JP2012008281A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that is configured to coat toner particles on a fixing liquid coating object with a fixing liquid, allows prevention of a toner offset caused by a coating member contacting the toner particles, and facilitates easy cleaning of the coating member, and an image forming apparatus equipped with the fixing device.SOLUTION: A fixing device and an image forming apparatus equipped with the same include: a foamy fixing liquid generation section as fixing liquid supply means for supplying a foamy fixing liquid F produced by dispersing air bubbles in a fixing liquid containing a softening agent that softens toner; and a foamy fixing liquid coating section 140 having a coating roller 141 for coating a surface of a transfer paper P carrying an unfixed toner image T with the foamy fixing liquid F supplied to a surface-moving surface. The fixing device and image forming apparatus with the same coat the transfer paper P with the foamy fixing liquid F at a coating nip C to fix the unfixed toner image T to the transfer paper P, and includes a gap agent applicator 150 as gap agent applying means for applying a gap agent G that allows a gap between the coating roller 141 and the transfer paper P in the coating nip C.

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and a fixing device applicable to the image forming apparatus. Specifically, a fixing liquid that dissolves or swells at least a part of the resin component of resin-containing fine particles such as toner and fixes the toner on the fixing medium is applied to the resin-containing fine particle layer on the fixing medium or the resin-containing fine particle support. The present invention relates to a fixing device and an image forming apparatus including the same.

  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. There are various types of image forming apparatuses, and electrophotographic image forming apparatuses are widely used in offices because they can form high-definition images on plain paper at high speed. In this electrophotographic image forming apparatus, there is a heat fixing type fixing device that heats and softens or melts toner on a recording medium and pressurizes the softened toner to fix the toner on the recording medium. Widely used. This thermal fixing method is preferably used because it can provide a high fixing speed and high fixed image quality.

More than half of the power consumption in an electrophotographic image forming apparatus having a fixing device employing such a heat fixing method is consumed for heating the toner in the fixing device. On the other hand, from the viewpoint of measures against environmental problems in recent years, an image forming apparatus with low power consumption (energy saving) is desired. Therefore, there is a demand for energy saving in the fixing device that consumes more than half of the power consumption in the conventional image forming apparatus. The conventional heat fixing type fixing device consumes a lot of electric power for the heat treatment, so the fixing method for heating the toner to fix the toner is extremely lower than before, or the toner is heated. A fixing method that does not require this is desired. In particular, a non-heat fixing method in which toner is fixed on a recording medium without heating the toner is ideal in terms of low power consumption.
In such a non-heat fixing type fixing device, a fixing solution containing a softening agent that softens the toner by dissolving or swelling at least a part of the resin component of the toner is applied to the toner image on the surface of the recording medium. A fixing device of a wet fixing type that fixes a toner image is known. In such a wet fixing type fixing device, heat treatment is not required to soften the toner, and energy saving can be realized as compared with the thermal fixing method.

However, in the conventional wet fixing type fixing device, the liquid fixing solution is applied to the surface of the recording medium by the application member, and a small amount of the fixing solution is applied to the surface of the recording medium and the toner offset to the application member is prevented. There was a problem that it was extremely difficult to achieve both.
In the configuration in which the fixing solution is applied using an application member, when a large amount of the fixing solution is applied, the image quality deteriorates due to the flow of toner particles on the recording medium, and the fixing responsiveness decreases due to the longer drying time of the fixing solution. However, depending on the recording medium, there is a problem that paper jam is likely to occur.
On the other hand, when a small amount of the fixing solution is applied, the following problems occur. That is, the toner particles on the recording medium are pulled by the surface tension of the liquid film of the fixing solution that is not applied to the recording medium and remains on the surface of the coating member at a position where the coating member comes into contact with the recording medium and then separates from the recording medium. Will be offset. As a result, offset toner particles adhere to the surface of the coating member, and the toner image on the recording medium after separation from the coating member is greatly disturbed.

  As a fixing method capable of satisfying both the application of a small amount of fixing solution and the prevention of toner offset, Patent Document 1 discloses that a fixing solution is used as a foam fixing solution in which bubbles are dispersed in the liquid, and the foam fixing solution is used as a recording medium. A configuration for application to the upper toner image is described. Thus, the bulk density of the fixing solution can be lowered by making the fixing solution foam. For this reason, the film thickness of the fixing liquid on the surface of the coating member can be increased with a smaller amount of fixing liquid than before, and the influence of the surface tension of the liquid on the toner particles on the fixing liquid application target can be reduced. As a result, toner offset can be prevented. Further, since the amount of the fixing solution is small, it is possible to suppress the residual liquid feeling on the recording medium. Further, since the foam-like fixing solution is less likely to flow than a normal liquid fixing solution, it is possible to prevent image deterioration caused by the toner particles on the fixing solution application target being caused to flow by the fixing solution. Therefore, by performing fixing using a foamy fixing solution as in the fixing device described in Patent Document 1, it is possible to fix the toner image without disturbing with a smaller amount of fixing solution applied than before.

  However, in the configuration using the coating member, when the coating member contacts the toner particles on the recording medium in the coating nip where the coating member applies the fixing liquid to the recording medium, the toner particles adhere to the surface of the coating member and the toner offset. Problem arises. The problem of toner offset caused by the application member coming into contact with the toner particles on the recording medium is a problem that can occur regardless of whether the fixing liquid applied by the application member is in a liquid state or a foam state. .

  As a configuration capable of preventing the problem of toner offset caused by contact of the coating member with the toner particles on the recording medium, Patent Document 2 discloses a gap that maintains a gap between the coating member and the recording medium at the coating nip. A configuration comprising a member is described. In such a configuration, by setting the gap by the gap member so that the coating member does not contact the toner particles on the recording medium, the toner offset caused by the coating member contacting the toner particles on the recording medium. Can be prevented.

  In the configuration in which the fixing liquid is applied to the recording medium using the coating member, it is necessary to remove the residual fixing liquid remaining on the surface of the coating member that has passed through the coating nip. This is because even when the toner offset is suppressed, the residual fixing liquid on the surface of the coating member that has passed through the coating nip may be mixed with a slightly offset toner. In the case of a configuration in which a foam fixing solution is applied, the foam fixing solution that has passed through the coating nip changes its properties as a foam fixing solution, such as a larger bubble diameter than before the coating nip. . When a new foam-type fixing solution is supplied to the surface of the coating member to which the foam-type fixing solution with changed properties adheres, the foam-type fixing solutions having different characteristics are mixed and the foam-type fixing solution is uniformly distributed on the recording medium. There is a risk that it may not be possible to apply to the surface.

  Further, the configuration including the gap member as in the fixing device described in Patent Document 2 needs to remove the residual fixing liquid from the gap member that has passed through the coating nip. However, the gap member described in Patent Document 2 is a wire member or mesh member fixed to the surface of the application member, or a mesh roller that moves endlessly outside the application member, and includes such a gap member. It is difficult to remove the residual fixing liquid from the application member having a complicated structure.

  In each of the fixing devices described above, the application target of the fixing liquid by the application member is the surface of the recording medium carrying the toner particles. As a fixing device for fixing a toner image on a recording medium using a fixing liquid, a fixing liquid is applied to a toner image carrier such as an intermediate transfer belt carrying toner particles, and the toner image on the toner image carrier is fixed. Some transfer to a recording medium together with liquid. As described above, the same problem may occur when the application target to which the application member applies the fixing liquid is not the recording medium but the toner image carrier.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is a configuration in which a fixing liquid is applied to toner particles on a fixing liquid application target, and a toner offset caused by an application member contacting the toner particles. It is an object of the present invention to provide a fixing device that can easily clean an application member while preventing the above, and an image forming apparatus including the fixing device.

In order to achieve the above object, the invention of claim 1 is characterized in that a surface of a fixing liquid containing a softening agent that softens resin fine particles by dissolving or swelling at least part of the resin is carried on the surface, and the surface moves. An application member for applying a fixing solution on the surface to the fixing solution application target at a position facing the fixing solution application target carrying the resin fine particles, a fixing solution supply means for supplying the fixing solution to the surface of the application member, and A pressure member that abuts against the application member across the fixing solution application target at a position where the application member applies the fixing solution to the application solution of the fixer, and forms an application nip with the application member; In a fixing device for fixing the resin fine particles softened by applying a fixing solution to a recording medium, a gap agent for providing a gap between the coating member and the fixing solution application target in the coating nip is provided in the coating nip. Grant in It is characterized in further comprising a cap agent deposition unit.
According to a second aspect of the present invention, there is provided the fixing device according to the first aspect, wherein the fixing liquid supply means disperses bubbles in the liquid fixing liquid to form a foamy fixing liquid, and the surface of the coating member. It is a fixing solution foaming means for supplying a foamy fixing solution to the liquid.
According to a third aspect of the present invention, in the fixing device of the first or second aspect, the gap agent applying means applies the gap agent onto the surface of the coating member.
According to a fourth aspect of the present invention, there is provided the fixing device according to the third aspect, wherein the gap agent applying means is provided on the coating member after passing through the coating nip and before the fixing liquid is supplied by the fixing liquid supply means. The gap agent is provided on the surface.
According to a fifth aspect of the present invention, in the fixing device according to the first aspect, the gap agent applying means applies the gap agent on the surface of the fixing liquid application target carrying the resin fine particles. Is.
According to a sixth aspect of the present invention, in the fixing device of the fifth aspect, the gap agent applying means includes a gap agent carrier that carries the gap agent and moves on the surface, and the gap agent carrier is used as the fixing liquid. It is made to contact the said resin fine particle layer on the surface of the application | coating object.
According to a seventh aspect of the present invention, in the fixing device according to the fifth aspect, the gap agent applying means includes an electrostatic latent image carrier and a latent image that forms an electrostatic latent image on the electrostatic latent image carrier. Forming means, developing means for developing an electrostatic latent image formed on the electrostatic latent image carrier using a gap agent to form a gap agent image, and forming on the electrostatic latent image carrier And a gap agent image transfer means for transferring the gap agent image formed on the surface of the fixing liquid application target.
The invention according to claim 8 is a toner image forming means for forming a toner image on a recording medium using a toner containing resin fine particles containing a resin and a colorant, and a toner carrying a toner image transferred to the recording medium. An image forming apparatus comprising: a fixing unit that applies a fixing liquid to a surface of an image carrier or a surface of a recording medium that carries a toner image, and fixes the toner image on the recording medium. The fixing device according to any one of claims 1 to 7 is used.

  In the present invention, since a gap is provided between the coating member in the coating nip and the fixing liquid application target by the gap agent applied by the gap agent applying means, the coating member is applied to the toner particles on the fixing liquid coating target. Toner offset caused by contact can be prevented. In addition, even if the gap agent is adhered to the application member that has passed through the application nip, the gap agent can be removed from the application member together with the residual fixer. For this reason, unlike the fixing device including the application member having a complicated configuration including the gap member, the application member can be easily cleaned.

  According to the present invention, the fixing liquid is applied to the toner particles on the fixing liquid application target, and the application member can be easily cleaned while preventing the toner offset caused by the application member coming into contact with the toner particles. Has an excellent effect.

FIG. 3 is an explanatory diagram of a fixing liquid application unit of the fixing device according to the first embodiment. 1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 3 is an explanatory diagram illustrating one of image forming units of the printer. 1 is a schematic configuration diagram illustrating a fixing device according to a first embodiment. FIG. 2 is a schematic configuration diagram illustrating a fixing liquid supply unit of the fixing device. An enlarged schematic view showing a film thickness adjusting blade and a coating roller in the fixing device, (a) is an explanatory diagram of a state where the film thickness adjusting gap is narrowed, and (b) is an explanation of a state where the film thickness adjusting gap is widened. Figure. The expansion explanatory view of the gap agent grant device of Embodiment 1. FIG. FIG. 3 is an enlarged explanatory diagram of a coating nip in the fixing device according to the first embodiment in a state where the amount of foamy fixing solution attached is reduced. FIG. 3 is a schematic configuration diagram illustrating a fixing device according to a second embodiment. The expansion explanatory drawing of the gap agent provision apparatus of Embodiment 2. FIG. Expansion explanatory drawing of the storage part vicinity of the gap agent provision apparatus of Embodiment 2. FIG. Enlarged explanatory view of the vicinity of the storage part of the gap agent applying device of the modified example FIG. 5 is a schematic configuration diagram illustrating a fixing device according to a third embodiment. The expansion explanatory drawing of the gap agent provision apparatus of Embodiment 3. FIG. FIG. 6 is an explanatory diagram of a printer unit of another example of an image forming apparatus in which a fixing device to which the present invention is applied can be arranged. FIG. 6 is a schematic configuration diagram of an example of a conventional fixing device that does not include a gap agent applying device. FIG. 17 is an enlarged explanatory view of a coating nip in a state where the amount of adhering foamy fixing solution is reduced in the conventional fixing device shown in FIG. 16.

Hereinafter, an embodiment of an electrophotographic tandem color printer (hereinafter simply referred to as a printer 100) will be described as an image forming apparatus to which the present invention is applied. The image forming apparatus to which the present invention is applied is not limited to a printer, and any image forming apparatus having a fixing device such as a copying machine or a facsimile can be applied.
First, a basic configuration of the printer 100 according to the embodiment will be described. FIG. 2 is a schematic configuration diagram illustrating a main part of the printer 100. In the figure, a printer 100 includes four image forming units 3 (Y, M, C, K) that form yellow (Y), magenta (M), cyan (C), and black (K) toner images, and transfer. A unit 20, a paper transport unit 28, a registration roller pair 15, a fixing device 30, an optical writing device (not shown), and the like are provided.
The transfer unit 20 includes an intermediate transfer belt 25 as a toner image carrier, and is an image forming unit for each color of black, yellow, magenta, and cyan along a stretched surface on the upper side of the intermediate transfer belt 25. Four image forming units 3 (Y, M, C, K) are arranged.

  An optical writing device (not shown) is arranged above the four image forming units 3 (Y, M, C, K). For example, when the printer 100 is a copying machine, image information of an original is read by a scanner, and a light source such as a laser diode or an LED of an optical writing device is driven according to the image information, thereby forming an image forming unit 3. Each laser beam L is irradiated toward the drum-shaped photoconductor 4 (Y, M, C, K) at (Y, M, C, K). By this irradiation, an electrostatic latent image is formed on the surface of the photoreceptor 4 (Y, M, C, K), and this latent image becomes a toner image through a predetermined development process. The subscripts Y, M, C, and K added after the reference numerals indicate the specifications for yellow, magenta, cyan, and black.

Each of the image forming units 3 (Y, M, C, K) supports the photosensitive member 4 as a latent image carrier and various devices arranged around it on a common support as a unit. It can be attached to and detached from the printer body. The image forming unit 3 (Y, M, C, K) has the same configuration except that the color of the toner to be used is different. FIG. 3 shows the four image forming units 3 (Y, M, C, K). FIG. 3 is an explanatory diagram of one of the image forming units 3.
As shown in FIG. 3, each of the four image forming units 3 includes a developing device 6, a charging device 7, a static eliminating lamp 8 for the static eliminating device, a drum cleaning device 9, and the like around the photosensitive member 4 in addition to the photosensitive member 4. I have. Further, a primary transfer roller 26 of the primary transfer device is disposed at a position facing the photoconductor 4 with the intermediate transfer belt 25 interposed therebetween.
The primary transfer device of this embodiment includes a roller-shaped primary transfer roller 26 as a primary transfer member, and the primary transfer roller 26 is disposed at a position where the intermediate transfer belt 25 is in contact with the photosensitive member 4. The primary transfer roller 26 contacts the photoconductor 4 with the intermediate transfer belt 25 interposed therebetween, thereby forming a primary transfer nip for transferring the toner image formed on the surface of the photoconductor 4 to the intermediate transfer belt 25. As the primary transfer member, a conductive brush, a non-contact corona charger, or the like can be employed.

As the photoreceptor 4, a drum-shaped member is used in which a photosensitive layer is formed by applying a photosensitive organic photosensitive material to a base tube made of aluminum or the like. The photoreceptor is not limited to a drum shape, but may be an endless belt shape.
The charging device 7 of the present embodiment is a contact-type charging device in which a charging roller to which a charging bias is applied is brought into contact with the photosensitive member 4. The charging device 7 uniformly charges the surface of the photosensitive member 4 by applying a charging bias to the charging roller that is in contact with the photosensitive member 4. The charging device 7 is not limited to the contact-type charging method, and a non-contact charging method charging device that employs a scorotron charger that performs a non-contact charging process on the photoconductor 4 may be used.

The developing device 6 obtains a toner image by attaching toner to the electrostatic latent image on the photoreceptor 4 using a two-component developer containing a magnetic carrier (not shown) and a non-magnetic toner. This is a two-component phenomenon system that develops and visualizes. Instead of the two-component developer, a one-component phenomenon type developing with a one-component developer not containing a magnetic carrier may be used. The toner image developed on the surface of the photoreceptor 4 is primarily transferred to the intermediate transfer belt 25 at the primary transfer nip.
Here, the toner corresponding to each color is composed of resin fine particles colored in the respective colors, and these resin fine particles are dissolved or swollen by a fixing solution described later. The developing device 6 includes a stirring unit that contains and stirs the two-component developer, and a developing unit in which the developing roller is disposed. The developer that is supplied to the surface of the developing roller and is not used for development is a stirring unit. Returned to be reused. The toner concentration of the two-component developer in the stirring unit is detected by a toner concentration sensor (not shown) and is controlled so that the toner concentration is constant.

Transfer residual toner adhering to the surface of the photoconductor 4 after passing through the primary transfer nip is removed from the surface of the photoconductor 4 by the drum cleaning device 9. The drum cleaning device 9 includes a drum cleaning blade 91 that is pressed against the photoreceptor 4. The transfer residual toner removed from the surface of the photoreceptor 4 by the drum cleaning device 9 is transported to the developing device 6 by a not-shown recovery screw and toner recycling device and reused. In the present embodiment, as the drum cleaning device 9, a system that scrapes off the transfer residual toner with a polyurethane rubber cleaning blade is shown.
The neutralization lamp 8 neutralizes the surface of the photoreceptor 4 by light irradiation.

When the image forming unit 3 forms a toner image on the surface of the photoconductor 4, the surface of the photoconductor 4 rotating counterclockwise in FIGS. 2 and 3 is uniformly charged by the charging device 7. The uniformly charged surface of the photoconductor 4 is irradiated with laser light L based on image information from an optical writing device (not shown), and an electrostatic latent image is formed on the surface of the photoconductor 4. Thereafter, the electrostatic latent image is developed on the surface of the photoconductor 4 by the developing device 6, and a toner image is formed on the surface of the photoconductor 4.
The surface of the photoreceptor 4 on which the toner image is formed is transferred onto the surface of the photoreceptor 4 after the toner image is transferred to the intermediate transfer belt 25 at a primary transfer nip that is a portion facing the primary transfer roller 26 and passed through the primary transfer nip. The remaining transfer residual toner is removed by the drum cleaning device 9. The surface of the photoreceptor 4 from which the transfer residual toner has been removed is neutralized by light irradiation of the neutralization lamp 8 and initialized, and is prepared for the next image formation starting from uniform charging by the charging device 7.

In FIG. 2, Y, M, C, and K toner images are formed on the photoreceptors 4 (Y, M, C, and K) of the four image forming units 3 (Y, M, C, and K) by the above-described process. Is done. A transfer unit 20 is arranged below the four image forming units 3 (Y, M, C, K).
In the transfer unit 20, an intermediate transfer belt 25 stretched by a plurality of stretching rollers (21, 22, 23) is brought into contact with the photosensitive member 4 (Y, M, C, K) to thereby make Y, M , C, K primary transfer nips are formed. The intermediate transfer belt 25 is moved endlessly in the clockwise direction in the figure (in the direction of arrow A in the figure) by the rotational drive of the drive roller 21.

  In the vicinity of the primary transfer nip for Y, M, C, and K, the intermediate transfer belt 25 is moved to the photosensitive member by the primary transfer roller 26 (Y, M, C, and K) disposed inside the belt loop of the intermediate transfer belt 25. 4 (Y, M, C, K). A primary transfer bias is applied to these primary transfer rollers 26 (Y, M, C, K) by a power source (not shown). As a result, a primary transfer electric field for electrostatically moving the toner image on the photoreceptor 4 (Y, M, C, K) toward the intermediate transfer belt 25 is present in the primary transfer nips for Y, M, C, and K. Is formed. As shown in FIG. 2, each of the color transfer toners passes through the primary transfer nips for Y, M, C, and K in sequence with the endless movement in the clockwise direction. The images are sequentially superimposed and primarily transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image) is formed on the front surface of the intermediate transfer belt 25.

  A paper transport unit 28 that functions as a secondary transfer device is provided at a position facing the transfer backup roller 23 across the intermediate transfer belt 25 below the transfer unit 20 in the drawing. The paper transport unit 28 is configured to endlessly move an endless paper transport belt 29 between two support rollers of a driving roller 29b and a secondary transfer roller 29a. The paper transport unit 28 sandwiches the paper transport belt 29 between its secondary transfer roller 29 a and the intermediate transfer belt 25 of the transfer unit 20. With such a configuration, a secondary transfer nip is formed in which the front surface of the intermediate transfer belt 25 and the front surface of the paper transport belt 29 abut. The secondary transfer device is not limited to the configuration in which the belt-shaped member is opposed to the intermediate transfer belt 25, but may be configured to have the roller-shaped member be opposed to the intermediate transfer belt 25.

  A secondary transfer bias is applied to the secondary transfer roller 29a of the paper transport unit 28 by a power source (not shown). On the other hand, the transfer backup roller 23 around which the intermediate transfer belt 25 is wound in the loop of the intermediate transfer belt 25 of the transfer unit 20 is grounded. As a result, a secondary transfer electric field acting so that the four-color toner image on the intermediate transfer belt 25 is directed to the secondary transfer roller 29a is formed in the secondary transfer nip.

  In the secondary transfer nip, the four-color toner image on the intermediate transfer belt 25 is transferred to a transfer paper P that is a recording medium supplied from a paper supply device (not shown). A registration roller pair 15 is disposed on the right side of the secondary transfer nip in the drawing, and the transfer paper P supplied from a sheet feeding device (not shown) is sandwiched between the rollers of the registration roller pair 15 and stopped. To do. The registration roller pair 15 sends the transfer sheet P sandwiched between the rollers to the secondary transfer nip at a timing to synchronize with the four-color toner image on the intermediate transfer belt 25. In the secondary transfer nip, the four-color toner images on the intermediate transfer belt 25 are collectively transferred onto the transfer paper P by the influence of the secondary transfer electric field and the nip pressure. As a result, the four-color toner image transferred to the transfer paper P is combined with the white color of the transfer paper P to form a full-color image. The transfer paper P that has passed through the secondary transfer nip is separated from the intermediate transfer belt 25 and is conveyed to the fixing device 30 along with its endless movement while being held on the front surface of the paper conveyance belt 29. Then, the unfixed toner image on the surface of the transfer paper P is fixed by the fixing device 30 and is discharged out of the printer 100.

  A belt cleaning device 24 is disposed at a position facing the cleaning counter roller 22 among the plurality of stretching rollers (21, 22, 23) of the intermediate transfer belt 25 with the intermediate transfer belt 25 interposed therebetween. The transfer residual toner that has not been transferred to the transfer paper P at the secondary transfer nip adheres to the surface of the intermediate transfer belt 25 that has passed through the secondary transfer nip, and this transfer residual toner is intermediated by the belt cleaning blade 24a. It is scraped off and removed by a belt cleaning device 24 in contact with the transfer belt 25.

[Embodiment 1]
Next, a first embodiment of the fixing device 30 (hereinafter referred to as the first embodiment) will be described. FIG. 4 is a schematic configuration diagram of the fixing device 30 according to the first embodiment.
The fixing device 30 converts the liquid fixing solution 132 into a foamy fixing solution F by foaming the liquid fixing solution 132, and the foamed fixing solution F generated by the foaming fixing solution generating unit 130 is not fixed. The image forming apparatus includes a fixing liquid application unit 140 that is applied to the surface of the transfer paper P that is an application target of the fixing liquid carrying the toner image T. The fixing liquid application unit 140 includes an application roller 141, a pressure roller 143, a film thickness adjustment blade 142, an application member cleaning device 160, and the like. Further, the fixing liquid application unit 140 includes a gap agent applying device 150 described later in detail.
The application roller 141 is an application member that supports the foam-like fixing liquid F generated by the foam-type fixing liquid generation unit 130 on the surface and applies it to the transfer paper P at the application nip C. The pressure roller 143 is a member that includes an elastic layer, faces the application roller 141, and presses the transfer paper P conveyed between the application roller 141. The film thickness adjusting blade 142 is a member of the application roller 141. This is a member for controlling the film thickness of the foam-like fixing liquid F carried on the surface. The coating member cleaning device 160 cleans the surface of the coating roller 141 that has passed through the coating nip C by the coating member cleaning blade 161 that is in contact with the coating roller 141. The gap agent applying device 150 is a device that applies a gap agent on the surface of the application roller 141.

  As shown in FIG. 4, the foamy fixing solution F is dropped between the application roller 141 and the film thickness adjusting blade 142. At this time, since the foam-like fixing liquid F has a low bulk density, the film thickness on the application roller 141 can be increased. As a result, it is possible to apply a sufficient volume of foam-like fixing solution F to the unfixed toner image T as compared with the case where a liquid fixing solution is used, and to fix the unfixed toner image T to the transfer paper P satisfactorily. be able to. Further, since the bulk density is small, the amount of the fixing solution relative to the volume is sufficiently smaller than that of the liquid fixing solution, so that the residual liquid feeling is prevented from being generated on the transfer paper P on which the fixed toner image Tb is formed. it can.

FIG. 5 is a schematic configuration diagram showing the foamy fixing solution generator 130 of the fixing device 30.
The foam-like fixing liquid generation unit 130 includes a fixing liquid container 131, a conveyance pump 133, a liquid conveyance pipe 134, a coarse bubble generation unit 135, a bubble refinement unit 138, and the like. The fixer container 131 stores the liquid fixer 132 before foaming, and the transport pump 133 transports the liquid fixer 132 from the fixer container 131 to the coarse bubble generator 135 through the liquid transport pipe 134. To do. The coarse bubble generating unit 135 generates coarse bubbles having a bubble diameter of 0.5 to 1 [mm] from the liquid fixing liquid 132 conveyed by the conveyance pump 133. In addition, the bubble refining unit 138 divides the coarse bubbles into fine bubbles by applying shear force to the foam-like fixing solution F including the coarse bubbles having a large bubble diameter generated by the coarse bubble generating unit 135, A foamy fixing solution F having a small diameter is produced.

  The transport pump 133 is not particularly limited, and a gear pump, a bellows pump, a tube pump, or the like can be used. Among these, it is desirable to use a tube pump. If there is a mechanism that is driven in the fixing liquid, such as a gear pump, the liquid bubbles in the pump, and the liquid may be compressible, resulting in a decrease in conveying ability. Further, there is a possibility that the liquid fixing liquid 132 is contaminated by the material constituting the driving mechanism, or the driving mechanism is deteriorated by the liquid fixing liquid 132. On the other hand, the tube pump is a mechanism that pushes out the liquid in the tube while deforming the tube, and since there is no mechanism for driving in the liquid to be conveyed, the only member that contacts the liquid fixing liquid 132 is the tube. For this reason, by using a tube having liquid resistance to the liquid fixing solution 132, contamination of the liquid fixing solution 132 and deterioration of pump components can be suppressed. Further, since only the tube is deformed, foaming of the liquid fixing liquid 132 can be suppressed, and a decrease in the conveyance capability can be suppressed.

  The coarse bubble generating unit 135 is provided with an air port 136 and a microporous sheet 137 having a hole diameter of 30 to 100 [μm]. In the coarse bubble generating unit 135, the liquid fixing solution 132 conveyed by the conveying pump 133 flows in, so that a negative pressure is generated in the air port 136 and the air introduced from the air port 136 is mixed with the liquid fixing solution 132. . Furthermore, when the liquid fixing solution 132 mixed with air passes through the microporous sheet 137, a foamy fixing solution F composed of coarse bubbles with uniform bubble diameters is generated.

As a configuration of the coarse bubble generation unit 135, a porous member having an open cell structure with a pore diameter of 30 to 100 μm may be used instead of the microporous sheet 137. Such a porous member is not particularly limited, and examples thereof include a sintered ceramic plate, a nonwoven fabric, and a foamed resin sheet. Further, as the configuration of the coarse bubble generating unit 135, instead of providing the air port 136 and the microporous sheet 137, the liquid fixer 132 is agitated using a blade-like stirrer, whereby bubbles are formed in the liquid fixer 132. It is also possible to generate a foam-like fixing solution F made of coarse bubbles while entraining. Further, as the configuration of the coarse bubble generating unit 135, the foamy fixing solution F made of coarse bubbles may be generated by bubbling the liquid fixing solution 132 using an air supply pump or the like.
Regardless of the configuration of the coarse bubble generation unit 135, bubbles having a relatively large bubble diameter of, for example, about 0.5 to 1 [mm] can be generated in a very short time. However, it is desirable to make the foam for fixing as fine as possible. Therefore, in the printer 100, the coarse bubbles of the foam-like fixing liquid F obtained by the coarse bubble generation unit 135 are refined by the foam refinement unit 138.

The foam-like fixing solution F containing coarse bubbles generated by the coarse bubble generating unit 135 is supplied to the bubble refining unit 138 through the bubble transport pipe 138c.
The bubble refining part 138 is divided into two or more and refined by applying a shearing force to the coarse bubbles. The bubble refining portion 138 has a double cylindrical structure including an inner cylinder 138b that can rotate inside the outer cylinder 138a. A foam-like fixer F containing coarse bubbles is supplied to a gap between the outer cylinder 138a and the inner cylinder 138b from a position where the bubble conveyance pipe 138c of the outer cylinder 138a is connected, and the inner cylinder 138b is allowed to pass through the gap. A shearing force is applied to the foamy fixing solution F by rotation. By applying a shearing force in this way, desired coarse bubbles are fed from the foam outlet 138d provided on the outer cylinder 138a to the foam supply nozzle 139 while dividing one coarse bubble into two or more fine bubbles. The foamy fixing solution F having a diameter is discharged. As the bubble refining section 138, a spiral groove may be provided on the outer periphery of the inner cylinder 138b to improve the transportability of the foam-like fixing liquid F in the outer cylinder 138a.

  In this way, a coarse bubble generating unit 135 that foams the liquid fixing solution 132 into a foamy fixing solution F containing coarse bubbles, and a bubble refining unit 138 that applies shear force to the coarse bubbles to divide them into fine bubbles. In combination, the liquid fixing solution 132 can be changed to a foamy fixing solution F composed of micro bubbles of about 5 to 50 [μm] in a very short time.

The bulk density of the foam-like fixing solution F is preferably in the range of 0.01 to 0.1 [g / cm ³ ], more preferably in the range of 0.01 to 0.05 [g / cm ³ ], and The range of 025-0.05 [g / cm < ³ >] is especially preferable. If the bulk density is less than 0.01 [g / cm ³ ], the application of the fixing solution may be insufficient. If the bulk density exceeds 0.1 [g / cm ³ ], the remaining amount on the transfer paper P after fixing is left. A liquid feeling may occur.
Moreover, it is preferable that the bubble-shaped fixing solution F applied to the transfer paper P has a bubble diameter of 5 to 50 [μm]. As a result, the foam-like fixing liquid F can be applied to the toner image without disturbing the toner image formed of toner particles having a particle diameter of 5 to 10 [μm] formed on the transfer paper P.
Further, the fixing solution only needs to be foamed when applied to a layer of resin-containing fine particles such as toner on the transfer paper P, and does not need to be foamed in the fixing solution container 131. The fixing liquid container 131 is in a liquid state that does not contain bubbles, and is formed into a foam state at the time when the liquid is supplied from the container or on the liquid conveyance path until it is applied to the resin-containing fine particle layer. The transportation volume and the storage volume can be reduced, and the transportation cost and the storage cost can be reduced.

As shown in FIG. 4, the foam-like fixing liquid F made of microbubbles obtained in the bubble refining unit 138 is supplied to the surface of the application roller 141 through the bubble supply nozzle 139. The thickness of the supplied foam-like fixing solution F on the surface of the application roller 141 is adjusted by a film thickness adjusting blade 142 whose tip is opposed to the surface of the application roller 141 with a predetermined gap. The
As shown in FIG. 6, the film thickness adjusting blade 142 is cantilevered and rotates about the blade rotation shaft 142 a on the fixed end side, so that its tip, the coating roller 141, It is a member that adjusts the gap. In the fixing device 30, the gap is changed in a range of 10 [μm] to 100 [μm].
A control unit (not shown) adjusts the gap by rotating the blade by driving a motor. When the film thickness of the foam-like fixing liquid F on the surface of the application roller 141 is made relatively thin, the gap is made small as shown in FIG. When the film thickness is relatively thick, the gap is adjusted to be large as shown in FIG.

  The film thickness of the foam-like fixing liquid F controlled by the film thickness adjusting blade 142 is the thickness of the unfixed toner image T formed on the transfer paper P, the bubble size, viscosity, and undetermined of the foam-like fixing liquid F. The pressure is appropriately selected according to the pressure applied when the toner image T is applied and the environmental temperature. Further, the film thickness adjusting blade 142 is based on image information (for example, a color image or a black solid image) used in an optical writing device (not shown) when the unfixed toner image T formed on the transfer paper P is formed. The film thickness of the foamed fixing solution F may be controlled by adjusting the gap between the coating roller 141 and the coating roller 141.

  As a configuration for adjusting the film thickness of the foam-like fixing solution F on the surface of the coating roller 141, the film thickness may be adjusted by a wire bar instead of the film thickness adjusting blade 142. In this case, compared to the film thickness adjusting blade 142, the film thickness in the axial direction on the surface of the coating roller 141 can be made uniform.

  A pressure roller 143 having an elastic layer is in contact with the application roller 141 for applying the foamy fixing solution F to the transfer paper P on which the toner image is formed, thereby forming an application nip C. The transfer paper P transported from the secondary transfer nip toward the fixing device 30 by the paper transport belt 29 described above is sandwiched in the coating nip C with the image surface facing the coating roller 141. In the application nip C, the foamy fixing solution F on the application roller 141 is applied to the image surface.

  The pressure roller 143 is configured by using, as an elastic layer, a sponge (elastic porous body) that can be greatly deformed with a weak pressure. Thereby, a nip time of 50 to 300 [ms] (milliseconds) can be secured. At this time, it is necessary to adjust the nip time so that the application roller 141 and the transfer paper P can be separated after the foamy fixing solution F penetrates the unfixed toner image T and reaches the transfer paper P.

Here, the nip time is a ratio of the nip width to the transfer speed of the transfer paper P, and can be calculated by an equation “(nip width) / (paper transfer speed)”. At this time, the “paper transport speed” can be obtained from design data of the paper transport drive mechanism. Further, the “nip width” is obtained by applying a thin color paint on the entire surface of the application roller 141 and then pressing the transfer paper P between the application roller 141 and the pressure roller 143 to apply the color paint to the transfer paper P. And the length of the colored paint adhering to the transfer paper P in the paper conveyance direction can be determined.
Therefore, in order to obtain a desired nip time, it is necessary to adjust the nip width according to the transfer speed of the transfer paper P. This nip width can be adjusted by changing the distance between the axes of the application roller 141 and the pressure roller 143.

The sponge used for the elastic layer of the pressure roller 143 is preferably made of a material that does not dissolve or swell in the softener, but is a flexible film in which the surface of the elastic layer made of sponge does not dissolve or swell in the softener. It may be a covered configuration. The material for the sponge is not particularly limited, and examples thereof include polyethylene, polypropylene, and polyamide. Further, the flexible film is not particularly limited, and examples thereof include polyethylene terephthalate, polyethylene, polypropylene, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), and the like.
As the elastic layer of the pressure roller 143, elastic rubber may be used instead of sponge.

  The fixing device 30 includes a leading edge detection sensor 120 that detects the leading edge of the transfer paper P on the upstream side in the conveyance direction of the transfer paper P with respect to the coating nip C. Then, in accordance with the detection signal of the leading edge detection sensor 120, control is performed so that a thin film of the foam-like fixing liquid F is formed on the application roller 141 so that the foam-like fixing liquid F is applied only on the transfer paper P. . As a result, even when the application roller 141 and the pressure roller 143 are always in contact with each other, the foam-like fixing liquid F on the application roller 141 is transferred to the pressure roller 143 during standby when the transfer paper P is not conveyed. It can suppress adhering to.

  Further, the fixing device 30 is provided with a contact / separation mechanism that contacts and separates the application roller 141 and the pressure roller 143 during standby when the transfer paper P is not being transported. The application roller 141 and the pressure roller 143 may be in contact with each other only when the foamy fixing solution F is applied. At this time, it is preferable that the application roller 141 and the pressure roller 143 are brought into contact with each other according to the detection signal of the tip detection sensor 120. Furthermore, it is preferable to provide a trailing edge detection means for detecting the trailing edge of the transfer paper P, and to separate the application roller 141 and the pressure roller 143 in accordance with a detection signal from the trailing edge detection means.

  Further, the fixing device 30 may have a pair of smoothing rollers (hard rollers) that pressurize the transfer paper P on which the fixed toner image Tb is formed. Thereby, the surface of the fixed toner image Tb is smoothed, and the glossiness of the image can be improved. Furthermore, the fixing property of the fixed toner image Tb to the transfer paper P can be improved.

  The fixing device 30 uses a liquid fixing solution 132 containing a softening agent, a foaming agent, and water that softens fine particles containing the resin by dissolving or swelling at least a part of the resin. Then, it is applied to the resin-containing fine particles on the surface of the recording medium as a foamy fixing solution F. Thus, a fixing method is adopted in which the resin-containing fine particles on the surface of the recording medium are softened and the resin-containing fine particles are fixed on the recording medium. Needless to say, the resin-containing fine particles described here are not particularly limited. Any fine particles containing a resin may be used, and fine resin-containing fine particles containing a conductive member may be used. When applied to an image forming apparatus such as the printer 100, the resin-containing fine particles refer to toner.

When the resin-containing fine particles are toner, the toner contains a colorant, a charge control agent, a binder resin, and a release agent, and further contains other components as necessary. Although it does not specifically limit as resin contained in a toner, A polystyrene, a styrene-acryl copolymer, polyester etc. are mentioned, You may use 2 or more types together. Although it does not specifically limit as a mold release agent, Carnauba wax, polyethylene wax, etc. are mentioned, You may use 2 or more types together.
The toner is preferably subjected to a water-repellent treatment by fixing hydrophobic particles such as hydrophobic silica having a methyl group and hydrophobic titanium oxide to the surface of the toner.

  The recording medium is not particularly limited, and examples thereof include paper (standard plain paper, continuous paper, letter paper, postcard, cardboard, etc.), cloth, plastic films such as OHP sheets, metals, resins, ceramics, and the like. . At this time, the recording medium preferably has permeability to the fixing solution. Examples of such a recording medium include a substrate that is permeable to a fixing solution and a layer on which a layer that is permeable to a fixing solution is formed. Further, the form of the recording medium is not particularly limited, and examples thereof include a three-dimensional object having a flat surface and a curved surface in addition to a sheet-like material.

Next, features of the fixing device 30 according to the first embodiment will be described.
FIG. 1 is a schematic explanatory diagram of the fixing solution application unit 140 of the fixing device 30 according to the first embodiment. As illustrated in FIG. 1, the fixing device 30 according to the first exemplary embodiment includes a gap agent applying device 150 that applies a gap agent G to the surface of the application roller 141. FIG. 7 is an enlarged explanatory view of the gap agent applying device 150 provided in the fixing device 30 according to the first embodiment.

As illustrated in FIG. 7, the gap agent application device 150 includes a storage unit 151, an application amount control member 152, and a delivery member 153. The gap agent G stored in the storage unit 151 is applied on the surface of the application roller 141 by the delivery member 153, and the gap agent G applied on the surface of the application roller 141 is applied by moving the surface of the application roller 141. It reaches the facing portion between the roller 141 and the application amount control member 152. The application amount control member 152 is a member that controls the application amount of the gap agent G to the application roller 141 by regulating the amount of the gap agent G that passes through the portion facing the application roller 141, and this application amount control member 152. Thus, the excess gap agent G is removed from the surface of the application roller 141.
The gap agent G that has passed through the facing portion between the application roller 141 and the application amount control member 152 reaches the application nip C by the surface movement of the application roller 141, and the application of the gap agent G into the application nip C is achieved. The
The application amount control member 152 is not particularly limited, but the application amount of the gap agent G can be controlled by using a brush adjusted in advance so that the application amount is constant, elastic rubber, or the like. If more gap agent G than necessary adheres to the transfer paper P, it causes a reduction in image quality. On the other hand, as in the first embodiment, by controlling the application amount of the gap agent G by the application amount control member 152, the gap agent G more than necessary adheres to the transfer paper P. A reduction in image quality can be prevented.

The application member cleaning device 160 includes an application member cleaning blade 161 made of elastic rubber that contacts the application roller 141. The coating member cleaning device 160 is applied together with the foamy fixing solution F (hereinafter referred to as the residual foamed fixing solution Fb) remaining on the surface of the coating roller 141 after passing through the coating nip C and the residual foamed fixing solution Fb. The gap agent G adhering to the roller 141 is scraped by the application member cleaning blade 161 to clean the surface of the application roller 141.
The application member cleaning blade 161 is preferably not softened, swollen or dissolved by a softening agent, and examples of the material include EPDM (ethylene-propylene-diene rubber) and modified silicone rubber. The surface layer may be covered with a film such as PET (polyethylene terephthalate) or a coating. The application member cleaning device 160 is not limited to a configuration using a blade-like cleaning member such as the application member cleaning blade 161. A configuration using a roller-shaped cleaning member, or a configuration including a mechanism for transporting an object to be cleaned by forming a spiral groove in the roller member may be used.

Here, a conventional fixing device in which the application roller 141 applies the foamy fixing solution F to the transfer paper P at the application nip C and the application of the gap agent G into the application nip C will be described.
FIG. 16 is a schematic configuration diagram of an example of a conventional fixing device 30 that does not include the gap agent applying device 150.
The conventional fixing device 30 shown in FIG. 16 has the same configuration as the fixing device 30 of Embodiment 1 shown in FIG. 4 except that the gap agent applying device 150 is not provided.

In the conventional fixing device 30 shown in FIG. 16, as in the fixing device 30 of the first embodiment, the foam-like fixing solution F generated by the foam-like fixing solution generation unit 130 is not fixed by the application roller 141 of the fixing solution application unit 140. In this configuration, the toner image T is applied to the transfer paper P. The unfixed toner image T on the transfer paper P is coated with the foam-like fixing liquid F at the application nip C, and the toner particles are softened, so that the toner particles are combined and fixed on the transfer paper P.
In addition, since the configuration is such that the foam-like fixing solution F is applied, a sufficient volume of the foam-like fixing solution can be applied to the unfixed toner image T as in the fixing device 30 of the first embodiment, and the fixing is performed. It is possible to suppress a residual liquid feeling from being generated on the transfer paper P on which the toner image Tb is formed.

In the configuration in which the foamy fixing solution F is applied, in order to further reduce the residual liquid feeling on the transfer paper P after fixing, it is possible to soften the unfixed toner image T so that it can be satisfactorily fixed on the transfer paper P. It is required to reduce the coating amount of the foam-like fixing solution F within the range that can be achieved.
However, even if the adhesion amount of the foam-like fixing solution F on the surface of the application roller 141 is reduced so that the amount of application of the foam-like fixing solution F to the transfer paper P is reduced within the above range, the toner is transferred onto the application roller. May be offset.

FIG. 17 is an enlarged explanatory view of the coating nip C with the conventional fixing device 30 shown in FIG. 16 in a state where the adhesion amount of the foamy fixing solution F to the surface of the coating roller 141 is reduced.
As a result of investigations by the present inventors, if the amount of adhesion of the foam fixing solution F is reduced, all of the foam fixing solution F penetrates into the unfixed toner image T at the coating nip C, and as shown in FIG. It was revealed that the toner image T and the application roller 141 are in direct contact. As a result of the direct contact between the unfixed toner image T and the application roller 141, the adhesive force of the softened toner particles acts on the application roller 141, and the toner is offset to the application roller 141 at the exit of the application nip C.
In order to prevent such an offset, a part of the foam-like fixing liquid F is interposed between the coating roller 141 and the unfixed toner image T so that all of the foam-like fixing liquid F does not penetrate into the unfixed toner image T. It is necessary to leave.

  The above-mentioned Patent Document 2 is configured to apply the fixing solution with the application member, and includes a gap member disposed so as to be positioned between the application member and the toner layer, and the gap between the application member and the toner layer is provided. A fixing device configured to keep constant is disclosed. However, the fixing device described in Patent Document 2 is configured to apply a liquid fixing solution, and is different in configuration from the conventional example shown in FIG. 16 that applies a foamy fixing solution and the fixing device 30 of the first embodiment. In the fixing device described in Patent Document 2, the gap member and the coating member are integrated, or the gap member is formed in a roller shape, and the gap member is positioned between the coating member and the transfer paper at the coating nip. It is the structure arranged to do. With such a configuration, it is difficult to clean the application member and the gap member. If the application member and the gap member are difficult to clean, there is a problem that reliability during long-term use cannot be obtained.

On the other hand, the fixing device 30 of the first embodiment includes a gap agent applying device 150, and applies a gap agent G that provides a gap between the application roller 141 and the transfer paper P in the application nip C to the application nip C. It is the structure to do.
FIG. 8 is an enlarged explanatory view of the coating nip C in the fixing device 30 according to the first embodiment in a state where the amount of the foamy fixing solution F attached to the surface of the coating roller 141 is reduced.

  In the application nip C of the first embodiment shown in FIG. 8, the foamed fixing liquid F is applied to the unfixed toner image T by the application roller 141 as in the case shown in FIG. Between the toner images T, the gap agent G applied by the gap agent applying device 150 exists. The gap agent G keeps a slight gap between the application roller 141 and the unfixed toner image T, and the foam fixing is performed in the application nip C even when the supply amount of the foam fixing liquid F is small. Since a part of the liquid F remains in the gap, it is possible to prevent the application roller 141 and the unfixed toner image T from coming into direct contact. As a result, the foamy fixer F is separated into both the application roller 141 and the unfixed toner image T at the exit of the application nip C, thereby preventing toner offset.

  In the fixing device 30 according to the first embodiment, the gap agent applying device 150 is disposed at a position facing the surface of the application roller 141, and the gap agent G is applied to the surface of the application roller 141. At this time, the gap agent G on the surface of the application roller 141 acts as an adhesive force, an electrostatic force, a magnetic force, or an adhesive force due to a slight amount of moisture remaining on the application roller 141 between the application roller 141 and the gap agent. Is held by a weak force.

In the fixing device 30 that applies the foam-like fixing solution F with the application roller 141, the foam-like fixing solution F generated by the foam-like fixing solution generator 130 is carried on the surface of the application roller 141 and conveyed to the application nip C. . With such a configuration, when the gap agent G is applied to the surface of the coating roller 141 after the foam-like fixing solution F is supplied, the gap agent G is attached to the surface layer of the foam-like fixing solution F. There is a possibility that the uniformity of the film thickness of the liquid F is impaired and fixing unevenness occurs.
On the other hand, in the fixing device 30 according to the first embodiment, the gap agent applying device 150 is located on the upstream side in the surface movement direction of the application roller 141 with respect to the position where the foamy fixing solution F is supplied from the foamy fixing solution generator 130. Is arranged. Thus, when the foam-like fixing liquid F is supplied from the foam-like fixing liquid generation unit 130 to the surface of the application roller 141, the gap agent G is already held on the surface of the application roller 141. Is applied so as to cover the gap agent G from above. For this reason, the gap agent G does not move to the surface layer of the foam-like fixing solution F, and no trouble occurs even when the film thickness adjusting blade 142 controls the film thickness of the foam-like fixing solution F on the application roller 141. The film thickness of the foamy fixing solution F can be made uniform.

  The gap agent G applied by the gap agent applying device 150 is not particularly limited, and examples thereof include fine particles such as a spherical shape, a hollow shape, a bead shape, a rod shape, and a polyhedral shape. At this time, it is preferable that the gap agent G is not softened by the softener contained in the fixing solution. Examples of the material of the gap agent G include silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, zinc oxide, iron oxide, fluororesin, silicone rubber, PET (polyethylene terephthalate) resin, polyacetal resin, polyethylene, polypropylene, polycar Examples include boronate, polyphenyl ether, and polyether ether ketone.

  In the fixing device 30 that applies the foamy fixing solution F, the residual liquid feeling of the transfer paper P after fixing can be reduced as compared with the configuration in which the liquid fixing solution is applied. However, in order to further reduce the feeling of residual liquid, it is necessary to reduce as much as possible the adhesion amount of the foamy fixing liquid F on the surface of the coating roller 141 reaching the coating nip C. In the fixing device 30 according to the first embodiment, even when the gap agent applying device 150 applies the gap agent G into the application nip C, the adhesion amount of the foamy fixing solution F on the surface of the application roller 141 is reduced. A good fixed image can be obtained without causing toner offset.

[Embodiment 2]
Next, a second embodiment of the fixing device 30 (hereinafter referred to as a second embodiment) will be described. FIG. 9 is a schematic configuration diagram of the fixing device 30 according to the second embodiment.
In the fixing device 30 according to the first embodiment illustrated in FIG. 4, a gap agent applying device 150 is provided at a position facing the surface of the application roller 141, and the gap agent G applied on the surface of the application roller 141 is applied to the surface of the application roller 141. It is a structure given in the coating nip C by surface movement.
On the other hand, in the fixing device 30 of the second embodiment, as shown in FIG. 9, a gap agent applying device 150 is provided at a position facing the surface of the transfer paper P carrying the unfixed toner image T before reaching the coating nip C. It differs from the fixing device 30 of the first embodiment in that it is arranged. In the fixing device 30 according to the second embodiment, the gap agent G applied on the surface of the transfer paper P is applied to the coating nip C when the transfer paper P is conveyed, and the gap agent G is applied. Except for the configuration, the fixing device 30 is the same as that of the first embodiment.

  FIG. 10 is an enlarged explanatory view of the gap agent applying device 150 provided in the fixing device 30 of the second embodiment. In the fixing device 30 of the second embodiment, the gap agent G is applied on the unfixed toner image T on the transfer paper P before reaching the application nip C by the gap agent holding roller 154, not on the surface of the application roller 141. To do. With such a configuration, it is possible to completely eliminate the influence of the gap agent G on the thin-layered foam-like fixing solution F formed on the surface of the application roller 141.

The gap agent application device 150 of the second embodiment includes a gap agent holding roller 154, a gap agent application pressure roller 155, a storage unit 151, a delivery member 153, and the like. FIG. 11 is an enlarged explanatory view of the vicinity of the storage unit 151 of the gap agent applying apparatus 150 of the second embodiment.
As shown in FIG. 11, a provision amount control member 152 is disposed in the storage unit 151.
Similar to the configuration in which the gap agent G in the storage unit 151 of the first embodiment is applied to the surface of the application roller 141, in the second embodiment, the gap agent G in the storage unit 151 is transferred to the gap agent holding roller 154 by the delivery member 153. Is applied on the surface. The gap agent G applied on the surface of the gap agent holding roller 154 reaches the facing portion between the gap agent holding roller 154 and the application amount control member 152 due to the surface movement of the gap agent holding roller 154. The application amount control member 152 is a member that controls the application amount of the gap agent G to the gap agent holding roller 154 by regulating the amount of the gap agent G that passes through the portion facing the gap agent holding roller 154. Excess gap agent G is removed from the surface of the gap agent holding roller 154 by the amount control member 152.

  The gap agent G applied on the surface of the gap agent holding roller 154 comes into contact with the transfer paper P carrying the unfixed toner image T at the facing portion between the gap agent holding roller 154 and the gap agent application pressure roller 155. And applied to the transfer paper P. At this time, the unfixed toner image T is charged by the charge received during the process of forming the toner image. For this reason, the gap agent G is applied to the unfixed toner image T by the potential of the toner even when the contact between the opposed portions of the gap agent holding roller 154 and the gap agent application pressure roller 155 is weak. On the other hand, the gap agent G is hardly applied to a portion where there is no unfixed toner image T on the surface of the transfer paper P. Therefore, the gap agent G can be efficiently applied only to the image portion where the unfixed toner image T is formed.

Further, the gap agent G that has not been applied to the transfer paper P at the facing portion between the gap agent holding roller 154 and the gap agent applying pressure roller 155 faces the storage portion 151 as the surface of the gap agent holding roller 154 moves. Reach the department. For this reason, it is preferable that the storage unit 151 is provided with a rear opening for collecting the gap agent G on the surface of the gap agent holding roller 154 that has not been applied to the transfer paper P. Further, in order to prevent the recovered gap agent G from leaking out, it is preferable that the rear opening has such a size that one particle of the gap agent G can barely pass through. Furthermore, it is preferable that the position is on the downstream side in the surface movement direction of the gap agent holding roller 154 from the position that is the uppermost part of the surface of the gap agent holding roller 154 vertically above the rotation center of the gap agent holding roller 154.
The application amount control member 152 included in the gap agent application device 150 of the second embodiment has the same configuration as the application amount control member 152 of the first embodiment. Further, if the application amount of the gap agent G is not controlled by the application amount control member 152, more gap agent G than necessary may adhere to the transfer paper P, resulting in a decrease in image quality.

[Modification]
FIG. 12 is an enlarged explanatory view of the vicinity of the storage unit 151 of a modification of the gap agent application device 150 according to the second embodiment. As shown in FIG. 12, a fine recess 154a is formed on the surface of the gap agent holding roller 154 provided in the gap agent applying device 150 of the modification. Then, the gap agent applying device 150 of the modified example controls the application amount of the gap agent G by the surface shape of the gap agent holding roller 154 instead of the application amount control member 152. Other configurations are the same as those of the gap agent applying device 150 of the second embodiment.
Here, it is assumed that the outlet side opening of the storage unit 151 through which the gap agent G attached to the gap agent holding roller 154 passes in the storage unit 151. In the gap agent applying device 150 of the modified example, the gap between the casing of the storage portion 151 of the outlet side opening and the surface of the portion where the recess 154a of the gap agent holding roller 154 is not formed is smaller than the size of the gap agent G. It has become. For this reason, the gap agent G that has not entered the recess 154a cannot be passed through the outlet opening and is removed from the surface of the gap agent holding roller 154. On the other hand, the gap agent G contained in the recess 154a passes through the outlet opening and is conveyed toward the portion facing the gap agent-applying pressure roller 155. With such a configuration, the amount of gap agent G passing through the outlet opening is regulated, and the amount of gap agent G applied to the gap agent holding roller 154 can be controlled.
In the configuration of the modified example, the application amount of the gap agent G can be adjusted by the size and number of the depressions 154a on the surface of the gap agent holding roller 154. Moreover, the structure which controls the application amount of the gap agent G in combination with the application amount control member 152 may be used.

[Embodiment 3]
Next, a third embodiment of the fixing device 30 (hereinafter referred to as a third embodiment) will be described. FIG. 13 is a schematic configuration diagram of the fixing device 30 according to the third embodiment. FIG. 14 is an enlarged explanatory view of a gap agent applying device 150 provided in the fixing device 30 of the third embodiment. The fixing device 30 according to the third embodiment is common to the fixing device 30 according to the first and second embodiments except for the configuration in which the gap agent G is applied.
Further, like the fixing device 30 of the second embodiment, the fixing device 30 of the third embodiment has a gap agent at a position facing the surface of the transfer paper P carrying the unfixed toner image T before reaching the coating nip C. An imparting device 150 is arranged. For this reason, the gap agent G applied on the surface of the transfer paper P is applied to the coating nip C when the transfer paper P is conveyed.
The gap agent application device 150 of the third embodiment is different from the gap agent application device 150 of the second embodiment in that the application amount and application site of the gap agent G can be freely controlled.

  As shown in FIG. 14, the gap agent applying apparatus 150 according to the third embodiment includes a gap agent photosensitive drum 181 that carries a gap agent G on the surface. Further, around the gap agent photosensitive drum 181, a gap agent charging roller 182, a gap agent developing device 183, a gap agent transfer roller 184, a gap agent cleaning device 185, and a gap agent neutralizing lamp 186 are arranged. Has been.

  The gap agent charging roller 182 is a contact charging type charging device, and the gap agent charging roller 182 is brought into contact with the gap agent photosensitive drum 181 to apply a voltage to the gap agent photosensitive drum 181. The surface of the gap agent photosensitive drum 181 is uniformly charged. Instead of the gap agent charging roller 182, a non-contact charging type charging device employing a non-contact scorotron or the like may be used.

The gap agent developing device 183 is a developing device that performs development using the gap agent G instead of the toner in the two-component developer of the two-component developing type developing device. On the surface of the gap agent photosensitive drum 181 uniformly charged by the gap agent charging roller 182, an electrostatic latent image for the gap agent is written by the exposure light Lg irradiated from a gap agent exposure device (not shown). . Then, the gap agent developing device 183 develops the electrostatic latent image written on the surface of the gap agent photosensitive drum 181 by attaching the gap agent G in the developer to form a gap agent image.
The gap agent developing device 183 includes a stirring unit (not shown) 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 concentration of the gap agent G in the developer in the stirring unit is detected by a concentration sensor, and is controlled so that the concentration of the gap agent G is constant.

The gap agent transfer roller 184 is provided at a position facing the gap agent photosensitive drum 181 across the transfer paper P, and forms a gap agent transfer nip. At this time, the gap agent image formed on the gap agent photosensitive drum 181 is transferred onto the transfer sheet P by pressing the transfer sheet P against the gap agent photosensitive drum 181 using the gap agent transfer roller 184. Is transcribed. Instead of the gap agent transfer roller 184, a conductive brush, a non-contact corona charger, or the like may be used.
The gap agent cleaning device 185 removes the gap material remaining on the gap agent photosensitive drum 181 that has passed through the gap agent transfer nip. The gap agent cleaning device 185 has a blade pressed against the gap agent photosensitive drum 181. Here, the gap agent G removed by the gap agent cleaning device 185 is transported to the gap agent developing device 183 and reused by a recovery screw (not shown) and a gap agent recycling device (not shown).
The gap agent neutralizing lamp 186 irradiates light to initialize the surface potential of the gap agent photosensitive drum 181.

  In the gap agent applying apparatus 150 according to the third embodiment, the unfixed toner image T is based on the image information based on the image information when the toner image is formed or the image information of the unfixed toner image T newly read by the scanner. Forming an electrostatic latent image. At this time, an electrostatic latent image for the gap agent is formed only at a portion where the unfixed toner image T on the transfer paper P passing through the gap agent transfer nip exists, so that the required gap agent amount is obtained. Then, the gap agent exposure device irradiates the gap agent photosensitive drum 181. This makes it possible to reliably apply the necessary amount of the gap agent G only to the portion where the unfixed toner image T exists on the transfer paper P.

The fixing device 30 according to the first to third embodiments has a configuration in which a roller-shaped pressure roller 143 is used as a pressure member that forms a coating nip C in contact with the coating roller 141 that is a coating member. As the pressure member, an endless belt-like pressure belt may be used instead of the pressure roller 143. Thereby, the nip width can be easily increased. The pressure belt is not particularly limited, and examples thereof include a belt in which a base material such as a seamless nickel belt or seamless PET is coated with a releasable fluororesin such as PFA.
Further, as the application member, an endless belt-like application belt may be used instead of the application roller 141. Further, the application belt may be used as the application member, and the pressure belt may be used as the pressure member. Good.

FIG. 15 is an explanatory diagram of a printer 100 that is an image forming apparatus in which the fixing device 30 to which the present invention is applied can be arranged.
In the printer 100 of FIG. 15, the same components as those of the printer 100 described with reference to FIG. 2 and FIG. The printer 100 shown in FIG. 15 includes a transfer conveyance belt 250 that is stretched by a first support roller 251 and a second support roller 252 and moves on the surface in the direction of arrow B in FIG. In the printer 100 shown in FIG. 15, the toner images of the respective colors formed on the four drum-shaped photosensitive members 4 (Y, M, C, K) are transferred onto the transfer paper P carried on the transfer conveyance belt 250. This is a structure for direct transfer.
Specifically, after the transfer paper P is fed using the registration roller pair 15, the transfer conveyance belt 250 is moved to the photosensitive member 4 using the respective transfer rollers 260 (Y, M, C, K). The toner images of the respective colors are sequentially transferred onto the transfer paper P by being pressed. As a result, the four color toner images are superimposed on the transfer paper P, and combined with the white color of the transfer paper P, the full-color image becomes an unfixed toner image T. The transfer paper P on which the unfixed toner image T is formed is transported to the fixing device 30 by the surface movement of the transfer transport belt 250, and the unfixed toner image T is fixed by the fixing device 30.

  Next, the composition of the fixing solution will be described. The fixing solution used in the fixing device 30 of the present invention contains at least a softening agent and a foaming agent.

First, the softener contained in the fixing solution will be described.
The softening agent is not particularly limited as long as it dissolves or swells at least part of the resin contained in the toner that is resin-containing fine particles, and examples thereof include aliphatic esters and carbonates.

The aliphatic ester desirably contains a monoester represented by the general formula “R1COOR2”. R1 in the general formula of this monoester represents an alkyl group having 11 to 14 carbon atoms, and R2 represents a linear or branched alkyl group having 1 to 6 carbon atoms.
By using an aliphatic ester containing such a monoester as a softening agent, the resin particles can be dissolved or swollen in a short time.

When the resin-containing fine particles are toner, for example, in high-speed printing of about 60 ppm, the time required for the fixing liquid to be applied to unfixed toner on the recording medium and for the toner to be fixed on the recording medium is 1 [second]. ] Is preferable. Here, by using an aliphatic ester containing a monoester as a softening agent, a time from when a fixing solution is applied to an unfixed toner image formed on a recording medium until the toner image is fixed is set to 1 [ Seconds]. Further, the monoester can reduce the stickiness of the toner image. This is presumably because the monoester forms an oil film on the surface of the dissolved or swollen toner image. At this time, if the carbon number of R1 in the chemical formula is less than 11, the odor index may exceed 10. On the other hand, when R1 has more than 14 carbon atoms and R2 has more than 6 carbon atoms, the ability to dissolve or swell resin particles may be reduced.
Examples of such monoesters include, but are not limited to, ethyl laurate, hexyl laurate, ethyl tridecylate, isopropyl tridecylate, ethyl myristate, isopropyl myristate, and the like, and two or more of them may be used in combination.

The ester of the saturated aliphatic carboxylic acid and the saturated aliphatic alcohol preferably contains a diester represented by the general formula “R3 (COOR4) ₂ ”. R3 in the general formula of this diester represents an alkylene group having 3 to 8 carbon atoms, and R4 represents a linear or branched alkyl group having 3 to 5 carbon atoms. By using such a softener containing a diester, the resin particles can be dissolved or swollen in a short time.

Specifically, by using a softening agent containing the diester represented by the above general formula, the time from when the fixing solution is applied to the unfixed toner image formed on the recording medium until the toner image is fixed can be reduced. It can be within 0.1 [second]. As a result, good fixing can be performed even when high-speed printing of about 60 ppm, which is required to be within 1 [second], is performed.
Further, by using a softener containing a diester, the content of the softener in the fixing solution can be reduced. At this time, when the number of carbon atoms of R3 in the above chemical formula is less than 3 and when the number of carbon atoms of R4 is less than 3, the odor index may exceed 10. On the other hand, when R3 has more than 8 carbon atoms and R4 has more than 5 carbon atoms, the ability to dissolve or swell resin particles may be reduced.
Examples of such diesters include, but are not limited to, 2-ethylhexyl succinate, dibutyl adipate, diisobutyl adipate, diisopropyl adipate, diisodecyl adipate, diethyl sebacate, dibutyl sebacate, etc. May be.

Furthermore, as an ester of a saturated aliphatic carboxylic acid and a saturated aliphatic alcohol, it is desirable to contain a diester represented by the general formula “R5 (COOR6OR7) ₂ ”. R5 in the general formula of this diester represents an alkylene group having 2 to 8 carbon atoms, R6 represents an alkylene group having 2 to 4 carbon atoms, and R7 has 1 to 4 carbon atoms. An alkyl group is shown. By using such a softening agent containing a diester, the resin particles can be dissolved or swollen in a shorter time.

Specifically, by using a softening agent containing the diester represented by the above general formula, the time from when the fixing solution is applied to the unfixed toner image formed on the recording medium until the toner image is fixed can be reduced. It can be within 0.1 [second]. As a result, good fixing can be performed even when high-speed printing of about 60 ppm, which is required to be within 1 [second], is performed.
Further, by using a softener containing a diester, the content of the softener in the fixing solution can be reduced. At this time, when the carbon number of R5 in the above chemical formula is 1 and when the carbon number of R6 is 1, the odor index may exceed 10. On the other hand, when R5 has more than 8 carbon atoms, R6 has more than 4 carbon atoms, and R7 has more than 4 carbon atoms, the ability to dissolve or swell resin particles may decrease.
Examples of such diesters include, but are not limited to, diethoxyethyl succinate, dibutoxyethyl succinate, dimethoxyethyl adipate, diethoxyethyl adipate, dibutoxyethyl adipate, diethoxyethyl sebacate, and the like. Two or more kinds may be used in combination.

Moreover, as ester of saturated aliphatic carboxylic acid and saturated aliphatic alcohol, it is desirable to contain the diester represented by the general formula of "R8 (COOR9OR10OR11) ₂ ". R8 in the general formula of this diester represents an alkylene group having 2 to 8 carbon atoms, R9 and R10 each independently represents an alkylene group having 2 or 3 carbon atoms, and R11 represents a carbon atom. The number represents an alkyl group having 1 to 4. By using such a softening agent containing a diester, the resin particles can be dissolved or swollen in a shorter time.

Specifically, by using a softening agent containing the diester represented by the above general formula, the time from when the fixing solution is applied to the unfixed toner image formed on the recording medium until the toner image is fixed can be reduced. It can be within 0.1 [second]. As a result, good fixing can be performed even when high-speed printing of about 60 ppm, which is required to be within 1 [second], is performed.
Further, by using a softener containing a diester, the content of the softener in the fixing solution can be reduced. At this time, when the carbon number of R8 in the above chemical formula is 1, the carbon number of R9 is 1, and the carbon number of R10 is 1, the odor index may exceed 10. On the other hand, when the carbon number of R8 exceeds 8, when the carbon number of R9 exceeds 3, when the carbon number of R10 exceeds 3, and when the carbon number of R11 exceeds 4, the resin particles are dissolved or swollen. Capability may be reduced.
Examples of such diesters include, but are not limited to, diethoxyethoxyethyl succinate, dimethoxyethoxyethyl succinate, dimethoxyethoxyethyl adipate, diethoxyethoxyethyl sebacate and the like, and two or more of them may be used in combination. .

Furthermore, as an ester of a saturated aliphatic carboxylic acid and a saturated aliphatic alcohol, it is desirable to contain a diester represented by the general formula “R12 (OCOR13) ₂ ”. R12 in the general formula of this diester represents an alkylene group having 2 to 8 carbon atoms, and R13 represents a linear or branched alkyl group having 2 to 5 carbon atoms. By using such a softening agent containing a diester, the resin particles can be dissolved or swollen in a shorter time.

Specifically, by using a softening agent containing the diester represented by the above general formula, the time from when the fixing solution is applied to the unfixed toner image formed on the recording medium until the toner image is fixed can be reduced. It can be within 0.1 [second]. As a result, good fixing can be performed even when high-speed printing of about 60 ppm, which is required to be within 1 [second], is performed.
Further, by using a softener containing a diester, the content of the softener in the fixing solution can be reduced. At this time, when the carbon number of R12 in the above chemical formula is 1 and when the carbon number of R13 is 1, the odor index may exceed 10. On the other hand, when the carbon number of R12 exceeds 8, and when the carbon number of R13 exceeds 5, the ability to dissolve or swell the resin particles may decrease.
Examples of such diesters include, but are not limited to, ethylene glycol diacetate, ethylene glycol dipropionate, propylene glycol diacetate, propylene glycol dibutyrate, butylene glycol dibutyrate and the like, and two or more of them may be used in combination. .

The ester of the saturated aliphatic carboxylic acid and the saturated aliphatic alcohol preferably contains a diester represented by the general formula “R14 (OR15OCOR16) ₂ ”. R14 in the general formula of this diester represents an alkylene group having 2 to 4 carbon atoms, R15 represents a linear or branched alkylene group having 2 or 3 carbon atoms, and R16 represents An alkyl group having 1 to 4 carbon atoms is shown. By using such a softening agent containing a diester, the resin particles can be dissolved or swollen in a shorter time.

Specifically, by using a softening agent containing the diester represented by the above general formula, the time from when the fixing solution is applied to the unfixed toner image formed on the recording medium until the toner image is fixed can be reduced. It can be within 0.1 [second]. As a result, good fixing can be performed even when high-speed printing of about 60 ppm, which is required to be within 1 [second], is performed.
Further, by using a softener containing a diester, the content of the softener in the fixing solution can be reduced. At this time, when the carbon number of R14 in the above chemical formula is 1 and when the carbon number of R15 is 1, the odor index may exceed 10. On the other hand, when the carbon number of R14 exceeds 4, when the carbon number of R15 exceeds 3, and when the carbon number of R16 exceeds 4, the ability to dissolve or swell resin particles may decrease.
Such a diester is not particularly limited, and examples thereof include triethylene glycol diacetate, triethylene glycol dipropionate, and tripropylene glycol diacetate, and two or more of them may be used in combination.

  Among the above carbonate esters, the carbonate ester of a divalent saturated aliphatic alcohol preferably contains a compound represented by the general formula (1).

  R17 in the general formula of this compound represents an alkylene group. By using a carbonic ester containing such a compound as a softening agent, the resin particles can be dissolved or swollen in a short time.

Specifically, by using a carbonic acid ester containing a compound represented by the above general formula as a softening agent, a fixing solution is applied to an unfixed toner image formed on a recording medium until the toner image is fixed. Can be set within 1 [second]. As a result, good fixing can be performed even when high-speed printing of about 60 ppm, which is required to be within 1 [second], is performed.
Further, such carbonate ester can reduce the stickiness of the toner image. This is considered to be because the carbonic ester forms an oil film on the surface of the dissolved or swollen toner image.
Such a carbonate ester is not particularly limited, and examples thereof include ethylene carbonate, propylene carbonate, butylene carbonate, and two or more of them may be used in combination.

Next, the foaming agent contained in the fixing solution will be described.
The foaming agent contained in the fixing solution used in the fixing device 30 is a surfactant and is not particularly limited, and examples thereof include an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant.

Although it does not specifically limit as an anionic surfactant, A C12-C18 fatty acid salt is mentioned. When the carbon number is less than 12, the foam stability may be lowered, and when the carbon number is larger than 18, the foamability may be lowered.
Although it does not specifically limit as nonionic surfactant, Alkyl glycoside which has C12-C18 alkyl groups, such as decyl glucoside and lauryl glucoside, polyoxyethylene lauryl ether sodium acetate, polyoxyethylene myristyl ether acetic acid Examples thereof include sodium and sodium polyoxyethylene palmityl ether acetate, and two or more kinds may be used in combination. When the number of carbon atoms is less than 12 or more than 18, the foamability may be lowered.
The amphoteric surfactant is not particularly limited, but fatty acid amidopropyldimethylaminoacetic acid betaine derived from fatty acids having 12 to 18 carbon atoms such as myristate amidopropyldimethylaminoacetic acid betaine; Alkyldimethylaminoacetic acid betaines having 12-18 alkyl groups; N-acyl sarcosine having 12 to 18 carbon atoms such as lauroyl sarcosine sodium, myrtoyl sarcosine sodium, palmitoyl sarcosine sodium and the like; and myristoyl glutamate N-acyl glutamic acid having a C 12-18 acyl group, such as palm fatty acid sodium glutamate, coconut oil fatty acid acyl glutamic acid triethanolamine, etc. It is, may be used in combination of two or more. When the number of carbon atoms is less than 12 or more than 18, the foamability may be lowered.

The fixing solution contains a softening agent, and this softening agent generally has a strong antifoaming action. For this reason, when the liquid fixing solution is used as the foamy fixing solution as in the fixing device of the present embodiment, the higher the concentration of the softening agent in the fixing solution, the worse the foaming property and foam stability of the fixing solution. Therefore, there is a possibility that foaming is difficult to occur or the foam-like fixing solution is easily broken. If it is difficult to foam, it is impossible to obtain a foam fixing solution having a low bulk density. Even if a foam fixing solution having a desired bulk density is obtained, if the foam fixing solution easily breaks, it is This causes the same problem as the configuration in which the liquid fixer is applied.
In addition, as a foaming agent, an anionic surfactant can achieve excellent foaming properties and foam stability, and is excellent as a foaming agent. Among anionic surfactants, fatty acid salts are most excellent in foam stability and are most suitable as a foaming agent for fixing solutions.
Here, foam stability refers to the property that the fixing solution in the form of foam is difficult to become liquid. As the foam-type fixing solution to be applied to the unfixed toner by the fixing device of the present embodiment, it is desirable that the foam does not disappear even if left in a foam state for 1 minute, and has foam stability enough to maintain the foam state. .

In order to solve the problem of deterioration of foamability and foam stability when the softener concentration in the fixing solution is increased, the present inventors have made various prototypes based on the type and concentration of the anionic surfactant. It was. Further, a prototype was made by paying attention to a technique called “super fat” described in Non-Patent Document 1, that is, a free fatty acid contained in a solid detergent (soap).
Here, to outline the technology called super fat, it is a method of adding a small amount of free fatty acids that are difficult to oxidize and increasing the excess fat and oil, leaving a small amount of fat and oil that is not saponified, for example, increasing the moisturizing action, etc. It is said to be effective. In Non-Patent Document 1, it is known that when a very small amount of fatty acid is added to a soap water-based system, the foaming performance is improved and the foam quality becomes more creamy, which is called super fat soap. It is described. Similar to this super fat, an attempt was made to foam by adding a very small amount of fatty acid to a fixing solution having a softening agent, but both foamability and foam stability were poor.

On the other hand, the present inventors use a fatty acid salt having 12 to 18 carbon atoms as a foaming agent, and further contain a fatty acid having 12 to 18 carbon atoms in the fixing solution, thereby increasing the concentration of the softening agent. The present inventors have found that it is possible to provide a foamy fixing solution that does not deteriorate the foamability of the fixing solution.
In the fixing solution containing the softening agent, the number of carbon atoms of the fatty acid salt is excellent in foaming property as compared with the case where water is simply foamed. Specifically, laurate (12 carbon atoms), myristate (14 carbon atoms), palmitate (16 carbon atoms), and stearate (18 carbon atoms) are suitable. Further, pentadecylic acid (carbon number 15), margaric acid (carbon number 17), and the like are also suitable.

  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.

  Even in the range of 12 to 18 carbon atoms, the smaller the number of carbons, the better the foaming property, but the foam stability is poor, and the larger the number of carbons, the less foaming properties, but the foam stability is extremely excellent. ing. For this reason, a single fatty acid salt may be contained in the fixing solution, but it is more excellent to mix and contain a fatty acid salt having 12 to 18 carbon atoms. As a mixing ratio, it is desirable to contain the most myristic acid salt (14 carbon atoms) and to lower the ratio of lauric acid salt (12 carbon atoms) and stearic acid salt. More specific fatty acid salt ratios are 0: 6: 3: 1, 1: 5: 3: 1, 1: 4 by weight ratio of laurate: myristate: palmitate: stearate. : 4: 1 is suitable.

  By the way, by containing the fatty acid having the same carbon number as the fatty acid salt as the foaming agent in the fixing solution, the foaming property and foam stability can be maintained even when the concentration of the softening agent is increased. If the concentration of the softening agent is less than 10 [wt%], there is no problem in foaming properties even if no fatty acid is contained. However, when the concentration of the softening agent is 10 [wt%] or more, particularly when the concentration of the softening agent is 30 [wt%] or more, only the fatty acid salt is hardly foamed and the foamability is deteriorated. In the fixing solution in which the concentration of the softening agent is 30 [wt%], when the fatty acid having the same carbon number as the fatty acid salt is contained, the foaming property can be maintained.

  However, if the fatty acid content is too high, the ratio of the fatty acid salt, which is a foaming agent, decreases, and the foamability deteriorates again. Therefore, it is better to make the number of moles of fatty acid salt the same as or larger than the number of moles of fatty acid. Or when the ratio of a fatty acid and a fatty acid salt is in the range of 5: 5 to 1: 9, the foamability is excellent.

  In addition to the combination of fatty acid and fatty acid salt having the same carbon number, for example, the fatty acid salt is amine myristate, the fatty acid is stearic acid, the fatty acid salt is potassium palmitate, and the fatty acid is stearic acid. Different combinations in the range of 12 to 18 may be used. In short, by containing a fatty acid having 12 to 18 carbon atoms in the fixing solution, even if a high-concentration softening agent is contained, the foamability is not deteriorated, the foam stability is excellent, and the bulk density is extremely high. Allows low foaming.

  In addition, even if the fixing solution contains a fatty acid having 12 to 18 carbon atoms using other anionic surfactants such as alkyl ether sulfate (AES) as a foaming agent, the foaming property due to an increase in the concentration of the softener It turns out that it is effective in preventing it from getting worse. However, the best combination is a combination with a fatty acid salt.

  Furthermore, fatty acid sodium, fatty acid potassium, and fatty acid amine are suitable as the fatty acid salt. Furthermore, the most suitable fatty acid amine is specifically prepared by heating water, adding a fatty acid, and then adding triethanolamine, followed by heating and stirring for a certain period of time for a saponification reaction. be able to. At this time, by increasing the molar ratio of fatty acid to triethanolamine in the range of 1: 0.5 to 1: 0.9 and the fatty acid ratio, unreacted fatty acid remains after saponification, and the fixing solution Fatty acid and fatty acid amine can be mixed therein. The same is possible with sodium and potassium salts.

  By the way, when the concentration of the softening agent in the fixing solution increases, the softening agent becomes difficult to dissolve in water as a dilution solvent. Therefore, as a result of investigation, by adding polyhydric alcohols, specifically ethylene glycol, diethylene glycol, propylene glycol, 1,3 butylene glycol, glycerin, etc., in the fixing solution, the softener can be dissolved even at a high concentration. And it was found that the foaming property by the fatty acid salt was not deteriorated, but rather the foaming property was improved. The content of the polyhydric alcohol is suitably in the range of 1 [wt%] to 30 [wt%]. If the content is more than 30 [wt%], the foamability is rather deteriorated, which is not suitable.

[Experimental example]
Next, an experimental example in which the fixing property of the fixing device 30 to which the present invention is applied has been confirmed will be described.
Hereinafter, a method for adjusting the fixing solution used in this experimental example will be described.
Fatty acid in which the mass ratio of myristic acid (manufactured by Kanto Chemical Co., Inc.), palmitic acid (manufactured by Kanto Chemical Co., Ltd.), stearic acid (manufactured by Kanto Chemical Co., Ltd.) was 4: 3: 1, and diethanolamine (a neutralizing agent) Kanto Chemical Co., Ltd.) was measured so that the molar ratio was 1: 0.7. This was stirred for 30 minutes in ion exchange water at a liquid temperature of 80 [° C.] and allowed to cool to room temperature to prepare a fatty acid diethanolamine salt, which was used as a foaming agent.
As the softening agent, dicarbitol succinate (High Aquastar DCS, manufactured by Higher Alcohol Industry Co., Ltd.) was used.

  And 30 wt% of the dicarbitol succinate as a softening agent, 4 wt% of the fatty acid diethanolamine salt as a foaming agent, and coconut oil fatty acid diethanolamide (1: 1) type (Matsumoto A fixing solution was prepared by stirring 0.5 [wt%] of Marpone MM manufactured by Yushi Seiyaku Co., Ltd. and 65.5 [wt%] of ion-exchanged water as a diluent with an ultrasonic homogenizer for 10 minutes.

Next, the image forming apparatus used in this experimental example will be described.
An unfixed toner color image was formed on PPC paper (Ricoh T-6200, A4 paper) as transfer paper P using an electrophotographic printer (IpsioColor CX8800 manufactured by Ricoh). Next, an unfixed toner image was fixed by using the fixing device 30 having different conditions for applying the gap agent G in each of the examples and the comparative examples.

Each fixing device 30 includes a foam-like fixer generating unit 130 as shown in FIG. 5, and the fixer obtained by the above adjustment method is stored as a liquid fixer 132 in the fixer container 131, and foam-fixed. Liquid F is produced.
The foamed fixing solution generator 130 used in this experimental example includes a fixing solution container 131 that is a bottle made of PET (polyethylene terephthalate) resin, and a tube pump (tube inner diameter 2 [mm], Tube material: silicone rubber). Moreover, the liquid conveyance flow path (liquid conveyance pipe 134 grade | etc.,) Which connects each member is a silicone rubber tube with an internal diameter of 2 [mm]. The microporous sheet 137 for generating the foam-like fixing liquid F in a state larger than the desired bubble diameter disposed in the coarse bubble generating unit 135 is a stainless mesh sheet (opening of about 40 [μm]). It has become.

In addition, the bubble refining unit 138 of the foam fixing solution generation unit 130 generates the foam fixing solution F having a desired bubble diameter from the foam fixing solution F having a large bubble diameter generated by the coarse bubble generation unit 135. In the bubble refining unit 138, an inner cylinder 138b fixed to a fixed shaft is rotated by a rotation drive motor (not shown). The material of the outer cylinder 138a and the inner cylinder 138b constituting the double cylinder structure was PET resin. The inner diameter of the outer cylinder 138a was 10 [mm], the inner length of the outer cylinder 138a was 120 [mm], the outer diameter of the inner cylinder 138b was 8 [mm], and the length of the inner cylinder 138b was 100 [mm]. With such a configuration, the rotational speed of the rotation drive motor (not shown) of the inner cylinder 138b is set so that the bulk density of the foam-like fixing liquid F obtained from the foam supply nozzle 139 is 0.04 [g / cm ³ ]. did.

Each fixing device 30 supplies the foamy fixing solution F obtained by the foamed fixing solution generator 130 onto the surface of the application roller 141 of the fixing solution application unit 140.
As the application roller 141, a SUS (stainless steel) roller having a diameter of 50 [mm], which is baked and coated with PFA (ethylene tetrafluoride / fluoroalkyl vinyl ether copolymer) resin, was used. As the pressure roller 143, a SUS roller (core metal) having a diameter of 22 [mm] and a silicon sponge formed so that the outer diameter is 40 [mm] was used.
The pressing force of the pressure roller 143 against the coating roller 141 was set so that the nip width of the coating nip C was 7 [mm] and the surface pressure at the coating nip C was 0.27 [kgf / cm ² ].

  As the film thickness adjusting blade 142, a flat glass with a thickness of 1 [mm] is bonded to an aluminum alloy support plate, the glass surface is directed to the coating roller 141 side, and the foam-like fixing solution F on the coating roller 141 is used. The gap with the coating roller 141 was set so that the thickness of the coating roller was about 50 [μm]. As a result, the application amount of the fixing liquid per A4 sheet is about 100 [mg]. Further, the transfer speed of the transfer paper P was set to 300 [mm / s]. At this time, image formation was performed so that the thickness of the unfixed toner image T on the transfer paper P was 30 to 40 [μm].

[Example 1]
In Example 1, fixing was performed using the fixing device 30 of Embodiment 1 including the fixing liquid application unit 140 illustrated in FIG. 1 as the fixing device.
As a casing forming the storage portion 151 of the gap agent applying device 150 shown in FIGS. 1 and 7, a PET plate having a thickness of 1 [mm] was used, and a nylon brush was used for the application amount control member 152. As the delivery member 153, a SUS roller having a diameter of 5 mm coated with PFA resin was used.
Silicone rubber (Nissho Sangyo, Tospearl 2000B) was used as the gap agent G, and was set to give 0.7 [mg / cm ² ] to the image area.

[Example 2]
In Example 2, fixing was performed using the fixing device 30 of Embodiment 1 including the fixing liquid application unit 140 illustrated in FIG. 1 as the fixing device. As a casing forming the storage portion 151 of the gap agent applying device 150 shown in FIGS. 1 and 7, a PET plate having a thickness of 1 [mm] was used, and a nylon brush was used for the application amount control member 152. As the delivery member 153, a SUS roller having a diameter of 5 mm coated with PFA resin was used.
As the gap agent G, silicon oxide (Tokai Chemical Industries, Microid ML-361) was used, and the gap amount was set to 0.2 [mg / cm ² ] with respect to the image portion.

Example 3
In Example 3, fixing was performed using the fixing device 30 of Embodiment 1 including the fixing solution application unit 140 illustrated in FIG. 1 as the fixing device.
In Example 3, unlike the application roller 141, an aluminum roller not subjected to surface treatment with PFA resin was used as the application roller 141. As a casing forming the storage portion 151 of the gap agent applying device 150 shown in FIGS. 1 and 7, a PET plate having a thickness of 1 [mm] was used, and a nylon brush was used for the application amount control member 152. As the delivery member 153, a SUS roller having a diameter of 5 mm coated with PFA resin was used.
Silicone rubber (Nissho Sangyo, Tospearl 2000B) was used as the gap agent G, and was set to give 0.7 [mg / cm ² ] to the image area.

Example 4
In Example 4, fixing was performed using the fixing device 30 (FIG. 9) of the second embodiment provided with the gap agent applying device 150 shown in FIG. 10 as the fixing device.
A PET plate having a thickness of 1 [mm] was used as a casing for forming the storage portion 151 of the gap agent applying device 150 shown in FIGS. Further, as the gap agent holding roller 154, a SUS roller (core metal) having a diameter of 20 [mm] and having a silicone rubber layer formed so that the outer diameter is 25 [mm] was used. As the gap agent-applying pressure roller 155, a SUS roller (core metal) having a diameter of 10 mm and having a silicon sponge layer formed so that the outer diameter is 20 mm was used. The nip width of the gap agent application nip formed by the gap agent application pressure roller 155 and the gap agent application pressure roller 155 is 2 [mm], and the surface pressure of the gap agent application nip is 0.1 [kgf / cm]. ² ].
A nylon brush was used for the application amount control member 152. As the delivery member 153, a SUS roller having a diameter of 5 mm coated with PFA resin was used.
Silicone rubber (Nissho Sangyo, Tospearl 2000B) was used as the gap agent G, and was set to give 0.7 [mg / cm ² ] to the image area.

Example 5
In Example 5, fixing was performed using the fixing device 30 (FIG. 9) of Embodiment 2 including the gap agent applying device 150 shown in FIG. 10 as the fixing device.
A PET plate having a thickness of 1 [mm] was used as a casing for forming the storage portion 151 of the gap agent applying device 150 shown in FIGS. Further, as the gap agent holding roller 154, a SUS roller (core metal) having a diameter of 20 [mm] and having a silicone rubber layer formed so that the outer diameter is 25 [mm] was used. As the gap agent-applying pressure roller 155, a SUS roller (core metal) having a diameter of 10 mm and having a silicon sponge layer formed so that the outer diameter is 20 mm was used. And it pressed so that the nip width of a gap agent provision nip might be set to 2 [mm], and the surface pressure of a gap agent provision nip might be set to 0.1 [kgf / cm < ² >].
A nylon brush was used for the application amount control member 152. As the delivery member 153, a SUS roller having a diameter of 5 mm coated with PFA resin was used.
As the gap agent G, silicon oxide (Tokai Chemical Industries, Microid ML-361) was used, and the gap amount was set to 0.2 [mg / cm ² ] with respect to the image portion.

Example 6
In Example 6, fixing was performed using the fixing device 30 (FIG. 13) of Embodiment 3 including the gap agent applying device 150 shown in FIG. 14 as the fixing device. That is, the gap agent G was applied only to a portion where the unfixed toner image T is present on the transfer paper P using the gap agent applying device 150 that forms a gap agent image and transfers it onto the transfer paper P.
Silicone rubber (Nissho Sangyo, Tospearl 2000B) was used as the gap agent G, and was set to give 0.3 [mg / cm ² ] to the image area.

Example 7
In Example 7, fixing was performed using the fixing device 30 (FIG. 13) of the third embodiment provided with the gap agent applying device 150 shown in FIG. 14 as the fixing device. That is, the gap agent G was applied only to a portion where the unfixed toner image T is present on the transfer paper P using the gap agent applying device 150 that forms a gap agent image and transfers it onto the transfer paper P.
As the gap agent G, silicon oxide (Tokai Chemical Industries, Microid ML-361) was used, and the gap amount was set to 0.1 [mg / cm ² ] with respect to the image area.

[Comparative Example]
In the comparative example, fixing was performed using a conventional fixing device 30 that does not include the gap agent applying device 150 shown in FIG. That is, fixing was performed without applying the gap agent G.

In this experimental example, the degree of toner offset was evaluated based on the following criteria for the image quality of the output image.
A: A good image was obtained without toner offset.
X: Toner offset occurs and the image is greatly disturbed.
The experimental results of this experimental example are shown in Table 1.

  From the experimental results shown in Table 1, it is possible to apply the gap agent G to the coating nip C in the fixing device 30 that applies the foam-like fixing liquid F to the transfer paper P carrying the unfixed toner image T. The knowledge that an image can be obtained was obtained. As described above, with the fixing device 30 having the configuration of the present invention, it is possible to prevent toner offset caused by the application member coming into contact with the toner particles.

In the fixing device 30 according to the first to third embodiments described above, the fixing liquid application target to which the application roller 141 as the application member applies the foamy fixing liquid F is the surface of the transfer paper P as a recording medium carrying a toner image. . As the fixing device 30 for fixing the toner image on the transfer paper P using the foam-like fixing liquid F, the toner image is applied by applying the foam-like fixing liquid F to a toner image carrier such as an intermediate transfer belt carrying the toner image. Even if the toner image on the carrier is transferred onto the transfer paper P together with the foam-like fixing liquid F, the present invention can be applied.
In addition, the configuration that is a color printer has been described as the image forming apparatus of the present embodiment to which the fixing device 30 of the first to third embodiments can be applied. The image forming apparatus provided with the fixing device 30 of the present invention is not limited to a printer. For example, a laser printer, a direct digital plate making machine, a full-color copying machine using a direct or indirect electrophotographic multicolor image developing system, a full-color copying machine. Widely applicable to laser printers and full-color plain paper fax machines.

  In the fixing device 30 of Embodiments 1 to 3 described above, the configuration in which the foamy fixing solution F is applied to the unfixed toner image T at the application nip C and the gap agent G is applied to the application nip C has been described. The configuration in which the gap agent is applied to the coating nip for applying the fixer is not limited to the configuration in which the foamy fixer is applied, but the configuration in which the liquid fixer is applied to the unfixed toner image by the coating member. Is applicable.

  As described above, the fixing device 30 according to the present exemplary embodiment includes the application roller 141 that is an application member, the foamy fixing liquid generation unit 130 that is a fixing liquid supply unit, and the pressure roller 143 that is a pressure member. The application roller 141 carries the fixing liquid on the surface and moves, and the fixing liquid on the surface is applied at the application nip C which is a position facing the transfer paper P which is a fixing liquid application target carrying the toner as resin fine particles. A member to be applied to the transfer paper P. Here, the fixing liquid applied to the transfer paper P by the application roller 141 contains a softening agent that softens the toner, which is resin fine particles, by dissolving or swelling at least part of the resin contained in the toner. . In addition, the foamy fixing solution generator 130 supplies the fixing solution to the surface of the application roller 141. The pressure roller 143 is in contact with the application roller 141 across the transfer paper P at the position where the application roller 141 applies the fixing liquid to the transfer paper P, and forms an application nip C with the application roller 141. . Then, the fixing device 30 fixes the toner softened by applying the fixing liquid onto the transfer paper P. In the fixing device 30 configured as described above, the fixing device 30 according to the first to third embodiments applies a gap agent G that provides a gap between the coating roller 141 and the transfer paper P in the coating nip C to the coating nip C. A gap agent applying device 150 which is a gap agent applying means. By supplying the gap agent G to the application nip C by the gap agent applying device 150, a gap is provided between the application roller 141 and the transfer paper P in the application nip C by the gap agent G. For this reason, it is possible to prevent toner offset caused by the application roller 141 coming into contact with the toner particles of the unfixed toner image T on the transfer paper P. Further, even if the gap agent G adheres to the residual foam fixing solution Fb on the application roller 141 that has passed through the application nip C, the gap roller G is applied to the application roller 141 by the application member cleaning device 160 together with the residual foam fixing solution Fb. Can be removed. For this reason, unlike the fixing device including the application member having a complicated configuration including the gap member, the application roller 141 can be easily cleaned. With such a configuration, the fixing device 30 according to the first to third embodiments is configured to apply the fixer to the toner particles on the transfer paper P, and prevents toner offset caused by the application roller 141 coming into contact with the toner particles. However, it is possible to realize a configuration in which the application roller 141 can be easily cleaned.

  In addition, the foam-like fixer generating unit 130 which is a fixer supply unit of the fixing device 30 of the present embodiment disperses bubbles in the liquid fixer to form a foam-like fixer F, and the application roller 141. Fixing solution foaming means for supplying F to the surface of the foam. For this reason, the fixing liquid applied to the unfixed toner image T by the application roller 141 at the application nip C is the foam-like fixing liquid F, and the toner is applied in a smaller amount of fixing liquid than the fixing device that applies the liquid fixing liquid. The image can be fixed without disturbing the image.

  In particular, in the fixing device 30 according to the first exemplary embodiment, the gap agent applying device 150 applies the gap agent G on the surface of the coating roller 141, and thus completely disturbs the unfixed toner image T that is an image of resin fine particles before fixing. Without offset.

  Further, in the fixing device 30 of the first embodiment, the gap agent applying device 150 passes through the coating nip C and then the surface of the coating roller 141 before the foamy fixing solution F is supplied by the foamed fixing solution generator 130. Gap agent G is applied on top. Thereby, the offset can be prevented without adversely affecting the foamy fixing solution F on the surface of the application roller 141 such as uneven thickness.

  In particular, in the fixing device 30 according to the second or third embodiment, the gap agent applying device 150 applies the gap agent G onto the surface of the transfer paper P carrying the unfixed toner image. Offset can be prevented without causing any adverse effects such as uneven thickness on the foamed fixing solution F.

  In particular, in the fixing device 30 of the second embodiment, the gap agent applying device 150 includes a gap agent holding roller 154 that is a gap agent carrier that supports the gap agent G and moves on the surface, and the gap agent holding roller 154 is transferred to the transfer paper. The unfixed toner image T on the surface of P is brought into contact. Thereby, since the gap agent G is preferentially applied on the charged unfixed toner image T, offset can be prevented while suppressing the consumption amount of the gap agent G.

  In particular, in the fixing device 30 of the third embodiment, the gap agent applying device 150 includes a gap agent photosensitive drum 181, a gap agent exposure device (not shown), a gap agent developing device 183, and a gap agent transfer roller. 184. The gap agent photosensitive drum 181 is a latent image carrier, and an electrostatic latent image for gap agent is formed on the surface thereof by exposure light Lg irradiated from a gap agent exposure device (not shown) which is a latent image forming unit. Is written. The gap agent developing device 183 is a developing unit that develops the electrostatic latent image formed on the gap agent photosensitive drum 181 using a gap agent to form a gap agent image. The gap agent transfer roller 184 is a gap agent image transfer unit that transfers the gap agent image formed on the gap agent photosensitive drum 181 onto the surface of the transfer paper P. As a result, the gap agent G can be applied to an arbitrary place on the transfer paper P, and therefore, the gap agent G is applied only to a portion where the unfixed toner image T exists without consuming an excessive amount of the gap agent G. To prevent offset.

A printer 100 as an image forming apparatus of the present embodiment is a toner image forming unit that forms an unfixed toner image T on a transfer paper P that is a recording medium, using toner containing resin fine particles containing a resin and a colorant. The image forming unit 3 and the like and a fixing unit that fixes the toner image on the transfer paper P are provided, and the fixing device 30 of the present embodiment is used as the fixing unit. As a result, the occurrence of an offset in the fixing device 30 can be prevented, so that high-quality image formation can be performed.
Note that the toner image formed by the image forming unit 3 or the like is transferred to the transfer paper P, as in the printer 100 shown in FIG. 15, the toner image formed on the photosensitive member 4 on the latent image carrier. The toner image formed on the photosensitive member 4 on the latent image carrier may be opposed to the photosensitive member 4 as in the printer 100 shown in FIG. A configuration may be employed in which the toner image formed on the intermediate transfer belt 25 is transferred onto the transfer paper P after being transferred to the intermediate transfer belt 25 which is a moving transfer member.

3 Image forming unit 4 Photoconductor 20 Transfer unit 25 Intermediate transfer belt 26 Primary transfer roller 28 Paper transport unit 30 Fixing device 100 Printer 130 Foam-like fixer generator 135 Coarse bubble generator 138 Foam refiner 140 Fixer application unit 141 Coating roller 142 Film thickness adjusting blade 143 Pressure roller 150 Gap agent applying device 151 Storage unit 152 Application amount control member 153 Delivery member 250 Transfer conveyance belt C Application nip F Foamed fixing liquid G Gap agent

JP 2007-219105 A Japanese Patent Laid-Open No. 2007-12785

"Foam Engineering" first edition (written by Ishii Ikuo, Techno System, Inc., published on March 25, 2005, P.489)

Claims (8)

A fixing solution containing a softening agent that softens resin fine particles by dissolving or swelling at least a part of the resin is carried on the surface and moved to the surface, and the surface is positioned opposite to the fixing solution application target carrying the resin fine particles. An application member for applying the above fixer to the fixer application target;
Fixing solution supply means for supplying a fixing solution to the surface of the coating member;
A pressure member that abuts against the application member at a position where the application member applies the fixing liquid to the application target of the fixer and sandwiches the application target of the fixer and forms an application nip with the application member; ,
In a fixing device for fixing the resin fine particles softened by applying a fixing solution to a recording medium,
A fixing device comprising gap agent applying means for applying a gap agent for providing a gap between the application member and the fixing liquid application target in the application nip. The fixing device according to claim 1.
The fixing solution supply means is a fixing solution foaming means for dispersing bubbles in a liquid fixing solution to form a foamy fixing solution and supplying the foaming fixing solution to the surface of the coating member. And a fixing device. The fixing device according to claim 1 or 2,
The fixing device according to claim 1, wherein the gap agent applying means applies the gap agent on the surface of the application member. The fixing device according to claim 3.
The fixing device characterized in that the gap agent applying means applies the gap agent onto the surface of the application member after passing through the application nip and before the fixing liquid is supplied by the fixing liquid supply means. The fixing device according to claim 1.
The fixing device characterized in that the gap agent applying means applies the gap agent onto the surface of the fixing liquid application target carrying the resin fine particles. The fixing device according to claim 5.
The gap agent applying means includes a gap agent carrier that carries the gap agent and moves on the surface, and the gap agent carrier is brought into contact with the resin fine particle layer on the surface of the fixing liquid application target. A fixing device. The fixing device according to claim 5.
The gap agent applying means is
An electrostatic latent image carrier;
Latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier;
Developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using a gap agent to form a gap agent image;
And a gap agent image transfer means for transferring the gap agent image formed on the electrostatic latent image carrier onto the surface of the fixing liquid application target. A toner image forming means for forming a toner image on a recording medium using a toner containing resin fine particles containing a resin and a colorant;
Fixing means for applying a fixing liquid to the surface of the toner image carrier that carries the toner image to be transferred to the recording medium or the surface of the recording medium that carries the toner image and fixing the toner image on the recording medium; An image forming apparatus comprising:
An image forming apparatus using the fixing device according to claim 1 as the fixing unit.

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