JP2006323196A - Fixing solution applying device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a wet image forming apparatus, wherein a fixing solution applying device capable of changing the applying area of a fixing solution in accordance with the size of a recording medium is used to prevent contamination due to a fixing solution, attain low consumption of the fixing solution and form a high-quality image over a long term. <P>SOLUTION: In the wet image forming apparatus, the fixing solution applying device 81 including: a rotary shaft member 82; a regulating roller 83; coating rollers 84a, 84b and 84c provided to separate from/contact with the surface of a transfer fixing roller 30 and having different length in a longitudinal direction; a supply roller 85 provided to separate from/contact with the surface of the coating roller 84a; a removing roller 86 press-contacting with the coating roller 84c which is not immersed in the fixing solution 40 and does not press-contact with the transfer fixing roller 30; a blade 87; and a casing 88 in which the fixing solution 40 is contained, is used as a fixing solution applying means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing liquid coating apparatus and an image forming apparatus.

  In an electrophotographic image forming apparatus often used in copying machines, printers, facsimiles, etc., a photosensitive drum having a photosensitive layer containing a photoconductive material formed on the surface is used, and a charge is applied to the surface of the photosensitive drum. After the toner is uniformly charged, an electrostatic latent image corresponding to the image information is formed by various image forming processes, and the electrostatic latent image is developed with toner supplied from the developing means to form a toner image. An image is formed by transferring the toner image directly or via an intermediate transfer medium to a recording medium such as paper and fixing the unfixed toner image on the recording medium.

  For fixing an unfixed toner image onto a recording medium, a heat fixing method for heating the toner image, a wet fixing method for applying a fixing solution for softening and / or swelling the toner to the toner image, and the like are known. Among these, in the wet fixing method, a toner image softened and / or swollen by applying a fixing solution is attached to a recording medium and pressed to fix the toner image on the recording medium. The wet fixing method has an advantage that it consumes much less power than the thermal fixing method, and many proposals have been made.

  For example, with respect to an unfixed toner image carried on an intermediate transfer medium or a recording medium, a fixing liquid is applied only to a toner adhesion portion from a fixing liquid ejecting member having a plurality of fine holes, and the toner and the fixing liquid are separated. A fixing device for heating has been proposed (see, for example, Patent Document 1). That is, this fixing device employs a method in which a fixing liquid is applied to a toner image on an intermediate transfer medium or a recording medium and then heated. Further, in Patent Document 1, when a toner image is carried on an intermediate transfer medium, an unfixed toner on the intermediate transfer belt is obtained by subjecting the intermediate transfer belt, which is an intermediate transfer medium, to liquid repellent treatment such as fluorine treatment. When a fixing solution is applied to an image, a configuration is described in which the fixing solution collects only in a toner portion (image portion), and the fixing solution does not remain in a portion where toner does not exist between toner images (non-image portion). .

  However, in the fixing device described in Patent Document 1, since the fixing solution is not applied according to the size of the recording medium, when the fixing solution is applied to a recording medium having a small size, the fixing device is not attached. There is a drawback that the fixing solution is also applied to this part. Specifically, such a defect is caused when a fixing solution is applied to a toner image carried on the intermediate transfer belt, and is not in the size range of the recording medium including the toner image on the intermediate transfer belt. The fixing solution adhering to the portion remains on the intermediate transfer belt as it is, and contaminates each member that the intermediate transfer belt such as the photosensitive drum and the fixing pressure roller contacts. When the fixing liquid adheres to the photosensitive drum, image defects such as image omission occur. Further, the fixing liquid adhering to the pressure roller adheres to the back surface of the recording medium when fixing the toner image on a large recording medium, and causes wrinkles and dirt. Accordingly, although it becomes necessary to provide a cleaning means for removing the residual fixing solution on the intermediate transfer belt, it is difficult to completely remove the fixing solution, and contamination by the fixing solution such as the photosensitive drum is inevitable. . Further, the fixing device of Patent Document 1 has a drawback in that the consumption of the fixing solution increases because the fixing solution is applied even to a portion of the intermediate transfer belt that does not require the application of the fixing solution.

JP 2004-109747 A

  SUMMARY OF THE INVENTION An object of the present invention includes a fixing solution applying apparatus capable of adjusting a fixing solution application area according to the size of a recording medium, and the fixing solution applying apparatus, and is free from adhesion of a fixing solution to an intermediate transfer medium or the like. It is an object of the present invention to provide a wet-fixing type image forming apparatus capable of forming a high-quality image over a long period of time without the pressure roller and the like being contaminated by the fixing solution and without increasing the consumption of the fixing solution. .

The present invention provides an image forming apparatus in which a fixing liquid is applied to an unfixed toner image formed on a recording medium or an intermediate transfer medium and made of a dry toner so that the toner can be fixed on the recording medium, and is fixed on the recording medium by a fixing unit. A fixing solution applying apparatus for applying a fixing solution to a toner image,
Fixing solution storage means for storing the fixing solution;
Size detecting means for detecting the size of the recording medium for fixing the unfixed toner image;
And a fixing liquid applying unit that applies a fixing liquid to an unfixed toner image and changes a fixing liquid application region in accordance with a detection result of the size detecting unit.

Further, in the fixing solution applying apparatus of the present invention, the fixing solution applying means described above is
An application roller that is rotatably driven about its axis, carries a fixing solution on its surface, and applies the fixing solution to an unfixed toner image on a recording medium or an intermediate transfer medium,
It includes a plurality of application rollers having different lengths in the longitudinal direction.

Furthermore, in the fixing solution coating apparatus of the present invention, the fixing solution applying means described above is
A plurality of application rollers having different lengths in the longitudinal direction;
A rotation shaft member provided so as to be rotationally driven around the axis, and supporting the plurality of application rollers so as to be rotationally driven.

  Furthermore, in the fixing solution coating apparatus of the present invention, the above-described coating roller has a fixing solution holding tank for storing the fixing solution therein.

Furthermore, in the fixing solution coating apparatus of the present invention, the fixing solution applying means described above is
An application roller that carries a fixing liquid on the surface thereof and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A supply roller for supplying a fixing solution to the surface of the application roller, the supply roller being provided so as to be separable from the surface of the application roller and capable of being driven to rotate; and a plurality of supply rollers having different lengths in the longitudinal direction. Features.

Furthermore, in the fixing solution coating apparatus of the present invention, the fixing solution applying means described above is
An application roller that carries a fixing liquid on the surface thereof and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A plurality of supply rollers having different longitudinal lengths;
A rotation shaft member provided so as to be rotationally driven around the axis, and supporting the plurality of supply rollers so as to be able to be separated from and applied to the application roller.

  Furthermore, the fixing liquid coating apparatus of the present invention is characterized in that the fixing liquid applying means further includes a fixing liquid removing means for removing and recovering the fixing liquid on the surface of the coating roller.

  Furthermore, the fixing liquid coating apparatus of the present invention is characterized in that the above-mentioned supply roller is provided so as to be driven to rotate following the rotational driving of the coating roller.

Furthermore, in the fixing solution coating apparatus of the present invention, the fixing solution applying means described above is
A supply roller which is rotatably provided and carries a fixing liquid on its surface;
A coating roller that carries a fixing liquid on its surface and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A plurality of application rollers which are provided so as to be able to be separated from and connected to the surface of the supply roller and which can be driven to rotate, have different lengths in the longitudinal direction and whose length in the longitudinal direction is shorter than the length in the longitudinal direction of the supply roller It is characterized by.

Furthermore, in the fixing solution coating apparatus of the present invention, the fixing solution applying means described above is
A supply roller which is rotatably provided and carries a fixing liquid on its surface;
A coating roller that carries a fixing liquid on its surface and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A plurality of application rollers having different lengths in the longitudinal direction and having a length in the longitudinal direction shorter than the length in the longitudinal direction of the supply roller;
And a rotary shaft member which is provided so as to be rotatable around its axis and supports the plurality of application rollers so as to be able to be separated from and supplied to the surface of the supply roller.

  Furthermore, the fixing solution coating apparatus of the present invention is provided such that, of the plurality of coating rollers described above, a coating roller other than the coating roller that applies the fixing solution to the toner image is immersed in the fixing solution. It is characterized by being able to.

  Furthermore, the fixing liquid coating apparatus of the present invention is characterized in that the fixing liquid applying means further includes a fixing liquid removing means for removing and recovering the fixing liquid on the surface of the coating roller.

  Furthermore, the fixing liquid applying apparatus of the present invention is characterized in that the above-mentioned coating roller is provided so as to be driven to rotate following the rotational driving of the intermediate transfer medium.

Furthermore, in the fixing solution applying apparatus of the present invention, the fixing solution applying means described above is
An application means that is made of an elastically deformable material, carries a fixing solution on the surface, and applies the fixing solution to an unfixed toner image on a recording medium or an intermediate transfer medium;
It is provided so as to face a recording medium or an intermediate transfer medium carrying an unfixed toner image via an application unit, and presses the application unit against the toner image, and adjusts the size of a fixing liquid application region by the application unit. Grant area adjustment means;
And a supply roller for supplying a fixing liquid to the coating means.

  Furthermore, the fixing liquid coating apparatus of the present invention is characterized in that the above-mentioned coating means is an endless belt supported so as to be rotatable.

Furthermore, in the fixing liquid coating apparatus of the present invention, the above-described application area adjusting means is
A plurality of pressing means that are cylindrical members having different lengths in the longitudinal direction;
A rotary shaft member provided so as to be rotationally driven around its axis, and supporting the pressing means so as to be rotationally driven;
The rotating shaft member is rotated in accordance with the detection result by the size detecting means, and the pressing means having a length in the longitudinal direction corresponding to the size of the recording medium is transferred to the unfixed toner image on the recording medium or the intermediate transfer medium and the applying means. And a movement instructing means for moving to the pressure contact position.

The present invention also provides a photosensitive drum, a charging unit that charges the surface of the photosensitive drum, an exposure unit that irradiates light to the charged surface of the photosensitive drum to form an electrostatic latent image based on image information, Developing means for supplying toner to the electrostatic latent image on the photosensitive drum to form a toner image, fixing liquid applying means for applying a fixing liquid to an unfixed toner image on the recording medium or intermediate transfer medium, and fixing liquid And an image forming apparatus including a fixing unit that fixes the unfixed toner image to which the toner image is attached to a recording medium.
The fixing solution applying means is any one of the fixing solution applying devices described above.

The image forming apparatus of the present invention further includes a heating unit that heats the unfixed toner image on the recording medium or the intermediate transfer medium,
The unfixed toner image on the recording medium or the intermediate transfer medium is heated to 65 ° C. or more by a heating unit before the fixing solution is applied by the fixing solution applying unit.

  According to the present invention, in a wet fixing type image forming apparatus that fixes an unfixed toner image onto a recording medium by applying a fixing liquid, the fixing liquid is applied to the unfixed toner image on the recording medium or the intermediate transfer medium. Fixing liquid applying means: fixing liquid storing means, size detecting means for detecting the size of the recording medium, and fixing for applying the fixing liquid to the toner image while changing the fixing liquid application area according to the detection result by the size detecting means. By using a fixing liquid application device including a liquid applying means, it is possible to prevent the fixing liquid from being applied outside the range of the size of the recording medium to which the fixing liquid is to be applied. As a result, the cleaning load is significantly reduced, and the other components such as the photosensitive drum and the pressure roller are significantly prevented from being contaminated by the fixing solution. Further, the consumption of the fixing solution does not increase, and the fixing solution can be used in an amount necessary and sufficient for fixing the toner image.

  According to the present invention, there is a coating roller (hereinafter simply referred to as “coating roller”) for applying a fixing solution to an unfixed toner image on a recording medium or an intermediate transfer medium, and a plurality of different lengths in the longitudinal direction. By using a fixing liquid application unit (hereinafter referred to as “fixing liquid application unit A”) configured to include an application roller, it is possible to appropriately adjust the fixing liquid application area according to the size of the recording medium.

  According to the present invention, the fixing liquid application unit A includes a plurality of application rollers having different lengths in the longitudinal direction and a rotation shaft member that rotatably supports the plurality of application rollers. By simply rotating the rotating shaft member, the application roller can be separated from the toner image, so that the application roller separation / contact mechanism can be simplified, which is advantageous in terms of size, cost, and reliability.

  According to the present invention, in the fixing liquid application unit A, by providing the fixing liquid holding tank for storing the fixing liquid inside the coating roller, a mechanism for supplying the fixing liquid to the coating roller becomes unnecessary. Even if a roller is provided, the configuration can be simplified. In addition, the space occupied by the fixing liquid applying unit A can be reduced, which can contribute to downsizing of the image forming apparatus.

  According to the present invention, there are an application roller and a supply roller (hereinafter simply referred to as “supply roller”) for supplying a fixing liquid to the surface of the application roller, which can be separated from the surface of the application roller and can be driven to rotate. A fixing liquid application unit (hereinafter referred to as “fixing liquid application unit B”) including a plurality of supply rollers having different lengths in the longitudinal direction is provided, and the longitudinal direction corresponding to the size of the recording medium is used. The fixing liquid application region can be easily adjusted by a simple configuration in which a supply roller having a length of 1 is selected. By using such a plurality of supply rollers, it is not necessary to immerse the application roller in the fixing solution in order to supply the fixing solution to the application roller. If the application roller is always immersed in the fixing solution, it may be difficult to adjust the fixing solution application area.

  According to the present invention, in the fixing liquid applying unit B, the application roller, the plurality of supply rollers having different lengths in the longitudinal direction, and the plurality of supply rollers can be separated from the surface of the application roller and can be rotationally driven. By adopting a configuration including a rotating shaft member that is supported on the feed roller, the supplying roller can be separated / attached by simply rotating the rotating shaft member, so that the separation / contact mechanism can be simplified, which is advantageous in terms of size and cost. Since the structure of the separation / connection mechanism is simple and difficult to break, its reliability increases.

  According to the present invention, the fixing liquid application unit B includes a fixing liquid removing unit that removes and collects the fixing liquid on the surface of the coating roller, so that, for example, the fixing liquid application area is reduced from a large recording medium size. When changing to the recording medium size, it is possible to remove and recover the fixing solution that is slightly outside the small recording medium size range on the surface of the coating roller, so that excess fixing solution on the recording medium or intermediate transfer medium can be recovered. Adhesion is prevented and wasteful consumption of the fixing solution can be reduced.

  According to the present invention, in the fixing liquid application unit B, it is not necessary to provide a driving unit that rotationally drives a plurality of supply rollers by adopting a configuration in which the supply roller is driven to rotate following the rotation of the application roller. Thus, the fixing liquid application device can be simplified.

  According to the present invention, a fixing liquid applying means (hereinafter referred to as “fixing liquid”) including a supply roller and a plurality of application rollers having different lengths in the longitudinal direction and having a length in the longitudinal direction shorter than the length in the longitudinal direction of the supply roller. The fixing liquid application region can be easily adjusted by a simple configuration in which the application roller is appropriately selected using the “applying means C”. In addition, since the fixing liquid application area is adjusted by selecting the application roller, there is an advantage that extra fixing liquid is very rarely attached to the recording medium or the intermediate transfer medium.

  According to the present invention, in the fixing liquid applying unit C, the supply roller, the plurality of application rollers having a different length in the longitudinal direction and having a length in the longitudinal direction shorter than the length in the longitudinal direction of the supply roller; By adopting a configuration that includes a rotating shaft member that supports the application roller so that it can be separated from and supplied to the surface of the supply roller, the application roller can be separated and attached only by rotating the rotating shaft member. The contact mechanism can be simplified, which is advantageous in terms of size and cost. Further, since the structure of the separation / connection mechanism is simple and hardly broken, the reliability thereof is increased.

  According to the present invention, in the fixing liquid application unit C, among the plurality of application rollers, a part or all of the application roller other than the application roller that contacts and applies the fixing liquid to the toner image is immersed in the fixing liquid. By adopting the configuration, it is possible to suppress evaporation of the liquid component in the fixing liquid remaining on the surface of the application roller after the fixing liquid is applied to the toner image, and to prevent wasteful consumption of the fixing liquid as much as possible.

  According to the present invention, the fixing liquid application unit C includes a fixing liquid removing unit that removes and collects the fixing liquid on the surface of the coating roller, thereby providing the surface of the coating roller after the fixing liquid is applied to the toner image. The evaporation of the liquid component remaining in the fixing solution can be suppressed and wasteful consumption of the fixing solution can be prevented as much as possible.

  According to the present invention, in the fixing liquid applying unit C, it is not necessary to provide a driving unit that rotationally drives a plurality of coating rollers by adopting a configuration in which the coating roller is driven to rotate following the rotational driving of the supply roller. Thus, the fixing liquid application device can be simplified.

  According to the present invention, an application means (preferably an endless belt supported so as to be able to be rotationally driven) made of an elastically deformable material and applying a fixing solution to an unfixed toner image, and an unfixed toner via the application means An application region adjustment unit (hereinafter simply referred to as “application region adjustment unit”) provided to face a recording medium or an intermediate transfer medium carrying an image and having a function of pressing the application unit against the toner image and a function of adjusting a fixing liquid application region And a supply roller for supplying the fixing liquid to the application means (hereinafter referred to as “fixing liquid application means D”), the application area recording means is used to apply the recording medium of the application means. Alternatively, by changing the area in contact with the intermediate transfer medium, the fixing liquid application can be performed without changing the longitudinal length of the application roller or the supply roller as in other fixing liquid application means. The frequency can be easily adjusted.

  According to the present invention, in the fixing liquid application unit D, a plurality of pressing units that are cylindrical members having different lengths in the longitudinal direction, and a rotary shaft member that supports the plurality of pressing units so as to be rotationally driven, The rotating shaft member is rotated in accordance with the detection result by the size detecting means, and the pressing means having a length in the longitudinal direction corresponding to the size of the recording medium is transferred to the unfixed toner image on the recording medium or the intermediate transfer medium and the applying means. A pressing means having a length in the longitudinal direction corresponding to the size of the recording medium from among a plurality of pressing means having different lengths in the longitudinal direction, using the application region adjusting means as a movement instruction means for moving the recording medium to the press contact position. By selecting, the coating means can be brought into pressure contact with the toner image by the length. As a result, the fixing solution can be easily applied only to the fixing solution application area corresponding to the size of the recording medium.

  According to the present invention, a photosensitive drum, a charging unit, an exposure unit, a developing unit, a fixing solution applying unit that applies a fixing solution to an unfixed toner image on a recording medium or an intermediate transfer medium, and a fixing solution application In an image forming apparatus including a fixing unit for fixing a toner image after that, by using the above-described fixing solution applying apparatus of the present invention as a fixing solution applying unit, there is no residual of the fixing solution on an intermediate transfer medium or the like. There is provided a wet-fixing type image forming apparatus capable of forming a high-quality image over a long period of time, without causing structural members such as a body drum and a pressure roller to be contaminated by the fixing liquid, increasing the consumption of the fixing liquid. can get.

  According to the present invention, the image forming apparatus of the present invention includes a heating unit that heats the unfixed toner on the recording medium or the intermediate transfer medium, and the unfixed toner image is formed on the unfixed toner image before applying the fixing liquid. By heating to 65 ° C. or higher, the binder resin or wax component contained in the toner is softened and the bonding force between the toner particles can be increased. As a result, it is possible to prevent the toner from adhering to the application roller or the application unit when the fixing solution is applied by contact with the application roller or the application unit.

  FIG. 1 is a cross-sectional view schematically showing a configuration of an image forming apparatus 1 according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a configuration of a main part (a toner image forming unit 2 described later) of the image forming apparatus 1 shown in FIG. FIG. 3 is an enlarged cross-sectional view showing a configuration of a main part (transfer fixing unit 4 described later) of the image forming apparatus 1 shown in FIG.

  The image forming apparatus 1 has a so-called tandem configuration in which toner images of four colors of yellow, magenta, cyan, and black are sequentially superimposed and transferred.

  The image forming apparatus 1 includes a toner image forming unit 2, an intermediate transfer unit 3, a transfer fixing unit 4, a recording medium supply unit 5, and a conveyance unit 6.

  The toner image forming unit 2 includes image forming units 10y, 10m, 10c, and 10b, which form an electrostatic latent image corresponding to image information of each color, develop the electrostatic latent image, and A toner image is formed. That is, the image forming unit 10y forms a toner image corresponding to yellow image information, the image forming unit 10m forms a toner image corresponding to magenta image information, and the image forming unit 10c uses cyan image information. The image forming unit 10b forms image information corresponding to black image information.

  The image forming unit 10y includes a photosensitive drum 11y, a charging roller 12y, an optical scanning unit 13, a developing device 14y, and a drum cleaner 15y.

  The photosensitive drum 11y is supported by a driving unit (not shown) so as to be rotatable around an axis, and a cylindrical, columnar, or thin film sheet-like conductive substrate (not shown), and a photosensitive layer formed on the surface of the conductive substrate. It is comprised including. As the photosensitive drum 11y, those commonly used in this field can be used. For example, the photosensitive drum 11y includes a conductive substrate such as an aluminum base tube and an organic photosensitive layer formed on the surface of the conductive substrate, and is connected to the GND potential. And a photosensitive drum having a diameter of 30 mm. The organic photosensitive layer is formed by laminating a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. Further, the photosensitive layer may include a charge generation material and a charge transport material in one layer. The layer thickness of the organic photosensitive layer is, for example, 20 μm. An underlayer may be provided between the organic photosensitive layer and the photosensitive drum. Further, a protective layer may be provided on the surface of the organic photosensitive layer. In addition to the organic photosensitive layer, a photosensitive layer made of zinc oxide, selenium, amorphous silicone, or the like can also be used. The photosensitive drum 11y is rotationally driven in a clockwise direction, for example, at a peripheral speed of 100 mm / s.

  The charging roller 12y is a cylindrical member that charges the surface of the photosensitive drum 11y to a predetermined polarity and potential. Instead of the charging roller 12y, a brush type charger, a charger type charger, a corona charger such as a scorotron, or the like can be used.

  The optical scanning unit 13 irradiates the surface of the photosensitive drum 11y in a charged state with laser light 13y that is signal light corresponding to yellow image information, and converts the yellow image information onto the surface of the photosensitive drum 11y. A corresponding electrostatic latent image is formed. For example, a semiconductor laser is used as a light source of the laser beam 13y.

  The developing device 14y includes a fixed magnetic pole (not shown), is provided so as to face the surface of the photosensitive drum 11y and can be driven to rotate about an axis, and supplies yellow toner 16y to the electrostatic latent image on the surface of the photosensitive drum 11y. A developing roller 17y, a developing blade 18y that is provided so as to be in contact with the surface of the developing roller 17y, and is a plate-like member that uniformizes (layer regulation) the yellow toner layer on the surface of the developing roller 17y, and a yellow toner 16y The developing tank 19y to be stored and stirring rollers 20y and 21y provided in the developing tank 19y so as to be in pressure contact with each other and rotatably driven around the axis line. The stirring roller 21y is in pressure contact with the surface of the developing roller 17y and yellow. And agitation rollers 20y and 21y for supplying the color toner 16y. Since the developing roller 17y is rotationally driven in a direction opposite to the rotational driving direction of the photosensitive drum 11y, the developing roller 17y is rotationally driven in the same direction at the pressure contact portion (nip portion) thereof. In the present embodiment, the peripheral speed of the developing roller 17y is, for example, 150 mm / s, which is 1.5 times the peripheral speed of the photosensitive drum 11y. The yellow toner 16y in the developing tank 19y is supplied to the surface of the developing roller 17y by the stirring rollers 20y and 21y to form a yellow toner layer, and the toner layer is made uniform in thickness by the developing blade 18y. The toner image corresponding to the yellow image information is formed by selectively supplying the electrostatic latent image on the surface of the photosensitive drum 11y almost selectively using a potential difference. In this embodiment, the yellow toner 16y is mixed with a magnetic carrier and used in the form of a two-component developer. When the yellow toner 16y is supplied into the developing tank 19y, it is mixed with the carrier in the developing tank 19y by the stirring rollers 20y and 21y to become a two-component developer.

  As will be described later, the drum cleaner 15y removes and collects the yellow toner remaining on the surface of the photosensitive drum 11y after the yellow toner image on the surface of the photosensitive drum 11y is intermediately transferred to the intermediate transfer belt 22.

  According to the image forming unit 10y, the surface of the photosensitive drum 11y is first charged to, for example, -600V by the charging roller 12y while the photosensitive drum 11y is rotationally driven. Next, an electrostatic latent image having an exposure potential of −70 V is formed on the surface of the charged photosensitive drum 11 y by irradiating the laser beam 13 y from the optical scanning unit 13. To this electrostatic latent image, the yellow toner 16y is attached due to a potential difference from the developer layer on the surface of the developing roller 17y to which a DC voltage of −240 V is applied as the developing potential, and the electrostatic latent image is developed and the yellow toner image is developed. Is formed. As will be described later, the toner image is intermediately transferred to an intermediate transfer belt 22 that is in pressure contact with the surface of the photosensitive drum 11y. The yellow toner 16y remaining on the surface of the photosensitive drum 11y is removed by the drum cleaner 15 and collected. Thereafter, the same toner image creation operation is repeatedly executed.

  The image forming units 10m, 10c, and 10b have a structure similar to that of the image forming unit 10y except that magenta toner 16m, cyan toner 16c, and black toner 16b are used, and the corresponding parts are the same. In addition, “m” indicating magenta color, “c” indicating cyan color, or “b” indicating black color is added instead of “y” indicating yellow color at the end of each reference code. The description is omitted. The image forming units 10y, 10m, 10c, and 10b are arranged in a line in this order from the upstream side in the moving direction (sub operation direction) of the intermediate transfer belt 22, that is, the direction of the arrow 28.

  Each color toner 16y, 16m, 16c, 16b (hereinafter collectively referred to as “toner 16” as necessary) contains a binder resin, a colorant, and a release agent.

  The binder resin is not particularly limited as long as it is a resin that can be swollen or softened by the fixing solution 40 described later. Specifically, for example, polystyrene, styrene and its substituted polymer homopolymer, styrene copolymer, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester resin, polyurethane resin, etc., alone or in combination of two or more Can be used in combination.

  As the colorant, any toner pigment and dye used in general electrophotographic technology can be used without any particular limitation. However, in order to prevent bleeding due to the fixing solution 40, those that do not dissolve in the fixing solution 40 are preferable. Dyes such as dyes are not preferred. Specific examples of the pigment include, for example, azo pigments, benzimidazolone pigments, quinacridone pigments, phthalocyanine pigments, isoindolinone pigments, isoindoline pigments, dioxazine pigments, anthraquinone pigments, perylene pigments, Organic pigments such as perinone pigments, thioindigo pigments, quinophthalone pigments, metal complex pigments, inorganic pigments such as carbon black, titanium oxide, molybdenum red, chrome yellow, titanium yellow, chromium oxide, Berlin blue, aluminum Examples thereof include metal powder such as powder. A pigment can be used individually by 1 type or can use 2 or more types together.

  If necessary, one or more general toner additives such as a charge control agent, a fluidity improver, a fixing accelerator, and a conductive agent can be appropriately selected and added to the toner 16.

The toner 16 used in this exemplary embodiment contains a binder resin, a colorant, and a release agent. The pigment content is 12% by weight of the total amount of the toner 16, and the content of wax as a release agent is the toner 16. This is a negatively chargeable insulating nonmagnetic toner having a composition of 7% by weight of the total amount and the remaining binder resin and having a volume average particle diameter of 6 μm. The toner amount per unit area necessary for obtaining a predetermined image density (a reflection density measurement value by a X-Rite 310 of 1.4) is 5 g / m ² . Each of the color toners 16y, 16m, 16c, and 16b has the above-described composition, volume average particle diameter, and characteristics except that the types of pigments are different.

  The intermediate transfer unit 3 includes an intermediate transfer belt 22, intermediate transfer rollers 23y, 23m, 23c, and 23b, a driving roller 24, a tension roller 25, and a belt cleaner 26.

  The intermediate transfer belt 22 is an endless belt that is stretched between a driving roller 24 and a tension roller 25 so as to be rotationally driven to form a loop-shaped movement path, and is substantially the same as the photosensitive drums 11y, 11m, 11c, and 11b. It rotates in the direction of the arrow 28 at the same peripheral speed. The intermediate transfer belt 22 is made of a material that does not penetrate the fixing liquid 40. In this embodiment, a polyimide substrate (polyimide film) having a fluororesin layer formed thereon is used. However, the present invention is not limited to this, and PTFE is applied to the surface of a substrate such as polycarbonate or fluororubber imparted with conductivity. In addition, one provided with a coating layer made of one or more of fluororesins such as PFA may be used. The toner image carrying surface 22a of the intermediate transfer belt 22 is in pressure contact with the photosensitive drums 11y, 11m, 11c, and 11b in this order. This pressure contact position is an intermediate transfer position for each color toner image. In this embodiment, a belt-like intermediate transfer is used, but the invention is not limited to this, and other forms of intermediate transfer bodies such as a drum shape can be used.

  The intermediate transfer rollers 23y, 23m, 23c, and 23b are respectively provided in pressure contact with the surface opposite to the toner image carrying surface 22a of the intermediate transfer belt 22 and capable of being driven to rotate about its axis by driving means (not shown). For example, a metal shaft body such as stainless steel, and a conductive elastic body formed on the surface of the shaft body, in which a conductive control agent such as carbon black is dispersed in a matrix such as EPDM, foamed EPDM, and foamed urethane It is a cylindrical member containing the electroconductive layer which consists of. An intermediate transfer bias voltage having a polarity opposite to the charging polarity of the toner is applied to the intermediate transfer rollers 23y, 23m, 23c, and 23b. As a result, yellow, magenta, cyan, and black toner images formed on the surfaces of the photosensitive drums 11y, 11m, 11c, and 11b are sequentially applied to predetermined positions on the toner image carrying surface 22a of the intermediate transfer belt 22. Overlaid and transferred, a multicolor toner image is formed. However, when image information of only a part of each color is input, a toner image is formed only in the corresponding image forming unit and transferred to the toner image carrying surface 22a.

  The driving roller 24 is provided so as to be rotatable around its axis by a driving means (not shown). As the driving roller 24, for example, a hollow roller made of a metal such as aluminum can be used.

  The tension roller 25 applies a predetermined tension to the intermediate transfer belt 22 in order to prevent the intermediate transfer belt 22 from sagging. The tension roller 25 includes, for example, a metal shaft body and a coating layer formed on the surface of the metal shaft body. Moreover, what consists only of metal shaft bodies may be sufficient. For example, stainless steel is used as the material of the metal shaft body, and fluororubber is used as the material of the coating layer.

  The belt cleaner 26 is provided so as to face the tension roller 25 through the intermediate transfer belt 22, and the toner image on the toner image carrying surface 22 a of the intermediate transfer belt 22 is transferred to the transfer fixing roller 30 in the transfer fixing unit 4 described later. It is a member that removes the toner remaining on the toner image carrying surface 22a after the transfer.

  According to the intermediate transfer means 3, each color toner image formed on the photosensitive drums 11y, 11m, 11c, and 11b is superposed on a predetermined position of the toner image carrying surface 22a of the intermediate transfer belt 22 and transferred, so that multicolor A toner image is formed. After the toner image is transferred to the transfer fixing roller 30 of the transfer fixing unit 4, residual toner, offset toner, paper dust, etc. on the toner image carrying surface 22a are removed by the belt cleaner 26, and the toner image carrying surface 22a The multicolor toner image is transferred again and the same operation is repeated.

  The transfer fixing unit 4 is provided so as to face the driving roller 24 via the intermediate transfer belt 22, and the transfer fixing roller 30 that retransfers the toner image from the intermediate transfer belt 22 and the toner image on the surface of the transfer fixing roller 30. A fixing liquid application device 33 for applying the fixing liquid 40 to the surface, a temperature sensor 34 for detecting the surface temperature of the transfer fixing roller 30, a roller cleaner 35, and a pressure roller 36 provided so as to be in pressure contact with the transfer fixing roller 30. It is comprised including.

The transfer and fixing roller 30 is a cylindrical member that is rotatably provided in the direction of an arrow 32 by a driving unit (not shown). The transfer fixing roller 30 includes, for example, a core metal made of carbon steel having a thickness of 1 mm, and a silicone rubber layer having a volume resistance of 10 ⁻⁸ to 10 ⁻⁹ Ω · cm and a thickness of 3 mm formed on the core metal surface. A roller member having an outer diameter of 30 mm is used, including a coating layer having a thickness of 20 μm made of PFA (copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether) formed on the surface of the silicone rubber layer. A transfer electric field is applied between the transfer fixing roller 30 and the intermediate transfer belt 22, and the multicolor or single color toner image on the intermediate transfer belt 22 is electrostatically retransferred to the transfer fixing roller 30. In this embodiment, the transfer fixing roller 30 is configured to be applied with a voltage of +1 kV opposite to the charging potential of the toner 16 and electrostatically attract and transfer the toner.

  In addition, a heater 31 such as a halogen lamp is provided inside the transfer / fixing roller 30 to heat the surface of the transfer / fixing roller 30 and thus the toner image. As a result, the toner image retransferred from the intermediate transfer belt 22 to the transfer fixing roller 30 is heated before receiving the application of the fixing liquid 40. Heating the toner image before the fixing liquid 40 is applied has the following advantages. For example, when the binder resin contained in the toner 16 has a glass transition point of 60 ° C. and the surface temperature of the transfer fixing roller 30 (that is, the heating temperature of the toner image) is set to 65 ° C., the fixing liquid 40 is applied. Before, the binder resin in the toner particles is softened and the adhesion force of the toner particles to the surface of the transfer and fixing roller 30 is increased, so that when the fixing liquid 40 is applied, the toner particles are offset to the application roller 41, It can prevent the image from being disturbed.

  In this embodiment, the surface temperature of the transfer and fixing roller 30 is set to 65 ° C., but the temperature of the transfer and fixing roller 30 is set to 75 ° C., and the contact start portion with the application roller 41 to which the fixing liquid 40 is applied. The temperature of the transfer fixing roller 30 and the toner image may be set to be higher than the softening point of the wax in the toner particles. With this configuration, the wax in the toner is softened before the fixing liquid 40 is applied, and the adhesion between the toners and between the toner and the transfer fixing roller 30 is increased. As a result, it is possible to prevent toner particles from moving and flowing due to the fixing liquid 40 when the fixing liquid 40 is applied. Further, it is possible to supply the toner image and the transfer-fixing roller 30 with the amount of heat that compensates for the temperature drop of the toner and the transfer-fixing roller 30 due to the application of the fixing liquid 40. As a result, the temperature drop of the toner image immediately after application, the transfer fixing roller 30 and the fixing solution 40 can be prevented, the diffusion and penetration of the fixing solution 40 into the toner image is fast, and the swelling and softening of the toner occurs instantaneously over a wide range. Thus, as will be described later, when the toner image is pressed against the recording medium P at the pressure contact portion between the transfer fixing roller 30 and the pressure roller 36, the toner image is fixed to the recording medium P with sufficient fixing strength. Furthermore, since the liquid temperature of the fixing liquid 40 after application increases, the fixing liquid 40 can be dried in a short time after application and after transfer and fixing of the toner image onto the recording medium P. Thereby, the throughput which is the number of output sheets per unit time of the image forming apparatus 1 can be further improved. Furthermore, since the time from the application of the fixing liquid 40 to the transfer to the recording medium P can be shortened, the interval between the application position of the fixing liquid 40 and the transfer position of the toner image to the recording medium P can be set short, and the apparatus Contributes to small size.

  The fixing liquid application device 33 is provided so as to be in pressure contact with the surface of the transfer fixing roller 30, and is applied so as to be in pressure contact with the application roller 41 that applies the fixing liquid 40 to the toner image on the surface of the transfer fixing roller 30. A supply roller 43 that supplies the fixing liquid 40 to the surface of the application roller 41 and a regulation roller 45 that is provided so as to be in pressure contact with the surface of the application roller 41 and adjusts (regulates) the amount of the fixing liquid on the surface of the application roller 41 to an appropriate amount. And a casing 47 that accommodates the fixing liquid 40, the application roller 41, the supply roller 43, and the regulating roller 45, a fixing liquid storage tank 51, and a fixing liquid supply pipe 52.

  The application roller 41 includes, for example, a cored bar and an elastic layer formed on the surface of the cored bar, and a rotating shaft member integrated with flanges (not illustrated) provided at both ends of the cored bar is provided with a bearing (not illustrated). The casing 47 is supported so as to be rotatable in the direction of the arrow 42. The application roller 41 is provided at one end of the casing 47 in the horizontal direction so as not to be immersed in the fixing liquid 40 held in the fixing liquid reservoir 48 below the casing 47. When the application roller 41 comes into contact with the surface of the transfer fixing roller 30, the fixing liquid 35 held on the surface of the application roller 41 and the surface layer oozes out, and the fixing liquid 40 is applied to the toner image. As the metal core of the application roller 41, for example, a metal core made of stainless steel or carbon steel can be used. The material of the elastic layer is not particularly limited as long as it has elasticity and good wettability with the fixing solution 40. For example, rubber materials such as ethylene propylene rubber and urethane rubber, metal materials such as aluminum, Examples thereof include hydrophilic resin materials. By forming the elastic layer using a material having good wettability with the fixing solution 40, the fixing solution 40 can be held on the surface of the application roller 41 as a thin layer. As a measure of wettability, the contact angle, which is an index for evaluating wettability by the shape of water droplets attached to the surface, is preferably 50 degrees or less. In the present embodiment, the application roller 41 includes, for example, a core metal having a diameter of 12 mm and an ethylene-propylene rubber layer having elasticity of Young's modulus of 2 MPa formed on the core metal surface and having a diameter of 20 mm. Members can be used. In the present embodiment, the application roller 41 is pressed against the transfer fixing roller 30 with a pressing force of 0.5 N / cm (linear pressure). Further, the application roller 41 carries the fixing solution 40 and is pressed against the transfer fixing roller 30 and is rotated at a speed equal to the surface speed of the transfer fixing roller 30 by a driving unit (not shown).

  The supply roller 43 is supported by a driving means (not shown) so as to be rotatable in the direction of the arrow 44, and a part of the supply roller 43 is provided so as to be immersed in the fixing liquid 40 in the casing 47. The fixing liquid 40 is supplied to the surface of the application roller 41 by rotating in a state where a part of the supply roller 43 is immersed in the fixing liquid 40 and pressed against the application roller 41. As the supply roller 43, for example, a sponge roller including a core metal having a diameter of 10 mm and a sponge layer having a thickness of 5 mm made of foamed open-cell foam formed on the surface of the core metal can be used.

  The regulating roller 45 is supported so as to be rotationally driven in the direction of the arrow 46 by a driving means (not shown). The regulation roller 45 forms a thin layer of the fixing solution 40 having a uniform layer thickness on the surface of the coating roller 41. For example, a metal hollow roller is used as the regulating roller 45. In the present embodiment, a stainless steel roller member having an outer diameter of 12 mm is used.

  The casing 47 has an opening 47 b at the end of the portion facing the transfer fixing roller 30 on the side surface 47 a facing the intermediate transfer belt 22 and the transfer fixing roller 30, and the opening 47 b faces the outside of the casing 47. Thus, a part of the application roller 41 is disposed so as to protrude and come into pressure contact with the surface of the transfer fixing roller 30. Further, a lower portion of the casing 47 serves as a fixing liquid reservoir 48 in which the fixing liquid 40 is held. The height of the fixing liquid surface of the fixing liquid reservoir 48 is kept constant in a range where, for example, a part of the supply roller 43 is immersed in the fixing liquid 40 and the coating roller 41 is not immersed in the fixing liquid 40. Further, in the casing 47, the pivot 49 passes through the casing 47 in the longitudinal direction of the casing 47 (direction perpendicular to the paper surface) at the other end with respect to the one end on the horizontal direction side where the application roller 41 is provided. And is rotatably supported by a bearing (not shown). Further, a pressing spring 50 that is supported by a support member (not shown) and presses the casing 47 is provided on the bottom surface of the end portion of the casing 47 where the application roller 41 is provided in the horizontal direction. By the action of the pivot 49 and the pressing spring 50, the application roller 41 is pressed against the transfer fixing roller 30 with a relatively light pressing force. As the pressing spring 50, for example, a coil spring, a leaf spring, a torsion spring or the like can be used.

  The fixer storage tank 51 stores the fixer 40, and the level of the fixer 40 in the fixer reservoir 48 of the casing 47 is made constant by replenishing means (not shown) according to the consumption state of the fixer 40. In addition, the fixing solution 40 is supplied to the casing 47 via the fixing solution supply pipe 52. In the casing 47, a sensor (not shown) detects the liquid level of the fixing liquid 40, and the detection result is stored in a CPU (not shown) that controls all operations of the image forming apparatus 1. The CPU fixes according to the detection result. When it is determined whether or not the liquid 40 can be replenished, a control signal is sent to a replenishing means (not shown). The fixer storage tank 51 can be formed in a cartridge type, for example. When the fixing liquid 40 in the fixing liquid storage tank 90 runs out, a sensor (not shown) detects it and stores the detection result in a CPU (not shown). The CPU sends a control signal to an operation panel (not shown) according to the detection result, and indicates that it is time to replenish the fixing solution 40 to the fixing solution storage tank 51 on the operation panel or it is time to replace the fixing solution storage tank 51. indicate.

  According to the fixing liquid application device 33, the toner image carried on the surface of the transfer fixing roller 30 is contacted and applied with the fixing liquid 40 via the application roller 41, so that the toner image is suitable for transfer and fixing onto the recording medium P. Soften and / or swell.

  In order to detect the surface temperature of the transfer fixing roller 30, the temperature sensor 34 is positioned upstream of the pressure contact portion between the transfer fixing roller 30 and the driving roller 24 in the rotation direction of the transfer fixing roller 30, that is, in the direction of the arrow 32. The transfer fixing roller 30 is provided so as to be in contact with or close to the surface. The detection result by the temperature sensor 34 is stored in a CPU (not shown), and the CPU determines whether or not the surface of the transfer fixing roller 30 needs to be heated according to the detection result. A control signal is sent to the heater 31 provided in the heater, causing the heater 31 to perform a heating operation, uniformly heating the entire surface of the transfer fixing roller 30, and maintaining the surface temperature constant. In the present embodiment, the surface temperature is 65 ° C.

  The roller cleaner 35 is a member that removes the toner 16, the fixing liquid 40, and paper dust remaining on the surface of the transfer fixing roller 30 after the toner image on the transfer fixing roller 30 is transferred to the recording medium P.

  The pressure roller 36 is provided so as to be rotationally driven in the direction of an arrow 37 by a driving unit (not shown) and to be in pressure contact with the transfer fixing roller 30. The pressure roller 36 is, for example, a roller member including a cored bar, an elastic layer formed on the surface of the cored bar, and a coating layer formed on the surface of the elastic layer. In the present embodiment, a pressure roller including a cored bar, a 2 mm thick elastic layer made of silicone rubber having a hardness of 50 degrees (JIS-A), and a 20 μm thick coating layer made of PFA is used. In the present embodiment, the pressure roller 36 is brought into pressure contact with the surface of the transfer fixing roller 30 with a pressing force of 10 N / cm (linear pressure). A toner image that is swollen and softened by the application and heating of the fixing liquid 40 on the transfer fixing roller 30 is conveyed to the pressure contact portion between the transfer fixing roller 30 and the pressure roller 36 by the rotation of the transfer fixing roller 30. . In synchronization therewith, the recording medium P is conveyed from a recording medium supply means 5 described later. The toner image on the transfer / fixing roller 30 is pressed by the pressure roller 36 and transferred and fixed to the recording medium P to form an image.

  The fixing solution 40 used here is a liquid that swells and softens the toner, and is, for example, a composition containing water and an auxiliary solvent. A co-solvent is an organic compound that can be dissolved or dispersed in water. Specific examples of the auxiliary solvent include, for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, octyl alcohol, decyl alcohol, diethylene glycol, glycerin, polyethylene glycol, phenols, benzyl alcohol, methylbenzyl alcohol and other alcohols, acetone, Ketones such as methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone and diethyl ketone, ethers such as methyl ethyl ether, diethyl ether, methyl butyl ether, methyl isobutyl ether, dimethyl ether, diisopropyl ether, octyl phenyl ether, methyl acetate, ethyl acetate , Ethyl oleate, ethyl acrylate, methyl methacrylate, dibutyl succinate, phthalate Diethyl, diethyl tartrate, ethyl palmitate, and the like esters such as dioctyl phthalate. These auxiliary solvents are excellent in the action of swelling and softening the binder resin of the toner 16 including polyester. Among these, ethers and esters are preferable, and esters are particularly preferable. The auxiliary solvent can be used alone or in combination of two or more.

  The content of the auxiliary solvent in the fixing solution 40 is not particularly limited, but is preferably 5 to 80% by weight, more preferably 10 to 70% by weight, based on the total amount of the fixing solution 40. If it is less than 5% by weight, the action of swelling and softening the binder resin in the toner 16 becomes weak, and sufficient fixing strength may not be obtained. On the other hand, when the amount exceeds 80% by weight, the permeability of the fixing liquid 40 to the toner image decreases, and particularly when the amount of toner is large, only the toner on the surface of the toner image swells and softens. Insufficient fixing to the toner may cause the toner to fall off.

  In addition to water and the auxiliary solvent, the fixing agent 40 can be added with one or more surfactants, dispersion assistants, and the like that maintain the dispersed state of the auxiliary solvent and improve the wettability with the toner 16. Examples of the surfactant include an anionic surfactant such as a higher alcohol sulfate such as lauryl sulfate sodium salt, a higher fatty acid metal salt such as sodium oleate, a fatty acid derivative sulfate, and a phosphate ester. , Quaternary ammonium salts, cationic surfactants such as heterocyclic amines, amino acid esters, zwitterionic surfactants such as amino acids, nonionic surfactants, polyoxyalkylene alkyl ethers, polyoxy An ethylene alkylamine etc. are mentioned. Examples of the dispersion aid include coupling agents such as diethylene glycol, triethylene glycol, polyethylene glycol, monobutyl ether, and diethylene glycol monomethyl ether.

  As described above, since the fixing solution 40 has a configuration in which an auxiliary solvent is dispersed in water, the fixing solution 40 does not penetrate the transfer fixing roller 30 mainly made of a resin material.

  The fixing solution 40 is not limited to the one containing each of the above components, and any conventionally known fixing solution can be used. Further, emulsion adhesive in which a fixing agent 40 is uniformly dispersed in water with a rubber-based adhesive mainly composed of a polymer elastomer such as chloroprene rubber, nitrile rubber or SBR rubber, or vinyl acetate, EVA or acrylic resin. It is also possible to contain various adhesives such as an agent. As a result, the adhesive force between the toner 16 and the recording medium P is applied not only by the swelling / softening of the toner but also by an adhesive, so that the adhesive force between the toner 16 and the recording medium P is improved, and the toner image The fixing strength on the recording medium P can be increased.

  According to the transfer fixing unit 4, the toner image is electrostatically transferred from the intermediate transfer belt 22 onto the transfer fixing roller 30 whose surface is heated to a uniform temperature, and this toner image is transferred by the fixing liquid application device 33. Upon receiving contact with the fixing solution 40, the heat and the fixing solution 40 swell and soften appropriately. This toner image is conveyed to a pressure contact portion between the transfer and fixing roller 30 and the pressure roller 36, where it is pressurized and transferred and fixed onto the recording medium P. After the toner image is transferred and fixed, the toner 16, the fixing liquid 40, paper dust and the like remaining on the surface of the transfer and fixing roller 30 are removed by the roller cleaner 35, and the next toner image is transferred onto the transfer and fixing roller 30. This transfer and fixing operation is repeatedly executed, and an image is formed on the recording medium P.

  The recording medium supply means 5 includes a recording medium cassette 53 that stores the recording medium P and a pickup roller 54 that feeds the recording medium P one by one. Further, by providing a pair of registration rollers (not shown) on the downstream side of the pickup roller 54 in the conveyance (feed) direction of the recording medium P, the toner image is conveyed to the pressure contact portion between the transfer fixing roller 30 and the pressure roller 36. In synchronism with this, the recording medium P can be easily fed to the press contact portion.

  According to the recording medium supply means 5, the recording medium P in the recording medium cassette 53 is fed to the conveyance path one by one by the pickup roller 54 and further fed to the pressure contact portion between the transfer fixing roller 30 and the pressure roller 36. Be paid.

  The transport unit 6 includes a pair of transport rollers 55 and 56 that transport the recording medium P on which the toner image has been fixed by the transfer fixing unit 4 and the recording medium P transported by the transport rollers 55 and 56. It includes paper discharge rollers 57 and 58 for discharging the image forming apparatus 1 to the outside.

  According to the conveying means 6, the image-formed recording medium P is discharged to the outside of the image forming apparatus 1 through the conveying rollers 55 and 56 and the paper discharge rollers 57 and 58.

  According to the image forming apparatus 1, the multicolor toner image formed on the intermediate transfer belt 21 by the toner image forming unit 2 is transferred onto the transfer and fixing roller 30, applied with the fixing liquid 40, and heated appropriately. It swells and softens, and is transferred and fixed to the recording medium P at the press-contact portion between the transfer fixing roller 30 and the pressure roller 36 to form an image.

  In the image forming apparatus of the present invention, a configuration in which the fixing liquid 40 is applied to the toner image on the intermediate transfer belt 22 can be adopted. However, as in the present embodiment, the fixing liquid is applied to the toner image on the transfer fixing roller 30. It is desirable to apply 40. The reason is as follows. That is, in the present embodiment, the fixing liquid 40 is applied to the toner image on the transfer fixing roller 30, so that the fixing liquid 40 does not adhere to the intermediate transfer belt 22. Further, since the transfer fixing roller 30 is heated, the temperature of the intermediate transfer belt 22 does not increase. As a result, it is possible to prevent temperature rise of components such as the photoconductor 20, contamination by the fixing liquid 40, toner deterioration during the toner image forming process, and the like, and a high-quality image can be stably formed over a long period of time.

  Further, although the surface of the toner image that contacts the transfer fixing roller 30 is moderately softened, the surface of the toner image is difficult to soften. Since the surface of the toner image serves as a fixing surface to the recording medium P, there is a case where sufficient fixing strength cannot be obtained with a configuration in which the toner is softened only by the action of heat. Accordingly, when the fixing liquid 40 is applied to the surface of the toner image, the toner on the surface of the toner image can be sufficiently softened and swollen, so that the fixing strength of the toner image on the recording medium P can be increased.

  FIG. 4 is a cross-sectional view schematically showing the configuration of the image forming apparatus 60 according to the second embodiment of the present invention. The image forming apparatus 60 is similar to the image forming apparatus 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  The image forming apparatus 60 is characterized in that after the toner image is transferred to the recording medium P, the fixing liquid 40 is applied to the toner image on the recording medium P under heating to fix the toner image on the recording medium P.

  The image forming apparatus 60 includes a toner image forming unit 2, an intermediate transfer unit 61, a secondary transfer unit 67, and a fixing unit 69.

  The intermediate transfer unit 61 includes an intermediate transfer belt 62, intermediate transfer rollers 23y, 23m, 23c, and 23b, support rollers 63, 64, and 65, and a belt cleaner 26.

  The intermediate transfer belt 62 is an endless belt that is stretched by support rollers 63, 64, and 65 to form a loop-shaped movement path, and has an arrow 66 at substantially the same peripheral speed as the photosensitive drums 11y, 11m, 11c, and 11b. Rotate in the direction of. The intermediate transfer belt 62 can be made of the same material as the intermediate transfer belt 22.

  Each of the support rollers 63, 64, 65 is supported so as to be rotatable around its axis, and for example, an aluminum cylindrical member having a diameter of 30 mm and a thickness of 1 mm is used. A support roller 64 that constitutes a secondary transfer unit 67 together with a secondary transfer roller 68 described later is electrically grounded.

  According to the intermediate transfer means 61, the respective color toner images formed on the photosensitive drums 11y, 11m, 11c, and 11b are superimposed and transferred onto a predetermined position on the toner image carrying surface of the intermediate transfer belt 62, so that the multicolor toner An image is formed. After the multicolor toner image is transferred to the recording medium P by the secondary transfer means 67 described later, the residual toner, offset toner, paper dust and the like on the toner image carrying surface are removed by the belt cleaner 26, and the toner image carrying surface. The toner image is transferred again to.

  The secondary transfer unit 67 includes a support roller 64 and a secondary transfer roller 68 that is in pressure contact with the support roller 64 via the intermediate transfer belt 62 and is rotatably driven about an axis. For the secondary transfer roller 68, for example, a cylindrical member including a core metal having a diameter of 10 mm and a urethane rubber layer having a thickness of 4 mm formed on the surface of the core metal is used. The urethane rubber layer is blended with a conductive agent such as carbon for imparting conductivity.

  According to the secondary transfer unit 67, a recording medium supply to be described later is synchronized with the intermediate transfer belt 62 carrying the multicolor toner image being conveyed to the pressure contact portion between the support roller 64 and the secondary transfer roller 68. The recording medium P is fed from the means 79, and the multicolor toner image on the intermediate transfer belt 62 is transferred onto the surface of the recording medium P by pressing. The recording medium P on which the multicolor toner image is transferred is conveyed to the fixing unit 69.

  The fixing unit 69 includes a conveyance belt 70 that conveys the recording medium P on which the multicolor toner image is transferred, a driving roller 71, a tension roller 73, a pressure roller 75, a fixing liquid applying unit 75, and a paper discharge roller. And a pair 77.

  The conveying belt 70 is an endless belt that is stretched between the driving roller 71 and the tension roller 73 to form a loop-shaped conveying path, and is rotatably provided by the rotational driving of the driving roller 71. For example, a surface layer having a thickness of 10 μm made of polytetrafluoroethylene (PTFE) is provided on the transport belt 70 on at least one surface of a polyimide film having a thickness of 100 μm that is provided with conductivity by mixing a conductive agent. Things can be used.

  The drive roller 71 is a cylindrical member provided so as to be rotatable around its axis by a drive means (not shown). For example, a hollow roller made of a metal such as aluminum can be used. Inside the driving roller 71, a heating unit 72 such as a heater is provided for heating the recording medium P and the toner image on the surface thereof. In the present embodiment, the heating temperature of the toner image on the recording medium P by the heating unit 72 is maintained at 65 ° C. by a control unit such as a CPU (not shown). When the toner image on the recording medium P is heated by the driving roller 71, the offset of the toner image to the fixing liquid applying unit 75 is prevented. Further, since the recording medium P is heated by the driving roller 71, drying of the fixing liquid 40 is promoted, and the toner 16 and the fixing liquid 40 adhere to the overlapping recording medium P after offset to the pressure roller 74 and paper discharge. Can be prevented.

  The tension roller 73 applies a predetermined tension to the conveyor belt 70 so that the conveyor belt 70 does not slack. For the tension roller 73, for example, a cylindrical member including a metal shaft made of stainless steel or the like and a coating layer formed on the surface of the metal shaft and made of fluorine rubber or the like can be used. Moreover, what consists only of metal shaft bodies may be sufficient. The tension roller 73 also has a function of pressurizing and fixing the toner image in the swollen / softened state to which the fixing liquid 40 is applied to the recording medium P.

  The pressure roller 74 is provided so as to be in pressure contact with the tension roller 73 via the conveyor belt 70 and to be rotatable around its axis. The pressure roller 74 applies a toner image to which the fixing liquid 40 is applied by the fixing liquid applying means 75 positioned upstream in the direction of an arrow 76 that is the conveyance direction of the recording medium P of the conveyance belt 70. 73 is pressed and fixed to the recording medium P together. Pressurizing the toner image with the pressure roller 74 has an effect of improving the glossiness of the toner image on the recording medium P.

  According to the fixing unit 69, the recording medium P onto which the toner image has been transferred by the secondary transfer unit 67 is transported on the transport belt 70 in the direction of the arrow 76 while being heated. The toner image is applied to the contact portion between the tension roller 73 and the pressure roller 74 in a state where the fixing liquid 40 is applied and the toner image is swollen and softened, and the toner image is fixed on the surface of the recording medium P by pressurization. Thereafter, the paper is discharged onto a paper discharge tray 78 provided outside the image forming apparatus 60 by a pair of paper discharge rollers 77.

  The recording medium supply unit 79 includes a recording medium cassette 53 that stores the recording medium P, a pickup roller 54 that feeds the recording medium P one by one, and a toner image on the intermediate transfer belt 70 that transfers the support roller 64 and the secondary transfer. In synchronism with being conveyed to the pressure contact portion with the roller 68, a registration roller pair 80 for feeding the recording medium P to the pressure contact portion is configured.

  According to the recording medium supply means 79, the recording medium P stored in the recording medium cassette 53 is fed to the transport path one by one by the pickup roller 54, and is further supported by the support rollers 64 and 2 by the registration roller pair 80. It is fed to the pressure contact portion with the next transfer roller 68.

  According to the image forming apparatus 60, the multicolor toner image formed on the intermediate transfer belt 21 by the toner image forming unit 2 is transferred to the recording medium P at the press contact portion between the support roller 64 and the secondary transfer roller 68. The fixing liquid 40 is applied to the multicolor toner image on the recording medium P from the fixing liquid applying device 75. When the recording medium P passes through the pressure contact portion between the tension roller 73 and the pressure roller 74, the recording medium P is pressurized, and the multicolor toner image is fixed on the recording medium P to form an image.

  FIG. 5 is a cross-sectional view schematically showing a configuration of a main part (fixing solution applying apparatus 81) of the image forming apparatus according to the third embodiment of the present invention. FIG. 6 is a diagram for explaining a method of adjusting the fixing liquid application region by the fixing liquid application device 81.

  The image forming apparatus shown in FIG. 5 is similar to the image forming apparatus 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. Also, illustration and description of the same parts are omitted. The image forming apparatus includes a fixing solution applying device 81 instead of the fixing solution applying device 33 in the image forming apparatus 1.

  The fixer coating device 81 is provided so as to be rotatable around its axis by a driving means (not shown), and a regulating roller 83 provided around the rotating shaft member 82 so as to coincide with the rotating shaft member 82. Coating rollers 84a, 84b, 84c having different lengths in the longitudinal direction, supported by the rotary shaft member 82 so as to be separated from the surface of the transfer fixing roller 30 and capable of being driven to rotate around the axis thereof; 84a, 84b, and 84c, a supply roller 85 that is detachable from the surface of the application roller (application roller 84a in the figure) that is in pressure contact with the transfer fixing roller 30 and that can be driven to rotate about its axis, and application 84a, 84b, 84c of the application roller (in the figure, application roller 84c) that is not immersed in the fixing liquid 40 and is not in pressure contact with the surface of the transfer fixing roller 30 and its shaft. A removal roller 86 that is rotatably driven around, a blade 87 that is provided so as to contact the surface of the removal roller 86, a rotating shaft member 82, a regulating roller 83, application rollers 84a, 84b, 84c, a supply roller 85, a removal roller A casing 88 that accommodates the roller 86 and the blade 87 and stores the fixing liquid 40 under the roller 86 and the blade 87 is configured.

  By the rotation shaft member 82, the application rollers 84 a, 84 b, 84 c are arranged so that the shaft centers 84 x, 84 y, 84 z are on the circumference of the virtual circle A centering on the shaft center of the rotation shaft member 82. It is rotatably supported so as to be inscribed in a virtual circle B having the same center as A and a larger radius. The rotary shaft member 82 is driven to rotate about its axis, thereby rotating the application rollers 84a, 84b, 84c all at once in the direction of the arrow 89, and separating the application rollers 84a, 84b, 84c from the surface of the transfer fixing roller 30. Perform the connection. The rotational drive of the rotary shaft member 82 is controlled according to the detection result by a size detection means (not shown). The size detection means is provided in a general image forming apparatus. The size is specified by the operator on the operation panel of the image forming apparatus and the size of the recording medium P is determined by an external device electrically connected to the image forming apparatus. The size of the recording medium P is detected by specifying the size of the recording medium P, and when copying is executed without specifying the size of the recording medium P, the size of the copy original is optically detected. The detection result by the size detection means is given to a CPU (not shown) that controls the entire operation of the image forming apparatus. The CPU determines the size of the recording medium P that is required, and sends a control signal to the drive means (not shown) of the rotary shaft member 82. Send to. Based on the control signal, the driving unit rotates the rotary shaft member 82 so that the application roller corresponding to the size of the recording medium P is in contact with the surface of the transfer fixing roller 30 among the application rollers 84a, 84b, and 84c. As a result, the fixing liquid 40 can be applied in accordance with the application area that matches the size of the recording medium P, and the fixing liquid 40 is prevented from being applied to a wider range than the size of the recording medium P.

  A regulating roller 83 provided around the rotating shaft member 82 and having the same axis as the rotating shaft member 82 equalizes (regulates) a fixing liquid layer (not shown) attached to the surfaces of the application rollers 84a, 84b, and 84c. To do. As a result, the fixing liquid 40 is uniformly applied to the toner image on the transfer fixing roller 30. The regulation roller 83 rotates following the rotation of the application rollers 84a, 84b, and 84c.

  The application rollers 84 a, 84 b, and 84 c are cylindrical members that contact and apply the fixing liquid 40 to the multicolor toner image on the surface of the transfer and fixing roller 30. The application rollers 84 a, 84 b, and 84 c are in pressure contact with the regulating roller 83 around the rotation shaft member 82. By the rotational drive of 82, it is supported so that it can contact or separate from the surface of the transfer and fixing roller 30. Two of the three application rollers 84a, 84b, and 84c are located in a space that does not come into contact with the fixing liquid 40 in the casing 88, and one of the two contacts the surface of the transfer fixing roller 30 and the remaining three of the three. One is supported so as to be immersed in the fixing solution 40. Of the waiting application rollers (application rollers that do not apply the fixing solution 40 to the transfer fixing roller 30), the application roller 84b is immersed in the fixing solution 40, so that drying of the fixing solution 40 on the surface thereof is prevented and fixing is performed. Wasteful consumption of the liquid 40 can be prevented. The arrangement of the application rollers 84a, 84b, and 84c changes with the rotation of the rotary shaft member 82, that is, with the size of the recording medium P to which the fixing liquid 40 is applied.

  The application rollers 84 a, 84 b, and 84 c rotate in the direction of the arrow 90 following the rotational driving of the transfer and fixing roller 30 in the direction of the arrow 32. The application rollers 84a, 84b, and 84c have different lengths in the longitudinal direction. In this embodiment, the application roller 84a contacts the A4 vertical toner image formable area, the application roller 84b contacts the B5 vertical toner image formable area, and the application roller 84c contacts the postcard toner image formable area. Can be granted. That is, as shown in FIG. 6, while the fixing liquid layer on the surface of the coating roller 84a, 84b or 84c is regulated by the regulation roller 83, any one of the coating rollers 84a, 84b, 84c is appropriately selected and the transfer fixing roller. The fixing liquid application region can be adjusted as appropriate by press-contacting 30.

  The supply roller 85 is provided so as to be detachable from the application roller (the application roller 84a in the figure) in contact with the surface of the transfer fixing roller 30 and immersed in the fixing liquid 40, and is fixed to the surface of the application roller. A cylindrical member for supplying the liquid 40. The supply roller 85 contacts the application roller 84a, 84b or 84c (fixing liquid supply position) when supplying the fixing liquid 40, and changes the position of the application rollers 84a, 84b, 84c by the rotational drive of the rotary shaft member 82. In this case, the sheet is retracted from the fixing solution supply position to the bottom surface of the casing 88 at a position 85a so as not to be an obstacle. The supply roller 85 rotates following the rotational drive of the application rollers 84a, 84b, 84c.

  The removal roller 86 is in contact with the surface of the application roller (application roller 84c in the figure) that does not contact the surface of the transfer fixing roller 30 among the two application rollers located in the space that does not contact the fixing liquid 40 in the casing 88. It is a cylindrical member that removes excess fixer 40 adhering to the surface of the application roller. The removing roller 86 is provided so as to be able to be driven to rotate, and rotates in accordance with the rotational driving of the application rollers 84a, 84b, 84c.

  The blade 87 is a plate-like member provided so as to be in contact with the surface of the removal roller 86, scrapes the fixing solution 40 adhering to the surface of the removal roller 86, and returns it to the fixing solution 40 stored in the lower part in the casing 88. Has a liquid recovery function. As described above, the fixing liquid 40 on the surface of the application roller 84 is returned to the fixing liquid 40 stored in the lower portion of the casing 88 by the removing roller 86 and the blade 87, so that wasteful consumption due to drying of the fixing liquid 40 can be prevented here. .

  The fixing solution application device 81 is supplied with the fixing solution 40 from a fixing solution storage tank via a fixing solution supply pipe (not shown) according to the consumption state of the fixing solution 40, and is stored in the lower part in the casing 88. The liquid level height of 40 is kept constant.

  According to the fixing liquid coating apparatus 81, coating rollers 84a, 84b, and 84c having different lengths in the longitudinal direction are attached to the rotating shaft member 82, and the rotating shaft member 82 is rotated so as to correspond to the size of the recording medium P. The coating roller 84 a, 84 b or 84 c having the length of is arranged so as to contact the surface of the transfer fixing roller 30, and the fixing liquid 40 is contacted and applied. As a result, the fixing liquid 40 is prevented from being applied to unnecessary portions, and contamination of the components inside the image forming apparatus by the fixing liquid 40 and wasteful consumption of the fixing liquid 40 are prevented.

  FIG. 7 is a cross-sectional view schematically showing a configuration of a main part (fixing solution applying apparatus 90) of the image forming apparatus according to the fourth embodiment of the present invention. FIG. 8 is a diagram for explaining a method of adjusting the fixing liquid application region by the fixing liquid application device 90.

  The image forming apparatus shown in FIG. 7 is similar to the image forming apparatus 1, and illustration and description of the same parts are omitted. The image forming apparatus shown in FIG. 7 is characterized by including a fixer application device 90 in place of the fixer application device 33 in the image forming apparatus 1.

  The fixing liquid application device 90 includes an application roller 91 for supplying the fixing liquid 40 to the surface of the transfer fixing roller 30, a fixing liquid supply unit 92 for supplying the fixing liquid 40 to the surface of the application roller 91, and fixing of the surface of the application roller 91 (not shown). A regulating roller 95 that regulates the liquid layer, a blade 96 that removes the fixing liquid 40 on the surface of the coating roller 91, a blade 97 that removes the fixing liquid 40 on the surface of the regulating roller 95, and each of the members (the coating roller 91, the fixing liquid). A supply unit 92, a regulation roller 95, and blades 96, 97) are accommodated, and a casing 98 for storing the fixing liquid 40 is stored in the lower part thereof.

  The application roller 91 is provided so as to be in pressure contact with the surface of the transfer fixing roller 30 at the opening 98 a of the casing 98, and to be driven to rotate in the direction of the arrow 99 by being driven to rotate in the direction of the arrow 32 of the transfer fixing roller 30. . In addition, the application roller 91 is provided at a position where the application roller 91 is not in contact with the fixing liquid 40 below the casing 98. In other words, it is preferable to adjust the liquid level of the fixing solution 40 to be constant so that at least a part of the application roller 91 is not immersed in the fixing solution 40. Accordingly, it is possible to prevent the fixing liquid 40 from being applied to a range wider than the size of the recording medium P on the surface of the application roller 91.

  The fixing liquid supply unit 92 is supported by a rotation shaft member 93 provided so as to be rotatable around its axis by a drive unit (not shown), and can be rotationally driven by the rotation shaft member 93 and detachable from the application roller 91. And supply rollers 94a, 94b, 94c having different lengths in the longitudinal direction.

  The supply shafts 94 a, 94 b and 94 c are rotatably supported by the rotation shaft member 93 so that the respective shaft centers are located on the circumference of a virtual circle C centering on the shaft center of the rotation shaft member 93. With the rotation of the rotating shaft member 93, the supply rollers 94a, 94b, and 94c rotate all at once, and come into and out of contact with the application roller 91. The rotation of the rotation shaft member 93 is controlled in the same manner as the rotation of the rotation shaft member 82. That is, a CPU (not shown) determines the size of the recording medium P according to the detection result of the size detection means provided in the image forming apparatus, and transmits a control signal to a drive means (not shown) of the rotary shaft member 93. A supply roller having a length in the longitudinal direction corresponding to the size of the recording medium P is selected, and the rotary shaft member 93 is rotated so that the supply roller contacts the surface of the application roller 91.

  In a state where any of the supply rollers 94a, 94b, 94c is in pressure contact with the surface of the application roller 91, a part of the supply roller (supply roller 94a in the figure) that is in pressure contact with the surface of the application roller 91 is immersed in the fixing liquid 40, and the like. The two supply rollers (supply rollers 94b and 94c in the figure) are arranged so as to be immersed in the fixing liquid 40. The arrangement of the supply rollers 94a, 94b, 94c changes with the rotation of the rotary shaft member 93, that is, with the size of the recording medium P to which the fixing liquid 40 is applied.

  The supply rollers 94a, 94b, and 94c are roller members having different lengths in the longitudinal direction, and the supply roller 94a applies and applies the fixing liquid 40 corresponding to the A4 size vertical image forming area to the application roller 91. Similarly, the supply rollers 94b and 94c apply the fixing liquid 40 corresponding to the B5 size vertical and postcard size image forming regions to the application roller 91, respectively. FIG. 8 shows the width of the fixing liquid applied to the application roller 91 of each supply roller. That is, when the supply roller 94a is selected, the fixing liquid 40 is applied to the application roller 91 with the A4 vertical size recording medium P width, and is applied to the transfer fixing roller 30 while maintaining the same size. Similarly, when the supply roller 94b or 94c is selected, the B5 vertical size or postcard size fixing solution 40 is applied to the transfer fixing roller 30 through the application roller 91.

  The regulation roller 95 is provided so as to be in pressure contact with the surface of the application roller 91 and to be driven to rotate following the rotation of the application roller 91 in the direction of the arrow 99. The regulation roller 95 regulates the layer of the fixing liquid 40 applied to the surface of the application roller 91 by the supply rollers 94a, 94b, or 94c. As a result, the application roller 91 can uniformly apply the fixing liquid 40 to the multicolor toner image on the transfer and fixing roller 30.

  The blade 96 is a plate-like member provided so as to be in contact with the surface of the regulating roller 95, scrapes off the fixing liquid 40 adhering to the surface of the regulating roller 95, and returns it to the fixing liquid 40 stored in the lower part in the casing 98. Has a liquid recovery function.

  The blade 97 is a plate-like member provided so as to be in contact with the surface of the application roller 91, and after the fixing solution 40 is applied to the multicolor toner image on the transfer fixing roller 30, the fixing solution adheres to the surface of the application roller 91. 40 has a fixing solution recovery function of scraping 40 and returning it to the fixing solution 40 stored in the lower part of the casing 98.

  Further, the blades 96 and 97 have the following functions. For example, when the supply roller 94a is selected in order to apply the A4 portrait on the entire surface, the fixing solution 40 is applied, and subsequently the fixing solution 30 is applied to the postcard size area, the application roller 91 and the regulating roller 95 include The fixing solution 40 adheres to a wider range than the postcard size. In the state as it is, when the fixing liquid 40 is applied from the supply roller 94 c to the application roller 91 and the fixing liquid 40 is applied to the toner image on the transfer fixing roller 30, the surface of the transfer fixing roller 30 is outside the range of the recording medium P size. Fixing liquid 40 is applied. In order to prevent this, the fixing liquid 30 is removed using the blades 96 and 97.

  The fixing liquid application device 90 is supplied with the fixing liquid 40 from a fixing liquid storage tank via a fixing liquid supply pipe (not shown) according to the consumption state of the fixing liquid 40, and is stored in the lower portion of the casing 98. The liquid level height of 40 is kept constant.

  In this embodiment, the application roller 91 is rotated by the rotation drive of the transfer fixing roller 30, and the supply rollers 94 a, 94 b, 94 c and the regulation roller 95 are rotated by the rotation drive of the application roller 91. Other than the drive means of the rotating shaft member 93, it is unnecessary.

  According to the fixing liquid coating apparatus 90, a supply roller having a length in the longitudinal direction corresponding to the size of the recording medium P is selected from the supply rollers 94a, 94b, 94c according to the detection result by the size detection means, and the rotation shaft The supply roller is pressed against the application roller 91 by the rotational driving of the member 93, the fixing liquid 40 corresponding to the recording medium P size is applied to the surface of the application roller 91, and the fixing liquid 40 is regulated by the regulation roller 95. The toner 40 on the transfer and fixing roller 30 is contacted and the fixing liquid 40 remaining on the application roller 91 and the regulating roller 95 is removed and collected by blades 97 and 96, respectively. This series of fixing liquid application operations is repeatedly executed.

  FIG. 9 is a cross-sectional view schematically showing a configuration of a main part (fixing solution coating apparatus 100) of the image forming apparatus according to the fifth embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing a configuration of a coating roller 102a described later. FIG. 11 is a diagram for explaining a method of adjusting the fixing liquid application region by the fixing liquid application apparatus 100.

  The image forming apparatus shown in FIG. 9 is similar to the image forming apparatus 1, and illustration and description of the same parts are omitted. The image forming apparatus shown in FIG. 9 is characterized by including a fixer coating apparatus 100 instead of the fixer coating apparatus 33 in the image forming apparatus 1.

  The fixing liquid coating apparatus 100 includes a rotation shaft member 101, application rollers 102a, 102b, and 102c that are supported by the rotation shaft member 101 so as to be rotationally driven and have different lengths in the longitudinal direction, and the members (the rotation shaft member 101 and the rotation shaft member 101). And a casing 103 containing a coating roller 102a, 102b, 102c). In the opening 103a of the casing 103, any one of the application rollers 102a, 102b, and 102c and the transfer fixing roller 30 are provided in pressure contact.

  The rotating shaft member 101 is provided so as to be rotatable around its axis by driving means (not shown). In addition, the application shafts 102 a, 102 b, and 102 c are rotatably supported by the rotation shaft member 101 so that the respective shaft centers are located on the circumference of a virtual circle D centering on the shaft center of the rotation shaft member 101. The By the rotation of the rotary shaft member 101, the application rollers 102a, 102b, and 102c rotate all at once, and the separation / contact operation with respect to the surface of the transfer fixing roller 30 is executed. The rotation of the rotating shaft member 101 is performed according to the detection result by the size detecting means for detecting the size of the recording medium P, similarly to the rotating shaft members 82 and 93 in the image forming apparatus shown in FIGS. Depending on the size of the recording medium P detected by the size detecting means, a rotation shaft is driven by a driving means (not shown) so that the coating roller having a length in the longitudinal direction corresponding to the size is pressed against the surface of the transfer fixing roller 30. The member 101 is rotated.

  The application rollers 102 a, 102 b, and 102 c are rotationally driven around their respective axes, and are rotated following the rotational drive in the direction of the arrow 32 of the transfer fixing roller 30 when pressed against the surface of the transfer fixing roller 30. In the present embodiment, the application rollers 102a, 102b, and 102c are brought into pressure contact with the transfer fixing roller 30 with a pressing force (linear pressure) of 0.1 N / cm.

  The application roller 102 a is formed on the core metal 105, the penetration control layer 106 made of a material that is elastically deformable and capable of holding the penetration of the fixing liquid 40, and the penetration control layer 106. And a porous film 107. The fixing liquid 40 is stored inside the cored bar 105, and a plurality of fixing liquid supply holes 105a for supplying the fixing liquid 40 to the permeation control layer 106 are provided in the cored bar 105 at predetermined intervals. Further, the thickness, porosity, material, and the like of the porous film 107 can be appropriately changed according to the composition of the fixing solution 40. In the present embodiment, specifically, a coating roller 102a having the following configuration is used. As the core metal 105, an aluminum core metal having an outer diameter of 30 mm and a wall thickness of 0.5 mm is used. The fixing solution supply holes 105a formed in the cored bar 105 have a diameter of 0.1 mm, are provided at 16 equiangular positions in the circumferential direction, and are provided at an interval of 5 mm with a half phase shift in the axial direction. For the permeation control layer 106, felt having a thickness of 5 mm, foamed rubber containing open cells, or the like can be used. As the porous membrane 107, a porous membrane made of PTFE and having a thickness of 50 μm can be used. This porous membrane has a pore diameter of 0.5 μm and a porosity of 80%. The specification of the porous film may be changed according to the components of the fixing solution. The material of the porous film 107 is not limited to PTFE, and synthetic resins such as polyurethane and polyimide can also be used.

  Since the application rollers 102b and 102c have the same configuration as the application roller 102a except that the lengths in the longitudinal direction are different, illustration and description thereof are omitted.

  Further, as shown in FIG. 11, the lengths of the application rollers 102a, 102b, and 102c in the longitudinal direction are different from each other. For example, the application roller 102a has a length in the longitudinal direction corresponding to the A4 size. That is, the application width of the fixing liquid 40 onto the surface of the transfer fixing roller 30 by the application roller 102a is the vertical sheet width of A4 size. Furthermore, the application roller 102b has a length in the longitudinal direction corresponding to the B5 size and the application roller 102c has a length in the longitudinal direction corresponding to the postcard size.

  According to the fixing liquid coating apparatus 100, the supply roller having a length in the longitudinal direction corresponding to the size of the recording medium P is selected from the supply rollers 102a, 102b, and 102c according to the detection result by the size detection unit, and the rotation shaft The supply roller is pressed against the transfer and fixing roller 30 by the rotation of the member 101, and the fixing liquid 40 corresponding to the size of the recording medium P is applied to the surface of the transfer and fixing roller 30. This series of fixing liquid application operations is repeatedly executed.

  FIG. 12 is a cross-sectional view schematically showing a configuration of a main part (fixing solution coating apparatus 110) of the image forming apparatus according to the sixth embodiment of the present invention. FIG. 13 is a view for explaining a method of adjusting the fixing liquid application region by the fixing liquid application apparatus 110.

  The image forming apparatus shown in FIG. 12 is similar to the image forming apparatus 1, and illustration and description of the same parts are omitted. The image forming apparatus shown in FIG. 12 includes a fixing solution applying device 110 instead of the fixing solution applying device 33 in the image forming apparatus 1.

  The fixer coating device 110 is provided with a rotary shaft member 111, pressure contact rollers 112a, 112b, and 112c that are supported by the rotary shaft member 101 so as to be rotationally driven and have different lengths in the longitudinal direction, and can be rotationally driven in the axial direction thereof. An application belt 115 which is stretched by one of the support rollers 113 and 114, one of the pressure rollers 112a, 112b and 112c and the support rollers 113 and 114 to form a loop-shaped movement path, and the application belt 115. A supply roller 116 provided so as to be in pressure contact with the support roller 113, a regulation roller 117 provided so as to be in pressure contact with the support roller 114 via the coating belt 115, and the respective members (the rotary shaft member 101, the pressure contact rollers 112a and 112b). 112c, support rollers 113 and 114, application belt 115, supply roller 116 and Configured to include a casing 118 for storing the fixer 40 on the lower housing the regulating roller 117). Note that the surface of the transfer fixing roller 30 and the coating belt 115 are configured to be in pressure contact with each other at the opening 118 a of the casing 118.

  The rotating shaft member 111 is provided so as to be rotatable around its axis by driving means (not shown). The rotary rollers 111 a, 112 b, and 112 c are rotatably supported by the rotary shaft member 111 so that the respective axes are located on the circumference of a virtual circle E centering on the axis of the rotary shaft 111. When the rotary shaft member 111 is driven to rotate about its axis, the pressure contact rollers 112a, 112b, and 112c are rotated all at once, and the application belt 115, which will be described later, is separated from the surface of the transfer fixing roller 30. The rotating shaft member 111 is implemented according to the detection result by the size detecting means for detecting the size of the recording medium P, similarly to the rotating shaft members 82, 93, and 101 in the image forming apparatus shown in FIGS. Is done. In accordance with the size of the recording medium P detected by the size detecting means, a driving roller (not shown) such that a pressure roller having a length in the longitudinal direction corresponding to the size presses the coating belt 115 against the surface of the transfer fixing roller 30. The rotating shaft member 111 is rotated by the means.

  The pressure rollers 112 a, 112 b, and 112 c are provided so as to be rotatable around their axes, and have a function of pressing the application belt 115 for applying the fixing liquid 40 to the surface of the transfer fixing roller 30 against the surface of the transfer fixing roller 30. Have. That is, the pressure roller disposed at a position facing the transfer fixing roller 30 by the rotation of the rotation shaft member 111 presses the application belt 115 against the transfer fixing roller 30.

  As shown in FIG. 13, the lengths of the pressure rollers 112a, 112b, and 112c in the longitudinal direction are different from each other. For example, the pressure roller 112a has a length in the longitudinal direction corresponding to A4 size length. That is, when the pressure roller 112 a is disposed at a position facing the transfer fixing roller 30, the coating belt 115 is deformed by the length in the longitudinal direction of the pressure roller 112 a and is pressed against the surface of the transfer fixing roller 30. Is applied to the surface of the transfer-fixing roller 30 with an A4 size vertical paper width. Further, since the pressure roller 112b has a length in the longitudinal direction corresponding to the B5 size length and the pressure roller 112c has a length in the longitudinal direction corresponding to the postcard size, the pressure roller 112b or 112c is the surface of the transfer fixing roller 30. When the application belt 115 is pressed against the sheet, the fixer 40 is applied with a B5 size vertical or postcard size paper width.

  Each of the support rollers 113 and 114 is a cylindrical member that is provided so as to be able to be driven to rotate about its axis, and that stretches the application belt 115 in a freely rotatable manner together with any one of the pressure contact rollers 112a, 112b, and 112c.

  The coating belt 115 is provided so as to be pressed against any one of the pressure rollers 112 a, 112 b, and 112 c so as to be in pressure contact with the surface of the transfer fixing roller 30, and the fixing liquid 40 carried on the surface thereof is transferred to the toner on the transfer fixing roller 30. Contact is applied to the fixing solution application area including the image. The coating belt 115 is provided so as not to be immersed in the fixing solution 40 stored in the lower part of the casing 118. The width of the coating belt 115 is formed larger than the length in the longitudinal direction of the pressure rollers 112a, 112b, and 112c. The coating belt 115 is made of a material that does not penetrate the fixing liquid 40, and for example, an elastic belt made of elastic rubber can be used. In the present embodiment, a belt made of ethylene propylene rubber is used.

  The supply roller 116 is a cylindrical member that can be rotationally driven around its axis and is partially immersed in the fixer 40 stored in the lower portion of the casing 118. Fixing liquid 40 adhering to the surface of the supply roller 116 by rotation of the supply roller 116 is supplied to the surface of the application belt 115 at the pressure contact portion between the supply roller 116 and the application belt 115.

  The regulating roller 117 is a cylindrical member that is provided so as to be rotatable around its axis and regulates the amount of the fixing liquid 40 carried on the surface of the coating belt 115 (or makes the fixing liquid layer uniform). The fixing roller 40 is uniformly applied to the surface of the transfer fixing roller 30 by the regulating roller 117.

  The fixing liquid application device 110 is supplied with the fixing liquid 40 from a fixing liquid storage tank via a fixing liquid supply pipe (not shown) according to the consumption state of the fixing liquid 40, and is stored in the lower part in the casing 118. The liquid level height of 40 is kept constant.

  According to the fixing liquid application device 110, the application belt 115 is supplied in accordance with the supply of the fixing liquid 40 from the supply roller 116, and is further selected according to the detection result by the size detection means after being regulated by the regulating roller 117. The pressure applied by the pressure roller is pressed against the surface of the transfer and fixing roller 30 to apply the fixing liquid 30 to the toner image. This fixing solution applying operation is repeatedly executed.

  In each of the above embodiments, an example of a fixer coating apparatus that can apply a fixer to three types of paper widths of A4 portrait, B5 portrait, and postcard size has been described. The paper width may be selected from two types or four or more types.

  Each member in the image forming apparatus of the present invention is not limited to the above-described configuration, and the material constituting each member, the dimensions of each member, the laminated structure, etc. are commonly used in the field of electrophotographic image formation. It is possible to appropriately select from those to be performed.

  The image forming apparatus of the present invention is not limited to the tandem color image forming apparatus shown in each of the above-described embodiments, and is a so-called four-rotation color that superimposes one color image every rotation of the intermediate transfer belt. It may be an image forming apparatus. Further, it may be configured as a monochrome image forming apparatus.

  As described above, according to the image forming apparatus of the present invention, it is possible to apply the fixing liquid having a width corresponding to the recording medium size, and therefore it is possible to reduce wasteful consumption of the fixing liquid. Further, the load on the cleaning member for cleaning the fixing liquid is also reduced.

  The image forming apparatus of the present invention can be used as, for example, a copying machine, a printer, a facsimile machine, or a multifunction machine having two or more of these functions.

1 is a cross-sectional view schematically showing a configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view illustrating a configuration of a main part of the image forming apparatus illustrated in FIG. 1. FIG. 2 is an enlarged cross-sectional view illustrating a configuration of a main part of the image forming apparatus illustrated in FIG. 1. It is sectional drawing which shows typically the structure of the image forming apparatus which is the 2nd Embodiment of this invention. It is sectional drawing which shows typically the structure of the principal part of the image forming apparatus which is the 3rd Embodiment of this invention. 6 is a diagram illustrating a method for adjusting a fixing liquid application region by the fixing liquid application apparatus shown in FIG. 5. It is sectional drawing which shows typically the structure of the principal part of the image forming apparatus which is 4th Embodiment of this invention. FIG. 8 is a diagram illustrating a method for adjusting a fixing liquid application region by the fixing liquid application apparatus shown in FIG. 7. It is sectional drawing which shows typically the structure of the principal part of the image forming apparatus which is 5th Embodiment of this invention. It is sectional drawing which shows the structure of an application roller typically. FIG. 11 is a diagram illustrating a method for adjusting a fixing liquid application region by the fixing liquid application apparatus shown in FIG. 10. It is sectional drawing which shows typically the structure of the principal part of the image forming apparatus which is 6th Embodiment of this invention. FIG. 13 is a diagram illustrating a method for adjusting a fixing liquid application region by the fixing liquid application apparatus shown in FIG. 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,60 Image forming apparatus 2 Toner image forming means 3,61 Intermediate transfer means 4 Transfer fixing means 5 Recording medium supply means 6 Conveying means 10y, 10m, 10c, 10b Image forming units 11y, 11m, 11c, 11b Photosensitive drum 12y , 12m, 12c, 11b Charging roller 13 Optical scanning unit 13y, 13m, 13c, 13b Signal light 14y, 14m, 14c, 14b Developing device 15y, 15m, 15c, 15b Drum cleaner 16, 16y, 16m, 16c, 16b Toner 22 Intermediate transfer belt 30 Transfer fixing roller 33, 81, 90, 100, 110 Fixing liquid application device 40 Fixing liquid 67 Secondary transfer means 69 Fixing means 82, 93, 101, 111 Rotating shaft member

Claims (18)

In an image forming apparatus in which a fixing liquid is applied to an unfixed toner image formed on a recording medium or an intermediate transfer medium and made dry toner so that the toner can be fixed to the recording medium, and the toner image is fixed on the recording medium by a fixing unit. A fixer application device for applying a fixer to
Fixing solution storage means for storing the fixing solution;
Size detecting means for detecting the size of the recording medium for fixing the unfixed toner image;
And a fixing liquid applying unit that applies a fixing liquid to an unfixed toner image and changes a fixing liquid application region in accordance with a detection result of the size detecting unit. Fixing liquid application means
An application roller that is rotatably driven about its axis, carries a fixing solution on its surface, and applies the fixing solution to an unfixed toner image on a recording medium or an intermediate transfer medium,
The fixing liquid coating apparatus according to claim 1, comprising a plurality of coating rollers having different lengths in the longitudinal direction. Fixing liquid application means
A plurality of application rollers having different lengths in the longitudinal direction;
The fixing liquid coating apparatus according to claim 2, further comprising: a rotary shaft member provided so as to be rotationally driven about the axis thereof and supporting the plurality of coating rollers so as to be rotationally driven. The application roller
4. The fixing solution applying apparatus according to claim 2, further comprising a fixing solution holding tank for storing the fixing solution therein. Fixing liquid application means
An application roller that carries a fixing liquid on the surface thereof and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A supply roller for supplying a fixing liquid to the surface of the coating roller,
2. The fixing liquid coating apparatus according to claim 1, further comprising a plurality of supply rollers which are provided so as to be able to be separated from and applied to the surface of the coating roller and which can be rotationally driven and have different lengths in the longitudinal direction. Fixing liquid application means
An application roller that carries a fixing liquid on the surface thereof and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A plurality of supply rollers having different longitudinal lengths;
6. A rotary shaft member provided so as to be rotationally driven about an axis thereof, and supporting the plurality of supply rollers so as to be able to be separated from and applied to the application roller. Fixer application device. Fixing liquid application means
7. The fixing liquid coating apparatus according to claim 5, further comprising a fixing liquid removing unit that removes and collects the fixing liquid on the surface of the coating roller. Supply roller
The fixing liquid coating apparatus according to claim 5, wherein the fixing liquid coating apparatus is provided so as to be driven to rotate following the rotation of the coating roller. Fixing liquid application means
A supply roller which is rotatably provided and carries a fixing liquid on its surface;
A coating roller that carries a fixing liquid on its surface and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A plurality of application rollers which are provided so as to be able to be separated from and connected to the surface of the supply roller and which can be driven to rotate, have different lengths in the longitudinal direction and whose length in the longitudinal direction is shorter than the length in the longitudinal direction of the supply roller The fixing solution applying apparatus according to claim 1. Fixing liquid application means
A supply roller which is rotatably provided and carries a fixing liquid on its surface;
A coating roller that carries a fixing liquid on its surface and applies the fixing liquid to an unfixed toner image on a recording medium or an intermediate transfer medium,
A plurality of application rollers having different lengths in the longitudinal direction and having a length in the longitudinal direction shorter than the length in the longitudinal direction of the supply roller;
The rotary shaft member is provided so as to be rotatable around its axis, and supports the plurality of application rollers so as to be able to be separated from and supplied to the surface of the supply roller. Fixer application device. Among the plurality of application rollers, the application rollers other than the application roller for applying the fixing liquid to the toner image are as follows:
11. The fixing solution coating apparatus according to claim 9, wherein a part or all of the fixing solution is provided so as to be immersed in the fixing solution. Fixing liquid application means
The fixing solution applying apparatus according to claim 9, further comprising a fixing solution removing unit that removes and recovers the fixing solution on the surface of the applying roller. The application roller
The fixing liquid coating apparatus according to claim 9, wherein the fixing liquid coating apparatus is provided so as to be driven to rotate following the rotation of the intermediate transfer medium. Fixing liquid application means
An application means that is made of an elastically deformable material, carries a fixing solution on the surface, and applies the fixing solution to an unfixed toner image on a recording medium or an intermediate transfer medium;
It is provided so as to face a recording medium or an intermediate transfer medium carrying an unfixed toner image via an application unit, and presses the application unit against the toner image, and adjusts the size of a fixing liquid application region by the application unit. Grant area adjustment means;
2. The fixing solution applying apparatus according to claim 1, further comprising a supply roller for supplying fixing solution to the applying means. Application means
The fixing liquid applying apparatus according to claim 14, wherein the fixing liquid applying apparatus is an endless belt supported so as to be rotatable. The grant area adjustment means
A plurality of pressing means that are cylindrical members having different lengths in the longitudinal direction;
A rotary shaft member provided so as to be rotationally driven around its axis, and supporting the pressing means so as to be rotationally driven;
The rotating shaft member is rotated in accordance with the detection result by the size detecting means, and the pressing means having a length in the longitudinal direction corresponding to the size of the recording medium is transferred to the unfixed toner image on the recording medium or the intermediate transfer medium and the applying means. 16. The fixing liquid coating apparatus according to claim 14, further comprising a movement instructing unit for moving to a pressure contact position. A photosensitive drum; a charging unit that charges the surface of the photosensitive drum; an exposure unit that irradiates light on the charged surface of the photosensitive drum to form an electrostatic latent image based on image information; Developing means for supplying toner to the electrostatic latent image to form a toner image, fixing liquid applying means for applying a fixing liquid to an unfixed toner image on a recording medium or intermediate transfer medium, and undecided to which a fixing liquid has been applied An image forming apparatus including a fixing unit that fixes a toner image to a recording medium.
Fixer application means
An image forming apparatus comprising the fixing liquid applying apparatus according to claim 1. Heating means for heating the unfixed toner image on the recording medium or the intermediate transfer medium,
18. The image formation according to claim 17, wherein the unfixed toner image on the recording medium or the intermediate transfer medium is heated to 65 ° C. or more by a heating unit before the fixing solution is applied by the fixing solution applying unit. apparatus.

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