JP5435335B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer, and a fixing device used in the image forming apparatus. More specifically, a fixing device that applies a fixing liquid that dissolves or swells at least a part of the resin component of the toner and fixes the toner component on the recording medium to the toner image on the recording medium or the toner image carrier, and an image including the fixing device. The present invention relates to a forming apparatus.

Image forming apparatuses such as printers, facsimile machines, and copying machines are apparatuses that form images including characters and symbols on recording media such as paper, cloth, and OHP sheets based on image information. In particular, electrophotographic image forming apparatuses are widely used in offices because they can form high-definition images on plain paper at high speed. In such an electrophotographic image forming apparatus, there are a wide variety of heat fixing type fixing devices that heat and melt the toner on the recording medium and press the molten toner to fix the toner on the recording medium. It is used.
As a fixing device that melts toner and fixes it on a recording medium, 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. There is known a fixing device of a wet fixing system that applies and fixes a toner image (for example, a fixing device described in Patent Documents 1 to 5). In such a fixing device of the wet fixing method, it is not necessary to perform a heat treatment in order to soften the toner, so that energy saving can be realized as compared with the heat fixing method.

  In the fixing device described in Patent Document 5, the fixing solution is made into a foamy fixing solution in which bubbles are dispersed in the solution, and the fixing solution is recorded by applying the foamed fixing solution to a recording medium using an application roller. This configuration is applied to an unfixed toner image on a medium. In this fixing device, the application roller includes a pressure roller that contacts the application roller at an application position where the foamy fixing liquid is applied to the recording medium, and an application nip is formed at a position where the application roller and the pressure roller contact each other. Yes. The recording medium carrying the unfixed toner image passes through the coating nip, whereby the fixing liquid is applied to the unfixed toner image on the recording medium.

  In the configuration in which the foamed fixing solution is applied by the application roller, it is desirable that the foamed fixing solution is applied only when the recording medium is present at the application position. This is because when the surface of the coating roller to which the foam-like fixing liquid is supplied reaches the coating nip where no recording medium is present, the foam-like fixing liquid adheres to the surface of the pressure roller, and the surface of the pressure roller is foam-fixed. This is because there is a risk of contamination with liquid. As long as the foam-like fixing liquid adhering to the pressure roller is not cleaned, it will eventually adhere to the back side of the recording medium, causing problems such as deterioration of the recorded image and in-machine diffusion of the foam-like fixing liquid. Even if the pressure roller is cleaned, it is desirable that the amount of foam-like fixing liquid adhering to the pressure roller is as small as possible in order to reduce the load on the cleaning mechanism.

  As a configuration for reducing the amount of foamy fixing solution adhering to the pressure roller, Patent Document 5 discloses that the recording roller is in contact with the application roller at the timing when the recording medium is present at the application position. A configuration is described in which the application roller and the pressure roller are separated from each other at the timing when the application is not performed. In this configuration, since the application roller and the pressure roller are separated from each other at the timing when the recording medium does not exist at the application position, it is possible to reduce the foamy fixing liquid adhering to the pressure roller.

  However, since application conditions such as the pressure applied at the application nip and the nip width greatly affect the fixability, changes in these application conditions lead to deterioration of the fixability. And in the structure which controls contact / separation of an application roller and a pressure roller by the presence or absence of the recording medium in an application position like the said patent document 5, it is applied after controlling to make an application roller and a pressure roller contact. In addition, it takes time until the nip width is stabilized at a predetermined coating condition. When the recording medium is passed through the coating nip before these coating conditions are stabilized at the predetermined conditions, the fixing property is deteriorated. When the recording medium is controlled to pass through the coating nip after being stabilized at the predetermined conditions, the fixing process is performed. The time required for the process becomes longer and the productivity is lowered. In addition, since the application roller and the pressure roller also have a function of conveying the recording medium with the application nip interposed therebetween, if the recording medium is brought into contact at the timing when it reaches the application position, image deterioration due to shock jitter will occur. May also occur.

  In the above description, the fixing device, which is a recording medium on which the fixing liquid application target on which the application member applies the foamy fixing liquid, carries an unfixed toner image, has been described. As a fixing device for fixing a toner image on a recording medium using a fixing liquid, a foam-like fixing liquid is applied to a toner image carrier such as an intermediate transfer belt carrying a toner image, and the toner image on the toner image carrier is Is transferred to a recording medium together with a foamy fixing solution. As described above, the same problem may occur when the fixing solution application target on which the application member applies the foamy fixing solution is not a recording medium but a toner image carrier. For example, when applying a foamy fixing solution to a toner image on the intermediate transfer belt, if the control is performed such that the application member contacts the intermediate transfer belt at the timing when the toner image is present on the intermediate transfer belt, image degradation due to shock jitter will occur. May also occur. In addition, even when the foam-like fixing liquid is applied to the toner image on the intermediate transfer belt, the application conditions such as the pressure and contact width between the intermediate transfer belt and the application member at the application position pass through the application position. This affects the application state of the foamy fixing solution to the toner image, and also affects the subsequent fixability. In the same manner as in the configuration of applying to the recording medium described above, it takes time until the application condition is stabilized to a predetermined condition after controlling the application member and the intermediate transfer belt to come in contact with each other. Balancing is difficult.

  As described above, if the position of the application position of the member constituting the application position is displaced in order to control the application timing of the foamy fixing solution, problems such as deterioration of fixability and deterioration of productivity occur.

  The present invention has been made in view of the above problems, and its object is to fix the application timing of the foam-like fixing liquid by the application member while preventing deterioration of fixability and productivity. And an image forming apparatus including the fixing device.

In order to achieve the above object, the invention of claim 1 is a foam fixing in which bubbles are dispersed in a fixer containing a softening agent that softens resin fine particles by dissolving or swelling at least part of the resin. A fixing solution foaming means as a liquid, and an application member for applying the foamed fixing solution supplied to the surface moving surface to the surface of the fixing solution application target carrying the resin fine particle layer made of the resin fine particles. In the fixing device for fixing the resin fine particle layer softened by applying the foamy fixing solution to the recording medium, the coating member is applied to the fixing solution application target after being generated by the fixing solution foaming means. An upstream side fixing liquid carrier and a downstream side fixing liquid carrier as two fixing liquid carriers that carry and transport the foamy fixing liquid on the surface moving surface before reaching the coating position for applying the foamy fixing liquid. An upstream fixing solution carrier The foam-like fixing solution supplied to the surface of the body is transported to a proximity position where the two fixing-solution carriers are close to or in contact with each other, and the foam-like fixing solution is supplied to the downstream-side fixing solution carrier at the proximity position. The foam-like fixing solution supplied to the surface of the downstream fixing solution carrier is transported to the coating position, and the proximity of the coating member without changing the position of the surface of the coating member at the coating position. Contact / separation control means for controlling contact / separation between the surface of the upstream fixing solution carrier at the position and the surface of the downstream fixing solution carrier, and with respect to the proximity position on the surface of the upstream fixing solution carrier Recovery for collecting the foam-like fixing solution on the surface of the upstream-side fixing solution carrier on the downstream side in the surface-movement direction and upstream of the surface-moving direction with respect to the position where the foam-like fixing solution is supplied and it is characterized in Rukoto to have a means.
According to a second aspect of the present invention, in the fixing device of the first aspect, the downstream fixing liquid carrier is the application member.
Further, the invention of claim 3 is the fixing device according to claim 1 or 2, wherein when the coating member applies the foamy fixing solution onto the surface of the fixing solution application target, the fixing solution application target is sandwiched between the fixing members. It has the application | coating opposition member which opposes this application | coating member, It is characterized by the above-mentioned.
The invention of claim 4 is the fixing device according to any one of claims 1 to 3, in and away from the control of the surface of the two foamed fixer carrier by the upper KiseHHanare control means It has a foam fixing solution recovery control means for controlling the recovery of the foam fixing solution by the recovery means according to the frequency with which the two foam fixing solution carriers come close to or in contact with each other. .
According to a fifth aspect of the present invention, there is provided the fixing device according to any one of the first to fourth aspects, wherein the upstream side fixing liquid carrier is endlessly moved by being stretched by a plurality of stretch members. The fixing member carrying belt, and one of the plurality of stretching members is in contact with the inner peripheral surface of the fixing solution carrying belt at the proximity position, and the downstream fixing solution is controlled by the contact / separation control means. A displaceable stretching member whose position with respect to the carrier changes, and the upstream fixing liquid carrier comprising the fixing liquid carrying belt by changing the position of the displaceable stretching member with respect to the downstream fixing liquid carrier. The contact / separation with respect to the downstream fixing liquid carrier is controlled.
According to a sixth aspect of the present invention, there is provided the fixing device according to any one of the first to fourth aspects, wherein the downstream side fixing liquid carrier is endlessly moved by being stretched by a plurality of stretch members. The fixing member carrying belt, and one of the plurality of stretching members contacts an inner peripheral surface of the fixing solution carrying belt at the close position, and the upstream fixing solution is controlled by the contact / separation control means. A displaceable stretching member whose position with respect to the carrier changes, and the downstream fixing liquid carrier comprising the fixing liquid carrying belt by changing the position of the displaceable stretching member with respect to the upstream fixing liquid carrier. The contact / separation of the upstream side fixing liquid carrier is controlled.
Further, the invention of claim 7 is the fixing device according to any one of claims 1 to 6 , wherein the surface of the upstream fixing solution carrier has a surface relative to a position where the foamy fixing solution is supplied. Bubbles for controlling the film thickness of the foam-like fixer on the surface of the upstream fixer carrier on the downstream side in the moving direction and on the upstream side in the surface moving direction with respect to the proximity position. And a fixing film thickness control means.
According to an eighth aspect of the present invention, in the fixing device according to the seventh aspect , the foam-like fixing liquid film thickness control means includes a blade member facing the surface of the upstream fixing liquid carrier. is there.
According to a ninth aspect of the present invention, in the fixing device of the eighth aspect , the blade member is disposed at a trailing position with respect to the surface movement direction of the upstream side fixing liquid carrier, and the upstream side fixing liquid carrier. It is characterized in that it is urged in a state where a constant gap is maintained with respect to the surface of the film.
According to a tenth aspect of the present invention, in the fixing device according to the eighth aspect , the blade member is disposed at a trailing position with respect to the surface movement direction of the upstream side fixing liquid carrier, and the upstream side fixing liquid carrier. It is characterized by being biased against the surface.
The invention according to claim 11 is the fixing device according to any one of claims 8 to 10 , wherein the upstream fixing solution is carried from a position where the film thickness of the foamy fixing solution is controlled by the blade member. A bubble pool detecting means for detecting the amount of the bubble pool formed on the upstream side of the body surface movement direction, and the upstream side when the amount of the bubble pool detected by the bubble pool detecting means is smaller than a predetermined amount; It is characterized by comprising supply control means for controlling the supply of the foam-like fixing solution so as to supply the foam-like fixing solution to the surface of the fixing solution carrier.
According to a twelfth aspect of the present invention, in the fixing device according to any one of the first to eleventh aspects, the surface of the upstream fixing liquid carrier is more water than the surface of the downstream fixing liquid carrier. A fixing device characterized by having a large contact angle with respect to.
The invention according to claim 13 is the fixing device according to any one of claims 1 to 12 , wherein a linear velocity of the upstream side fixing liquid carrier and a line of the downstream side fixing liquid carrier in the proximity position are set. And a fixing liquid carrier linear velocity ratio control means for controlling a linear velocity ratio which is a ratio to the velocity.
According to a fourteenth aspect of the present invention, in the fixing device according to any one of the first to thirteenth aspects, the fixing solution application target on which the coating member applies the foamy fixing solution is a recording medium. It is a feature.
The fifteenth aspect of the invention is the fixing device according to the fourteenth aspect , further comprising recording medium position detecting means for detecting the position of the recording medium before reaching the application position, and the contact / separation control means includes the recording medium. The contact / separation of the two fixing liquid carriers is controlled based on the detection result of the position detection means.
According to a sixteenth aspect of the present invention, in the fixing device according to the fifteenth aspect , the recording medium position detecting means passes through a detection position upstream of the coating position in the conveyance direction of the recording medium with respect to the application position. The length of the conveyance distance of the recording medium between the detection position and the application position is supplied to the surface of the downstream fixing liquid carrier at the proximity position. The foam-type fixing solution is longer than the length of the surface carried until the coating position.
According to a seventeenth aspect of the present invention, there is provided a toner image forming means for forming a toner image on a recording medium based on image information using a toner containing resin fine particles containing a resin and a colorant, and transferring the toner image to the recording medium. A foam-like fixer is applied to the surface of the toner image carrier that carries the toner image or the surface of the fixing liquid application target that is the surface of the recording medium that carries the toner image, and the toner image is fixed on the recording medium. An image forming apparatus including a fixing unit for fixing, wherein the fixing unit according to any one of claims 1 to 16 is used as the fixing unit.
According to an eighteenth aspect of the present invention, in the image forming apparatus according to the seventeenth aspect , the contact / separation control means controls contact / separation of the two fixing liquid carriers based on the image information used by the toner image forming means. It is characterized by this.

  In the present invention, the foamy fixing solution supplied from the upstream fixing solution carrier to the downstream fixing solution carrier is transported to the application position at the close position. For this reason, by controlling the timing of supplying the foam-like fixing solution from the upstream-side fixing solution carrier to the downstream-side fixing solution carrier at the proximity position, the application timing of the foam-like fixing solution by the application member at the application position can be controlled. Can be controlled. Further, the contact / separation control unit controls contact / separation between the surface of the upstream fixing solution carrier and the surface of the downstream fixing solution carrier at the proximity position, so that the downstream from the upstream fixing solution carrier at the proximity position. The timing for supplying the foamy fixing solution to the side fixing solution carrier can be controlled. Further, the contact / separation control means controls contact / separation between the surface of the upstream fixing liquid carrier and the surface of the downstream fixing liquid carrier at the proximity position without changing the position of the surface of the coating member at the coating position. . Therefore, the contact / separation control means controls the contact / separation between the surface of the upstream fixer carrier and the surface of the downstream fixer carrier, so that the application position can be changed without changing the position of the surface of the application member. The application timing of the foam-like fixing liquid by the application member at the position can be controlled. Since the position of the surface of the coating member at the coating position does not change, the foamed state of the coating member at the coating position without changing the coating conditions such as pressure and contact width between the coating member and other members at the coating position The application timing of the fixing solution can be controlled.

  According to the present invention, since the coating conditions do not change due to the contact / separation operation between the surface of the upstream side fixing liquid carrier and the surface of the downstream side fixing liquid carrier, it is possible to prevent deterioration of fixability and productivity. By controlling the contact / separation operation, there is an excellent effect that it is possible to control the application timing of the foamy fixing solution by the application member.

FIG. 3 is an explanatory diagram schematically illustrating a fixing device according to the first exemplary embodiment. 1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 2 is a schematic configuration diagram of one image station in the printer. FIG. 4 is an enlarged explanatory view of a portion where the application roller of the fixing device according to the embodiment contacts the transfer paper. FIG. 3 is an enlarged schematic diagram of a foamy fixing solution. FIG. 3 is a schematic explanatory diagram of a fixing liquid foaming device provided in the fixing device according to the embodiment. FIG. 6 is an explanatory diagram of a conventional fixing device. Explanatory drawing of the structure which controls the pushing pressure of the blade for liquid film thickness control, (a) is explanatory drawing of the state which increased the pressure, (b) is explanatory drawing of the state which made the pressure small. Explanatory drawing of a structure provided with a gap control member by the structure which controls the pressing force of the blade for liquid film thickness control. An explanatory view of a configuration for controlling the width of the blade gap, (a) is an explanatory view of a state where the blade gap is narrowed, (b) is an explanatory view of a state where the blade gap is widened. Explanatory drawing of a bubble pool. Explanatory drawing of a bubble pool detection means. An explanatory diagram of the transfer rate of the foam-like fixing solution, (a) is an explanatory diagram of the state where the surface properties of the thin film forming belt and the application roller are the same, and (b) is an explanatory diagram of a state where the transfer rate is close to 100 [%]. Figure. Explanatory drawing in case there exists a speed difference in the surface moving speed of a thin film formation belt and an application | coating roller. The block diagram of control of a foam-like fixing liquid linear velocity control part. Explanatory drawing of arrangement | positioning of a paper edge part detection sensor. 6 is a timing chart of separation control based on transfer paper position information. 6 is a timing chart of separation control based on image data information. FIG. 6 is an explanatory diagram schematically illustrating a fixing device according to a second embodiment. FIG. 6 is an explanatory diagram schematically illustrating a fixing device according to a third embodiment. An explanatory view when the film thickness of the fixing solution is thin in a fixing device using a liquid fixing solution, (a) is a schematic explanatory view of the fixing device, and (b) is an application roller that contacts the transfer paper and applies the fixing solution. Explanatory drawing of the application | coating position where a transfer paper contacts. FIG. 3 is an explanatory diagram when the film thickness of the fixing solution is sufficiently thick in the fixing device using the liquid fixing solution.

Hereinafter, an embodiment in which the present invention is applied to a full-color printer (hereinafter referred to as a printer 100) which is an image forming apparatus will be described.
FIG. 2 is a configuration diagram illustrating a schematic configuration of the printer 100.
As shown in FIG. 2, the printer 100 includes an apparatus main body 1 that is fixed in position for storing each component as an image forming unit, and a drawable paper feed cassette 2 for storing transfer paper P. The central portion of the apparatus main body 1 includes image stations 3Y, 3C, 3M, and 3K for forming toner images of yellow (Y), cyan (C), magenta (M), and black (K) colors. Yes. Hereinafter, the subscripts Y, C, M, and K of the respective symbols indicate members for yellow, cyan, magenta, and black, respectively.

  FIG. 3 is a configuration diagram showing a schematic configuration of one of the image stations (Y image station 3Y). As shown in FIGS. 2 and 3, the image stations 3Y, 3C, 3M, and 3K include drum-shaped photoreceptors 10Y, 10C, 10M, and 10K that rotate in the direction of arrow A in FIG. The photoreceptor 10 is composed of an aluminum cylindrical base and an OPC (organic photo semiconductor) photosensitive layer that covers the surface of the photoreceptor. Each image station 3 has charging devices 11Y, 11C, 11M, and 11K that charge the photoconductor 10 around the photoconductor 10, and developing devices 12Y, 12C, 12M, and 12K that develop a latent image formed on the photoconductor 10. And cleaning devices 13Y, 13C, 13M, and 13K for cleaning residual toner on the photoconductor 10. Below each image station 3, an optical unit 4 is provided as exposure means capable of irradiating the photoreceptors 10Y, 10C, 10M, and 10K with the laser light L. Above each image station 3, an intermediate transfer unit 5 including a transfer belt 20 to which a toner image formed by each image station 3 is transferred is provided. Further, a fixing device 6 for fixing the toner image transferred to the transfer belt 20 to the transfer paper P is provided. In addition, toner bottles 7Y, 7C, 7M, and 7K that store toner of each color of yellow (Y), cyan (C), magenta (M), and black (K) are loaded on the upper portion of the apparatus main body 1. . The toner bottles 7 </ b> Y, 7 </ b> C, 7 </ b> M, and 7 </ b> K are configured to be detachable from the apparatus main body 1 by opening a paper discharge tray 8 formed on the upper part of the apparatus main body 1.

  The optical unit 4 reflects laser light L emitted from a laser diode as a light source by a polygon mirror or the like, and sequentially scans the photosensitive members 10Y, 10C, 10M, and 10K while irradiating them. The transfer belt 20 of the intermediate transfer unit 5 is wound around a drive roller 21, a tension roller 22, and a driven roller 23, and is driven to rotate counterclockwise in the drawing at a predetermined timing. The intermediate transfer unit 5 includes primary transfer rollers 24Y, 24C, 24M, and 24K that transfer the toner images formed on the photoreceptors 10Y, 10C, 10M, and 10K to the transfer belt 20. The intermediate transfer unit 5 includes a secondary transfer roller 25 that transfers the toner image transferred onto the transfer belt 20 onto the transfer paper P, and a belt that cleans residual toner on the transfer belt 20 that has not been transferred onto the transfer paper P. A cleaning device 26 is provided.

  Next, the process of obtaining a color image in the printer 100 will be described. First, in the image stations 3Y, 3C, 3M, and 3K, the photoreceptors 10Y, 10C, 10M, and 10K are uniformly charged by the charging devices 11Y, 11C, 11M, and 11K. Thereafter, the laser light L is scanned and exposed by the optical unit 4 based on the image information, and latent images are formed on the surfaces of the photoreceptors 10Y, 10C, 10M, and 10K. The latent images on the photoconductors 10Y, 10C, 10M, and 10K are developed by the toners of the respective colors carried on the developing rollers 15Y, 15C, 15M, and 15K of the developing device 12, and are visualized as toner images. The toner images on the photoreceptors 10Y, 10C, 10M, and 10K are sequentially superimposed and transferred onto the transfer belt 20 that is rotated counterclockwise by the action of the primary transfer rollers 24Y, 24C, 24M, and 24K. The image forming operation for each color at this time is executed while shifting the timing from the upstream side toward the downstream side in the moving direction of the transfer belt 20 so that the toner image is transferred to the same position on the transfer belt 20. The The surfaces of the photoreceptors 10Y, 10C, 10M, and 10K after the completion of the primary transfer are cleaned by the cleaning blades 13a of the cleaning devices 13Y, 13C, 13M, and 13K, and are prepared for the next image formation. The toner filled in the toner bottles 7Y, 7C, 7M, and 7K is supplied to a developing device 12Y of each of the image stations 3Y, 3C, 3M, and 3K by a toner replenishing device (not illustrated) via a conveyance path (not illustrated) as necessary. , 12C, 12M, and 12K are replenished by a predetermined amount.

On the other hand, the transfer paper P in the paper feed cassette 2 is conveyed into the apparatus main body 1 by a paper feed roller 27 disposed in the vicinity of the paper feed cassette 2 and is subjected to secondary transfer at a predetermined timing by a registration roller pair 28. The roller 25 and the driving roller 21 are conveyed to the opposing secondary transfer unit. Then, the toner image formed on the transfer belt 20 is transferred to the transfer paper P in the secondary transfer portion. The transfer paper P onto which the toner image has been transferred passes through the fixing device 6 to be fixed, and is discharged to the paper discharge tray 8 by the discharge roller 29. Similar to the photoconductor 10, the untransferred toner remaining on the transfer belt 20 is cleaned by a belt cleaning device 26 that contacts the transfer belt 20.
The order of arrangement of the four image stations 3Y, 3C, 3M, and 3K and the toner bottles 7Y, 7C, 7M, and 7K is not limited to the example illustrated in FIG.
Further, the image forming apparatus including the fixing device 6 having the characteristic portion of the present invention is not limited to the configuration of the printer 100 in FIG.

Next, the principle of fixing of the fixing device 6 according to the present invention will be outlined.
In the present invention, a foamy fixing solution containing a softening agent that softens fine particles containing a resin by dissolving or swelling at least a part of the resin is used as a resin fine particle on the surface of a fixing solution application target such as a recording medium. Give. Thus, a fixing method is adopted in which the resin fine particles on the surface of the fixing liquid application target are softened and the resin fine particles are fixed on the recording medium. Needless to say, the resin fine particles described here are not particularly limited as to what they are, but they refer to toner when applied to an image forming apparatus.

Next, a fixing device using a conventional wet fixing method will be described.
The above-mentioned Patent Document 1 describes a wet fixing type fixing device that uses an oil-in-water type fixing solution in which an organic compound that can dissolve or swell toner and is insoluble or hardly soluble in water is dispersed and mixed in water. Has been. In this fixing device, unfixed toner is sprayed or dripped on the surface of the fixing object disposed at a predetermined position to dissolve or swell the toner, and then the fixing object is dried. is there.

  However, the fixing device of Patent Document 1 uses an oil-in-water type fixing solution in which an organic compound insoluble or hardly soluble in water is dispersed and mixed in water. For this reason, when a large amount of fixing solution is applied to the unfixed toner, a recording medium (non-fixed material) such as transfer paper absorbs moisture of the fixing solution, and wrinkles and curls are generated on the recording medium. This significantly impairs the stable and high-speed conveyance of the recording medium required for the image forming apparatus. Therefore, if water is removed from the fixing liquid applied to the recording medium by evaporating a large amount of water contained in the fixing liquid using a drying apparatus, the power consumption of the image forming apparatus using the thermal fixing method is reduced. You will need comparable power.

  In addition, several oil-based fixing solutions in which a material that dissolves or swells toner is dissolved in an oil-based solvent have been proposed as fixing solutions that do not repel water-repellent unfixed toner. As one example, for example, in Patent Document 2 described above, an aliphatic dibasic acid ester or the like having a material that dissolves or swells the resin component constituting the toner as a diluent (solvent) is diluted with nonvolatile dimethyl silicone. A fixed (dissolved) fixer has been proposed. Patent Document 3 discloses a compatibility state in which 8 to 120 parts by volume of silicone oil is mixed with 100 volumes of a solvent that dissolves toner and is compatible with silicone oil. Fixers for unfixed toner images have been proposed. As a result, an unfixed toner image formed by an electrostatic method can be fixed clearly and easily on a recording medium without disturbing the image. Such an oil-based fixing solution contains an oil-based solvent having a high affinity with the water-repellent-treated unfixed toner, so that the toner is dissolved or swollen without repelling the water-repellent-treated unfixed toner, The toner can be fixed on the recording medium.

  In such a conventional wet fixing method, since the fixing liquid is applied to the toner image on the recording medium in a normal liquid state, a small amount of the fixing liquid is applied to the toner image on the recording medium and the toner offset to the fixing roller. There was a problem that it was extremely difficult to achieve both preventions. This problem will be described with reference to FIGS.

FIG. 21 is an explanatory diagram of a fixing device 30 using a conventional liquid fixing liquid of a wet fixing system. FIG. 21A is a schematic explanatory diagram of a fixing device 30 using a liquid fixing solution. FIG. 21B shows a transfer sheet P that is a recording medium in the fixing device 30 that uses a liquid fixing liquid, and an application roller 141 that is an application member that contacts the transfer paper P and applies the liquid fixing liquid 132. It is expansion explanatory drawing of a proximity | contact part.
In order to apply a small amount of the fixing liquid 132 to the transfer paper P in the configuration in which the fixing liquid 132 is applied to the unfixed toner layer T on the transfer paper P using the application roller 141 as shown in FIG. When the film thickness of the fixing liquid 132 on the application roller 141 is smaller than the thickness of the toner layer T, the result is as shown in FIG. The fixing liquid 132 on the application roller 141 is applied to the transfer paper P from the application roller 141 at the application position where the surface of the application roller 141 is in contact with the transfer paper P, as well as an arrow F1 in FIG. As shown in FIG. 4, there are some that remain on the surface of the application roller 141 even after passing through the application position. Then, at the position where the surface of the application roller 141 is separated from the transfer paper P, the surface tension (acting in the direction of arrow F2 in FIG. 21) generated by the liquid film of the fixing liquid 132 remaining on the surface of the application roller 141 is The toner particles are pulled. As a result, the offset toner particles Ta adhere to the surface of the coating roller 141, and the image formed by the toner layer T on the transfer paper P after peeling off from the coating roller 141 is greatly disturbed.

Conversely, when the film thickness of the fixing liquid 132 on the application roller 141 is made sufficiently thicker than the unfixed toner layer T, the result is as shown in FIG. At the position where the surface of the application roller 141 is separated from the transfer paper P, the amount of the fixing liquid 132 is large, so that the surface tension due to the liquid film on the surface of the application roller 141 hardly acts on the toner particles of the toner layer T. This makes it difficult for the offset toner to adhere to the application roller 141 side, but since a large amount of the fixing liquid 132 is applied to the surface of the transfer paper P, the toner particles on the transfer paper P are caused to flow by the excessive fixing liquid 132. As a result, the image quality is deteriorated, or the drying time of the fixing liquid 132 applied to the transfer paper P is lengthened, thereby causing a problem in fixing responsiveness. In addition, a noticeable residual liquid feeling (a wet feeling when the paper is touched by hand) occurs on the transfer paper P. Further, if the fixing liquid 132 contains water, when the amount of the fixing liquid 132 applied to the transfer paper P containing cellulose such as paper as a recording medium is large, the transfer paper P such as paper curls remarkably. There is a risk that a paper jam will occur when the recording medium is transported in an apparatus such as an image forming apparatus.
As described above, in the configuration in which the fixing liquid 132 is applied using the application roller 141, if the amount of the fixing liquid 132 applied is too large, the image quality deteriorates due to the flow of toner particles, and the drying time of the fixing liquid 132 increases. There arises a problem that the fixing responsiveness is lowered due to the above. Further, depending on the material of 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 liquid 132 is applied in order to prevent these problems, the toner particles Ta are offset on the surface of the application roller 141 as described above. Therefore, it is possible to achieve both the application of a small amount of the fixing liquid to the toner layer on the transfer paper P and the prevention of the toner offset to the application roller 141 in order to improve the fixing response, reduce the residual liquid feeling, and prevent the curling. Extremely difficult.

As a fixing method capable of achieving both the application of a small amount of fixing solution and the prevention of toner offset, Patent Document 5 discloses that the fixing solution is a foam-like fixing solution in which bubbles are dispersed in the solution. A configuration in which a toner image on a recording medium is applied using an application roller is described. In this way, since the density of the fixing solution can be lowered by making the fixing solution foamy, the thickness of the fixing solution on the surface of the coating roller can be increased with a smaller amount of fixing solution than in the past. The influence of the surface tension on the toner particles on the recording medium can be reduced. Also, since the amount of the fixing solution is small, the residual liquid feeling on the recording medium can be suppressed, and the foam-like fixing solution is less likely to flow than the normal liquid fixing solution. It is also possible to prevent image deterioration due to the occurrence of image deterioration. Therefore, by performing fixing using a foamy fixing solution as in Patent Document 5, the toner image can be fixed without disturbing the toner with a smaller amount of fixing solution applied than before.
The fixing device 6 of the present embodiment is also configured to apply a fixer in the form of foam to the toner layer on the recording medium, as in the above-mentioned Patent Document 5.

  The fixing device described in Patent Document 5 includes a foam-like fixing liquid film thickness control unit that controls the film thickness of the foam-like fixing liquid on the coating roller that is a coating member. Then, the time during which the coating roller is in contact with the recording medium and applying the foamy fixing solution to the resin fine particles on the recording medium penetrates the resin fine particle layer on the recording medium. Thus, the film thickness is controlled to be the same or longer than the permeation time to reach the recording medium. As a result, offset adhesion of resin fine particles to the application roller can be prevented, and the resin fine particles can be quickly fixed to the recording medium after the fixing liquid is applied to the recording medium carrying the resin fine particles without disturbing the resin fine particles. It becomes. Therefore, it is possible to perform fixing with excellent fixing response.

[Example 1]
Next, a first embodiment (hereinafter, referred to as Embodiment 1) of the fixing device 6 having the characterizing portion of the present invention will be described.
FIG. 1 is an explanatory diagram schematically showing a fixing device 6 of Example 1 provided in the printer 100 of the present embodiment. The resin fine particles in the present invention are toner particles.
The fixing device 6 includes a foam-like fixer generating unit 130 as a foam-like fixer generating means for generating a foam-like fixer F in which a fixer 132 containing a softening agent is foamed, and the generated foam-like fixer F. A fixing liquid application unit 140 that is a foam-like fixing liquid application unit that is applied to the transfer paper P that is a recording medium. Further, a foam fixing solution thinning unit 150 is provided which is a foam fixing solution thinning means for making the foam fixing solution F generated by the foam fixing solution generating unit 130 into a thin film. As described above, the fixing device 6 can be roughly divided into three types according to the function of each part, such as the foam-like fixing liquid generation unit 130, the fixing liquid application unit 140, and the foam-like fixing liquid thinning unit 150.

As will be described in detail later, the foam-like fixer generation unit 130 has a function of generating large bubbles from the liquid fixer 132 and then separating the large bubbles to generate minute bubbles. have.
The foam-like fixer generation unit 130 includes a fixer bottle 131 as a fixer containing means for storing the liquid fixer 132, and contains a large amount of bubbles by dispersing bubbles in the liquid fixer 132. And a fixing solution foaming device 500 as a fixing solution foaming means for forming a foamy fixing solution F. In addition, as a fixing liquid conveying means for conveying the fixing liquid 132 from the fixing liquid bottle 131 to the fixing liquid foaming device 500, a fixing liquid conveying pump 133 and a fixing liquid conveying pipe 134 are provided. The fixer 132 in the fixer bottle 131 is transported to the fixer foaming device 500 via the fixer transport pipe 134 by driving the fixer transport pump 133, and the fixer foaming device 500 performs foam fixing. It becomes liquid F.
The fixing liquid application unit 140 is supplied with the foam fixing solution F from the fixing solution supply port 501 of the fixing solution foaming device 500 via the thin film forming belt 151 of the foam fixing solution thinning unit 150, and the foam fixing solution F is supplied. Is provided with a coating roller 141 as a coating member for coating the transfer paper P.
In this fixing device 6, the thin film forming belt 151 is an upstream side fixing liquid carrier, and the application roller 141 is a downstream side fixing liquid carrier.

The foam fixing solution F generated by the foam fixing solution generator 130 is supplied to the thin film forming belt 151 of the foam fixing solution thinning unit 150. The foam-like fixer thin film forming unit 150 uniformly thins the foam-like fixer F supplied from the foam-like fixer generating unit 130, and the thin-film-like fixer Fc is thinned on the thin film forming belt 151. Has the function of forming.
The fixing liquid application unit 140 includes an application roller 141 that contacts the thin film forming belt 151 of the foamy fixing liquid thinning unit 150 at the contact position G. The fixer application unit 140 receives the foamy fixer F from the foamy fixer thinning unit 150 by transfer, and applies the foamy fixer F to the toner layer T on the transfer paper P at the application position C, thereby the toner. It has a function of fixing the layer T to the transfer paper P. The fixer application unit 140 mainly includes an application roller 141 that is an application member and a pressure roller 143 that is an application counter member. In the fixing liquid application unit 140 of the present embodiment, the application counter member presses the application roller 141 as the pressure roller 143. However, the application counter member is a fixed roller and the application member is a pressure against the application counter member. It may be a configuration in which is applied.
In addition, an application member cleaning member 200 is disposed on the downstream side in the surface movement direction of the application roller 141 with respect to the application position C where the application roller 141 and the pressure roller 143 come into contact with each other.
In the fixing device 6, when the transfer paper P that has passed through the secondary transfer section passes through the application position C, the foamed fixing solution F is applied to the unfixed toner layer T on the transfer paper P by the application roller 141, The toner layer Tb on the transfer paper P becomes the fixed toner layer Tb.

Next, the principle of the configuration using a foamy fixing solution as in the fixing device 6 of the present embodiment will be described.
This configuration focuses on the fact that a foam-like liquid containing a large amount of bubbles has a very low bulk density. As described above, in order to perform application without causing toner offset to the application roller 141 using the application roller 141 which is a contact-type application member that contacts the transfer paper P and applies the fixing liquid, application is performed. The fixing solution on the roller 141 needs to be formed thick. This means that a certain volume of the fixing solution is required on the surface of the application roller 141 in order to uniformly apply the fixing solution so that the resin fine particles are not offset.
On the other hand, the smaller the amount of the fixing solution on the resin fine particle layer on the recording medium after applying the fixing solution, the better the fixing responsiveness and the residual liquid feeling, which means that it is desirable that the weight of the fixing solution is small. To do.
In order to satisfy the condition that the volume of the fixer is large when applied to the recording medium and the weight of the fixer on the recording medium after application is small, the density of the fixer at the time of application should be low, and the bulk density of the fixer By lowering the value, even if the volume is large at the time of application, the substantial application weight can be reduced. That is, if a fixing solution having a low bulk density (the value obtained by dividing the weight of the fixing solution by its volume) is used, the fixing responsiveness and residual liquid feeling are improved while preventing the offset when the fixing solution is applied. It is possible.

The fixing device 6 of the present embodiment has a configuration to which the invention in consideration of the principle described above is applied, and a foam-like fixing solution F that is a foam-like fixing solution in order to reduce the bulk density of the fixing solution at the time of application. Is applied to the transfer paper P as a recording medium. FIG. 4 is an enlarged explanatory view of a portion (application position C) where the application roller 141 contacts the transfer paper P in the fixing device 6 of the present embodiment.
As shown in FIG. 4, the fixing liquid foaming device 500 converts the liquid fixing liquid 132 into a foam-like fixing liquid F composed of bubbles, whereby the density of the fixing liquid can be reduced, and a small amount of the fixing liquid can be applied. The film thickness of the fixing solution on the roller 141 can be increased. Furthermore, since the influence of the surface tension of the fixing solution is suppressed, it has been found that the resin fine particles can be prevented from being offset to the coating roller 141 even if the amount of the fixing solution is small.

Further, as a result of extensive studies by the present inventors, when the size of the resin fine particles is about 5 [μm] to 10 [μm], the foamed fixing solution F is the resin fine particle layer without disturbing the fine particle layer. For application to the toner layer T, it was found that the bubble diameter range of the foam-like fixing liquid F is about 5 [μm] to 50 [μm].
FIG. 5 is an enlarged schematic view of the foam-like fixing solution F. As shown in FIG. 5, the foam-like fixing solution F in which a large number of bubbles Fb are dispersed in the solution becomes foamed. The liquid film boundary (hereinafter referred to as a plateau boundary Fa) that divides each of the above.
Generally, when a foam liquid containing large bubbles of about 0.5 [mm] to 1 [mm] is generated from a normal liquid liquid, bubbles can be generated relatively easily by simple stirring or the like. A foamy liquid composed of large bubbles can be produced in a time of several seconds or less (not taking 0.1 [s]). On the other hand, when a foam liquid containing minute bubbles of about 5 [μm] to 50 [μm] is generated from a normal liquid liquid, it is difficult to reduce the diameter of the bubbles, and it takes time to generate the bubbles. There was a problem.
Therefore, the inventors of the present invention have produced a bubble liquid containing bubbles larger than the desired bubble diameter (about 5 [μm] to 50 [μm]) and including bubbles of a size that can be visually observed. We focused on the point that it is easy and can be obtained quickly. And the method of producing | generating rapidly the foam liquid containing the micro bubble about 5 [micrometers]-50 [micrometers] from the foam liquid with a large foam diameter was investigated earnestly. As a result, when a large bubble is separated by applying a shearing force to a foam-like liquid containing large bubbles, the desired size can be obtained very quickly compared to the method of generating fine bubbles from a normal liquid liquid as described above. It was found that a foamy liquid containing minute bubbles can be generated.

FIG. 6 is a schematic explanatory diagram of a fixing liquid foaming device 500 included in the fixing device 6 of the present embodiment.
In the fixing liquid foaming device 500 shown in FIG. 6, after the foam fixing liquid containing large bubbles is generated by the gas / liquid mixing unit 510, the large bubbles of the foam fixing liquid are separated by the minute diameter foam generating unit 520. It is an apparatus that generates bubbles to form a foam-like fixing solution having a fine bubble diameter.
As shown in FIG. 6, an air port 512 is provided in the gas / liquid mixing unit 510 to which the fixing solution transport pipe 134 to which the liquid fixing solution 132 is transported is connected. Along with the flow of the fixing liquid 132 to which the conveying force is applied by the fixing liquid conveying pump 133, a negative pressure is generated in the air port 512, and gas is introduced into the gas / liquid mixing unit 510 from the air port 512. As a result, the liquid fixing solution 132 and the gas are mixed, and further, the mixed material passes through the microporous sheet 511, thereby generating a large bubble fixing solution F having a uniform bubble diameter. it can.
The hole diameter of the microporous sheet 511 is preferably about 30 [μm] to 100 [μm]. The member that uses the liquid fixing solution 132 as the foam fixing solution F is not limited to the microporous sheet 511 provided in the fixing device 6. It may be a porous member having a continuous foam structure, and may be a sintered ceramic plate, a nonwoven fabric or a foamed resin sheet having pores with a pore diameter of about 30 [μm] to 100 [μm]. As another method for generating large bubbles, bubbles are entrained in the fixing liquid 132 while stirring the liquid fixing liquid 132 supplied by the fixing liquid conveying pump 133 and the air from the air port 512 with a blade-shaped stirrer. However, it may be configured to generate a foam-like fixing solution F containing large bubbles. Further, the liquid fixing solution 132 supplied by the fixing solution transport pump 133 may be bubbled with an air supply pump or the like to generate a foamy fixing solution F containing large bubbles.

  The foam-like fixer F containing large bubbles generated in the gas / liquid mixing unit 510 is conveyed to the micro-bubble generation unit 520 through the in-foaming device conveyance tube 515. The micro-bubble generating unit 520 is configured to apply a shearing force to the foam fixing solution F containing large bubbles in order to divide the large foam of the foam fixing solution F into two or more bubbles. The micro-bubble generating unit 520 provided in the fixing device 6 is a closed double cylinder including an outer cylindrical part 521 and an inner cylindrical part 522, and the inner cylindrical part 522 is configured to be rotatable with respect to the outer cylindrical part 521. ing. An in-foaming device transport pipe 515 is connected to the fixing liquid inlet 521a opened in a part of the outer cylindrical portion 521, and the foam-like fixing liquid F containing large bubbles is supplied from the fixing liquid inlet 521a. It is supplied to the gap between the outer cylindrical portion 521 and the inner cylindrical portion 522. The foam-like fixer F supplied from the gas / liquid mixing unit 510 to the micro-bubble generating unit 520 passes through a gap (this is a flow path) between the outer cylindrical unit 521 and the inner cylindrical unit 522. The shearing force is received by the rotation of the inner cylindrical portion 522. Due to this shearing force, the large bubbles are changed to micro bubbles, and are conveyed from the fixing solution outlet 521b provided in a part of the outer cylindrical portion 521 to the fixing solution supply port 501, and from the fixing solution supply port 501 to the thin film. A foamy fixing solution F is supplied onto the surface of the forming belt 151. Thereby, the foam-like fixing solution F having a desired fine bubble diameter can be obtained.

As a result of the experiments by the present inventors, the liquid conveyance speed for efficiently obtaining the foam-like fixing liquid F having a desired fine bubble diameter is determined by the rotational speed of the rotating inner cylindrical portion 522 and the longitudinal direction of the inner cylindrical portion 522. It was found to be determined by the length of the. As shown in FIG. 6, the outer cylindrical portion 521 has an inner diameter d1 [mm], an inner cylindrical portion 522 has a length L [mm], an inner cylindrical portion 522 has an outer diameter d2 [mm], and the inner cylindrical portion 522 has an outer diameter d2. Assuming that the rotation speed is R [rpm], it was found that the desired liquid conveyance speed V [mm ³ / s] for generating minute bubbles is determined by the following equation (1).
V = {L × π × (d1 ² −d2 ² ) / 4} / (1000 / R) (1)

For the above formula (1), for example, when d1 is 10 [mm], d2 is 8 [mm], L is 50 [mm], and the rotation speed R is 1000 [rpm], the liquid conveyance speed is about 1400 [mm]. ³ / s] (1.4 [cc / s]). Assuming that the foamy fixing solution F required for fixing the A4 paper is 3 [cc], the rise time is about 2 to generate the necessary amount of the foaming fixing solution F from the liquid fixing solution 132. With [s], it is possible to generate the foam-like fixing solution F having a desired bubble diameter very quickly. Note that a spiral groove may be provided on the outer periphery of the inner cylindrical portion 522 to improve the transportability of the foam-like fixing liquid F in the outer cylindrical portion 521.
A fixing liquid foaming device 500 shown in FIG. 6 includes a gas / liquid mixing section 510 that is a large-diameter foam generating section that changes the liquid fixing liquid 132 into a foam-like fixing liquid F containing a large foam diameter, and a large foam. And a micro-bubble generating unit 520 that generates a foam-like fixing solution F containing micro-bubbles by applying a shearing force. In this way, by combining the gas / liquid mixing unit 510 and the micro-bubble generating unit 520, the foam-like fixing solution having a micro bubble diameter of about 5 [μm] to 50 [μm] from the liquid fixing solution 132 is obtained. F can be generated in a very short time.

  The fixing device 6 of the present embodiment uses a fixing solution transport pump 133 as a means for transporting the liquid fixing solution 132 from the fixing solution bottle 131 to the fixing solution foaming device 500. As the fixing liquid transport pump 133, a gear pump, a bellows pump, or the like is applicable, but a tube pump is preferable. If there is a vibration mechanism or a rotation mechanism in the path through which the fixing liquid passes, such as a gear pump, the liquid bubbles in the pump, the liquid may be compressible, and the conveyance capability may be reduced. In addition, there is a possibility that the parts of the mechanism contaminate the fixing liquid, and conversely the fixing liquid deteriorates the parts of the mechanism. On the other hand, since the tube pump is a mechanism that pushes out the liquid in the tube while deforming the tube, the only member in contact with the fixing liquid is the tube, and a member having liquid resistance to the fixing liquid is used as the tube. Thus, it is possible to prevent contamination of the fixing solution and deterioration of the pump system parts. In addition, since the conveying force is applied to the liquid passing through the inside simply by deforming the tube, the fixing liquid does not foam, and it is possible to prevent the conveyance capacity from being lowered due to the foaming.

The bulk density of the foam-like fixing solution F supplied to the application roller 141 is preferably in the range of about 0.01 [g / cm ³ ] to 0.1 [g / cm ³ ]. Further, the fixer only needs to be foamed when applied to a layer of resin-containing fine particles such as a toner layer on a recording medium such as transfer paper P. The fixer is foamed in the fixer bottle 131 as a storage container. There is no need. For this reason, the fixing liquid 132 is a normal liquid containing no bubbles in the fixing liquid bottle 131. The fixing liquid 132 is supplied when the fixing liquid is supplied from the fixing liquid bottle 131 or until it is applied to the toner layer on the transfer paper P. It is desirable to provide a means for forming bubbles in the transport path. This is because the configuration in which the fixing liquid bottle 131 as a storage container is in a normal liquid state and the liquid is taken out from the fixing liquid bottle 131 to form a foam has a great advantage that the fixing liquid bottle 131 can be downsized. It is for having.

Next, the liquid formulation of the fixing solution will be described.
As described above, the foamy fixing solution F has a structure in which bubbles are contained in the liquid fixing solution 132 containing a softening agent. The fixing solution 132 containing the softening agent stably contains bubbles when the foam-like fixing solution F is used, and forms a bubble layer composed of bubbles having a uniform size as much as possible. It is desirable to have a foam booster. Moreover, it is desirable to contain a thickener since the bubbles are more stably dispersed in the liquid when the viscosity is higher to some extent.
As the foaming agent, an anionic surfactant, particularly a fatty acid salt is desirable. Since the fatty acid salt has surface activity, the surface tension of the fixing solution 132 containing water is lowered to make the fixing solution 132 easily foamed, and the fatty acid salt has a layered lamellar structure on the foam surface, so that the foam wall (plateau boundary Fa ) Is stronger than other surfactants and the foam stability is extremely high. Further, in order to make the foaming property of the fatty acid salt effective, it is desirable that the fixing solution 132 contains water. As the fatty acid, a saturated fatty acid resistant to oxidation is desirable from the viewpoint of long-term stability in the air. However, the fixing solution 132 containing a saturated fatty acid salt contains a slight amount of unsaturated fatty acid salt, thereby helping to dissolve and disperse the fatty acid salt in water, and at low temperatures from 5 [° C.] to 15 [° C.] It can have excellent foaming properties, can stabilize the fixing property in a wide environmental temperature range, and can prevent separation of fatty acid salt in the fixing solution when the fixing solution 132 is left for a long period of time. .

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

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

  Further, when the saturated fatty acid salt or the unsaturated fatty acid salt is used as a foaming agent for the fixing solution 132 in the fixing device 6 of the present embodiment, it is preferably a sodium salt, a potassium salt or an amine salt. It is an important factor as the commercial value of the fixing device 6 that the fixing device 6 can be quickly fixed after the power is turned on. In order to make the fixing device 6 ready for fixing, it is essential that the fixing liquid 132 is in a suitable foam form (foamed fixing liquid F). However, the fatty acid salt is quickly foamed. It is possible to create a fixable state in a short time after the power is turned on. In particular, when an amine salt is used, foaming fixer F can be easily produced by foaming in a shorter time than other foaming agents when shear force is applied to fixing solution 132. Thus, it is possible to create a fixable state in a short time after the power supply to the fixing device 6 is turned on.

The softening agent that is softened by dissolving or swelling the resin contains an aliphatic ester. This aliphatic ester is excellent in solubility or swelling property that dissolves or swells at least a part of the resin contained in the toner or the like.
Further, the toner is fixed to the recording medium by a device that is frequently used in a sealed environment. After the toner is fixed to the recording medium, the softening agent remains in the toner. Fixing preferably does not involve the generation of volatile organic compounds (VOC) and unpleasant odors. That is, the softener preferably does not contain volatile organic compounds (VOC) and substances that cause unpleasant odors. Aliphatic esters have a high boiling point and low volatility and have no irritating odor as compared to generally used organic solvents (toluene, xylene, methyl ethyl ketone, ethyl acetate, etc.).
In addition, as a practical odor measurement scale that can measure odor in office environments with high accuracy, the odor index (10 × log {substance odor is felt by the three-point comparison odor bag method, which is a sensory measurement) The dilution factor of the substance until it disappears}) can be used as an indicator of odor. The odor index of the aliphatic ester contained in the softener is preferably 10 or less. In this case, an unpleasant odor is not felt in a normal office environment. Furthermore, it is preferable that not only the softening agent but also other liquid agents contained in the fixing solution have no unpleasant odor and irritating odor.

  In the fixing liquid 132 in the fixing device 6 to which the present invention is applied, the aliphatic ester preferably includes a saturated aliphatic ester. When the aliphatic ester contains a saturated aliphatic ester, the storage stability (resistance to oxidation, hydrolysis, etc.) of the softener can be improved. Also, many saturated aliphatic esters can dissolve or swell the resin contained in the toner within 1 second. Furthermore, saturated aliphatic esters can reduce the tackiness of the toner provided on the recording medium. This is considered to be because the saturated aliphatic ester forms an oil film on the surface of the dissolved or swollen toner.

Therefore, in the fixing solution 132 in the present invention, preferably, the saturated aliphatic ester is
R1COOR2
R1 is an alkyl group having 11 to 14 carbon atoms, and R2 is a linear or branched alkyl group having 1 to 6 carbon atoms. If the number of carbon atoms in R1 and R2 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability is lowered.
That is, the saturated aliphatic ester includes a compound represented by the general formula R1COOR2, R1 is an alkyl group having 11 to 14 carbon atoms, and R2 is a linear type having 1 to 6 carbon atoms Alternatively, in the case of a branched alkyl group, the solubility or swelling property with respect to the resin contained in the toner can be improved. Moreover, the odor index of the said compound is 10 or less, and the said compound does not have an unpleasant odor and an irritating odor.

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

In the fixing solution 132 of the present invention, the aliphatic ester preferably includes an aliphatic dicarboxylic acid ester. When the aliphatic ester contains an aliphatic dicarboxylic acid ester, the resin contained in the toner can be dissolved or swollen in a shorter time. For example, in high-speed printing of about 60 [ppm], it is desirable that the time until the fixing liquid is applied to the unfixed toner on the recording medium and the toner is fixed on the recording medium is within 1 second. When the aliphatic ester contains an aliphatic dicarboxylic acid ester, the time required for fixing the toner to the recording medium by applying the fixing solution to the unfixed toner on the recording medium is within 0.1 seconds. It becomes possible to. Furthermore, since the resin contained in the toner can be dissolved or swollen by adding a smaller amount of the softening agent, the content of the softening agent contained in the fixing liquid can be reduced.
Therefore, in the fixing solution 132 in the present invention, preferably, the aliphatic dicarboxylic acid ester is
R3 (COOR4) ₂
In which R3 is an alkylene group having 3 to 8 carbon atoms, and R4 is a linear or branched alkyl group having 3 to 5 carbon atoms. If the number of carbon atoms in R3 and R4 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability decreases.
That is, the aliphatic dicarboxylic acid ester includes a compound represented by the general formula R3 (COOR4) ₂ , R3 is an alkylene group having 3 to 8 carbon atoms, and R4 has 3 to 5 carbon atoms. In the case of the following linear or branched alkyl group, the solubility or swelling property with respect to the resin contained in the toner can be improved. Moreover, the odor index of the said compound is 10 or less, and the said compound does not have an unpleasant odor and an irritating odor.
Examples of the aliphatic dicarboxylic acid ester as the above compound include 2-ethylhexyl succinate, dibutyl adipate, diisobutyl adipate, diisopropyl adipate, diisodecyl adipate, diethyl sebacate, dibutyl sebacate and the like. Many of these aliphatic dicarboxylic acid esters which are the above compounds are soluble in oily solvents, but not in water. Therefore, in an aqueous solvent, glycols are contained in the fixing solution as a dissolution aid and are in the form of a solution or microemulsion.

Furthermore, in the fixing solution 132 used in the fixing device 6 to which the present invention is applied, the aliphatic ester preferably contains an aliphatic dicarboxylic acid dialkoxyalkyl. When the aliphatic ester contains an aliphatic dicarboxylate dialkoxyalkyl, the fixability of the toner to the recording medium can be improved.
In the fixing liquid 132 used in the fixing device 6 to which the present invention is applied, the aliphatic dicarboxylic acid dialkoxyalkyl is
R5 (COOR6-O-R7) ₂
It is preferable that the compound represented by general formula of this is included. In this general formula, R5 is an alkylene group having 2 to 8 carbon atoms, R6 is an alkylene group having 2 to 4 carbon atoms, and R7 is an alkyl group having 1 to 4 carbon atoms. It is. If the number of carbon atoms in R5, R6, and R7 is less than the desired range, odor is generated, and if it is greater than the desired range, the resin softening ability decreases.
That is, the aliphatic dicarboxylic acid dialkoxyalkyl includes a compound represented by the general formula R5 (COOR6-O-R7) ₂ , R5 is an alkylene group having 2 to 8 carbon atoms, and R6 is: When R 7 is an alkylene group having 2 to 4 carbon atoms and R 7 is an alkyl group having 1 to 4 carbon atoms, it can improve the solubility or swellability of the resin contained in the toner. Moreover, the odor index of the said compound is 10 or less, and the said compound does not have an unpleasant odor and an irritating odor.
Examples of the aliphatic dicarboxylate dialkoxyalkyl which is the above compound include diethoxyethyl succinate, dibutoxyethyl succinate, diethoxyethyl adipate, dibutoxyethyl adipate, diethoxyethyl sebacate and the like. In an aqueous solvent, these aliphatic dicarboxylic acid dialkoxyalkyls are contained in the fixing solution as a solubilizing agent, and dissolved or microemulsified.
Although not fatty acid esters, citrate esters, ethylene carbonate, and propylene carbonate are also suitable as softening or swelling agents.
By the way, in the foam-like fixing solution, if the foam breaks when the foam-like fixing solution is permeated while being pushed into the fine particle layer such as toner at the coating contact nip portion, the penetration is inhibited. Therefore, a foam excellent in foam stability is required. For this reason, it is desirable to contain a fatty acid alkanolamide (1: 1) type in the fixing solution. Fatty acid alkanolamides include (1: 1) type and (1: 2) type, but it was found that (1: 1) type is suitable for foam stability in the present invention.

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

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

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

When using an aqueous solvent, it is preferable to add a surfactant to make the surface tension 20-30 [mN / m]. In the case of an aqueous solvent, it is desirable to contain a unit price or a polyhydric alcohol. These materials have the advantage of increasing the stability of bubbles in the foam-like fixing solution and making it difficult to break the bubbles. For example, monohydric alcohols such as cetanol, and polyhydric alcohols such as glycerin, propylene glycol, and 1,3 butylene glycol are desirable. Further, containing these unit price or polyhydric alcohols has an effect of preventing curling of a medium such as paper.
In addition, it is also desirable to form an O / W emulsion or a W / O emulsion containing an oil component in order to improve permeability and prevent curling of a medium such as paper, in which case, as a specific dispersant Are preferably sorbitan fatty acid esters such as sorbitan monooleate, sorbitan monosterate and sorbitan sesquioleate, and sucrose esters such as sucrose laurate and sucrose stearate.

As a method for dissolving the softener or dispersing the microemulsion in the fixing solution, for example, mechanical stirring means such as a homomixer or a homogenizer using a rotary blade, and vibration such as an ultrasonic homogenizer is applied. Means are mentioned. In any case, a strong shear stress is added to the softener in the fixing solution to dissolve or disperse the microemulsion.
In addition, the toner fixing device pressurizes the dissolved or swollen toner with a component (softener) that dissolves or swells at least a part of the resin contained in the toner after supplying the fixing liquid in the present invention to the toner. You may have a pair of smoothing roller (hard roller). By pressurizing the dissolved or swollen toner with a pair of smoothing rollers (hard rollers), the surface of the layer of the dissolved or swollen toner can be smoothed to give gloss to the toner. Furthermore, by fixing the dissolved or swollen toner into the recording medium, the fixability of the toner to the recording medium can be improved.

An example of a specific formulation of the fixing solution that can be used as the fixing solution 132 of the fixing device 6 of the present embodiment is shown below.
・ Diluting solvent: Ion-exchanged water 53 [wt%]
・ Softening agent: Diethoxyethyl succinate (Croda Croda DES)
10 [wt%]
Propylene carbonate 20 [wt%]
・ Thickener: Propylene glycol 10 [wt%]
・ Foaming agent: Palm fatty acid diethanolamide (1: 1) type (Matsumoto Yushi Marpong MM)
0.5 [wt%]
・ Foaming agent: amine palmitate 2.5 [wt%]
Amine myristate 1.5 [wt%]
Amine stearate 0.5 [wt%]
Dispersant: POE (20) lauryl sorbitan (Kao Leodol TW-S120V)
1 [wt%]
Polyethylene glycol monostearate (Kao Emanon 3199)
1 [wt%]

Here, the configuration of the conventional fixing device described in Patent Document 5 will be described with reference to the drawings.
FIG. 7 is an explanatory diagram schematically showing a conventional fixing device 60, FIG. 7A is a schematic explanatory diagram of the entire conventional fixing device 60, and FIG. 7B is a diagram illustrating the conventional fixing device 60. It is the perspective explanatory view which looked at the application roller 141 provided from the arrow B direction in Drawing 7 (a).
In the conventional fixing device 60, the foamy fixing solution F generated by the foamy fixing solution generator 130 is supplied onto the surface of the application roller 141 of the fixing solution application unit 140 that is a foamy fixing solution application unit. The fixing liquid application unit 140 includes an application roller 141 and a pressure roller 143 disposed at a position facing the application roller 141. Furthermore, a liquid film thickness control blade 154 is provided that is close to or in pressure contact with the surface of the application roller 141 on the upstream side in the surface movement direction of the application roller 141 with respect to the application position C where the application roller 141 and the pressure roller 143 face each other. The liquid film thickness control blade 154 controls the film thickness of the foamy fixing liquid F on the surface of the coating roller 141. Thus, since the conventional fixing device 60 controls the film thickness of the foam-like fixing solution F on the surface of the application roller 141, the foam-like fixing solution thinning means included in the fixing device 6 shown in FIG. In this configuration, the fixing liquid application unit 140 also has the function as the fixing liquid thinning unit 150. Thus, it goes without saying that the configuration of the conventional fixing device 60 is simpler and has fewer parts than the fixing device 6 shown in FIG. 1, but has the following problems.

  The conventional fixing device 60 sandwiches the transfer paper P between an application roller 141 on which a layer of foamy fixing solution F is formed and a pressure roller 143 provided opposite to the application roller C at an application position C. In this configuration, a foamy fixing solution F is applied to the transfer paper P. In such a configuration, when the transfer paper P is not conveyed (when there is no transfer paper P at the application position C), the foamy fixing liquid F on the application roller 141 may adhere to the pressure roller 143 and become dirty. . Unless the foam-like fixing liquid F adhering to the pressure roller 143 is cleaned, it eventually adheres to the back side of the transfer paper P, causing problems such as deterioration of the recorded image and diffusion of the foam-like fixing liquid F in the apparatus. It will be. Even if the pressure roller 143 is cleaned, it is desirable that the foam-like fixing liquid F adhered to the pressure roller 143 is as small as possible in order to reduce the load on the cleaning mechanism.

  The conventional fixing device 60 includes a paper edge detection sensor 170 as a recording medium leading edge trailing edge detecting means for detecting the leading edge and trailing edge of the transfer paper P on the upstream side in the conveyance direction of the transfer paper P with respect to the coating position C. Prepare. In Patent Document 5, the foam-like fixing liquid F is applied only when the transfer paper P is present at the application position C in accordance with the recording medium leading edge trailing edge detection signal of the paper edge detection sensor 170. As described above, a configuration is described in which the application roller 141 and the pressure roller 143 are contacted and separated.

  However, in recent electrophotographic image forming apparatuses, the linear speed of conveyance of the recording medium is very high, and in the middle class apparatuses, those of 200 [mm / s] or more are common. As the recording medium, a standard size transfer paper such as A4 is most often used. Therefore, the recording medium is continuously conveyed while taking a certain distance between the recording media. Therefore, in the configuration in which the application roller 141 and the pressure roller 143 are brought into contact with and separated from each other according to the recording medium leading edge / rear edge detection signal, the application roller 141 and the pressure roller 143 are separated from each other between the recording media (so-called paper intervals). There is a need to. For this reason, in the conventional fixing device 60, it is necessary to perform the contact / separation operation between the application roller 141 and the pressure roller 143 at a very fast timing. Furthermore, with respect to the pressure applied by the application roller 141 and the pressure roller 143, conditions such as the pressure and the nip width have a great effect on the fixability, so it is not desirable to change, and a further appropriate pressure is required. And Therefore, frequent contact / separation between the application roller 141 and the pressure roller 143 is likely to cause problems such as deterioration of fixability and large energy required for operation. Further, the application roller 141 and the pressure roller 143 apply a foam-like fixing liquid F to the transfer paper P and also have a function of conveying the transfer paper P. Frequent contact and separation cause image deterioration due to shock jitter. There are also concerns.

Due to the above-described problems, the application roller 141 and the pressure roller 143 are contacted and separated according to the recording medium leading end / back end detection signal so that the application roller 141 and the pressure roller 143 are separated from each other between the recording media. Such a configuration is difficult to realize.
As described above, when it is difficult to control the contact / separation between the application roller 141 and the pressure roller 143, the foam-like fixing liquid F is carried on the portion corresponding to the space between the recording media on the surface of the application roller 141. The structure which is not allowed is considered. In the conventional fixing device 60 shown in FIG. 7, the configuration in which the foam-like fixing liquid F is not carried on a part of the surface of the application roller 141 is directed to the application position C according to the signal from the recording medium leading edge / end edge detecting means. It is configured to control ON / OFF of the supply of the foamy fixing liquid F to the surface of the application roller 141.

  As a specific method for turning ON / OFF the supply of the foam-like fixing liquid F to the surface toward the application position C, the gap and the pressing force of the liquid film thickness control blade 154 to the surface of the application roller 141 are changed. A method for controlling the ON / OFF of the supply of the foam-like fixing solution F by using the above method is conceivable. Further, a method of controlling the supply of the foam-like fixing liquid F from the foam-like fixing liquid generation unit 130 which is a foam-like fixing liquid generation unit to the surface of the coating roller 141 is conceivable.

  Incidentally, it goes without saying that the foam-like fixing solution F must be uniformly applied to the image forming portion on which the toner layer T on the transfer paper P is carried. This is because unevenness in the application amount of the fixer becomes unevenness in fixing property, and unevenness in fixing property becomes a fatal problem in image quality. On the other hand, from the viewpoint of contamination of the pressure roller 143 and cleaning thereof, it is desirable that the foam-like fixing liquid F is not supplied to the application position C as much as possible at the timing when the transfer paper P does not exist at the application position C. In addition, in recent electrophotographic apparatuses, it is common to output photographic image quality, that is, there is a high need for outputting an image having almost no margin. From these things, the application of the foam-like fixing solution F to the transfer paper P is a highly accurate and uniform distribution of physical properties (film thickness, average particle diameter of bubbles, bulk density of bubbles) of the foam-like fixing solution F. Need to be made.

  Considering these, as a method for controlling ON / OFF of the supply of the foam-like fixing liquid F to the application roller 141 toward the application position C, the gap and the pressing force of the liquid film thickness control blade 154 are changed. It must be said that the method is difficult to implement. In recent electrophotographic image forming apparatuses, the linear velocity of conveyance of the recording medium is very high as described above, and in the middle class apparatus, the one of 200 [mm / s] or more is common. For this reason, it is necessary to complete the change of the gap and the pressing force of the liquid film thickness control blade 154 in a very short time. There is a possibility that the supply of the foamy fixing solution F can be turned off in a short time by increasing the pressing force of the liquid film thickness control blade 154 or closing the gap. However, since it is necessary to stabilize the supply of the foamy fixing solution F to an appropriate gap and pressing force, it is difficult to control in a short time.

  Further, regarding the method for controlling the supply of the foam-like fixing liquid F from the foam-like fixing liquid generating unit 130 to the surface of the application roller 141, it is difficult to realize at least the configuration of the conventional fixing device 60. . This is because, in the conventional fixing device 60, a bubble pool is formed on the upstream side in the surface movement direction with respect to the position where the liquid film thickness control blade 154 is provided on the surface of the coating roller 141. Due to the presence of the bubble reservoir, even if the supply of the foam fixer F from the foam fixer generator 130 to the surface of the application roller 141 is stopped, the amount of the foam fixer F forming the bubble reservoir is reduced. As a result, the foam-like fixing liquid F is carried on the surface of the application roller 141 toward the application position C. For this reason, the supply of the foam-like fixer F to the surface of the application roller 141 toward the application position C is controlled by controlling the supply of the foam-like fixer F to the surface of the application roller 141 from the foam-like fixer generator 130. It is difficult to accurately control ON / OFF of the.

  Further, when the fixing operation is performed after being left for a certain period of time, the characteristics of the foam-like fixing liquid F change depending on the time, so that the surface of the coating roller 141 moves upstream of the position where the liquid film thickness control blade 154 is provided. The formed bubble-like fixing solution F cannot be used as it is. Even if the foam-like fixing liquid F in the bubble pool is recovered, the application roller 141 needs a cleaning mechanism for recovery. Further, since the cleaning mechanism also cleans the toner offset on the application roller 141, the recovered foamy fixing solution F can only be discarded.

Next, the fixing device 6 according to this embodiment having a configuration capable of solving the problems of the conventional fixing device 60 shown in FIG. 7 will be described.
As described above, the fixing device 6 shown in FIG. 1 is roughly divided into a foam-like fixer generating unit 130 as a foam-type fixer generating unit, and a foam-type fixer thinning unit 150 as a foam-type fixer thinning unit. , And a fixing liquid application unit 140 which is a foam-like fixing liquid application unit. A significant difference from the configuration of the conventional fixing device 60 is that the foam-like fixing liquid thinning section 150 and the fixing liquid coating section 140 are provided separately. Further, the surface of the thin film forming belt 151 of the foam-like fixing liquid thinning section 150 and the surface of the coating roller 141 of the fixing liquid coating section 140 are configured to be able to contact and separate.
Further, a contact / separation control unit 250 is provided as contact / separation control means for controlling contact / separation between the surface of the thin film forming belt 151 and the surface of the application roller 141. The contact / separation control unit 250 controls the contact / separation between the surface of the thin film forming belt 151 and the surface of the coating roller 141, thereby controlling the supply of the foamy fixing solution F to the fixing solution coating unit 140 as necessary. It becomes possible.

  In the fixing device 6, the foamy fixer F generated by the foamy fixer generator 130 is supplied to the foamy fixer thinning unit 150. Referring to FIG. 1, the foam-like fixing liquid thinning unit 150 includes two stretching rollers and a thin film forming belt 151 that is stretched with a predetermined tension across the stretching rollers. Then, the foam-like fixing liquid F is supplied from the foam-like fixing liquid generation unit 130 and the foam-like fixing liquid F is fixed onto the thin film forming belt 151 by using a liquid film thickness control blade 154 which is a foam-like fixing liquid film thickness control means. A thin layer of the liquid F is formed.

One of the two stretching rollers is a blade facing roller 152 facing the liquid film thickness control blade 154 with the thin film forming belt 151 interposed therebetween. Since the liquid film thickness controlling blade 154 needs to apply a suitable pressure to form a thin layer of the foam-like fixing solution F, a member for receiving the pressure of the liquid film thickness controlling blade 154 is necessary. This is the configuration.
Further, the blade facing roller 152 is connected to a drive source (not shown), and the thin film forming belt 151 is moved in the direction of arrow I in FIG. 1 when the blade facing roller 152 is rotationally driven in the direction of arrow H in FIG. Move the surface.

  On the surface of the thin film forming belt 151, the liquid film thickness control blade 154 acts to form a foam-like shape upstream of the surface moving direction of the thin film forming belt 151 with respect to the portion where the foam-like fixing solution F on the surface is thinned. The foamy fixing solution F generated by the fixing solution generator 130 is supplied. The liquid film thickness control blade 154 forms an optimal film thickness by thinning the foamy fixing solution F supplied on the surface of the thin film forming belt 151. The film thickness required here is such that an optimal film thickness is formed on the surface of the application roller 141 of the fixing liquid application unit 140 when applying to the transfer paper P at the application position C. is there. At this time, the thin film forming belt in consideration that the foamy fixing solution F is transferred from the surface of the thin film forming belt 151 of the foam fixing solution thinning unit 150 onto the surface of the application roller 141 of the fixing solution applying unit 140. The optimal film thickness on the surface of 151 is required.

Next, control of the film thickness of the foam-like fixing liquid F on the surface of the thin film forming belt 151 by the liquid film thickness control blade 154 will be described.
FIG. 8 is an explanatory diagram of a configuration for controlling the pressing force of the liquid film thickness control blade 154 against the thin film forming belt 151. FIG. 8A is an explanatory diagram of a state where the pressure by the spring 157 is increased, and FIG. 8B is an explanatory diagram of a state where the pressure by the spring 157 is decreased. Further, the drawing on the left side in FIG. 8 is an explanatory diagram of the state before the foamy fixing solution F passes through the position where the film thickness is controlled by the liquid film thickness control blade 154. On the other hand, in the drawing on the right side in FIG. 8, the foamy fixing solution F passes through the position where the film thickness is controlled by the liquid film thickness control blade 154 and is thinned on the surface of the thin film forming belt 151. It is explanatory drawing of the state in which the foamy fixing solution Fc was formed.

  The liquid film thickness control blade 154 is disposed such that the blade free end 154b can swing around the blade fixed end 154a, and one end of a spring 157 is fixed to the blade free end 154b. The other end of the spring 157 is fixed to a spring support 158 a of the solenoid 158. The spring support portion 158a can be displaced in the direction of arrow J in FIG. 8 by controlling the solenoid 158. As shown in FIG. 8A, the pressure of the spring 157 against the blade free end 154b of the liquid film thickness control blade 154 increases by bringing the position of the spring support portion 158a closer to the thin film forming belt 151. Thereby, the film thickness of the thinned foamy fixing solution Fc is reduced. On the other hand, as shown in FIG. 8B, the spring 157 pushes the liquid film thickness control blade 154 against the blade free end 154b by reducing the position of the spring support portion 158a away from the thin film forming belt 151. Thereby, the film thickness of the thinned foamy fixing solution Fc is increased.

The foam-like fixer F supplied from the foam-like fixer generator 130 is used for controlling the liquid film thickness based on its own viscosity, surface tension, etc. with respect to the liquid film thickness control blade 154 provided at the trailing position. The blade 154 is pushed away and passes through the liquid film thickness control blade 154. As a result, a thin layer is formed using the thinned foamy fixing solution Fc. Therefore, as the pressing force of the liquid film thickness control blade 154 to the thin film forming belt 151 increases, the film thickness of the thinned foam fixing solution Fc decreases. Using this characteristic, the film thickness is controlled.
In order to easily control the pressing force of the liquid film thickness control blade 154 against the thin film forming belt 151, a combination of a spring 157 and a solenoid 158 is typical as shown in FIG. Can be mentioned.
As a configuration for controlling the pressing force of the liquid film thickness control blade 154 against the thin film forming belt 151, as shown in FIG. 9, the distance between the liquid film thickness control blade 154 and the thin film formation belt 151 is closest. A gap regulating member 159 may be provided. 9 is also an explanatory diagram of the state before the foamy fixing liquid F passes through the position where the film thickness is controlled by the liquid film thickness control blade 154, as in FIG. . Further, in the drawing on the right side in FIG. 9, the foam-like fixing solution F passes through the position where the film thickness is controlled by the liquid film thickness control blade 154 and is thinned on the surface of the thin film forming belt 151. It is explanatory drawing of the state in which the foamy fixing solution Fc was formed.

As another configuration for controlling the film thickness of the foam-like fixing solution F on the surface of the thin film forming belt 151, as shown in FIG. 10, the gap between the liquid film thickness controlling blade 154 and the thin film forming belt 151 (hereinafter referred to as the film forming belt 151). In some cases, this is performed by controlling the width of the blade gap.
FIG. 10A is an explanatory diagram in a state where the blade gap is small, and FIG. 10B is an explanatory diagram in a state where the blade gap is large. In the configuration shown in FIG. 10, by driving the solenoid 158, the position of the blade abutting portion 158b is displaced in the direction of arrow J in FIG. Then, the displacement amount of the blade free end 154b against which the blade contact portion 158b comes into contact changes, and the width of the blade gap can be controlled.
As shown in FIG. 10A, the blade gap is narrowed when the thickness of the thinned foam fixing solution Fc is reduced, and the blade gap is increased when the thickness is increased. Various driving means such as a motor and a solenoid can be considered as specific driving means for changing the width of the blade gap.

  Regardless of the configuration for controlling any film thickness, the liquid film thickness control blade 154 is provided at the trailing position with respect to the thin film forming belt 151. That is, in the liquid film thickness control blade 154, the direction from the blade fixed end 154a toward the blade free end 154b is the same as the surface moving direction of the thin film forming belt 151. In the liquid film thickness control blade 154, the direction in which the direction from the blade fixed end 154a to the blade free end 154b and the surface moving direction of the thin film forming belt 151 are opposite is called a counter position. Further, the portion where the liquid film thickness control blade 154 and the thin film forming belt 151 come into contact with each other or the closest distance is not limited to the edge portion at the blade free end 154b of the liquid film thickness control blade 154, as shown in FIG. Alternatively, it may be the surface of the liquid film thickness control blade 154.

  Note that the film thickness can be controlled even if the liquid film thickness control blade 154 is disposed on the thin film forming belt 151 at the counter position. However, at the counter position, if the liquid film thickness control blade 154 and the thin film forming belt 151 are in contact with each other, the film thickness is substantially zero. The gap between the edge of the liquid film thickness control blade 154 and the thin film forming belt 151 is directly reflected as the film thickness. Therefore, the film thickness control at the tens [μm] level is severe control. On the other hand, the method of controlling the pressing force of the liquid film thickness control blade 154 to the thin film forming belt 151 at the trailing position can control the film thickness at several tens [μm] level even if the pressure slightly fluctuates. It turns out that the impact is not so great.

  Further, of the two stretching rollers of the thin film forming belt 151, the blade facing roller 152 facing the liquid film thickness controlling blade 154 has a deflection of several tens [μm] even when precision processing is performed. Yes. Accordingly, it goes without saying that there is a problem that it is impossible to control the film thickness of several tens of [μm] unless the liquid film thickness control blade 154 follows this vibration. Then, in any case, it is the easiest to solve the above problem that the liquid film thickness control blade 154 directly presses the thin film forming belt 151 or via the gap regulating member 159 as shown in FIG. It becomes a means. Further, in the configuration in which the film thickness is controlled by controlling the pressing force of the liquid film thickness controlling blade 154 against the thin film forming belt 151, the requirement that the liquid film thickness controlling blade 154 directly applies pressure to the thin film forming belt 151 is already satisfied. ing.

Of the two stretching rollers of the thin film forming belt 151, the other stretching roller is an arrow in FIG. 1 in order to enable the application roller 141 of the fixing liquid application unit 140 and the thin film forming belt 151 to be contacted and separated. A movable roller 153 is provided so as to be displaceable in the E direction. The power that displaces the movable roller 153 may be brought into and out of contact by rotating the cam 155 via the cam 155 as shown in FIG. 1, or a solenoid may be used. In either case, the important thing is to make contact quickly. This is because on the surface of the application roller 141, the boundary between the transfer portion to which the foam-like fixing solution F has been transferred and the non-transfer portion to which the foam-like fixing solution F has not been transferred needs to be made clear. This is because, as described above, it is necessary to apply the foamy fixing solution F from the coating roller 141 to the transfer paper P with a highly accurate and uniform distribution of physical properties of the foaming fixing solution F. Therefore, it is desirable that the movable roller 153 has a mass as small as possible. Possible methods include reducing the diameter, using resin as the material, and using a hollow roller. This is because the smaller the mass, the smaller the force required to move the movable roller 153 quickly.
In the fixing device 6, the contact / separation control unit 250 controls the rotation of the cam 155 to control the contact / separation between the surface of the thin film forming belt 151 and the surface of the application roller 141.

  The film thickness of the thinned foam fixing solution Fc on the thin film forming belt 151 is usually formed around 100 [μm], but is about 200 [μm] at the maximum. Therefore, if the distance between the thin film forming belt 151 and the application roller 141 is 200 [μm] or more at the contact position G, transfer of the foamy fixing solution F to the application roller 141 does not occur. If the separation state is 0 to 200 [μm], the transfer is unstable. Therefore, if the separated state of 0 to 200 [μm] is as short as possible, the unstable transfer region can be reduced as much as possible. For example, when the contact / separation speed of the movable roller 153 is 40 [mm / s] and the process linear velocity is 200 [mm / s], the process is 1 [mm] while the movable roller 153 moves by 200 [μm]. Therefore, an unstable transfer region of 1 [mm] is formed, and a non-uniform portion of the boundary between the transfer portion and the non-transfer portion is 1 [mm]. This part is applied to the margin, but the margin is a sufficiently small value. Further, if it is desired to reduce the unstable transfer area, the contact / separation speed of the movable roller 153 may be increased, and if the margin is allowed, the contact / separation speed of the movable roller 153 may be decreased.

  By adopting such a configuration, it is possible to supply the foam-like fixing liquid F, which has been thinned almost uniformly, to the application roller 141 on demand. Here, in order to supply a uniform and always stable physical property of the foam fixing solution F, such as film thickness, average particle diameter of foam, and bulk density of the foam, in the foam fixing solution thinning unit 150 The physical properties of the foam-like fixing solution F must always be stable. In other words, since the foam-like fixer thin film forming unit 150 is separate from the fixer-applying unit 140, it is not necessary to consider contact with the transfer paper P, and the foam-type fixer having stable physical properties. It can be specialized to form a thin layer of F.

  Particularly, since the foam fixing solution F changes with time depending on the bubble breakage and the like, the average particle diameter of the foam, the bulk density of the foam, and the like change, the foam fixing solution F that has been used for a long time cannot be used as it is. Therefore, the foam fixing liquid thinning section 150 is provided with a foam suction section 156 as a collecting means for recovering the foam fixing liquid F that has passed the contact position G after being thinned from the thin film forming belt 151. . The collection means is not limited to the suction means such as the bubble suction unit 156, and various methods such as a collection blade can be considered. The foam-like fixing solution F sucked by the bubble suction unit 156 is returned to the fixing solution bottle 131 through the recovered solution transport path 156a and reused. The foamy fixing solution F collected from the thin film forming belt 151 may be stored separately from the fixing solution 132 in the fixing solution bottle 131.

The recovery of the foamy fixing solution F by the foam suction unit 156 may be performed at any time, but may be performed as necessary. Here, if necessary, the foam fixing solution F supplied to the foam fixing solution thinning unit 150 is not supplied to the fixing solution application unit 140 even after a certain period of time, and its physical properties have changed. Refers to the case. The determination can be made based on the contact frequency between the thin film forming belt 151 of the foam-like fixing liquid thinning section 150 and the coating roller 141 of the fixing liquid coating section 140. The contact frequency is a frequency including the time when the power of the machine is turned off (when the power is turned off, it is not usually in contact). In the fixing device 6 of the present embodiment, a foam-like fixing solution recovery control means (not shown) is provided, and when the contact frequency between the thin film forming belt 151 and the application roller 141 is less than a predetermined value, the foam-like fixing solution F is foam-fixed. It is determined that the physical properties have changed in the liquid thinning unit 150, and the bubble suction unit 156 is operated to collect the bubbles. Thereby, the foamy fixing solution F supplied to the fixing solution application unit 140 can always have stable physical properties.
It is most desirable that the foam-like fixing liquid F collected from the thin film forming belt 151 by the foam suction unit 156 is liquefied and returned to the fixing liquid bottle 131.

In the case where the foam-like fixing solution F on the thin film forming belt 151 is always collected, the configuration can be greatly simplified by using, for example, a fixed blade. Furthermore, although the foam fixing solution recovery control means is unnecessary, since the foam fixing solution is always recovered, a large amount of bulk bubbles are recovered, and the frequency of the operation of liquefying the bubbles increases. To do.
In this respect, it is advantageous to collect the foam-like fixing solution F as necessary because the collected amount can be minimized. However, in the configuration using a contact-type recovery member such as a blade as the recovery means, it may be necessary to contact the recovery member with the thin film forming belt 151 only when the foam-like fixing liquid F is recovered. An approach / separation mechanism is required.

  Further, in order not to increase the recovery amount of the foam fixing solution F by the collecting means more than necessary, the foam fixing solution F is appropriately supplied from the foam fixing solution generator 130 to the foam fixing solution thinning unit 150. Need to control. That is, it is desirable to supply on demand as much as possible. In the foam-like fixing solution thinning section 150, the foam-like fixing solution F is thinned by using a liquid film thickness control blade 154. For this reason, on the upstream side of the surface movement direction of the thin film forming belt 151 with respect to the position where the liquid film thickness control blade 154 controls the film thickness, as shown in FIG. When the bubble reservoir Fd disappears, it means that the foam-like fixing solution F in the foam-like fixing solution thinning portion 150 is insufficient. On the other hand, when the bubble pool Fd becomes large, it means that the foam-like fixing solution F is excessively supplied to the foam-like fixing solution thinning section 150. For this reason, it is desirable that there is always a certain amount of bubble reservoir Fd.

Therefore, the fixing device 6 includes a bubble accumulation detection unit that detects the size of the bubble accumulation Fd on the surface of the thin film forming belt 151. 12 is a perspective explanatory view of the portion where the bubble pool Fd on the surface of the thin film forming belt 151 shown in FIG. 11 is formed as seen from the direction of the arrow M in FIG.
As the bubble sensor 160 which is the bubble accumulation detection means shown in FIG. 12, the structure using the optical system detection means provided with the light emitting element 160a and the light receiving element 160b is typical. In the bubble sensor 160 in the example of FIG. 12, the light emitting element 160a and the light receiving element 160b are arranged in three places. In the light emitting element 160a, the emitted light has a different wavelength or is uniquely modulated. The light receiving elements 160b are configured to detect light from the light emitting elements 160a facing each other. In such a bubble sensor 160, if the bubble reservoir Fd becomes large, the path of light emitted from the light emitting element 160a is blocked by the bubble reservoir Fd, so that each light receiving element 160b cannot detect predetermined light. Thus, it is possible to determine the size of the bubble reservoir Fd. An inexpensive light emitting diode (LED) can be used as the light emitting element 160a, and a photodiode (PD) can also be used as the light receiving element 160b. A supply control unit (not shown) serving as a supply control means receives a detection result signal from each light receiving element 160b, and bubbles from the foam-like fixing liquid generation unit 130 to the foam-like fixing liquid thinning unit 150 based on this detection result. The supply of the fixing solution F is controlled.
When the bubble reservoir Fd detected by the bubble sensor 160 is smaller than a predetermined amount, the supply control unit (not shown) sends the foam-like fixing solution F from the foam-like fixing solution generation unit 130 to the foam-like fixing solution thinning unit 150. If the control is performed so that the operation of supplying the water is performed, it is possible to always make the bubble accumulation Fd exist in a certain amount.

Next, a configuration in which the thin film-like foam fixing solution F is transferred from the thin film forming belt 151 of the foam-like fixing solution thinning section 150 onto the application roller 141 of the fixing solution application section 140 will be described.
FIG. 13 is an explanatory diagram of the transfer rate of the foamy fixing solution F at the contact position G. FIG. Here, the transfer rate is present on the surface of the coating roller 141 after passing through the contact position G with respect to the pre-transfer foam fixing solution Fg existing on the surface of the thin film forming belt 151 before reaching the contact position G. This is the ratio of the foamy fixing solution Fh after transfer.
If the surface characteristics of the thin film forming belt 151 and the coating roller 141 that are the fixing liquid carrier are the same, the two fixing liquid carriers are brought into contact with each other at the contact position G, and are carried on the surface that has passed through the contact position G by the surface movement. The foamed fixing solution F is distributed substantially evenly between the thin film forming belt 151 and the application roller 141. That is, the foam-like fixing solution F is transferred from the thin film forming belt 151 to the application roller 141 by about 50%. If the transfer rate is stable, the film thickness of the foamy fixing solution Fh after the transfer on the coating roller 141 can be controlled as long as the film thickness of the foamy fixing solution Fg before the transfer on the thin film forming belt 151 can be controlled. It will be possible. However, if the film thickness is increased, the peeling portion of the foamy fixing solution F at the time of transfer becomes unstable, and the transfer rate changes as shown in FIG. Variation in the film thickness of the foam-like fixing solution Fh.

  For such a problem that the transfer rate varies, it is desirable to increase the transfer rate as much as possible. If the transfer rate is 100 [%] or a value corresponding to it, the variation in the film thickness of the foamed fixing liquid Fh after transfer formed on the application roller 141 is reduced as shown in FIG. 13B. Needless to say. As the simplest method for increasing the transfer rate, it is only necessary to make a difference in the peelability of the thin film forming belt 151 and the coating roller 141 from the foamy fixing solution F. That is, the peelability of the thin film forming belt 151 with respect to the foamy fixing solution F may be increased with respect to the application roller 141. As a typical index regarding peelability, a contact angle with water can be mentioned. The larger the contact angle, the higher the water repellency, that is, the higher the peelability.

Therefore, by increasing the contact angle of water on the surface of the thin film forming belt 151 with respect to the surface of the coating roller 141, transferability of the foamy fixing liquid F from the thin film forming belt 151 to the coating roller 141 is improved. Thereby, the variation in the film thickness of the foam-like fixing liquid F formed on the application roller 141 is reduced.
As described above, if the transfer of the foam-like fixing liquid F from the thin film forming belt 151 to the coating roller 141 is a one-to-one transfer, that is, if the transfer rate is 100%, the film is formed on the thin film forming belt 151. The film thicknesses of the foam-like fixing solution Fg before transfer and the foam-like fixing solution Fh after transfer transferred onto the application roller 141 are equal. However, this major premise is that the thin film forming belt 151 and the coating roller 141 are moving at the same speed in the same direction at the contact position G where the thin film forming belt 151 and the application roller 141 are in contact. Of course, if the moving speeds of the two are different, the film thickness of the foam-like fixing solution F formed on the surfaces of the two will be different. For example, as shown in FIG. 14, the case where the surface moving speed V1 of the thin film forming belt 151 is 50% (V1: V2 = 1: 2) with respect to the surface moving speed V2 of the coating roller 141 will be described. In this case, assuming that the transfer rate is 100%, the post-transfer foam fixing transferred onto the application roller 141 with respect to the film thickness of the pre-transfer foam fixing liquid Fg formed on the thin film forming belt 151 is performed. The film thickness of the liquid Fh is 50 [%].

By utilizing such characteristics, it is possible to control the film thickness of the foamed fixing liquid Fh after transfer transferred onto the application roller 141. Specifically, by changing the surface moving speed of the thin film forming belt 151 with respect to the surface moving speed of the coating roller 141 (depending on the process speed), the post-transfer foamy fixing liquid Fh transferred onto the coating roller 141. It becomes possible to control the film thickness.
FIG. 15 is a block diagram of control of the foam-like fixing liquid linear speed control unit 300 which is a foam-like fixing liquid linear speed control means utilizing such characteristics.
The foam-like fixing liquid linear speed control unit 300 shown in FIG. 15 is provided, and the film thickness of the foam-like fixing liquid F on the surface of the coating roller 141 is variable. By controlling the moving speed, the film thickness of the foam-like fixing liquid F on the surface of the application roller 141 can be controlled to a desired film thickness.

In the fixing device 6, the foam-like fixing liquid thinning section 150 and the fixing liquid coating section 140 are separately provided so that the thin film forming belt 151 and the coating roller 141 can be brought into contact with and separated from each other. The purpose of such a configuration is to form a thin film in a state where the physical properties of the foam-like fixing solution F such as the film thickness, the average particle diameter of the foam-like fixing solution F, and the bulk density of the foam-like fixing solution F are uniform. This means that the foamy fixing solution F is supplied on-demand with high accuracy onto the surface of the coating roller 141 of the fixing solution coating unit 140.
This is because, when the transfer paper P carrying the unfixed toner layer T is at the application position C, the foamy fixing solution F is applied to the toner particles forming the toner layer T on the transfer paper P, and the toner particles Is fixed to the transfer paper P. On the other hand, control is performed so that the foamy fixing liquid F is not supplied to the portion passing through the application position C at the timing when the transfer paper P is not present at the application position C on the surface of the application roller 141.

As such control, a configuration in which supply control of the foamy fixing liquid F to the surface of the application roller 141 of the fixing liquid application unit 140 is controlled based on information on the presence or absence of the transfer paper P at the application position C is used. it can.
Hereinafter, a configuration for controlling the supply of the foam-like fixing liquid F to the surface of the application roller 141 based on the information on the presence or absence of the transfer paper P at the application position C will be described.
FIG. 16 illustrates a paper edge detection sensor 170 that is a leading edge trailing edge detection unit that detects a leading edge and a trailing edge of the transfer paper P that passes a detection position N upstream of the application position C in the conveyance direction of the transfer paper P. It is explanatory drawing of arrangement | positioning. FIG. 17 is a timing chart of the separation control based on the position information of the transfer paper P obtained from the detection result of the paper edge detection sensor 170. In the lower part of FIG. 17, a schematic diagram of the application state of the fixing liquid on the transfer paper P by controlling the contact / separation timing is shown. In the schematic diagram of the transfer paper P, a hatched portion β indicates an application region of the foam-like fixing liquid F on the transfer paper P appropriately applied by contact / separation control.

The paper edge detection sensor 170 is provided on the entrance side of the transfer paper P of the fixing device 6, and the detection method by the paper edge detection sensor 170 is most commonly a photointerrupter method using LEDs and PDs. There are, but not limited to this method. Here, the length of the transfer distance of the transfer paper P from the detection position N where the paper edge detection sensor 170 detects the edge of the transfer paper P to the application position C is L1. On the other hand, the surface length from the contact position G on the surface of the coating roller 141 to the coating position C (the center of the coating nip) is L2.
At this time, the relationship between L1 and L2 is L2 <L1.

Considering when the transfer paper P enters the fixing device 6, the contact / separation control unit 250 starts controlling the rotation of the cam 155 from when the paper edge detection sensor 170 detects the transfer paper P. Specifically, it waits for the time of “(L1−L2) / (process speed) + α” and commands the operation of bringing the movable roller 153 of the foam-like fixing liquid thinning section 150 into contact with the application roller. Here, the time + α corresponds to a part of the margin of the leading edge P1 of the transfer paper P.
By performing such control, the tip of the region (transfer portion) to which the foamy fixing solution F is supplied on the surface of the application roller 141 is located at a position that is inward by + α from the tip P1 of the transfer paper P. Will be applied. The same applies to the rear end P2 of the transfer paper P. Specifically, when the paper end detection sensor 170 detects the rear end P2 of the transfer paper P, specifically, “(L1-L2) / (process speed) − The operation waits for the time “α”, and commands to move the movable roller 153 of the foam-like fixing liquid thinning portion 150 away from the application roller 141.
With the above contact / separation control, the foamy fixing solution F can be accurately applied onto the transfer paper P as indicated by the hatched portion β in the figure.

Note that the timing chart shown in FIG. 17 is control for applying the foam-like fixing solution F to the entire region other than the blank portion of the transfer paper P, but the foam-like fixing solution F is applied even to the toner layer T on the transfer paper P. It only has to be done. That is, it is not necessary to apply the foam-like fixing liquid F to the area on the transfer paper P where the toner image composed of the toner layer T is not formed. The presence or absence of the toner image on the transfer paper P can be determined based on image information at the time of image formation. An image is formed on the photoconductor 10 according to the image information, and the toner image transferred from the photoconductor 10 onto the transfer paper P is fixed after a predetermined time. Therefore, the contact / separation control unit 250 can perform control according to the image information and the writing timing to the photoconductor 10 based on the information. Then, like the control described with reference to the timing chart of FIG. 17, by controlling as in the timing chart shown in FIG. 18, only the area on the transfer paper P where the toner image is formed is accurately foamed. Fixing liquid F can be applied.
In the timing chart shown in FIG. 18, by performing contact / separation control based on the image data, the foam-like fixing liquid on the transfer paper P can be obtained without applying the foam-like fixing liquid F to the entire surface of the transfer paper P. Application can be performed so that the toner image area γ is included in the application area β of F. By performing such control, the application amount of the foam-like fixing solution F becomes the minimum necessary, and the consumption amount of the foam-like fixing solution F can be reduced.

  The fixing liquid application unit 140 includes an application member cleaning member 200, and removes the foamy fixing liquid F that has not been supplied to the transfer paper P and the offset toner from the application roller 141, so that the application roller 141 is always provided. Keep the surface clean. As a result, the transferability when the foam-like fixer F thinned by the foam-like fixer thinning unit 150 is transferred from the thin film forming belt 151 to the coating roller 141 and the foam-like fixer onto the transfer paper P are transferred. The fixing property can be stabilized by applying F.

The fixing device 6 of Example 1 is a fixing device that performs fixing by applying a foamy fixing solution F to the toner layer T on the transfer paper P, and the contact / separation control unit 250 applies the coating to the surface of the thin film forming belt 151. The contact / separation with the surface of the roller 141 can be accurately controlled. For this reason, it is possible to accurately apply the foamy fixing solution F having stable characteristics only to the portion where the transfer paper P exists at the application position C.
The characteristics of the foam-like fixing solution F include the film thickness, the average particle diameter of the foam, the bulk density of the foam, and the like. It will change. Therefore, since the characteristics of the foamed fixing solution F that has just been generated and the foamed fixing solution F that has been left for a certain period of time are completely different, there is a difference in fixing conditions. If a difference occurs in the fixing conditions, stable image quality cannot be obtained. In order to solve such a problem, in the fixing device 6 according to the first embodiment, the foam-like fixing liquid F that has passed a certain amount of time on the thin film forming belt 151 is collected by the foam suction unit 156 and is not used for application. The physical properties of the foam-like fixing solution F applied at 141 are stabilized. By stabilizing the physical properties of the foam-like fixing solution F, it is possible to suppress a difference in fixing conditions and obtain a stable image quality.

Further, the foamy fixing solution F needs to be uniformly applied onto the transfer paper P on which an image is formed with toner, and further, the pressure roller 143 is stained at a timing when the transfer paper P does not exist at the application position C. In order to prevent this, it is required to stop supplying the foamy fixing solution F. On the other hand, in the fixing device 6 according to the first embodiment, since the foamy fixing solution F having stable characteristics can be accurately applied only to the portion where the transfer paper P exists at the application position C, the pressure roller 143 is used. Can prevent dirt.
Further, it is required to prevent image deterioration due to shock jitter or the like due to the contact / separation operation. However, in the fixing device 6 according to the first embodiment, a part of the thin film forming belt 151 moves to form a thin film. The belt 151 and the application roller 141 are brought into contact with and separated from each other. Since the position of the surface of the application roller 141 at the application position C is not displaced, image degradation due to shock jitter or the like can be prevented.

[Example 2]
Next, a second embodiment (hereinafter referred to as a second embodiment) of the fixing device 6 having the features of the present invention will be described.
FIG. 19 is an explanatory diagram schematically showing the fixing device 6 of Example 2 provided in the printer 100 of the present embodiment.
The main difference from the configuration of the fixing device 6 of Example 1 shown in FIG. 1 is that the surface of the upstream side fixing liquid carrier provided in the foam-like fixing liquid thinning section 150 and the downstream side fixing liquid carrier provided in the fixing liquid coating section 140. It is a mechanism related to the contact and separation of the body surface. Each configuration described in the first embodiment can be applied to the fixing device 6 according to the second embodiment as long as the configuration does not contradict the configuration of the fixing device 6 according to the second embodiment.

  In the fixing device 6 of the second embodiment, as shown in FIG. 19, the foam-like fixer thin film forming unit 150 is configured around a thin film forming roller 151 b that is an upstream fixer carrier instead of the thin film forming belt 151. Has been. In the thin film forming roller 151b, a liquid film thickness control blade 154 as a film thickness control unit and a bubble suction unit 156 as a recovery unit are disposed around the thin film formation roller 151b.

  On the other hand, with respect to the fixing liquid application unit 140, an application belt 141b, which is a downstream side fixing liquid carrier, is provided instead of the application roller 141. The coating belt 141b is stretched between two stretching rollers, and the coating belt 141b moves on the surface when the coating position support roller 147 of the two stretching rollers is rotationally driven. Of the two stretching rollers, the application position support roller 147 is opposed to the pressure roller 143 at the application position C, and the transfer paper P is sandwiched between the pressure roller 143 and the application belt 141b. It is configured to apply the foam-like fixing liquid F and transport the transfer paper P. The other of the two stretching rollers is provided so as to be displaceable in the direction of arrow K in FIG. 19 in order to enable contact / separation control between the thin film forming roller 151b and the coating belt 141b. The application side movable roller 146. The application side movable roller 146 operates as indicated by an arrow K in FIG. 19 when the contact / separation control unit 250 controls the rotation of the application side cam 145.

That is, as compared with the configuration of the fixing device 6 according to the first embodiment described with reference to FIG. 1, the upstream fixing liquid carrier of the foamy fixing liquid thinning unit 150 and the downstream fixing liquid carrier of the fixing liquid application unit 140. The difference is in which the movable roller for contacting and separating from the body is provided.
The fixing device 6 of the second embodiment is superior to the configuration of the first embodiment in that the impact when the upstream side fixing liquid carrier and the downstream side fixing liquid carrier are in contact with each other during the contact / separation operation is applied. It is not directly transmitted to the application position support roller 147 that forms the application nip at position C, and shock jitter is hardly generated. However, the disadvantage is that the position of a part of the application belt 141b is displaced during the contact / separation operation. There is a concern about the effect of displacement.

The advantages and disadvantages of the fixing device 6 according to the first embodiment over the configuration of the second embodiment are just the opposite of the advantages and disadvantages of the fixing device according to the second embodiment. That is. In the first embodiment and the second embodiment, it is not possible to say which configuration is better, but it should be decided depending on whether or not the influence is regarded as a problem in creating the fixing device 6. It will be.
As another configuration example, a belt is not used for the upstream side fixing liquid carrier of the foam-like fixing liquid thinning unit 150 or the downstream side fixing liquid carrier (coating member) of the fixing liquid application unit 140. Both are composed of rollers and may be in contact with or separated from each other. In this configuration example, since the number of component parts is reduced, the cost is the lowest.

[Example 3]
Next, a third embodiment (hereinafter referred to as a third embodiment) of the fixing device 6 having the characterizing portion of the present invention will be described.
FIG. 20 is an explanatory diagram schematically showing the fixing device 6 of Example 3 provided in the printer 100 of the present embodiment.
The configuration of the third embodiment is the same as that of the first embodiment, except that the thin film forming belt 151 of the foam-like fixing liquid thinning section 150 and the coating roller 141 of the fixing liquid coating section 140 are in contact position G. It differs from the fixing device 6 of the first embodiment in that the surface movement direction is the reverse direction.
In this way, when the thin film forming belt 151 and the application roller 141 are in contact with each other with a suitable pressure, most of the foamy fixing solution F other than the slip-through portion can be transferred. That is, a high transfer rate can be realized without considering the contact angle of the surface of the fixing liquid carrier with water. However, the smoothness of the surface of the foam-like fixing liquid F transferred to the application roller 141 is not necessarily smooth. In this respect, like the fixing device 6 of the first and second embodiments, it can be said that it is more advantageous that the surface movement direction of the thin film forming belt 151 and the application roller 141 at the contact position G is the same direction. . Needless to say, which one is to be adopted may be determined depending on which influence is considered as a problem in creating the fixing device 6. Each configuration described in the first embodiment can be applied to the fixing device 6 of the third embodiment as long as the configuration is consistent with the configuration of the fixing device 6 of the third embodiment.

  In the fixing device 6 of the first to third embodiments described above, the configuration in which the downstream fixing liquid carrier that is controlled to contact and separate from the upstream fixing liquid carrier is an application member has been described. However, the configuration for controlling the supply timing of the foamy fixing solution to the surface of the coating member by controlling the contact and separation between the upstream fixing solution carrier and the downstream fixing solution carrier is not limited to this. For example, the configuration may be such that the foamy fixing solution is supplied from the upstream fixing solution carrier to the coating member via a downstream fixing solution carrier different from the coating member. An example of this configuration will be described using the members of the fixing device 6 according to the first embodiment. The configuration includes a fixing liquid carrying roller having a function as a downstream fixing liquid carrying body that is always in contact with the application roller 141. . In such a configuration, by controlling the contact and separation of the thin film forming belt 151 with respect to the fixing liquid carrying roller, the foamy fixing liquid F by the application roller 141 at the application position C is controlled in the same manner as the fixing device 6 of the first embodiment. Application timing can be controlled.

  Further, in the fixing device 6 of the first to third embodiments, the fixing liquid application target on which the coating member applies the foamy fixing liquid F is the surface of the transfer paper P as a recording medium carrying the toner image. As the fixing device 6 for fixing the toner image on the transfer paper P using the foam-like fixing solution F, the foam-like fixing solution F is applied to a toner image carrier such as an intermediate transfer belt carrying the toner image, and the toner image is obtained. 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.

  Further, in the fixing device 6 of the first to third embodiments, the upstream side fixing liquid carrier and the downstream side fixing liquid carrier are in contact at the contact position G, and the upstream side fixing liquid carrier and the downstream side fixing liquid carrier. In this configuration, the foamy fixing solution F is supplied. However, the configuration in which the foam-like fixing solution F is supplied from the upstream fixing solution carrier to the downstream fixing solution carrier is not limited to the configuration in which the upstream fixing solution carrier and the downstream fixing solution carrier are in contact with each other. Absent. As long as the foam-like fixing solution F can be supplied from the upstream fixing solution carrier to the downstream fixing solution carrier, the upstream fixing solution carrier and the downstream fixing solution carrier are close to each other at the supply timing. It may be configured to.

As described above, the fixing device 6 of Example 1 is a foam-type fixing in which bubbles are dispersed in a fixing solution 132 containing a softening agent that softens toner composed of resin fine particles by dissolving or swelling at least part of the resin. The fixing liquid foaming means 130 which is a fixing liquid foaming means to be the liquid F, and the transfer paper P which is the target for applying the fixing liquid carrying the toner layer T, the foaming fixing liquid F supplied to the surface moving surface. A fixing device for fixing the toner layer T softened by applying the foam-like fixing liquid F to the transfer paper P. The two fixings that are carried by the application roller 141 are carried on the surface of the moving surface before the application roller 141 reaches the application position C where the application fixing agent F is applied to the transfer paper P. An upstream fixing liquid carrier as a liquid carrier. A thin film forming belt 151 and a coating roller 141 which is a downstream fixing liquid carrier are provided, and the bubble-shaped fixing liquid F supplied to the surface of the thin film forming belt 151 is brought into contact as a proximity position where the two fixing liquid carriers are in contact with each other. The foam fixing solution F is conveyed to the position G, the foam-like fixing solution F is supplied to the application roller 141 at the contact position G, and the foam-like fixing solution F supplied to the surface of the application roller 141 is conveyed to the application position C. The contact / separation control unit 250 is a contact / separation control unit that controls contact / separation between the surface of the thin film forming belt 151 and the surface of the application roller 141 at the contact position G without changing the position of the surface of the application roller 141 in C. Is provided.
Such a fixing device 6 has a configuration in which the foamy fixing solution F supplied from the thin film forming belt 151 to the application roller 141 is conveyed to the application position C at the contact position G. For this reason, by controlling the timing at which the foam-like fixing liquid F is supplied from the thin film forming belt 151 to the application roller 141 at the contact position G, the application timing of the foam-like fixing liquid F by the application roller 141 at the application position C is controlled. Can be controlled. Further, the contact / separation control unit 250 controls the contact / separation between the surface of the thin film forming belt 151 and the surface of the application roller 141 at the contact position G, so that bubbles are applied from the thin film formation belt 151 at the contact position G to the application roller 141. The timing for supplying the state fixer F can be controlled. Further, the contact / separation control unit 250 controls contact / separation between the surface of the thin film forming belt 151 and the surface of the application roller 141 at the contact position G without changing the position of the surface of the application roller 141 at the application position C. Accordingly, the contact / separation control unit 250 controls the contact / separation between the surface of the thin film forming belt 151 and the surface of the application roller 141, so that the position of the surface of the application roller 141 at the application position C is not changed. The application timing of the foamy fixing solution F by the application roller 141 can be controlled. Since the position of the surface of the application roller 141 at the application position C does not change, the application conditions such as the pressure and contact width between the application roller 141 at the application position C and the pressure roller 143 which is another member are not changed. The application timing of the foamy fixing solution F by the application roller 141 at the application position C can be controlled.
As described above, in the fixing device 6 according to the first embodiment, the application condition of the application roller 141 does not change due to the contact / separation operation between the surface of the thin film forming belt 151 and the surface of the application roller 141. By controlling the contact / separation operation, the application timing of the foamy fixing liquid F by the application roller 141 can be controlled.
In the fixing device 6 of the first embodiment, the foam-like fixer thin film forming unit 150 can be specialized in the function of forming a thin layer of the foam-like fixer F having a uniform film thickness and uniform physical properties. it can. Furthermore, since it becomes possible to supply the foam-like fixing solution F to the fixing solution application unit 140 at a fast timing as necessary without separating the application roller 141 and the pressure roller 143, and with high accuracy, There is almost no shock jitter, and it is possible to intermittently apply the foam-like fixing solution F at the application position C with no variation in characteristics over the entire application region. Thereby, the foamy fixing solution F can be applied in synchronization with the timing when the transfer paper P is present at the application position C.
In the fixing device 6 of the second embodiment, the same effect as that of the first embodiment can be achieved by controlling the contact and separation between the surface of the thin film forming roller 151b and the surface of the coating belt 141b.

  In the fixing device 6 of the first embodiment, the application roller 141 is the downstream side fixing liquid carrier that is brought into contact with and separated from the surface of the thin film forming belt 151 that is the upstream side fixing liquid carrier. Since it is not necessary to provide a downstream fixing solution carrier separately from the application member that applies the foamy fixing solution F to the transfer paper P, it is possible to suppress the configuration of the fixing device 6 from becoming complicated.

  In addition, the fixing liquid application unit 140 of the fixing device 6 according to the first exemplary embodiment sandwiches the transfer paper P when the application roller 141 applies the foamy fixing liquid F to the surface of the transfer paper P that is an application target of the fixing liquid. A pressure roller 143 that is a coating facing member that faces the coating roller 141 is provided. By applying the foamy fixing solution F with the pressure roller 143 and the application roller 141 sandwiching the transfer paper P at the application position C, the foamy fixing solution F can be stably applied to the transfer paper P. it can. Further, since it can be intermittently applied to the transfer paper P, it is possible to suppress adhesion of the foamy fixing solution F to the pressure roller 143 at the application position C.

  Further, the fixing device 6 according to the first exemplary embodiment is downstream of the contact position G on the surface of the thin film forming belt 151 that is the upstream side fixing liquid carrier, in the surface moving direction, and from the foam-like fixing liquid generating unit 130. A foam suction unit 156 that is a collection unit that collects the foam-like fixer F on the surface of the thin film forming belt 151 on the upstream side in the surface movement direction with respect to the position where the state fixer F is supplied. The foam-like fixing solution F deteriorates with time, and if the deteriorated foam-like fixing solution F is applied to the toner layer T, the desired fixing property cannot be obtained, and the image quality may be lowered. On the other hand, since the fixing device 6 according to the first embodiment includes the foam suction unit 156, the deteriorated foam-like fixing solution F on the surface of the thin film forming belt 151 can be recovered, and the fresh foam-like fixing solution is always fresh. A liquid layer can be formed on the thin film forming belt 151 by F. This makes it possible to supply the foam-like fixing solution F to the fixing-solution application unit 140 in a stable state with respect to characteristics such as the average particle diameter and bulk density of the foam-like fixing solution F.

  Further, the fixing device 6 according to the first exemplary embodiment is configured so that the thin film forming belt 151 and the application roller 141 come into contact with each other according to the frequency of contact between the thin film formation belt 151 and the application roller 141 by the contact / separation control unit 250. A foam fixing solution recovery control unit (not shown) that controls recovery of the foam fixing solution F by the suction unit 156 is provided. Thereby, since the foamy fixing solution F is collected as required, the amount collected can be minimized.

  Further, in the fixing device 6 according to the first exemplary embodiment, the thin film forming belt 151 includes a belt-like fixing liquid carrying belt that moves endlessly with the upstream side fixing liquid carrying body being stretched by stretching rollers that are two stretching members. One of the two stretching rollers is in contact with the inner peripheral surface of the thin film forming belt 151 at the contact position G, and the displaceable stretching in which the position with respect to the application roller 141 changes under the control of the contact / separation control unit 250. The movable roller 153 is a member, and the contact / separation of the thin film forming belt 151 with respect to the application roller 141 is controlled by changing the position of the movable roller 153 with respect to the application roller 141. By using a roller with a small mass as the movable roller 153, the thin film forming belt 151 and the application roller 141 can be contacted / separated quickly and with low energy. Further, since the application roller 141 is not displaced during the contact / separation operation of the thin film forming belt 151 and the application roller 141 for controlling the ON / OFF switching of the supply of the foam-like fixing liquid F, the shock jitter is also reduced. In a state where there is almost no, the ON / OFF switching operation of the supply of the foamy fixing solution F becomes possible.

  Further, in the fixing device 6 according to the second embodiment, the downstream side fixing solution carrier is an application belt 141b including a belt-like fixing solution carrying belt that is stretched around two stretching members, which are stretched by a stretching roller. Yes, one of the two stretching rollers is in contact with the inner peripheral surface of the coating belt 141b at the contact position G, and is controlled by the contact / separation control unit 250 with respect to the thin film forming roller 151b that is the upstream fixing liquid carrier. Is a coating-side movable roller 146 as a displaceable stretching member that changes. The position of the coating-side movable roller 146 relative to the thin film forming roller 151b is changed to control the contact and separation of the coating belt 141b with respect to the thin film forming roller 151b. The By using a roller having a small mass as the application side movable roller 146, the thin film forming roller 151b and the application belt 141b can be brought into contact with and separated from each other quickly and with low energy. Further, when the thin film forming roller 151b and the application belt 141b are in contact with and separated from each other to control ON / OFF switching of the supply of the foam-like fixing liquid F, the position of the surface of the application belt 141b at the application position C is determined. Since there is no displacement, it is possible to switch ON / OFF the supply of the foam-like fixer F with almost no shock jitter.

  Further, the fixing device 6 according to the first embodiment is on the downstream side in the surface movement direction with respect to the position where the foamy fixing solution F is supplied on the surface of the thin film forming belt 151 and on the upstream side in the surface movement direction with respect to the contact position G. On the side, there is a foam fixing solution film thickness control means for controlling the film thickness of the foam fixing solution F on the surface of the thin film forming belt 151 to a desired film thickness. Thereby, the foamy fixing solution F having a desired film thickness can be supplied to the application roller 141.

  Further, the fixing device 6 of the first embodiment includes a liquid film thickness control blade 154 as a blade member facing the surface of the thin film forming belt 151 as a foamy fixing liquid film thickness control unit. Thereby, the structure for forming the foam-like fixing liquid layer having a stable film thickness can be realized with a simple structure.

  Further, as shown in FIG. 9, as the fixing device 6 of Example 1, a liquid film thickness control blade 154 is disposed at a trailing position with respect to the surface movement direction of the thin film forming belt 151, and a gap regulating member 159 is provided. The liquid film thickness control blade 154 may be provided so as to be urged by the spring 157 while maintaining a certain gap with respect to the surface of the thin film forming belt 151. By disposing the liquid film thickness control blade 154 in this way, it becomes possible to form a layer of the foam-like fixing liquid F having a further stable film thickness. In this configuration, the liquid film thickness control blade 154 is interposed between the thin film forming belt 151 and the thin film forming belt 151 via the gap regulating member 159 when there is no foamy fixing solution F between the thin film forming belt 151. It becomes the structure pressed against.

  Further, as shown in FIG. 8, the fixing device 6 of the first embodiment has a liquid film thickness control blade 154 disposed at a trailing position with respect to the surface movement direction of the thin film forming belt 151 to control the liquid film thickness. The blade 154 may be configured to be biased against the surface of the thin film forming belt 151. By disposing the liquid film thickness control blade 154 in this way, it becomes possible to form a layer of the foam-like fixing liquid F having a further stable film thickness. In the case of this configuration, the liquid film thickness controlling blade 154 directly presses against the thin film forming belt 151 when the liquid film thickness controlling blade 154 is not in the state of the foam-like fixing solution F between the thin film forming belt 151. It becomes the composition to do.

  Further, as shown in FIG. 12, the fixing device 6 according to the first embodiment has an upstream side in the surface movement direction of the thin film forming belt 151 from a position where the film thickness of the foam-like fixing liquid F is controlled by the liquid film thickness control blade 154. It has a bubble sensor 160 which is a bubble accumulation detecting means for detecting the amount of the bubble accumulation Fd. Then, when the amount of the bubble reservoir Fd detected by the bubble sensor 160 is smaller than a predetermined amount, the supply control unit (not shown) supplies the foam-like fixing solution F to the surface of the thin film forming belt 151. Control the supply of F. Thereby, it becomes possible to control the amount of the foam-like fixer F supplied from the foam-like fixer generation unit 130 to the foam-like fixer thinning unit 150, and to reduce the supply of wasted foam-fixing solution F; It is possible to form a layer of the foamed fixing solution F having a more stable film thickness and to control the film thickness.

  Further, in the fixing device 6 of Example 1, the surface of the thin film forming belt 151 that is the upstream side fixing liquid carrier has a larger contact angle with water than the surface of the application roller 141 that is the downstream side fixing liquid carrier. This facilitates the movement of the foam-like fixing solution F from the thin film forming belt 151 to the coating roller 141 at the contact position G, and the foam-like fixing solution F from the foam-like fixing solution thinning unit 150 to the fixing solution application unit 140. It becomes possible to make the transfer stable.

  Further, the fixing device 6 of the first embodiment controls the linear velocity of the fixing liquid carrier that controls the linear velocity ratio that is the ratio of the linear velocity of the thin film forming belt 151 and the linear velocity of the coating roller 141 at the contact position G, which is the proximity position. A foam-like fixing liquid linear velocity control unit 300 as a ratio control means is provided. The foam-like fixing liquid linear velocity control unit 300 can control the linear velocity ratio by independently controlling the linear velocity of the thin film forming belt 151 with respect to the linear velocity of the application roller 141. By controlling the linear speed ratio, the film thickness of the foam-like fixing liquid F on the surface of the application roller 141 can be freely controlled.

  In the fixing device 6 according to the first exemplary embodiment, the fixing liquid application target on which the application roller 141 serving as the application member applies the foamy fixing liquid F is the transfer paper P. The fixing device 6 does not change the position at the application position C on the surface of the application roller 141 and the pressure roller 143 that are in contact with the transfer paper P at the application position C, and the foaming fixer F is applied by the application roller 141 at the application position C. Application can be carried out intermittently. Thereby, it is possible to prevent the shock jitter from being transmitted to the transfer paper P due to the contact and separation of the members forming the application position C, and it is possible to prevent the image from being disturbed due to the shock jitter.

  Further, the fixing device 6 according to the first exemplary embodiment includes a paper edge detection sensor 170 that is a recording medium position detection unit that detects the position of the transfer paper P before reaching the application position C. The contact / separation control unit 250 includes: Based on the detection result of the paper edge detection sensor 170, the contact and separation of the two fixing liquid carriers are controlled. The paper edge detection sensor 170 detects the positions of the leading edge P1 and the trailing edge P2 of the transfer paper P input to the fixing device 6, and the contact / separation control unit 250 detects the position of the thin film forming belt according to the detected information. The contact / separation between 151 and the application roller 141 is controlled. Therefore, the foam-like fixing solution F is accurately applied only on the transfer paper P at the application position C, and the foam-like fixing solution F is not applied at the timing when there is no transfer paper P at the application position C. It becomes possible to prevent contamination.

  Further, the paper edge detection sensor 170 of the fixing device 6 according to the first exemplary embodiment detects the leading edge P1 and the trailing edge P2 of the transfer paper P passing through the detection position N on the upstream side in the conveyance direction of the transfer paper P with respect to the application position C. It is the front-end | tip rear-end detection means to do. The length L1 of the transfer distance of the transfer paper P from the detection position N to the application position C is such that the foamy fixing liquid F supplied to the surface of the application roller 141 at the contact position G is between the application position C and the length L1. It is longer than L2, which is the length of the surface carried on the surface. Accordingly, the thin film forming belt 151 is brought into contact with the application roller 141 at the contact position G based on the detection result of detecting the front end P1 at the detection position N, so that the application is performed in accordance with the timing at which the front end P1 reaches the application position C. Application of the foam-like fixing liquid F at the position C by the application roller 141 can be started. In Example 1, as shown in FIG. 17, the application of the foam-like fixing liquid F by the application roller 141 at the application position C is performed at a timing slightly behind the timing at which the leading edge P1 of the transfer paper P reaches the application position C. Has started. Thereby, it is possible to prevent the transfer paper P from being separated from the application roller 141 or the pressure roller 143 due to the leading edge P1 of the transfer paper P getting wet. Similarly, on the rear end P2 side, the rear end P2 is moved to the application position C by separating the thin film forming belt 151 from the application roller 141 at the contact position G based on the detection result of detecting the rear end P2 at the detection position N. The application of the foam-like fixing liquid F by the application roller 141 at the application position C can be stopped in accordance with the timing of reaching the position. In Example 1, as shown in FIG. 17, the foam-like fixing liquid F is applied by the application roller 141 at the application position C at a timing slightly earlier than the timing at which the trailing edge P2 of the transfer paper P reaches the application position C. It has stopped. As described above, the relationship of L1> L2 makes it possible to improve the application accuracy of the foamy fixing liquid F at the application position C.

  In addition, the image station 3 that is a toner image forming unit that forms a toner image on the transfer paper P that is a recording medium using toner including a resin fine particle layer that contains a resin and a colorant, and the toner on the transfer paper P In a printer 100 as an image forming apparatus including a fixing unit that fixes an image, the fixing device 6 of the present embodiment is used as a fixing unit. As a result, the application timing of the foam-like fixing solution F by the application member is controlled by controlling the contact and separation between the upstream fixing solution carrier and the downstream fixing solution carrier, thereby preventing unnecessary consumption of the fixing solution. In addition, it is possible to prevent image disturbance due to shock jitter, and to obtain an image forming apparatus with low power consumption and high reliability.

  In the printer 100, the contact / separation control unit 250 of the fixing device 6 controls the contact / separation of the two fixing liquid carriers based on the image information used by the toner image forming unit as described with reference to FIG. May be. This is because the optical unit 4 irradiates the photosensitive member 10 with the laser light L to form a latent image, and in accordance with the information of the signal of the image data used for the control of irradiating the laser light L in the latent image forming process. It controls contact and separation of the fixing liquid carrier. Thereby, it is possible to accurately apply the foam-like fixing liquid F only to the portion on the transfer paper P where the toner image is formed, and to reduce the consumption of the foam-like fixing liquid F.

DESCRIPTION OF SYMBOLS 1 Device main body 2 Paper feed cassette 3 Image station 4 Optical unit 5 Intermediate transfer unit 6 Fixing device 7 Toner bottle 8 Paper discharge tray 10 Photoconductor 11 Charging device 12 Developing device 13 Cleaning device 13a Cleaning blade 20 Transfer belt 21 Drive roller 22 Tension Roller 23 driven roller 24 primary transfer roller 25 secondary transfer roller 26 belt cleaning device 27 paper feed roller 28 resist roller pair 29 discharge roller 30 fixing device 60 using liquid fixer conventional fixing device 100 printer 130 foam-like fixer generating unit 131 Fixing solution bottle 132 Fixing solution 133 Fixing solution conveying pump 134 Fixing solution conveying tube 140 Fixing solution applying part 141 Application roller 141b Application belt 143 Pressure roller 145 Application side cam 146 Application side movable roller 147 Application position support Roller 150 Foam-like fixing liquid thinning section 151 Thin film forming belt 151b Thin film forming roller 152 Blade facing roller 153 Movable roller 154 Liquid film thickness controlling blade 154a Blade fixed end 154b Blade free end 155 Cam 156 Bubble suction section 156a Collected liquid transport Path 157 Spring 158 Solenoid 158a Spring support portion 158b Blade contact portion 159 Gap regulating member 160 Foam sensor 160a Light emitting element 160b Light receiving element 170 Paper edge detection sensor 200 Application member cleaning member 250 Contact / separation control unit 300 Foamed fixing liquid linear velocity control Unit 500 fixing liquid foaming device 501 fixing liquid supply port 510 gas / liquid mixing unit 511 micropore sheet 512 air port 515 foaming device internal conveyance pipe 520 micro diameter bubble generating unit 521 outer cylindrical unit 521a fixing liquid inlet 5 1b Fixing solution outlet 522 Inner cylindrical portion C Application position F Foamed fixing solution Fa Plateau boundary Fb Bubble Fc Thinned foamed fixing solution Fd Bubble accumulation Fg Foamed fixing solution Fh Before transfer Foamed fixing after transfer Liquid G Contact position N Detection position P Transfer paper P1 Front end P2 Rear end T Toner layer Ta Toner particle Tb Fixed toner layer

Japanese Patent No. 3290513 JP 2004-109749 A JP 59-119364 A JP 2004-109747 A JP 2009-008967 A

Claims (18)

A fixing liquid foaming means for making a fixing liquid containing a softening agent that softens resin fine particles by dissolving or swelling at least a part of the resin into a foamy fixing liquid in which bubbles are dispersed in the liquid;
An application member for applying the foamy fixing solution supplied to the surface moving surface to the surface of the fixing solution application target carrying the resin fine particle layer made of the resin fine particles;
In a fixing device for fixing the resin fine particle layer softened by applying the foamy fixing solution to a recording medium,
After being generated by the fixing solution foaming means, the application member carries the foamy fixing solution on the surface moving surface before reaching the application position for applying the foamed fixing solution to the fixing solution application target. An upstream fixing solution carrier and a downstream fixing solution carrier as two fixing solution carriers to be conveyed,
The foam-like fixing solution supplied to the surface of the upstream-side fixing solution carrier is transported to a close position where the two fixing solution carriers are close to or in contact with each other, and the foam-like fixing solution is sent to the downstream side at the close position. Supplying to the fixing liquid carrier, the foamy fixing liquid supplied to the surface of the downstream side fixing liquid carrier is transported to the application position,
Contact / separation control for controlling contact / separation between the surface of the upstream side fixing liquid carrier and the surface of the downstream side fixing liquid carrier at the proximity position without changing the position of the surface of the application member at the application position With means ,
The upstream side fixer on the upstream side of the upstream fixer carrier on the downstream side in the surface moving direction and on the upstream side in the surface moving direction with respect to the position where the foamy fixer is supplied. the fixing device according to claim Rukoto to have a recovery means for recovering該泡fixer on the surface of the carrier. The fixing device according to claim 1.
The fixing device according to claim 1, wherein the downstream fixing liquid carrier is the coating member. The fixing device according to claim 1 or 2,
A fixing device comprising: an application counter member that opposes the application member across the fixing solution application target when the application member applies the foamy fixing solution to the surface of the fixer application target. The fixing device according to any one of claims 1 to 3 ,
Depending on how often the two foamed fixer carrier in contact and separation of the control of the surface of the two foamed fixer carrier by the upper KiseHHanare control means close to or in contact, the foam by the collecting means A fixing device comprising foamy fixing solution recovery control means for controlling recovery of fixing solution. The fixing device according to any one of claims 1 to 4 ,
The upstream fixing solution carrier is a belt-like fixing solution carrier belt that is stretched around a plurality of stretching members and moves endlessly,
A displacement in which one of the plurality of stretching members comes into contact with the inner peripheral surface of the fixing solution carrying belt at the close position, and the position relative to the downstream fixing solution carrying member is changed by the contact / separation control means. Is a possible tension member,
By changing the position of the displaceable stretching member with respect to the downstream side fixing liquid carrier, contact and separation of the upstream side fixing liquid carrier comprising the fixing liquid carrier belt with respect to the downstream side fixing liquid carrier is controlled. A fixing device. The fixing device according to any one of claims 1 to 4 ,
The downstream fixing solution carrier is a belt-like fixing solution carrier belt that is stretched around a plurality of stretching members and moves endlessly,
A displacement in which one of the plurality of stretching members is in contact with the inner peripheral surface of the fixing liquid carrying belt at the close position, and the position relative to the upstream fixing liquid carrying body is changed by the contact / separation control means. Is a possible tension member,
By changing the position of the displaceable stretching member with respect to the upstream side fixing liquid carrier, contact and separation of the downstream side fixing liquid carrier comprising the fixing liquid carrier belt with respect to the upstream side fixing liquid carrier is controlled. A fixing device. The fixing device according to any one of claims 1 to 6 ,
The upstream side fixing liquid on the surface of the upstream side fixing liquid carrier on the downstream side in the surface movement direction with respect to the position where the foamy fixing liquid is supplied and on the upstream side in the surface movement direction with respect to the proximity position. A fixing device comprising: a foam-like fixing liquid film thickness controlling means for controlling a film thickness of the foam-like fixing liquid on a surface of a carrier to be a desired film thickness. The fixing device according to claim 7 .
The foaming fixing liquid film thickness control means includes a blade member facing the surface of the upstream fixing liquid carrier. The fixing device according to claim 8 .
The blade member is arranged at a trailing position with respect to the surface movement direction of the upstream fixing liquid carrier, and is energized in a state of maintaining a certain gap with respect to the surface of the upstream fixing liquid carrier. A fixing device. The fixing device according to claim 8 .
The fixing device is characterized in that the blade member is arranged at a trailing position with respect to the surface movement direction of the upstream side fixing liquid carrier and is urged against the surface of the upstream side fixing liquid carrier. . The fixing device according to any one of claims 8 to 10,
A bubble accumulation detecting means for detecting the amount of bubble accumulation formed on the upstream side in the surface movement direction of the upstream side fixing liquid carrier from the position where the film thickness of the foamy fixing liquid is controlled by the blade member;
The supply of the foam-like fixing solution is controlled so that the foam-like fixing solution is supplied to the surface of the upstream-side fixing solution carrier when the amount of the bubble accumulation detected by the bubble-well detection means is smaller than a predetermined amount. A fixing device comprising supply control means. The fixing device according to any one of claims 1 to 11 ,
A fixing device, wherein the surface of the upstream side fixing liquid carrier has a larger contact angle with water than the surface of the downstream side fixing liquid carrier. The fixing device according to any one of claims 1 to 12 ,
And a fixing liquid carrier linear speed ratio control means for controlling a linear speed ratio which is a ratio of a linear speed of the upstream fixing liquid carrier and a linear speed of the downstream fixing liquid carrier in the proximity position. A fixing device. The fixing device according to any one of claims 1 to 13,
The fixing device, wherein the application member to which the foaming fixing solution is applied is a recording medium. The fixing device according to claim 14 .
A recording medium position detecting means for detecting the position of the recording medium before reaching the application position;
The fixing device according to claim 1, wherein the contact / separation control unit controls contact / separation of the two fixing liquid carriers based on a detection result of the recording medium position detection unit. The fixing device according to claim 15 .
The recording medium position detecting means includes a leading edge trailing edge detecting means for detecting a leading edge and a trailing edge of the recording medium passing through a detection position on the upstream side in the conveyance direction of the recording medium with respect to the application position,
The length of the conveyance distance of the recording medium between the detection position and the application position is that the foamy fixing solution supplied to the surface of the downstream fixing solution carrier at the proximity position is between the application position and the application position. A fixing device characterized in that the fixing device is longer than the length of the surface carried by the printer. A toner image forming means for forming a toner image on a recording medium based on image information using a toner containing resin fine particles containing a resin and a colorant;
Applying a foamy fixing solution 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 fixing solution application target that is the surface of the recording medium carrying the toner image,
An image forming apparatus comprising fixing means for fixing the toner image on the recording medium,
As the fixing means, an image forming apparatus which comprises using a fixing device according to any one of claims 1 to 16. The image forming apparatus according to claim 17 .
The image forming apparatus, wherein the contact / separation control unit controls contact / separation of the two fixing liquid carriers based on the image information used by the toner image forming unit.

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