to the surface thereof. Further, if the surface coverage is 50% or less, the resin fine particles 23 maintain a hydrophobic property that is not easily affected by humidity as water vapor, while maintaining a surface state that is sufficiently hydrophilic to liquids. be able to. Therefore, by using the hydrophilic resin fine particles 23 to which the hydrophobic fine particles 25 are adhered with a coverage of 50% or less, an action that the liquid in the plateau boundary easily moves to the surface of the resin fine particles 23 can be obtained. Then, as shown in FIG. 6B, immediately after the bubble 22 comes into contact with the resin fine particles 23, the resin fine particles 23 are hydrophilic as described above. The surface of the fine particles 23 is expanded and wetted, and a part of the liquid film at the plateau boundary 21 becomes extremely thin and bubbles are broken. In this way, as shown in FIG. 6C, the fixing solution 24 that has broken and liquefied penetrates into the resin fine particles 23. As a method for measuring the degree of hydrophilicity of the resin fine particles, the resin fine particles are dispersed on the surface of ion-exchanged water having a surface tension of 70 mN / m, and when most of the fine particles sink within one minute, the hydrophilicity is judged. .

  FIG. 7 is a schematic view showing a state of fixing by the fixing device according to the third embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 5 denote the same components. In (a) of the figure, as a configuration that facilitates bubble breakage, a configuration in which a part of the plateau boundary is mechanically thinned is conceivable because a part of the plateau boundary may be extremely thinned. Therefore, in addition to the resin fine particles 23 such as toner having a uniform diameter such as a substantially spherical shape manufactured by secondary processing after the primary processing, resin fine particles 26 having a sharp protrusion shape manufactured by the primary processing are mixed. However, if all the resin fine particles have a sharp protrusion shape, there is a possibility that toner dust or the like may occur due to the development characteristics and transfer characteristics, and cleaning defects may occur. Therefore, most of the resin fine particles are resin fine particles 23 having a uniform shape (for example, spherical and having a uniform diameter) after the primary processing, and a sharp protrusion shape other than the resin fine particles 23 is formed. A configuration in which the resin fine particles 26 are mixed is desirable. As shown in FIG. 7B, when the bubbles 22 are in contact with the resin fine particle layer, a part of the bubbles 22 is in contact with the protruding resin fine particles 26, the plateau boundary 21 becomes extremely thin, and the bubble breakage occurs. To do. Here, the plateau boundary is desirably thinner than the toner diameter, but the protrusion shape is desirably higher than the plateau boundary. Thereafter, the bubbles are broken, and the liquefied fixing solution 24 penetrates into the resin fine particles 23 and 26 as shown in FIG.

  Next, the fixing solution applying means in the fixing device of the present invention will be described. FIG. 8 is a schematic configuration diagram showing an example of a fixing solution applying unit in the fixing device of the present invention. The fixing solution applying unit 30 shown in the figure applies a foamy fixing solution to a foamy fixing solution generating unit that uses a liquid fixing solution in a fixing solution container as a foamed fixing solution, and a resin fine particle layer (toner particle layer). The application roller 31 is provided with a pressure roller 36 at a position opposite to the application roller 31. Further, the liquid film thickness control blade 32 is pressed against the application roller surface to control the film thickness of the foam-like fixing solution, and thus the foam-like fixing. The optimal film thickness of the liquid is controlled. Here, the resin fine particles in the present invention are toner particles. As shown in FIG. 4B, a foam-like fixing solution layer is formed on the coating roller 31 through a liquid film thickness control blade 32, and the bubble size and pressure of the foam-like fixing solution are formed. In addition, the film thickness of the fixing liquid layer is optimized in accordance with the layer thickness of the unfixed toner. By using the foamy fixing solution applied by the fixing solution applying means 30 shown in the figure, the resin fine particles are not offset on the coating roller. Even if the foam-like fixing solution is thickly applied to the resin fine particle layer and the recording medium, the bulk density of the foam-like fixing solution is extremely low. By foaming, it is possible to give a small amount to the layer of liquid resin fine particles containing a softening agent. As shown in FIG. 8 (a), the foam-like fixer is a gas that generates a large bubble by mixing the substrate with the fixer contained in the fixer hermetically sealed container 33-1. A foam-type fixing solution generating unit 33 including the liquid mixing unit 33-2; and a shearing force applying unit 34 for separating large bubbles generated by the foam-type fixing solution generating unit 33 with a shearing force. Then, it is dropped from the liquid supply port 35 between the liquid film thickness control blade 32 and the coating roller 31.

  In the fixing liquid applying means 30 having such a configuration, paper is used as a medium, and a foamy fixing liquid is applied to the surface of the unfixed toner by the application roller 31 while conveying the paper to which the unfixed toner is adhered. The liquid film thickness control blade 32 may be in the counter direction or the tailing direction. Further, a spacer for controlling the gap between the coating roller 31 and the liquid film thickness control blade 32 may be provided. Further, the liquid fixer in the fixer hermetic container 33-1 is supplied to the gas / liquid mixing unit 33-2 using a liquid transporting unit such as a transport pump. Large bubbles with uniform bubble diameters are generated by this route. Thereafter, in the shearing force applying means 34, the large foam-like fixing solution is supplied into the closed double cylinder, the inner cylinder is rotatable, and a larger foam-like fixing solution is supplied from a part of the outer cylinder, While passing through the gap between the inner rotating cylinder and the outer cylinder (this is the flow path), the rotating cylinder receives a shearing force. Due to this shearing force, the large bubbles change to fine bubbles, and a foam-like fixing liquid having a desired fine bubble diameter can be obtained from the foam outlet provided in the outer cylinder. A transport pump is used as means for transporting the liquid fixer from the fixer hermetic container 33-1 to the foaming mechanism. As the transport pump, there are a gear pump, a bellows pump, and the like, and a tube pump is desirable. If there is a vibration mechanism or a rotation mechanism in the fixing liquid, such as a gear pump, the liquid foams in the pump, and the liquid may be compressible, resulting in a decrease in conveying ability. In addition, the above-mentioned mechanical parts or the like may contaminate the fixer or conversely deteriorate the mechanical parts. On the other hand, since the tube pump is a mechanism that pushes out the liquid in the tube while deforming the tube, the only member in contact with the fixer is the tube. There is no deterioration of pump system parts. In addition, since the tube is only deformed, the liquid does not foam, and the conveyance capacity can be prevented from being lowered.

  The bulk density of the foam-like fixing solution is preferably in the range of about 0.01 g / cm3 to 0.1 g / cm3. Further, the fixer only needs to be foamed when applied to a layer of resin fine particles such as toner on a recording medium such as paper, and need not be foamed in the storage container 33-1. The storage container 33-1 is a liquid that does not contain air bubbles, and has a configuration in which a means for making bubbles is provided at the time when the fixing liquid is supplied from the storage container 33-1 or the liquid transport path until it is applied to the resin fine particle layer. desirable. This is because the storage container 33-1 is a liquid, and the foamed configuration after taking out the fixing solution from the storage container 33-1 has a great advantage that the storage container can be downsized.

  FIG. 9 is a schematic configuration diagram showing another example of the fixing solution applying means in the fixing device of the present invention. In the figure, the same reference numerals as those in FIG. 8 denote the same components. According to the fixing solution applying means 40 shown in the figure, the foam-like fixing solution is generated with large bubbles by the gas / liquid mixing means 33-2, and the large bubbles are separated by the shearing force applying means 34 with the shearing force. Then, it is dropped from the liquid supply port 35 between the wire bar 37 for controlling the liquid film thickness and the application roller 31. Then, the thickness of the foamy fixing solution on the application roller 31 is controlled by the wire bar 37. Thus, by using the wire bar 37 as the liquid film thickness control means, the film uniformity of the foam-like fixing liquid in the axial direction of the coating roller surface is improved as compared with the liquid film thickness control blade 32 of FIG.

  FIG. 10 is a schematic configuration diagram showing another example of the fixing solution applying means in the fixing device of the present invention. In the figure, the same reference numerals as those in FIG. 8 denote the same components. The fixing liquid applying means 50 shown in the figure applies to the unfixed toner on the recording medium using an application belt 51 instead of the application roller 31 shown in FIG. According to the fixing solution applying means 50 shown in the figure, the foam-like fixing solution is generated with large bubbles by the gas / liquid mixing means 33-2, and the large bubbles are separated by the shearing force applying means 34 with the shearing force. Then, it is dropped from the liquid supply port 35 between the liquid film thickness control blade 32 and the coating belt 51. Then, the gap between the liquid film thickness control blade 32 and the coating belt 51 is adjusted, the film thickness of the foam-like fixing solution on the coating belt 51 is controlled, and the optimum film thickness of the foam-like fixing solution is controlled. . As the coating belt, for example, a member such as a seamless nickel belt or a seamless PET file, which is coated with a releasable fluororesin such as PFA, is used.

  Next, the liquid formulation of the fixing solution will be described. As described above, the foam-like fixing liquid has a configuration in which bubbles are contained in a liquid containing a softening agent. Water is used as the substrate. The liquid containing the softening agent preferably contains a foaming agent and a foam-increasing agent in order to stably contain bubbles and to form a foam layer constituting a bubble layer having a uniform bubble size as much as possible. Moreover, it is desirable to contain a thickener since the bubbles are more stably dispersed in the liquid when the viscosity is higher to some extent.

  As the foaming agent, a fatty acid salt is desirable. Since the fatty acid salt has surface activity, the surface tension of the fixer containing water is lowered to make the fixer easier to foam, and the fatty acid salt has a layered lamellar structure on the surface of the foam, so the foam wall (plateau boundary) is another It is desirable to contain water in the fixing solution in order to make the foam solution stronger than the surfactants, and to have extremely high foam stability. As the fatty acid, a saturated fatty acid resistant to oxidation is desirable from the viewpoint of long-term stability in the air. However, the presence of some unsaturated fatty acid salt in the fixing solution containing saturated fatty acid salt helps to dissolve and disperse the fatty acid salt in water, and has excellent foaming properties at low temperatures from 5 ° C to 15 ° C. The fixing can be stabilized in a wide environmental temperature range, and separation of the fatty acid salt in the fixing solution during long-term standing of the fixing solution can be prevented.

  Further, as the fatty acid used in the saturated fatty acid salt, saturated fatty acids having 12, 14, 16, and 18 carbon atoms, specifically lauric acid, myristic acid, palmitic acid, and stearic acid are suitable. A saturated fatty acid salt having 11 or less carbon atoms has a large odor and is not suitable for an image forming apparatus used in offices and homes using the fixing solution. In addition, saturated fatty acid salts having 19 or more carbon atoms are less soluble in water and significantly lower the stability of the fixing solution. Saturated fatty acid salts with these saturated fatty acids are used alone or in combination as a foaming agent.

  An unsaturated fatty acid salt may be used, and an unsaturated fatty acid having 18 carbon atoms and 1 to 3 double bonds is desirable. Specifically, oleic acid, linoleic acid, and linolenic acid are suitable. Since the reactivity is strong when the double bond is 4 or more, the stability of the fixing solution is poor. These unsaturated fatty acid salts with unsaturated saturated fatty acids are used alone or in combination as a foaming agent. Moreover, you may mix and use the said saturated fatty acid salt and unsaturated fatty acid salt as a foaming agent.

  Furthermore, in order to prevent offset, it is desirable that the thickness of the foam-like fixing liquid layer at the application portion is thicker than the thickness of the resin fine particle layer. Further, it is desirable that the bubbles be larger than the resin fine particles in order to make the bubbles easily adhere to the resin fine particles. When the resin fine particles are toner particles, in the dry electrophotographic system, the toner particles are about 4 to 10 μm in size, and the unfixed toner layer on the paper medium is about 10 to 30 μm. The thickness of the liquid fixing solution is preferably 10 μm to 30 μm or more, and the bubble diameter is preferably about 5 μm to 50 μm.

  Moreover, the softening agent softened by dissolving or swelling the resin fine particles contains an aliphatic ester. This aliphatic ester is excellent in solubility or swelling property that dissolves or swells at least a part of the resin contained in the toner or the like.

  Further, the softening agent has an acute oral toxicity LD50 of more than 3 g / kg, more preferably 5 g / kg, from the viewpoint of safety to the human body. As aliphatic esters are frequently used as cosmetic raw materials, they are highly safe for the human body.

  In addition, the toner is fixed to the recording medium in a device that is frequently used in a sealed environment, and the softener remains in the toner even after the toner is fixed to the recording medium. Preferably does not involve the generation of volatile organic compounds (VOC) and unpleasant odors. That is, the softener preferably does not contain volatile organic compounds (VOC) and substances that cause unpleasant odors. Aliphatic esters have a high boiling point and low volatility and have no irritating odor as compared to generally used organic solvents (toluene, xylene, methyl ethyl ketone, ethyl acetate, etc.).

  In addition, as a practical odor measurement scale that can measure odors in office environments with high accuracy, the odor index (10 × log) by the three-point comparison odor bag method that is sensory measurement The dilution factor of the substance until it disappears)) can be used as an indicator of odor. The odor index of the aliphatic ester contained in the softener is preferably 10 or less. In this case, an unpleasant odor is not felt in a normal office environment. Furthermore, it is preferable that not only the softening agent but also other liquid agents contained in the fixing solution have no unpleasant odor and irritating odor.

  In the fixing solution of the present invention, preferably, the aliphatic ester includes a saturated aliphatic ester. When the above aliphatic ester contains a saturated aliphatic ester, the storage stability (resistance to oxidation, hydrolysis, etc.) of the softener can be improved. Further, saturated aliphatic esters are highly safe for the human body, and many saturated aliphatic esters can dissolve or swell the resin contained in the toner within 1 second. Furthermore, saturated aliphatic esters can reduce the tackiness of the toner provided on the recording medium. This is considered to be because the saturated aliphatic ester forms an oil film on the surface of the dissolved or swollen toner.

  Therefore, in the fixing solution in the present invention, preferably, the general formula of the saturated aliphatic ester includes a compound represented by R1COOR2, wherein R1 is an alkyl group having 11 to 14 carbon atoms, and R2 is , A linear or branched alkyl group having 1 to 6 carbon atoms. If the number of carbon atoms in R1 and R2 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability is lowered.

  That is, the saturated aliphatic ester includes a compound represented by the general formula R1COOR2, R1 is an alkyl group having 11 to 14 carbon atoms, and R2 is a straight chain having 1 to 6 carbon atoms. In the case of a type or branched type alkyl group, the solubility or swelling property with respect to the resin contained in the toner can be improved. Moreover, the odor index of said compound is 10 or less, and said compound does not have an unpleasant odor and an irritating odor.

  Examples of the aliphatic monocarboxylic acid ester that is the above compound include ethyl laurate, hexyl laurate, ethyl tridecylate, isopropyl tridecylate, ethyl myristate, isopropyl myristate, and the like. Many of these aliphatic monocarboxylic acid esters, which are the above compounds, are soluble in oily solvents, but not in water. Therefore, for many of the aliphatic monocarboxylic acid esters which are the above-mentioned compounds, in an aqueous solvent, glycols are contained in the fixing solution as a solubilizing agent and are in the form of a solution or a microemulsion.

  In the fixing solution of the present invention, preferably, the aliphatic ester includes an aliphatic dicarboxylic acid ester. When the aliphatic ester includes an aliphatic dicarboxylic acid ester, the resin contained in the toner can be dissolved or swollen in a shorter time. For example, in high-speed printing of about 60 ppm, it is desirable that the time until the fixing liquid is applied to the unfixed toner on the recording medium and the toner is fixed on the recording medium is within 1 second. When the aliphatic ester includes an aliphatic dicarboxylic acid ester, the time required for fixing the toner on the recording medium by applying a fixing solution to the unfixed toner or the like on the recording medium is 0.1 second. It is possible to be within. Furthermore, since the resin contained in the toner can be dissolved or swollen by adding a smaller amount of the softening agent, the content of the softening agent contained in the fixing liquid can be reduced.

Therefore, in the fixing solution of the present invention, preferably, the general formula of the aliphatic dicarboxylic acid ester includes a compound represented by R3 (COOR4) ₂ , and R3 is an alkylene group having 3 to 8 carbon atoms. And R4 is a linear or branched alkyl group having 3 to 5 carbon atoms. If the number of carbon atoms in R1 and R2 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability is lowered.

That is, the aliphatic dicarboxylic acid ester includes a compound represented by the general formula R3 (COOR4) ₂ , R3 is an alkylene group having 3 to 8 carbon atoms, and R4 has 3 or more carbon atoms. In the case of a linear or branched alkyl group of 5 or less, the solubility or swelling property with respect to the resin contained in the toner can be improved. Moreover, the odor index of said compound is 10 or less, and said compound does not have an unpleasant odor and an irritating odor.

  Examples of the aliphatic dicarboxylic acid ester that is the above compound include 2-ethylhexyl succinate, dibutyl adipate, diisobutyl adipate, diisopropyl adipate, diisodecyl adipate, diethyl sebacate, and dibutyl sebacate. Many of these aliphatic dicarboxylic acid esters, which are the above compounds, are soluble in oily solvents, but not in water. Therefore, in an aqueous solvent, glycols are contained in the fixing solution as a dissolution aid and are in the form of a solution or microemulsion.

  Furthermore, in the fixing solution according to the present invention, the aliphatic ester preferably contains a dialkoxyalkyl aliphatic dicarboxylate. When the above aliphatic ester contains an aliphatic dicarboxylic acid dialkoxyalkyl, the fixing property of the toner to the recording medium can be improved.

In the fixing solution of the present invention, preferably, the general formula of the aliphatic dicarboxylic acid dialkoxyalkyl includes a compound represented by R5 (COOR6-O-R7) ₂ , and R5 has 2 to 8 carbon atoms. R6 is an alkylene group having 2 to 4 carbon atoms, and R7 is an alkyl group having 1 to 4 carbon atoms. If the number of carbon atoms in R1 and R2 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability is lowered.

That is, the above-mentioned aliphatic dicarboxylate dialkoxyalkyl includes a compound represented by the general formula R5 (COOR6-O-R7) ₂ , wherein R5 is an alkylene group having 2 to 8 carbon atoms, and R6 is In the case where it is an alkylene group having 2 to 4 carbon atoms and R7 is an alkyl group having 1 to 4 carbon atoms, it is possible to improve the solubility or swelling property with respect to the resin contained in the toner. . Moreover, the odor index of said compound is 10 or less, and said compound does not have an unpleasant odor and an irritating odor.

  Examples of the aliphatic dicarboxylate dialkoxyalkyl which is the above compound include diethoxyethyl succinate, dibutoxyethyl succinate, diethoxyethyl adipate, dibutoxyethyl adipate, diethoxyethyl sebacate and the like. Can be mentioned. In an aqueous solvent, these aliphatic dicarboxylic acid dialkoxyalkyls are contained in the fixing solution as a solubilizing agent, and dissolved or microemulsified.

Further, in the fixing solution in the present invention, it is desirable that the softening agent is a citrate ester. Furthermore, the citrate ester preferably contains a trialkyl citrate. As a result, the resin contained in the toner can be dissolved or swollen within 1 second, so that the resin softening property is excellent and the fixing responsiveness can be improved. Furthermore, the safety to the human body is increased.
In the present invention, trialkyl citrate has the general formula

  Wherein R1 is an alkyl group having 1 to 5 carbon atoms. As a result, the viscosity of the liquid is not increased, the permeability of the liquid to the toner or the recording medium is improved, and the solubility in the resin contained in the toner can be improved. Further, the odor index is 10 or less, and there is no unpleasant odor or irritating odor.

  Examples of the trialkyl citrate include trimethyl citrate, triethyl citrate, tri-n-propyl citrate, tri-isopropyl citrate, tri-n-butyl citrate, tri-isobutyl citrate, and tri-n-hexyl citrate.

  The fine particles containing the resin to be fixed are not limited to toner, and any fine particles containing resin may be used. For example, resin fine particles containing a conductive member may be used. Further, the recording medium is not limited to recording paper, and any of metal, resin, ceramics and the like may be used. However, it is desirable that the medium has permeability to the fixing solution. When the medium substrate does not have liquid permeability, a medium having a liquid-permeable layer on the substrate is desirable. The form of the recording medium is not limited to a sheet shape, and may be a three-dimensional object having a flat surface and a curved surface. For example, the present invention can also be applied to applications in which transparent resin fine particles are uniformly fixed on a medium such as paper to protect the paper surface (so-called varnish coating).

  Of the fine particles containing the resin, the toner used in the electrophotographic process has the highest fixing effect in combination with the fixing solution of the present invention. The toner contains a colorant, a charge control agent, and a resin such as a binder resin and a release agent. The resin contained in the toner is not particularly limited. Examples of suitable binder resins include polystyrene resins, styrene-acrylic copolymer resins, polyester resins, and the like, and examples of the release agent include carbanau wax and polyethylene. And wax components. The toner may contain a known colorant, charge control agent, fluidity-imparting agent, external additive and the like in addition to the binder resin. Further, the toner is preferably subjected to a water repellency treatment by fixing hydrophobic fine particles such as hydrophobic silica having a methyl group and hydrophobic titanium oxide to the surface of the toner particles. Among the media, the recording medium is not particularly limited, and examples thereof include paper, cloth, and a plastic film such as an OHP sheet having a liquid permeable layer. The oiliness in the present invention means a property that the solubility in water at room temperature (20 ° C.) is 0.1% by weight or less.

  The charge control agent is not particularly limited and may be appropriately selected from known ones according to the purpose. Examples thereof include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, and molybdate chelate. Pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus alone or compounds thereof, tungsten alone or compounds thereof, fluorine activators, salicylic acid metals Salts, metal salts of salicylic acid derivatives, and the like. These may be used individually by 1 type and may use 2 or more types together.

  As such a charge control agent, a commercially available product may be used. Examples of the commercially available product include bontron 03 of a nigrosine dye, bontron P-51 of a quaternary ammonium salt, and bontron S of a metal-containing azo dye. -34, E-82 of oxynaphthoic acid metal complex, E-84 of salicylic acid metal complex, E-89 of phenol condensate (above, manufactured by Orient Chemical Industries), TP of quaternary ammonium salt molybdenum complex -302, TP-415 (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-14 which is a boron complex 7 (manufactured by Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

  Further, it is preferable that the foamed fixing solution has sufficient affinity for the water-repellent treated toner particles. Here, affinity means the degree of extended wetting of the liquid with respect to the surface of the solid when the liquid comes into contact with the solid. That is, it is preferable that the foamed fixing solution exhibits sufficient wettability with respect to the water-repellent treated toner. The surface of the toner subjected to water repellency treatment with hydrophobic fine particles such as hydrophobic silica and hydrophobic titanium oxide is covered with methyl groups present on the surfaces of hydrophobic silica and hydrophobic titanium oxide, and is approximately 20 mN / m. Has a surface energy of a degree. In reality, since the entire surface of the water-repellent treated toner is not completely covered with hydrophobic fine particles, the surface energy of the water-repellent treated toner is estimated to be approximately 20 to 30 mN / m. The Therefore, in order to have affinity for the water-repellent toner (having sufficient wettability), the surface tension of the foamed fixing solution is preferably 20 to 30 mN / m.

  Moreover, when using an aqueous solvent, it is preferable that surface tension shall be 20-30 mN / m by adding surfactant. In the case of an aqueous solvent, it is desirable to contain a unit price or a polyhydric alcohol. These materials have the advantage of increasing the stability of bubbles in the foam-like fixing solution and making it difficult to break the bubbles. For example, monohydric alcohols such as cetanol, and polyhydric alcohols such as glycerin, propylene glycol, and 1,3 butylene glycol are desirable. Further, containing these unit price or polyhydric alcohols has an effect of preventing curling of a medium such as paper.

  Furthermore, it is also desirable to form an O / W emulsion or a W / O emulsion containing an oily component in order to improve the permeability in the fixing solution or prevent curling of a medium such as paper. In that case, as a specific dispersant Are preferably sorbitan fatty acid esters such as sorbitan monooleate, sorbitan monosterate and sorbitan sesquioleate, and sucrose esters such as sucrose laurate and sucrose stearate.

  In addition, as a method for dissolving the softening agent or fixing the microemulsion during fixing, for example, a mechanical stirring means such as a homomixer or a homogenizer using a rotary blade, and a means for applying vibration such as an ultrasonic homogenizer Is mentioned. In any case, a strong shear stress is added to the softener in the fixing solution to dissolve or disperse the microemulsion.

  In addition, the toner fixing device pressurizes the dissolved or swollen toner with a component (softener) that dissolves or swells at least a part of the resin contained in the toner after supplying the fixing liquid in the present invention to the toner. You may have a pair of smoothing roller (hard roller). By pressurizing the dissolved or swollen toner with a pair of smoothing rollers (hard rollers), the surface of the layer of the dissolved or swollen toner can be smoothed to give gloss to the toner. Furthermore, by fixing the dissolved or swollen toner into the recording medium, the fixability of the toner to the recording medium can be improved.

  In an image forming apparatus according to another embodiment of the present invention, an image of resin fine particles containing a resin is formed on a recording medium using the image forming method according to the present invention described above. Therefore, according to the image forming apparatus of another embodiment of the present invention, as described above, an image forming method and an image forming apparatus capable of fixing toner onto a recording medium more efficiently, respectively. Can be provided.

  FIG. 11 is a schematic diagram showing the configuration of an image forming apparatus according to another invention. The image forming apparatus shown in the figure may be a copying machine or a printer. FIG. 11A is a schematic view of the entire color electrophotographic tandem type image forming apparatus, and FIG. 11B is a configuration of one image forming unit of the image forming apparatus of FIG. FIG. An image forming apparatus 60 shown in FIGS. 11A and 11B has an intermediate transfer belt 61 as a toner image carrier. The intermediate transfer belt 61 is stretched around three support rollers 62 to 64 and rotates in the direction of arrow A in the drawing. On the intermediate transfer belt 61, black, yellow, magenta and cyan image forming units 65 to 68 are arranged. Above these image forming units, an exposure device (not shown) is arranged. For example, when the image forming apparatus is a copying machine, each exposure L1 to L4 for reading image information of an original with a scanner and writing an electrostatic latent image on each photosensitive drum according to the image information is performed. Irradiated by an exposure apparatus. A secondary transfer device 69 is provided at a position facing the support roller 64 of the intermediate transfer belt 61 with the intermediate transfer belt 61 interposed therebetween. The secondary transfer device 69 includes a secondary transfer belt 72 that is stretched between two support rollers 70 and 71. As the secondary transfer device 69, a transfer roller other than the transfer belt may be used. A belt cleaning device 73 is disposed at a position facing the support roller 62 of the intermediate transfer belt 61 with the intermediate transfer belt 61 interposed therebetween. The belt cleaning device 73 is arranged to remove toner remaining on the intermediate transfer belt 61.

  A recording sheet 74 as a recording medium is guided to a secondary transfer unit by a pair of paper feed rollers 75, and the secondary transfer belt 72 is pressed against the intermediate transfer belt 61 when the toner image is transferred to the recording sheet 74. Thus, the toner image is transferred. The recording paper 74 to which the toner image has been transferred is conveyed by the secondary transfer belt 72, and the unfixed toner image transferred to the recording paper 74 is in the form of a foam based on image information from an exposure device (not shown). Fixing is performed by the fixing device of the present invention that controls the film thickness of the fixing solution. That is, for the unfixed toner image transferred to the recording paper 74, the film thickness of the foam-like fixing liquid layer is controlled based on image information from an exposure device (not shown) such as a color image or a black solid image. A part (softener) which is provided with the foam-like fixing solution supplied from the toner fixing device and dissolves or swells at least a part of the resin contained in the toner contained in the foam-like fixing solution. Thus, the unfixed toner image is fixed on the recording paper 74.

  Next, the image forming unit will be described. As shown in FIG. 11B, in the image forming units 65 to 68, a charging device 77, a developing device 78, a cleaning device 79, and a charge removal device 80 are disposed around the photosensitive drum 76. Further, a primary transfer device 81 is provided at a position facing the photosensitive drum 76 via the intermediate transfer belt 61. The charging device 77 is a contact charging type charging device employing a charging roller. The charging device 77 uniformly charges the surface of the photosensitive drum 76 by bringing a charging roller into contact with the photosensitive drum 76 and applying a voltage to the photosensitive drum 76. As the charging device 77, a non-contact charging type charging device using a non-contact scorotron or the like may be used. Further, the developing device 78 causes the toner in the developer to adhere to the electrostatic latent image on the photosensitive drum 76 to visualize the electrostatic latent image. Here, the toners corresponding to the respective colors are made of resin materials colored in the respective colors, and these resin materials are dissolved or swollen by the fixing solution in the present invention. The developing device 78 has a stirring unit and a developing unit (not shown), and the developer not used for development is returned to the stirring unit and reused. The toner concentration in the agitation unit is detected by a toner concentration sensor, and is controlled so that the toner concentration is constant. Further, the primary transfer device 81 transfers the toner visualized on the photosensitive drum 76 to the intermediate transfer belt 61. Here, a transfer roller is employed as the primary transfer device 81, and the transfer roller is pressed against the photosensitive drum 76 with the intermediate transfer belt 61 interposed therebetween. As the primary transfer device 81, a conductive brush, a non-contact corona charger, or the like can be employed. The cleaning device 79 removes unnecessary toner on the photosensitive drum 76. As the cleaning device 79, a blade having a tip pressed against the photosensitive drum 76 can be used. Here, the toner recovered by the cleaning device 79 is recovered by the developing device 78 and reused by a recovery screw and a toner recycling device (not shown). Further, the static eliminator 80 is constituted by a lamp, and initializes the surface potential of the photosensitive drum 76 by irradiating light.

Next, specific examples of the fixing solution and fixing in the present invention will be described.
In the following specific examples of the present invention, toner was used as the resin fine particles, and the toner was produced by an example of the following manufacturing method.

[Specific Example 1]
<Prescription of fixer>
◇ Liquid diluent solvent containing softener: ion-exchanged water 65wt%
Softener: Diethoxyethyl succinate (Croda Croda DES)
10wt%
Thickener: Propylene glycol 10wt%
Foam enhancer: palm fatty acid diethanolamide (comicado DEA)
2wt%
Foaming agent: potassium palmitate 5 wt%
Potassium myristate 3wt%
Potassium stearate 2wt%
Dispersant: POE (20) lauryl sorbitan (Kao Leodol TW-S120V) 2 wt%
Polyethylene glycol monostearate (Kao Emanon 3199) 1wt%

  The dispersant was used to promote the solubility of the softener in the diluent solvent. First, at the above component ratio, a softening agent was removed at a liquid temperature of 120 ° C. and mixed and stirred to prepare a solution. Next, a softener was mixed, and a fixing solution (raw solution before foaming) in which the softener was dissolved was prepared using an ultrasonic homogenizer.

<Coating device>
◇ Foam fixer generating means for generating a large foam fixer Prepared based on FIG.
Storage container for the above liquid fixer: bottle made of PET resin Liquid transport pump: Tube pump (tube inner diameter 2 mm, tube material: silicone rubber)
Conveying flow path: Silicone rubber tube with an inner diameter of 2 mm Microporous sheet for creating large bubbles: # 400 stainless steel mesh sheet (opening approx. 40 μm)
◇ Shearing force imparting means for generating fine bubbles from large bubbles. The inner cylinder of the double cylinder is fixed to a rotation shaft and is rotated by a rotation drive motor (not shown). The material of the double cylinder was PET resin. Outer cylindrical inner diameter: 10 mm / length 120 mm, inner cylindrical outer shape: 8 mm / length 100 mm. The number of rotations was variable in the range of 1000 rpm to 2000 rpm.

◇ Fixing solution applying means: Prepared based on FIG. A foam fixing solution having a desired bubble diameter is prepared using the foam fixing solution generating unit and the shearing force applying unit, and is supplied to a blade for controlling the liquid film thickness. The gap between the liquid film thickness control blade and the application roller was 25 μm and 40 μm.
Pressure roller: Aluminum roller (φ30mm)
Coating roller: SUS roller (30mm diameter) coated with PFA resin
Liquid film thickness control blade: SUS sheet Paper transport speed: 150 mm / s
Load between pressure roller and application roller: 10N on one side
◇ Means for charging unfixed toner on paper Using a commercially available ionizer (Keyence Co., Ltd., micro static elimination SJ-M), the toner surface was positively charged to 10 KV.

<Results>
Using an electrophotographic printer (Ricoh's IpsioColorCX8800), a fine bubble with a bubble diameter of 5 μm to 30 μm at the timing when a PPC paper (Ricoh T-6200) on which a color image of unfixed toner is formed is inserted into the fixing device. The foamy fixing solution was applied to the unfixed toner image while supplying the foaming fixing solution having the above to the coating roller. When the toner surface was visually observed when passing through the application roller, residual bubbles on the surface of the toner layer observed when the foam-like fixing solution was applied without charging the toner were hardly observed in the case of toner charging. . When the toner surface was rubbed with a finger after a certain period of time after paper discharge, the toner was not removed from the paper even when rubbed in a short time, and the fixing property was good.

[Specific Example 2]
<Prescription of fixer>
Same as Example 1 <Coating device>
Same as Example 1 <Ingenuity to make the toner layer easy to break bubbles>
Hydrophobic silica fine particles (Nippon Aerosil Co., Ltd. 970) are applied to the toner at a coverage of an area ratio of 30% by SEM observation.

<Results>
Using an electrophotographic printer (Ricoh's IpsioColorCX8800), a fine bubble with a bubble diameter of 5 μm to 30 μm at the timing when a PPC paper (Ricoh T-6200) on which a color image of unfixed toner is formed is inserted into the fixing device. The foamy fixing solution was applied to the unfixed toner image while supplying the foaming fixing solution having the above to the coating roller. When the toner surface was visually observed when it passed through the application roller, almost no residual bubbles on the surface of the toner layer were observed.

[Specific Example 3]
<Prescription of fixer>
Same as Example 1 <Coating device>
Same as Example 1 <Ingenuity to make the toner layer easy to break bubbles>
An almost spherical toner (average particle size 6 μm) was used as a developer, and pulverized toner having protrusions was mixed with 5 wt% of the developer.

<Results>
Using an electrophotographic printer (Ricoh's IpsioColorCX8800), a fine bubble with a bubble diameter of 5 μm to 30 μm at the timing when a PPC paper (Ricoh T-6200) on which a color image of unfixed toner is formed is inserted into the fixing device. The foamy fixing solution was applied to the unfixed toner image while supplying the foaming fixing solution having the above to the coating roller. When the toner surface was visually observed when it passed through the application roller, almost no residual bubbles on the surface of the toner layer were observed.

  The present invention is not limited to the above embodiments, and it goes without saying that various modifications and substitutions are possible as long as they are described in the scope of the claims.

It is a schematic sectional drawing which shows the mode of fixation of the resin fine particle after the fixing liquid provision in the principle of this invention. It is a schematic sectional drawing which shows the structure of a foamy fixing solution. FIG. 2 is a schematic cross-sectional view showing a state of a fixing solution having broken bubbles after applying a fixing solution according to the principle of the present invention. It is an expansion conceptual diagram when a foamy fixing solution is applied to the surface of the resin fine particle layer. FIG. 3 is a schematic diagram showing a state of fixing by the fixing device according to the first embodiment of the present invention. FIG. 6 is a schematic diagram showing a state of fixing by a fixing device according to a second embodiment of the present invention. FIG. 10 is a schematic diagram showing a state of fixing by a fixing device according to a third embodiment of the present invention. FIG. 3 is a schematic configuration diagram illustrating an example of a fixing solution applying unit in the fixing device of the present invention. FIG. 6 is a schematic configuration diagram illustrating another example of a fixing solution applying unit in the fixing device of the present invention. FIG. 6 is a schematic configuration diagram illustrating another example of a fixing solution applying unit in the fixing device of the present invention. It is the schematic which shows the structure of the image forming apparatus of another invention. FIG. 10 is a schematic cross-sectional view illustrating a configuration of a conventional fixing device. FIG. 10 is a schematic cross-sectional view illustrating a configuration of a conventional fixing device.

Explanation of symbols

21; liquid film boundary, 22; bubbles, 23 and 26; resin fine particles,
24; fixing solution; 25; hydrophobic fine particles;
30, 40, 50; foam fixing solution applying means,
31; coating roller, 32; blade for liquid film thickness control,
33; foamy fixing solution generating means, 33-1; fixing solution sealed container,
33-2; gas / liquid mixing means, 34; shearing force applying means,
35; liquid supply port, 36; pressure roller, 37; wire bar,
51; coating belt, 60; image forming apparatus.

Claims (16)

A foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A charging step of charging resin fine particles containing a resin;
A fixing solution supply step for supplying the foamy fixing solution in the vicinity of the surface of the resin fine particle layer on the medium composed of the charged resin fine particles,
The foam-like fixing solution supplied in the vicinity of the surface of the resin fine particle layer is attracted to the charged resin fine particles, enters between the particles of the resin fine particles, breaks and liquefies, and a liquefied fixing solution is obtained. A fixing method which penetrates into the resin fine particle layer. A foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A fixing solution applying step of applying the foamy fixing solution to a resin fine particle layer on a medium composed of resin fine particles containing a hydrophilic resin,
The foamy fixing solution applied to the resin fine particle layer expands by contacting with the hydrophilic resin, breaks and liquefies, and the liquefied fixing solution penetrates the resin fine particle layer. Fixing method.   The fixing method according to claim 2, wherein the fine resin particles are formed by locally attaching a hydrophobic resin to a surface of the hydrophilic resin. A foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
Resin fine particle layer on medium in which second resin fine particles containing sharp protrusion-shaped resin are mixed in part of resin fine particle layer on medium consisting of first resin fine particles containing resin having uniform particle diameter A fixing solution applying step for applying the foamy fixing solution to
The foamy fixing solution applied to the resin fine particle layer breaks and liquefies by the sharp protrusion shape of the second resin fine particles, and the liquefied fixing solution penetrates into the resin fine particle layer. Fixing method.   The fixing method according to claim 1, wherein the fixing solution contains water and a fatty acid salt. A fixing liquid containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin is supplied to the resin fine particle layer composed of resin fine particles containing the resin on the medium, and the resin fine particle layer is used as a medium. In the fixing device for fixing,
A foam-like fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
Charging means for charging resin fine particles containing a resin;
A fixing solution supply means for supplying the foam-like fixing solution in the vicinity of the surface of the resin particle layer on the charged resin particle medium;
The foam-like fixer supplied to the vicinity of the surface of the resin fine particle layer by the fixer supplying means is attracted to the resin fine particles charged by the charging means and enters between the particles of the resin fine particles to break the bubbles. The fixing device is characterized in that the liquefied and liquefied fixing solution penetrates into the resin fine particle layer. A fixing liquid containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin is applied to the resin fine particle layer composed of resin fine particles containing the resin on the medium, and the resin fine particle layer is used as a medium. In the fixing device for fixing,
A foam-like fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A fixing solution applying means for applying the foamy fixing solution to a resin particle layer on a medium composed of resin particles containing a hydrophilic resin;
The foamy fixing solution applied to the resin fine particle layer by the fixing solution applying means expands by contacting the hydrophilic resin, breaks and liquefies, and the liquefied fixing solution is applied to the resin fine particle layer. A fixing device that penetrates.   The fixing device according to claim 7, wherein the resin fine particles are formed by locally attaching a hydrophobic resin to a surface of the hydrophilic resin. A fixing liquid containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin is applied to the resin fine particle layer composed of resin fine particles containing the resin on the medium, and the resin fine particle layer is used as a medium. In the fixing device for fixing,
A foam-like fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
Resin fine particle layer on medium in which second resin fine particles containing sharp protrusion-shaped resin are mixed in part of resin fine particle layer on medium consisting of first resin fine particles containing resin having uniform particle diameter A fixing solution applying means for applying the foamy fixing solution to
The foamy fixing solution applied to the resin fine particle layer by the fixing solution applying means breaks up and liquefies by the sharp protrusion shape of the second resin fine particles, and the liquefied fixing solution becomes the resin fine particle layer. Fixing device characterized in that it penetrates into.   The fixing device according to claim 6, wherein the fixing solution contains water and a fatty acid salt. An image forming step of forming an unfixed toner image on a medium by performing an electrostatic recording process with a developer containing resin fine particles containing a resin and a colorant;
A foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A charging step for charging the resin fine particles of the unfixed toner image formed in the image forming step;
A fixing solution supplying step of supplying the foamy fixing solution to the resin fine particle layer on the medium composed of the resin fine particles charged in the charging step to fix the unfixed toner image on the medium to form an image on the medium. An image forming method comprising: An image forming step of forming an unfixed toner image on a medium by performing an electrostatic recording process with a developer containing fine resin particles containing a hydrophilic resin and a colorant;
A foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A fixing liquid applying step of applying the foamy fixing solution to the resin fine particle layer on the medium composed of the resin fine particles to fix the unfixed toner image on the medium to form an image on the medium. Image forming method. An electrostatic recording process using a developer by mixing a second resin fine particle containing a sharp protrusion-shaped resin in a part of a developer composed of a first resin fine particle containing a resin having a uniform particle diameter and a colorant. Forming an unfixed toner image on the medium, and
A foam-like fixing solution generating step for generating a fixing solution containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A fixing liquid applying step of applying the foamy fixing solution to the resin fine particle layer on the medium composed of the first and second resin fine particles to fix the unfixed toner image on the medium to form an image on the medium; An image forming method comprising: Image forming means for forming an unfixed toner image on a medium by performing an electrostatic recording process with a developer containing resin fine particles containing a resin and a colorant;
A foam-like fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
Charging means for charging the resin fine particles of the unfixed toner image formed by the image forming means;
Fixing liquid supply means for supplying the foamy fixing liquid to the resin fine particle layer on the medium composed of the resin fine particles charged by the charging means to fix the unfixed toner image on the medium to form an image on the medium. And an image forming apparatus. An image forming means for forming an unfixed toner image on a medium by performing an electrostatic recording process with a developer containing fine particles of resin containing a hydrophilic resin and a colorant;
A foam-like fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
A fixing liquid applying means for applying the foamy fixing solution to the resin fine particle layer on the medium composed of the resin fine particles and fixing the unfixed toner image on the medium to form an image on the medium. Image forming apparatus. An electrostatic recording process using a developer by mixing a second resin fine particle containing a sharp protrusion-shaped resin in a part of a developer composed of a first resin fine particle containing a resin having a uniform particle diameter and a colorant. Image forming means for forming an unfixed toner image on the medium,
A foam-like fixer generating means for generating a fixer containing a softening agent that softens the resin by dissolving or swelling at least a part of the resin;
Fixing liquid application means for applying the foamy fixing solution to the resin fine particle layer on the medium composed of the first and second resin fine particles and fixing the unfixed toner image on the medium to form an image on the medium; An image forming apparatus comprising:

Images