JP2011085639A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent both offset and tack and to perform good fixing without image omission.
A fixing device 10 of the present invention includes a foamed resin agent generating unit 20, a fixing solution applying unit 30, and a coating unit 40. The foamed resin agent generating means 20 generates a foamed resin agent as a fixing solution holding medium for holding a fixing solution by foaming a resin agent solution containing at least a foaming agent, a water-soluble resin, and water. To do. The fixing liquid applying unit 30 applies the fixing liquid onto the layer surface of the foamed resin agent generated by the foamed resin agent generating unit 20 and holds the fixing liquid in the layer of the foamed resin agent. The applying means 40 applies the fixing liquid retained in the foamed resin layer to the resin fine particles on the medium.
[Selection] Figure 1

Description

  The present invention relates to a fixing device and an image forming apparatus, and more particularly, to a technique for fixing toner, which is resin fine particles containing resin, using a fixing solution that fixes fine particles containing resin on a medium.

  Image forming apparatuses such as printers, facsimile machines, and copying machines are apparatuses that form images including characters and symbols on recording media such as paper, cloth, and OHP sheets 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.

  However, although Patent Documents 1 to 3 are also configured to apply the fixing solution to the unfixed toner layer, as shown in FIGS. 7A and 7B, the application roller 201 is used as the contact applying unit. In the configuration in which the fixing solution is applied to the unfixed toner layer 203 on the recording medium 202, the thickness of the fixing solution layer 204 on the coating roller 201 is larger than that of the unfixed toner layer 203 in order to apply a small amount of the fixing solution to the recording medium 202. If the coating roller 201 is too thin, unfixed toner particles are pulled by the surface tension generated by the liquid film of the fixing liquid on the surface of the coating roller 201 at a position where the coating roller 201 is separated from the recording medium 202, and the toner particles on the surface of the coating roller 201. Offset, and the image on the recording medium 202 is greatly disturbed.

  Conversely, as shown in FIG. 8, when the thickness of the fixing liquid layer 204 on the application roller 201 is sufficiently thicker than the unfixed toner layer 203, the amount of liquid is large at a position where the application roller 201 is separated from the recording medium 202. Therefore, the surface tension due to the liquid film on the surface of the coating roller 201 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 202 to cause deterioration of image quality, and the drying time becomes longer, causing a problem in fixing responsiveness. 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 medium such as paper curls remarkably, and the medium such as paper in the apparatus in the image forming apparatus is conveyed. There is a risk of paper jam. Therefore, in such a configuration in which the roller application is performed with the fixing liquid, a small amount of the fixing liquid is applied to the toner layer on the paper and the toner offset is prevented from being applied to the fixing roller in order to improve the fixing response, reduce the residual liquid feeling, and prevent curling. It is extremely difficult. Even when a die coating unit, a blade coating unit, or a wire bar coating unit is used as the contact coating unit, if the amount of the fixer becomes very small, toner adheres to the contact coating unit due to surface tension, resulting in image deterioration.

  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. Further, the present invention is not limited to the toner on the recording medium, and is a problem that occurs in any case in the configuration in which the liquid fixing liquid is applied to the resin-containing fine particle layer on the medium.

  Therefore, according to Patent Document 4 proposed to solve these problems, a foam-like fixer is applied to fine particles containing a resin such as toner on a medium such as paper, whereby Fixing of the resin-containing fine particles to the medium is quickly performed after the fixing solution is applied to the medium on which the resin-containing fine particles are adhered without disturbing the fine particle layer.

  However, according to the above cited document 4, offset can be prevented, but there remains a problem that tack remains in an image portion where the amount of fixing solution applied is excessive, for example, when the toner adhesion amount is different on the same sample.

  SUMMARY An advantage of some aspects of the invention is that it provides a fixing device and an image forming apparatus capable of preventing both offset and tack and performing good fixing without image omission.

  In order to solve the above problems, the fixing device of the present invention is a softening agent that softens resin fine particles by dissolving or swelling at least part of the resin in the resin fine particles formed on the medium by an electrostatic recording process. A fixing solution containing is applied to fix the resin fine particles on the medium. The fixing device of the present invention includes a foamed resin agent generating unit, a fixing solution applying unit, and a coating unit. The foamed resin agent generating means generates a foamed resin agent as a fixing solution holding medium for holding the fixing solution by foaming a resin agent solution containing at least a foaming agent, a water-soluble resin, and water. . The fixing solution applying unit applies the fixing solution onto the layer surface of the foamed resin agent generated by the foamed resin agent generating unit, and holds the fixing solution in the layer of the foamed resin agent. The applying means applies the fixer held in the foamed resin layer to the resin fine particles on the medium. Therefore, it is possible to provide a fixing device that can quickly fix resin fine particles onto a medium, prevent offset, and reduce the tack of the resin fine particles on a recording medium.

  Further, by providing a liquid film thickness control means for controlling the liquid film thickness of the fixing liquid in the fixing liquid applying means, the resin fine particles can be efficiently fixed on the medium to prevent the offset and tack of the resin fine particles on the recording medium. Therefore, it is possible to provide a fixing device with high reliability.

  Furthermore, an image forming apparatus as another invention includes an image forming unit that forms an unfixed image on a medium by performing an electrostatic recording process with a developer containing resin fine particles containing a resin and a colorant, and the fixing device. It is characterized by comprising fixing means for applying a fixing solution to resin fine particles of an unfixed image on the medium to fix the resin fine particles on the medium. Accordingly, the rise time can be shortened, the fixing can be stably performed with a small amount of coating, and the image can be formed on the medium such as paper without a fixing defect. In addition, there is no fixing failure or tacky fixing, fixing reliability is increased, and application of extra fixing liquid is reduced, so that consumption of fixing liquid can be reduced, and non-heating is conventionally performed. Compared with, extremely low power fixing is possible. Furthermore, it is possible to suppress an increase in the number of parts due to the separation of the softener liquid and the foaming liquid.

  According to the present invention, a foamed resin agent serving as a fixing solution holding medium for holding a fixing solution by foaming a resin agent solution containing at least a foaming agent, a water-soluble resin, and water is produced. A fixing solution is applied on the layer surface of the foamed resin agent to hold the fixing solution in the layer of the foamed resin agent, and the held fixing solution is applied and fixed to the resin fine particle layer. Therefore, both offset and tack can be prevented, and good fixing without image omission can be performed.

1 is a schematic configuration diagram illustrating a configuration of a fixing device according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a fixing liquid applying unit in the fixing device of the present embodiment. It is a schematic block diagram which shows another structure of the fixing device of this Embodiment. FIG. 6 is an enlarged cross-sectional view showing a state of fixing solution application. FIG. 3 is an enlarged cross-sectional view showing a state in which a fixing solution is held by a foamed resin agent. 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 an offset state generated in a conventional fixing device. FIG. 7 is a schematic cross-sectional view showing a state of fixing when a fixing liquid layer on a coating roller is sufficiently thicker than an unfixed toner layer in a conventional fixing device.

  FIG. 1 is a schematic configuration diagram showing a configuration of a fixing device according to an embodiment of the present invention. The fixing device 10 of the present embodiment shown in the figure mainly includes a foamed resin agent generating unit 20, a fixing solution applying unit 30, and a fixing solution applying unit 40. First, the foamed resin agent generation unit 20 generates a large resin foam and then separates the large bubbles as a fixing solution holding medium for holding the fixing solution, thereby generating a foam resin agent with a fine prescription. For this purpose, first, as a large foam generating means in the foamed resin agent generating unit 20, the resin agent liquid 22 containing the liquid foaming agent liquid in the foaming agent liquid container 21 is transferred to a transport pump 23, a liquid transport pipe or the like. The gas / liquid mixing means 24 is supplied using the liquid transport means. The gas / liquid mixing unit 24 generates bubbles in the liquid resin agent liquid 22 while stirring the resin agent liquid 22 containing the liquid foaming agent liquid supplied from the transport pump 23 and the air from the air port with a blade-shaped stirrer. A large foam resin agent having a uniform bubble diameter can be generated by entraining. The pore diameter is desirably about 5 to 50 μm. As another method for generating large bubbles, an air port is provided and a negative pressure is generated in the air port along with the flow of the liquid resin agent liquid, so that the gas and the liquid from the air port are mixed. A configuration in which large bubbles are generated by passing through the tube and a configuration in which large bubbles are generated by bubbling the liquid resin agent liquid supplied from the above-described transport pump with an air supply pump or the like are also desirable.

  Next, in order to divide a large bubble into two or more bubbles, a minute bubble generating means 25 in the foamed resin agent generating unit 20 as shown in FIG. As a closed double cylinder, the inner cylinder can be rotated, a larger foam-like resin agent is supplied from a part of the outer cylinder, and the gap between the inner rotating cylinder and the outer cylinder (this is the flow path) And a shearing force is received by the rotating cylinder. Due to this shearing force, the large foam changes into fine foam, and a foamed resin agent having a desired fine foam diameter can be obtained from the foam outlet provided in the outer cylinder. In addition, a spiral groove may be provided in the inner cylinder to increase the liquid transport capability in the cylinder.

  In this way, a large foam generating means for changing a liquid resin agent liquid into a foam resin agent having a large foam diameter is combined with a fine foam generating means for generating a small foam by applying shearing force to the large foam. As a result, it is possible to produce a foamed resin agent having a fine bubble diameter of about 5 μm to 50 μm from the liquid resin agent solution in a very short time.

  Next, as an example of the fixing liquid application unit 30 in the fixing device 10 of the present embodiment, as can be seen from FIG. 2 showing a detailed configuration, the fixing liquid application unit 30 is a fixing liquid of the fixing liquid application unit 40 described later. On the surface of the fixing liquid application roller 32, a fixing liquid application roller 32 for applying and laminating the fixing liquid 31 stored in the housing onto the layer of the foamed resin agent applied on the application roller 41. A liquid film thickness control blade 33 for controlling the liquid film thickness of the fixing liquid 31 to a desired liquid film thickness is provided.

  Further, as an example of the fixing liquid application unit 40 in the fixing device 10 of the present embodiment, as shown in FIG. 1, a fixing liquid application roller that applies a fixing liquid to unfixed toner on the recording medium in contact with the recording medium. 41, a film thickness control blade 42 for controlling the film thickness of the foamed resin agent on the fixing liquid application roller 41 to a desired film thickness, and a pressure roller 43 at a position facing the fixing liquid application roller 41. ing. Here, the resin fine particles are toner particles. As described above, the desired fine foamed foam resin agent includes a large foam generating means for generating large foam and a fine foam generating means for separating the large foam with a shearing force to generate fine foam. The foamed resin agent 27 generated and contained in the foamed resin agent generating means 20 including the fixing solution application roller 41 and the film thickness control blade 42 of the fixer application unit 40 described later from the supply port 26. It is dripped in between. Although the pressure roller 43 is used as the pressure means in the fixing device 10 of the present embodiment shown in FIG. 1, the present invention is not limited to this, and the endless belt-like pressure belt 44 as shown in FIG. May be used. Further, as the pressure belt 44, for example, a member such as a seamless nickel belt, a seamless PET file, or the like coated with a releasable fluororesin such as PFA is used. Thus, in the configuration using the belt, the nip width can be easily widened. Therefore, the configuration using a belt is not limited to that shown in FIG. In addition, it is possible to easily widen the nip width by using at least one of the application side and the pressure side as a belt, and without applying an excessive force that generates wrinkles on the paper, the nip time can be reduced. If it is the same, it becomes possible to increase the paper conveyance speed, and high-speed fixing is possible.

  As a means for conveying the liquid fixing solution from the fixing solution container to the foaming mechanism, a conveying pump is used in FIG. Examples of the transfer pump include a gear pump and a bellows pump, and a tube pump is preferable. If there is a vibration mechanism or a rotation mechanism in the foaming agent liquid such as a gear pump, the liquid is foamed in the pump, the liquid may be compressible, and the conveyance capability may be reduced. Moreover, there exists a possibility that said mechanical components etc. may contaminate a foaming agent liquid, or conversely degrade mechanical components. 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 foaming agent liquid is the tube, and a member having liquid resistance to the foaming agent liquid is used. Therefore, there is no contamination of the liquid or deterioration of the 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.

  Here, as shown in FIG. 4 which is a partially enlarged view showing the state of the application of the fixing solution, in the fixing device of the present embodiment, the foamed resin material is formed by the foamed resin material generating means 20 in FIG. Since the effect of the surface tension of the fixing liquid 31 is further suppressed by using the resin-like resin agent 27 as a fixing liquid holding means for holding the fixing liquid, the offset of the resin fine particles 52 to the fixing liquid application roller 41 can be prevented. all right. Further, when the size of the resin fine particles 52 is about 5 μm to 10 μm, the fixing liquid 31 held by the foamed resin agent 27 is not changed into the resin fine particle 52 layer without disturbing the resin fine particle 52 layer on the recording medium 51. In order to give, it turned out that the foam diameter range of the foamed resin agent 27 needs about 5 micrometers-50 micrometers. Further, as shown in FIG. 5, in the portion of the mixed layer 53 in the entire layer of the foamed resin agent 27 as the fixing solution holding medium, the applied fixing solution 31 enters between the boundaries of the foamed resin agent 27. Occurring and the entire fixing solution 31 is held in the layer of the foamed resin agent 27 by the phenomenon and the tension of the fixing solution itself.

  An image forming apparatus according to an embodiment of another invention described below includes the above-described fixing device of the present invention, and forms an image of resin fine particles containing a resin on a recording medium. Therefore, according to the image forming apparatus of another embodiment of the present invention, as described above, it is possible to provide an image forming apparatus capable of fixing toner onto a recording medium more efficiently. it can.

  FIG. 6 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. 6A is a schematic view of the entire color electrophotographic tandem type image forming apparatus, and FIG. 6B is a configuration of one image forming unit of the image forming apparatus of FIG. FIG. An image forming apparatus 100 shown in FIGS. 6A and 6B includes an intermediate transfer belt 101 as a toner image carrier. The intermediate transfer belt 101 is stretched around three support rollers 102 to 104 and rotates in the direction of arrow A in the figure. On the intermediate transfer belt 101, black, yellow, magenta and cyan image forming units 105 to 108 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 109 is provided at a position facing the support roller 104 of the intermediate transfer belt 101 with the intermediate transfer belt 101 interposed therebetween. The secondary transfer device 109 includes a secondary transfer belt 112 that is stretched between two support rollers 110 and 111. As the secondary transfer device 109, a transfer roller may be used in addition to the transfer belt. A belt cleaning device 113 is disposed at a position facing the support roller 102 of the intermediate transfer belt 101 with the intermediate transfer belt 101 interposed therebetween. The belt cleaning device 113 is arranged to remove toner remaining on the intermediate transfer belt 101.

  A recording sheet 114 as a recording medium is guided to a secondary transfer unit by a pair of paper feed rollers 115, and the secondary transfer belt 112 is pressed against the intermediate transfer belt 101 when the toner image is transferred to the recording sheet 114. Thus, the toner image is transferred. The recording paper 114 to which the toner image has been transferred is conveyed by the secondary transfer belt 112, and the unfixed toner image transferred to the recording paper 114 is formed in a form 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 114, the film thickness of the foam-like fixing liquid layer is controlled based on image information from an exposure device (not shown), for example, 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. As a result, the unfixed toner image is fixed on the recording paper 114.

  Next, the image forming unit will be described. As shown in FIG. 6B, in the image forming units 105 to 108, a charging device 117, a developing device 118, a cleaning device 119, and a charge removal device 120 are disposed around the photosensitive drum 116. A primary transfer device 121 is provided at a position facing the photosensitive drum 116 with the intermediate transfer belt 101 interposed therebetween. The charging device 117 is a contact charging type charging device employing a charging roller. The charging device 117 uniformly charges the surface of the photosensitive drum 116 by bringing a charging roller into contact with the photosensitive drum 116 and applying a voltage to the photosensitive drum 116. As the charging device 117, a non-contact charging type charging device using a non-contact scorotron or the like may be employed. Further, the developing device 118 causes the toner in the developer to adhere to the electrostatic latent image on the photosensitive drum 116 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 118 includes a stirring unit and a developing unit (not shown), and the developer that has not been 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 121 transfers the toner visualized on the photosensitive drum 116 to the intermediate transfer belt 101. Here, a transfer roller is employed as the primary transfer device 121, and the transfer roller is pressed against the photosensitive drum 116 with the intermediate transfer belt 101 interposed therebetween. As the primary transfer device 121, a conductive brush, a non-contact corona charger, or the like can be adopted. The cleaning device 119 removes unnecessary toner on the photosensitive drum 116. As the cleaning device 119, a blade having a tip pressed against the photosensitive drum 116 can be used. Here, the toner collected by the cleaning device 119 is collected by the developing device 118 by a collecting screw and a toner recycling device (not shown) and reused. Further, the static elimination device 120 is constituted by a lamp, and initializes the surface potential of the photosensitive drum 116 by irradiating light. Since the image forming apparatus of the present invention uses the fixing device of the present invention, it has good fixability and can form a high-quality image without curling a recording medium such as paper.

  The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, and other steps appropriately selected as necessary, for example, a static elimination step, a cleaning step. , Including recycling process, control process, etc.

  The image forming apparatus according to the present invention includes at least an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit, and other types appropriately selected as necessary. Means, for example, static elimination means, cleaning means, recycling means, control means and the like.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by an electrostatic latent image forming unit, and the developing step is performed by the developing unit. The transfer step can be performed by a transfer unit, the fixing step can be performed by a fixing unit, the recharging step can be performed by a recharging unit, and the other steps can be performed by other units. it can.

  The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier. There are no particular restrictions on the material, shape, structure, size, etc. of the electrostatic latent image carrier (hereinafter referred to as an electrophotographic photoreceptor, a photoreceptor or an image carrier), and it is appropriately selected from known ones. However, the shape is preferably a drum shape, and examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine. Among these, amorphous silicon or the like is preferable in terms of long life.

  The formation of the electrostatic latent image can be performed by, for example, uniformly charging the surface of the electrostatic latent image carrier and then exposing it like an image, and can be performed by electrostatic latent image forming means. The electrostatic latent image forming means includes, for example, at least a charger that uniformly charges the surface of the electrostatic latent image carrier and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise.

  Charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using a charger. The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charger including a conductive or semiconductive roll, brush, film, rubber blade, etc. Examples thereof include a non-contact charger using corona discharge such as corotron and scorotron.

  The exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier imagewise using an exposure device. The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger as an image to be formed, and can be appropriately selected according to the purpose. Examples of the exposure apparatus include a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. In the present invention, a back light system in which imagewise exposure is performed from the back side of the electrostatic latent image carrier may be employed.

  The development step is a step of developing the electrostatic latent image with toner to form a visible image. The visible image can be formed, for example, by developing the electrostatic latent image using the toner, and can be performed by a developing unit. The developing means is not particularly limited as long as it can be developed using toner, for example, and can be appropriately selected from known ones. For example, the toner is accommodated and the electrostatic latent image is brought into contact or non-contact with the toner. A developer having at least a developer that can be applied in a contactable manner is preferably used, and a developer having a container containing toner is more preferred.

  The developing device may be of a dry development type, may be of a wet development type, may be a single color developer, or may be a multicolor developer, For example, a toner having a stirrer for charging toner by frictional stirring and a rotatable magnet roller can be preferably used.

  In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. Since this magnet roller is disposed in the vicinity of the electrostatic latent image carrier (photoconductor), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrostatically attracted by an electric attractive force. It moves to the surface of the latent image carrier (photoconductor). As a result, the electrostatic latent image is developed with toner, and a visible image is formed with the toner on the surface of the electrostatic latent image carrier (photoconductor).

  The transfer process is a process of transferring a visible image to a recording medium. After using the intermediate transfer member to primarily transfer the visible image onto the intermediate transfer member, the visible image is then transferred onto the recording medium. A transfer mode is preferable, and a primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer member using two or more colors, preferably full color toner as a toner, and a composite transfer image on a recording medium A mode including a secondary transfer step of transferring the image onto the surface is more preferable. The transfer can be performed, for example, by charging the latent electrostatic image bearing member (photoconductor) with a transfer charger using a visible image, and can be performed by a transfer unit. The transfer unit includes a primary transfer unit that transfers a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. Is preferred. The intermediate transfer member is not particularly limited and can be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The transfer means (primary transfer means, secondary transfer means) has at least a transfer device that peels and charges the visible image formed on the electrostatic latent image carrier (photoconductor) to the recording medium side. preferable. There may be one transfer means, or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device. In addition, there is no restriction | limiting in particular as a recording medium, It can select suitably from well-known recording media (recording paper).

  The fixing step is a step of fixing the transferred image transferred to the recording medium, and is performed using the fixing device of the present invention. The fixing means is means for fixing the transferred image transferred to the recording medium, and is performed using the fixing device of the present invention.

  The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit. The neutralizing means is not particularly limited as long as it can apply a neutralizing bias to the electrostatic latent image carrier, and can be appropriately selected from known neutralizers. For example, a neutralizing lamp is preferable. It is done.

  The cleaning step is a step of removing toner remaining on the electrostatic latent image carrier, and can be suitably performed by a cleaning unit. The cleaning means is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, static Preferred examples include an electric brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

  The recycling process is a process in which the toner removed by the cleaning process is recycled to the developing unit, and can be suitably performed by the recycling unit. There is no restriction | limiting in particular as a recycle means, A well-known conveyance means etc. are mentioned.

  A control process is a process of controlling each process, and can be suitably performed by a control means. The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

Hereinafter, an example of a softener solution, a foaming agent solution and the like used in the present invention will be outlined.
(Softener liquid)
The softening agent liquid may be a softening agent alone, but contains a polyhydric alcohol as a foaming agent component, particularly propylene glycol, dipropylene glycol, tripropylene glycol and glycerin, in order to further suppress hydrolysis. Is also desirable. In addition, if some water is contained, there is an advantage that the flammability is reduced and it is not necessary to handle the hazardous material. When water is contained, it is desirable to set the pH of the softener solution to a weak acid of 6-7. However, when the foaming agent solution and the softening agent solution are mixed, it is desirable to set the concentration of the pH adjusting agent for making the weak acid so that the pH of the whole mixture does not become 7 or less. As a pH adjuster in the softening solution, an organic acid is desirable, and lactic acid, citric acid, malic acid and the like are suitable.

(Foaming agent liquid)
It is desirable that the foaming agent liquid contains a foaming agent, a foaming agent, water as a diluent and a pH adjuster. As the foaming agent, an anionic surfactant, particularly a fatty acid salt is desirable, and as the fatty acid salt, a fatty acid amine salt is desirable. For the fatty acid, an optimal combination is selected from lauric acid, myristic acid, palmitic acid and stearic acid having an alkyl group with 12, 14, 16, 18 carbon atoms. As the salt, sodium salt, potassium salt and amine salt are preferable, and triethanolamine salt and diethanolamine salt are particularly desirable. As the foam-increasing agent, fatty acid alkanolamides, particularly fatty acid alkanolamides, include (1: 1) type and (1: 2) type, but (1: 1) type is suitable for foam stability in the present invention. Furthermore, it is suitable to use polyhydric alcohols, particularly propylene glycol, dipropylene glycol, tripropylene glycol, glycerin and the like alone or as a foaming agent. Amines are suitable as a pH adjuster for maintaining the pH of the liquid at a weak alkalinity of 7 to 10.

  The softening agent has a function of softening fine particles containing the resin by dissolving and swelling at least a part of the resin. The softener is preferably an ester compound. The ester compound is excellent in solubility / swellability for dissolving / swelling at least part of a resin contained in resin fine particles such as toner. Of the ester compounds, aliphatic esters and carbonates are particularly preferable because of their excellent resin softening ability. Moreover, it is preferable also from the point which does not inhibit the foaming property by the anionic surfactant as a foaming agent mentioned later.

  In addition, the softening agent has an acute oral toxicity LD50 of preferably greater than 3 g / kg, more preferably 5 g / kg or more, from the viewpoint of safety to the human body. Fatty acid esters are highly safe for the human body, as are often used as cosmetic raw materials. Further, the fixing of the toner as the resin fine particles to the recording medium is performed by an apparatus frequently used in a sealed environment, and the softening agent remains in the toner even after the toner is fixed on the recording medium. It is preferable that the fixing of the toner with respect to the toner does not involve generation of a volatile organic compound (VOC) and an unpleasant odor. That is, the softening agent 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 (substance odor is felt by 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.

  Aliphatic esters include saturated aliphatic esters. When the 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 and 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 presumably because the saturated aliphatic ester forms an oil film on the surface of the dissolved and swollen toner.

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

  Examples of the aliphatic monocarboxylic acid ester include ethyl laurate, hexyl laurate, ethyl tridecylate, isopropyl tridecylate, ethyl myristate, isopropyl myristate, and the like. Many of these aliphatic monocarboxylic acid esters are soluble in oily solvents but not in water. Therefore, for many of the aliphatic monocarboxylic acid esters, in an aqueous solvent, glycols are contained in the fixing solution as a dissolution aid and are in the form of a solution or a microemulsion.

  The aliphatic ester preferably contains an aliphatic dicarboxylic acid ester. When the aliphatic ester contains an aliphatic dicarboxylic acid ester, the resin contained in the toner can be dissolved and swollen in a shorter time. For example, in high-speed printing of about 60 ppm, it is preferable 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 contains an aliphatic dicarboxylic acid ester, the time required for fixing the toner to the recording medium by applying a fixing solution to the unfixed toner or the like on the recording medium is within 0.1 seconds. It becomes possible to do. Furthermore, since the resin contained in the toner can be dissolved and 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 R3 and R4 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability decreases. 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 to 5 carbon atoms. In the case of the following linear or branched alkyl group, the solubility or swelling property with respect to the resin contained in the toner can be improved. Moreover, the odor index of the compound represented by the general formula R3 (COOR4) ₂ is 10 or less, and the compound does not have an unpleasant odor and an irritating odor.

  Examples of the aliphatic dicarboxylic acid ester include 2-ethylhexyl succinate, dibutyl adipate, diisobutyl adipate, diisopropyl adipate, diisodecyl adipate, diethyl sebacate, dibutyl sebacate and the like. Many of these aliphatic dicarboxylic acid esters 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 of the present invention, preferably, the aliphatic ester contains a dialkoxyalkyl aliphatic dicarboxylate. When the 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 R5, R6, and R7 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability decreases. That is, the aliphatic dicarboxylic acid 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 carbon. When R7 is an alkylene group having 2 or more and 4 or less and R7 is an alkyl group having 1 or more and 4 or less carbon atoms, it can improve the solubility or swelling property with respect to the resin contained in the toner. Further, the odor index of the compound represented by the general formula R5 (COOR6-O-R7) ₂ is 10 or less, and the compound does not have an unpleasant odor or an irritating odor.

  Examples of the aliphatic dicarboxylic acid dialkoxyalkyl include diethoxyethyl succinate, dibutoxyethyl succinate, dicarbitol succinate, dimethoxyethyl adipate, diethoxyethyl adipate, dibutoxyethyl adipate, diethoxyethyl sebacate, etc. Is mentioned. When these aliphatic dicarboxylic acid dialkoxyalkyls are used in an aqueous solvent, glycols are included in the fixing solution as a dissolution aid, if necessary, to form a solution or microemulsion. Examples of the carbonate ester include ethylene carbonate, propylene carbonate (propylene carbonate), glycerol 1,2-carbonate, 4-methoxymethyl-1,3-dioxolan-2-one and the like.

  Other ester compounds include, for example, citric acid esters such as triethyl citrate, triethyl acetyl citrate, tributyl citrate, and tributyl acetyl citrate; ethylene glycol diacetate, diethylene glycol diacetate, triethylene glycol diacetate And compounds obtained by esterifying glycols such as monoacetin, diacetin, triacetin and the like.

  0.5 mass%-50 mass% are preferable, and, as for content of a softening agent, 5 mass%-40 mass% are more preferable. If the content is less than 0.5% by mass, the effect of dissolving and swelling the resin contained in the toner may be insufficient. If the content exceeds 50% by mass, the resin contained in the toner for a long time. The fluidity of the toner cannot be lowered, and the fixing toner layer may have adhesiveness.

-Dissolution aid-
When the concentration of the softening agent in the fixing solution increases, the softening agent may become difficult to dissolve in water as a dilution solvent. Therefore, polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butylene glycol, glycerin and the like are used as dissolution aids. It was found that the inclusion in the fixing solution dissolves the softener even at a high concentration and does not deteriorate the foaming property by the fatty acid salt, but rather the foaming property is improved. Moreover, the content of the polyhydric alcohol is preferably in the range of 1% by mass to 30% by mass. If the content exceeds 30% by mass, the foamability is rather deteriorated, which is not suitable.

-Nonionic water-soluble resin-
The fixing solution of the present invention contains a nonionic water-soluble resin that does not inhibit foaming by an anionic surfactant, prevents offset, and reduces toner tack on the recording medium. The offset and the remaining tack of the toner on the recording medium are caused by the tack of the resin generated by the resin dissolved and swollen in the toner. The water-soluble resin is dissolved in the fixing solution with good dispersibility, but when applied to the toner on the recording medium, the water-soluble resin stays on the surface of the toner layer and increases the gloss while reducing the surface area of the toner layer. Can be reduced. Nonionic water-soluble resins hardly affect the pH of the fixing solution, prevent the foaming property of the anionic surfactant, prevent offset and reduce toner tack on the recording medium, When the foamed resin agent holds the fixing solution containing the softening agent, rapid bubble breakage can be alleviated.

  Nonionic water-soluble resins such as polyvinyl resins, polyethylene oxide resins, and cellulose derivatives include, for example, polyvinyl alcohol, polyvinyl butyral, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, polyethylene oxide alkyl ether, Examples include polyethylene oxide alkyl phenyl ether.

  The content of the nonionic water-soluble resin is preferably 0.05% by mass to 20% by mass, and more preferably 0.1% by mass to 10% by mass. If the content is less than 0.05% by mass, tack may not be sufficiently suppressed. If the content exceeds 20% by mass, the foaming property is deteriorated, which is not suitable.

-Anionic surfactant-
Anionic surfactants can realize excellent foaming properties and foam stability, and are used as foaming agents. Among anionic surfactants, fatty acid salts are most excellent in foam stability and are most suitable as a foaming agent for fixing solutions. On the other hand, the softening agent has a strong defoaming effect, and as the concentration of the softening agent increases in the fixing solution, the foaming property and foam stability of the fixing solution deteriorates, so it is difficult to foam and the foam breaks immediately. It becomes impossible to obtain a foam-like fixing solution having a low foam density.

  Therefore, in order to solve the problem of foaming deterioration by affecting the foamed resin agent holding the fixing solution when the concentration of the softening agent in the fixing solution is increased, various types and concentrations of anionic surfactants are used as factors. As a result of the trial production, using a fatty acid salt having 12 to 18 carbon atoms as a foaming agent and further containing a fatty acid having 12 to 18 carbon atoms in the fixing solution, the concentration of the softening agent is increased, It is possible to prevent the foamability of the foamed resin agent from being deteriorated.

  Here, the action of the fatty acid and the softening agent will be described. The softening agent has an ester group in the chemical structure, and the fatty acid has a carbonyl group in the chemical structure. From this point, the ester group of the softener and the carbonyl group of the fatty acid show an electrical action in the fixing solution system, and this causes a binding action between molecules, and the fixing solution is characterized by foaming properties and Improves foam stability.

-Recording media-
The recording medium is not limited to recording paper, and any of metal, resin, ceramics, and the like may be used. However, the medium is preferably permeable to the fixing solution, and when the medium substrate does not have the liquid permeability, a medium having a liquid permeable layer on the substrate is preferable. The form of the 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). Among the media, the recording medium is not particularly limited and may be appropriately selected according to the purpose. Examples thereof include paper, cloth, and a plastic film such as an OHP sheet having a liquid permeable layer.

-Solvent-
As the solvent, water, an aqueous solvent obtained by adding alcohol or the like to water, and the like are preferable. As water, for example, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used. When an aqueous solvent is used, it is preferable that the surface tension be 20 mN / m to 30 mN / m by adding a surfactant. As alcohols, for example, unitary alcohols such as cetanol, etc .; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene, because of the advantage of improving the stability of bubbles in the foam-like fixing solution and making it difficult to break bubbles Polyhydric alcohols such as glycol, tripropylene glycol, 1,3-butylene glycol and glycerin are preferred. Further, containing these unit price or polyhydric alcohols has an effect of preventing curling of a medium such as paper.

  Also preferred is a constitution in which an O / W emulsion or a W / O emulsion is formed by containing an oily component in the fixing solution in order to improve permeability and prevent curling of a medium such as paper. In this case, as a specific dispersant, sorbitan fatty acid esters such as sorbitan monooleate, sorbitan monosterate and sorbitan sesquioleate, and sucrose esters such as sucrose laurate and sucrose stearate are preferable.

  As a method for dissolving or dispersing the microemulsifier during fixing, there are, 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. Can be mentioned. In any case, a strong shear stress is added to the softener in the fixing solution to dissolve or disperse the microemulsion.

-Resin fine particles-
The resin fine particles containing a resin to be fixed are not limited to toner, and any fine particles containing a resin may be used, and resin fine particles containing a conductive member may be used. Of the resin fine particles, the toner used in the electrophotographic process has the highest fixing effect in combination with the fixing solution of the present invention.

<Toner>
The toner contains a colorant, a charge control agent, a binder resin, and a release agent, and further contains other components as necessary. There is no restriction | limiting in particular as binder resin, According to the objective, it can select suitably, For example, a polystyrene resin, a styrene-acryl copolymer, a polyester resin etc. are mentioned. There is no restriction | limiting in particular as a mold release agent, According to the objective, it can select suitably, For example, wax components, such as a carbanau wax and polyethylene, etc. are mentioned. There is no restriction | limiting in particular as a coloring agent, According to the objective, it can select suitably from well-known dyes and pigments. The charge control agent is not particularly limited and can be appropriately selected from known materials according to the purpose. Examples thereof include triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, and quaternary ammonium. Examples include salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus alone or compounds thereof, tungsten alone or compounds thereof, fluorine-based activators, metal salts of salicylic acid, 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.

  There is no restriction | limiting in particular as another component, According to the objective, it can select suitably, For example, an external additive, a fluid improvement agent, a cleaning property improvement agent, a magnetic material, a metal soap etc. are mentioned. 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.

  Further, the fixing solution of the present invention preferably has sufficient affinity for the toner particles that have been subjected to the water-repellent treatment. 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 fixing liquid of the present invention exhibits sufficient wettability with respect to the toner subjected to the water repellent treatment. 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. Actually, 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 approximately 20 mN / m to 30 mN / m. Guessed. Therefore, the surface tension of the fixing solution of the present invention is preferably 20 mN / m to 30 mN / m in order to have an affinity for the water-repellent toner (having sufficient wettability).

-Foamed resin agent production step and fixing solution applying means-
The foam resin agent production step is a step of producing a foam resin agent as a fixing solution holding medium for foaming the foaming agent liquid and applying and laminating a fixing solution containing a softening agent. It is carried out by means of a resin-like resin production means. In general, in the case of large bubbles of about 0.5 mm to 1 mm, it is possible to generate bubbles relatively easily by simple stirring or the like, and the generation of large bubbles takes less than a few seconds (not taking 0.1 seconds). can do. Therefore, paying attention to the fact that bubbles that are larger than the desired bubble diameter and that can be visually observed can be easily and quickly obtained, and from about 5 μm to 50 μm quickly from the large bubbles. As a result of diligently studying the method for generating microbubbles, it was found that if a large bubble was separated by applying shear force to a large bubble, it would be extremely quick compared to the method for foaming a microbubble from the above liquid state. Microbubbles having a desired size can be generated.

  The fixing solutions, fixing methods and fixing devices obtained in the following examples and comparative examples, and evaluation items and evaluation methods for image forming methods and image forming apparatuses are shown below. The present invention is not limited to these examples. It is not limited.

-Preparation of fatty acid triethanolamine salt fixing solution-
Fatty acid with a mass ratio of 4: 3: 1 of myristic acid (manufactured by Kanto Chemical Co., Ltd., reagent), palmitic acid (manufactured by Kanto Chemical Co., Ltd., reagent), stearic acid (manufactured by Kanto Chemical Co., Ltd., reagent), Weighed so that the molar ratio of triethanolamine (Kanto Chemical Co., Ltd., reagent), which is a solubilizing agent, was 1: 0.7, stirred in ion-exchanged water at a liquid temperature of 80 ° C. for 30 minutes, The mixture was allowed to cool until it became a fatty acid triethanolamine salt.

-Preparation of softener liquid 1-
A mixed liquid of 90% by mass of propylene carbonate (Kanto Chemical Reagent, PC) and 10% by mass of dipropylene glycol was bubbled with dry nitrogen gas for 10 minutes to remove moisture.

-Preparation of softener liquid 2-
Diethoxyethyl succinate (Croda Corporation, Croda DES) was bubbled with dry nitrogen gas for 10 minutes to remove moisture.

-Preparation of foaming agent liquid 1-
Fatty acid triethanolamine salt (foaming agent 1) 6.7% by mass, coconut oil fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Seiyaku Co., Ltd., Marpon MM) 0.8% by mass, A nonionic water-soluble resin, polyethylene oxide (manufactured by Meisei Kagaku Kogyo Co., Ltd., Alcox L-11) 1.0 mass% and ion-exchanged water 91.5 mass% as a diluent are stirred for 10 minutes with an ultrasonic homogenizer. Thus, a foaming agent liquid 1 (stock solution before foaming) was prepared.

-Preparation of foaming agent liquid 2-
Fatty acid triethanolamine salt (foaming agent 1) 6.7% by mass, coconut oil fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Seiyaku Co., Ltd., Marpon MM) 0.6% by mass, A nonionic water-soluble resin, methylcellulose (manufactured by Sakai Kogyo Co., Ltd., Messelose PMC-15U (S)) 5.0 mass%, and ion-exchanged water 87.7 mass% as a diluent are stirred for 10 minutes with an ultrasonic homogenizer. Thus, a foaming agent liquid 2 (raw solution before foaming) was prepared.

-Preparation of foaming agent liquid 3-
Fatty acid triethanolamine salt (foaming agent 1) 4.5% by mass, palm oil fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Seiyaku Co., Ltd., Marpon MM) 0.6% by mass, A nonionic water-soluble resin, polyvinyl alcohol (Denka Poval K-05, manufactured by Denki Kagaku Kogyo Co., Ltd.), 3.0% by mass, and ion-exchanged water, 91.9% by mass, are stirred for 10 minutes with an ultrasonic homogenizer. Then, a foaming agent liquid 3 (stock solution before foaming) was prepared.

-Preparation of foaming agent liquid 4-
Fatty acid triethanolamine salt (foaming agent 1) 4.5% by mass, palm oil fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Seiyaku Co., Ltd., Marpon MM) 0.6% by mass, A nonionic water-soluble resin, polyethylene oxide (manufactured by Meisei Chemical Industry Co., Ltd., Alcox L-11) 1.0 mass% and ion-exchanged water 93.9 mass% as a diluent are stirred for 10 minutes with an ultrasonic homogenizer. The foaming agent liquid 4 (stock solution before foaming) was prepared.

<Fabric resin preparation>
-Large bubble generation part-
Based on the foamed resin agent generator 20 shown in FIG. 1, a foaming agent liquid in a large foam state was prepared from the liquid foaming agent liquid. The large foam generation part of FIG. 1 is a storage container for liquid foaming agent liquid: a bottle made of polyethylene terephthalate (PET) resin, liquid transport pump: tube pump (tube inner diameter 2 mm, tube material: silicone rubber), transport flow path: A silicone rubber tube having an inner diameter of 2 mm, a microporous sheet for producing a large bubble: a # 400 stainless steel mesh sheet (opening of about 40 μm) is used.

-Microbubble generator-
Based on the foamed resin agent production | generation part 20 shown in FIG. 1, the fine foaming foaming agent was produced from the foaming foaming agent of a large foam state. The inner cylinder of the double cylinder in FIG. 1 is fixed to a rotary shaft and is rotated by a rotary drive motor (not shown). The material of the double cylinder was PET resin. Outer cylinder inner diameter: 10 mm, length 120 mm, inner cylinder outer shape: 8 mm, length 100 mm. The rotation speed was 300 rpm. The rotation time was 10 seconds.

-Fixing liquid application part-
A fixing liquid application roller 32 in the fixing liquid application unit 30 shown in FIGS. 1 and 2 applies and fixes a fixing liquid containing at least a softening agent on the layer of the foamed resin agent, and stacks the fixing liquid on the foamed resin agent. Held. The gap between the coating roller 41 and the fixing liquid application roller 32 is 150 μm, the liquid film thickness control blade 33 is 50 μm with the fixing liquid application roller 32, and the number of rotations of each roller is adjusted so that the linear speed is 300 mm / s. .

Example 1
-Production of foamy resin agent 1-
A foamed resin agent 1 is produced using the foaming agent liquid 1 by the large foam producing part and the fine foam producing part described above, and the fixing liquid 1 containing the softening agent 1 is added to the produced foamed resin agent 1. Held.

(Example 2)
-Production of foamed resin agent 2-
A foamed resin agent 2 is produced using the foaming agent liquid 2 by the large foam producing part and the fine foam producing part described above, and the fixing liquid 1 containing the softening agent 1 is added to the produced foamed resin agent 2. Held.

(Example 3)
-Production of foamed resin agent 3-
A foamed resin agent 3 is produced using the foaming agent liquid 3 by the large foam producing part and the fine foam producing part described above, and the fixing liquid 2 containing the softening agent 2 is added to the produced foamed resin agent 3. Held.

Example 4
-Production of foamed resin agent 4-
A foamed resin agent 4 is produced by using the foaming agent liquid 4 by the large foam producing part and the fine foam producing part described above, and the fixing liquid 2 containing the softening agent 2 is added to the produced foamed resin agent 4. Held.

On the other hand, as a comparative example, a softening agent solution and a foaming agent solution were mixed in advance to prepare a foam-like fixing solution.
(Comparative Example 1)
-Preparation of Fixer 3-
45% by mass of propylene carbonate (manufactured by Kanto Chemical Co., Ltd., reagent) as a softening agent, 15% by mass of dipropylene glycol (manufactured by Kanto Chemical Co., Ltd., reagent) as a thickener, and fatty acid diethanolamine salt (raising agent) as a foaming agent Foam 2) 4.0% by mass, coconut oil fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Seiyaku Co., Ltd., Marpon MM) 0.5% by mass, a nonionic water-soluble resin Polyethylene oxide (manufactured by Meisei Chemical Industry Co., Ltd., Alcox L-11) 1.0% by mass and 34.5% by mass of ion-exchanged water as a diluent were stirred for 10 minutes with an ultrasonic homogenizer, and fixing solution 3 (foam Stock solution before shaping) was prepared. The fixer 3 was bubbled based on the above-mentioned means to prepare a foamy fixer 1.

(Comparative Example 2)
-Preparation of Fixer 4-
50% by mass of dicarbitol succinate as a softening agent (manufactured by Higher Alcohol Industry Co., Ltd., reagent), 4.0% by mass of fatty acid triethanolamine salt (foaming agent 1) as a foaming agent, palm oil as a foaming agent Fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Seiyaku Co., Ltd., Marpon MM) 0.5% by mass, nonionic water-soluble resin polyvinyl alcohol (manufactured by Denki Kagaku Co., Ltd., Denkapoval K-05) 3 0.0% by mass and 42.5% by mass of ion-exchanged water as a diluent were stirred for 10 minutes with an ultrasonic homogenizer to prepare Fixer 4 (stock solution before foaming). The fixing solution 4 was bubbled based on the above means to prepare a foamy fixing solution 2.

  Based on the obtained fixing liquids 3 and 4 based on the fine bubble generating means shown in FIG. 1, the foaming fixing liquid 1 and the foaming fixing liquid 2 of each comparative example were produced. For controlling the bubble film thickness, the film thickness control blade 42 shown in FIG. 1 was used. The gap between the film thickness control blade 42 and the coating roller 41 was 100 μm.

<Application of foamy fixing solution>
-Measuring means for foamy fixing solution-
Pressure roller: Sponge roller with aluminum alloy roller (diameter 10 mm) as the core and polyurethane foam material (product name “Color Foam EMO” manufactured by INOAC) with an outer diameter of 50 mm, Application roller: PFA resin baked The coated SUS roller (diameter: 30 mm), linear speed: 300 mm / s, paper transport speed: 300 mm / s. Using an electrophotographic printer (Imagio MPC2500, manufactured by Ricoh Co., Ltd.), a color image of unfixed toner was formed on PPC paper (T-6200, manufactured by Ricoh Co., Ltd.). A foamy fixing solution was applied to the unfixed toner based on the fixing solution applying means. At this time, the thickness of the toner layer was 30 μm to 40 μm, and the thickness of the foamy fixing solution on the coating roller was about 70 μm. The coating amount of the foamed fixing solutions 1 and 2 of each comparative example was calculated from the weight of the paper before and after coating.

<Evaluation of offset>
After applying the fixing solution of each example and immediately after applying the foamy fixing solution of each comparative example, it was visually observed whether the toner was offset or not, and evaluated according to the following evaluation criteria. The results are shown in Table 1 below.

〔Evaluation criteria〕
When the toner is not offset on the application roller: ○ (no offset)
When toner is slightly offset on the application roller:
When toner is offset on the application roller: × (with offset)
When the toner is offset on the application roller and the image on the paper is missing: XX (with offset)

<Tack evaluation of toner on recording medium>
The tack of the toner on the recording medium was evaluated using a tackiness tester (manufactured by Reska Co., Ltd.). In a sample similar to the above fixability evaluation, a cylindrical stainless steel probe (φ8.0 mm) is compressed in the image area (toner on the recording medium) after applying the fixing solution in each example and after applying the foamy fixing solution in each comparative example. After pressing for 20 sec with a load of 100 gf, the stress applied at the time of drawing and drawing was measured at 120 mm / min, and evaluated according to the following evaluation criteria. The results are shown in Table 1 below.

〔Evaluation criteria〕
0.0 to 4.0 kPa: ○ (same as non-image part or almost no tack)
4.1 to 10.0 kPa: x (small tack)
10.1 kPa or more: XX (tack size)

  From the results shown in Table 1, Examples 1 to 4 using a fixing solution which was prepared by applying a fixing solution containing a softening agent to a foam made of a foaming agent solution and laminating them were mixed in advance to form a foam. Compared with Comparative Examples 1 and 2 using a foamy fixing solution, the tack was superior. With respect to the offset, no great difference was observed in all of Examples 1 to 4 and Comparative Examples 1 and 2. This is because the fixing solution containing the softening agent is laminated and held in the foam made of the foaming agent solution, so that the concentration of the softening agent is locally higher than in each comparative example, and the toner is softened and fixed. It is suggested that tack was suppressed by overcoating with a foaming agent solution containing a water-soluble resin. Further, since the softening agent concentration is locally increased, superiority in color developability immediately after fixing can be expected.

<Evaluation of storage stability>
The fixing solutions 1 and 2 obtained above, the foamed resin agents 1 to 4 and the foamed fixing solutions 1 and 2 are heated to 60 ° C. and allowed to stand for a certain period of time. After returning, the fixing property was evaluated. In the standing test after heating at 60 ° C., an accelerated test of standing deterioration due to heating is performed. This is a calculated numerical value obtained by an accelerated test (Arrhenius method) by heating at 60 ° C. That is, the test for heating at 60 ° C. for 1 day shows that it was left for 1 month at 25 ° C. (room temperature), and the test for heating at 60 ° C. for 20 days is left for 1 year at 25 ° C. (room temperature). This is equivalent to

<Evaluation of fixability>
The fixability before and after the acceleration test was evaluated. Fixing solutions 1 and 2, each fixing solution held by foamed resin agents 1 to 4 and foamed fixing solutions 1 and 2 were applied onto the paper on which unfixed toner was formed by the method described above. Fixability was evaluated according to the following criteria. The results are shown in Table 2.

〔Evaluation criteria〕
A state where most of the toner is removed from the paper by rubbing the toner after fixing with a cloth: XX
Rub the toner after fixing with a cloth to remove some toner from the paper: ×
Rub the toner after fixing with a cloth.

  In the evaluation results in Table 2, Examples 1 to 4 showed good fixability even after the acceleration test. On the other hand, in Comparative Examples 1 and 2, a clear decrease in fixing performance after the acceleration test was confirmed. This is a result that occurs when the softener liquid and the foaming agent liquid are premixed. When premixed, the ester component of the softener is decomposed by hydrolysis, so that the toner is sufficiently fixed. Indicates that it will not be done. Therefore, it was found that if the softener solution and the foaming agent solution are stored separately and mixed immediately before use to form a fixing solution, the storage stability of the storage container filled with the fixing solution is dramatically improved. .

  In addition, this invention is not limited to the said embodiment, It cannot be overemphasized that various deformation | transformation and substitution are possible if it is description in a claim.

10; Fixing device, 20; Foamed resin agent generation unit, 30; Fixing liquid application unit,
40; Fixing liquid application part, 21; Foaming agent container, 22; Resin agent liquid,
23; transport pump, 24; gas / liquid mixing means,
25; Fine foam generating means, 26; Supply port, 27; Foam resin agent,
31; Fixing liquid, 32; Fixing liquid application roller, 33; Liquid film thickness control blade,
41; fixing solution application roller, 42; film thickness control blade,
43; pressure roller, 44; pressure belt, 51; recording medium,
52; resin fine particles, 53; mixed layer, 100; image forming apparatus.

Japanese Patent No. 3,290,513 JP 2004-109749 A JP 59-119364 A JP 2007-219105 A

Claims (3)

The resin fine particles are fixed on the medium by applying a fixing solution containing a softening agent that softens the resin fine particles by dissolving or swelling at least part of the resin in the resin fine particles formed on the medium by the electrostatic recording process. In the fixing device to be
A foamed resin agent generating means for foaming a resin agent liquid containing at least a foaming agent, a water-soluble resin, and water, and generating a foamed resin agent as a fixing liquid holding medium for holding the fixing liquid;
A fixing solution applying unit that applies the fixing solution onto the layer surface of the foamed resin agent generated by the foamed resin agent generating unit and holds the fixing solution in the layer of the foamed resin agent;
And a coating unit that coats the resin fine particles on the medium with a fixing solution held in the foamed resin layer.   The fixing device according to claim 1, wherein a liquid film thickness control unit that controls a film thickness of the fixing liquid is provided in the fixing liquid application unit.   3. An image forming means for forming an unfixed image on a medium by performing an electrostatic recording process with a developer containing resin fine particles containing a resin and a colorant; and a fixing liquid on the medium by the fixing device according to claim 1 or 2. An image forming apparatus comprising: a fixing unit that is applied to resin fine particles of an unfixed image and fixes the resin fine particles to a medium.

Images