JP2012037678A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a toner suitable to fixation to a recording medium by using a fixation liquid but not limited to liquid development, to reduce power consumption of heating during fixation, to prevent image disturbance due to the fixation liquid, to prevent increase of power consumption required for drying and increase of time for fixation, and to prevent absurd influence to inner components and unevenness of an amount of fixation liquid coated on the recording medium.SOLUTION: The fixation liquid contains a plasticizer for bringing the toner to a state suitable to fixation to the recording medium S by swelling and softening the toner. The fixation liquid is coated on the recording medium S before carrying a toner image. The toner image on the toner image carrier 11 is transferred to the recording medium S after coating the fixation liquid while making the toner image contact with the fixation liquid on the recording medium S. The toner image and the fixation liquid on the recording medium S are heated to bring the toner to the state for fixing the toner to the recording medium S. Coating means 41 of the fixation liquid uses a coating member 44 for coating the fixation liquid on the recording medium S and fixation liquid removing means 49 for removing the fixation liquid from the coating member 41.

Description

  The present invention relates to an image forming apparatus for forming an image by heating a toner constituting a toner image and fixing the toner image on a recording medium such as a sheet during fixing on the recording medium. The present invention relates to an image forming apparatus such as a copying machine, a facsimile, or a printer that performs image fixing and image formation as a state suitable for fixing on a recording medium.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers, facsimiles, printers, and the like that perform image formation by heating and fixing toner constituting a toner image onto a recording medium such as paper upon fixing to a recording medium. Are known. In this image forming apparatus, the toner is softened by heating and fixed on the recording medium. Therefore, in order to obtain reliable fixing properties, it is sufficient that the toner in the portion in contact with the recording medium is sufficiently softened. Cost. In order to sufficiently perform such softening, it is necessary to sufficiently heat such toner or the like, but such heating requires a lot of electric power. However, recently, there is an increasing demand for power saving of the entire image forming apparatus. In view of the fact that the ratio of the amount of power required for such heating to the power consumption of the entire image forming apparatus is relatively large, it is desirable to reduce this amount of power. For this purpose, various techniques using a liquid for improving the fixing property of toner to a recording medium have been proposed (see, for example, [Patent Document 1] to [Patent Document 4]).

  For example, a technique for applying a fixing solution that softens and / or swells toner onto a toner image on a recording medium has been proposed (see, for example, [Patent Document 1]). In such a technique, fixing without using heat is possible, so that significant power saving can be achieved as compared with the conventional technique. Similarly, as a technology that can save energy without the need to soften the toner by heat, a fixing solution is applied from above the toner image on the intermediate transfer member, and the toner is changed into a sticky film, There has been proposed a technique for transferring and fixing the filmed toner onto a recording medium by its own adhesiveness (see, for example, [Patent Document 2]).

  However, when a fixing liquid is applied on the toner image carried on the recording medium or the intermediate transfer member, there is a problem that the image is disturbed. To solve this problem, a technique has been proposed in which the fixing solution is applied by means such as a non-contact ink jet method, and the amount of application is gradually increased in the recording paper moving direction (for example, [Patent Document 1]). (Refer to the above)) When ejecting fixer to a powder toner image with an inkjet head, even if the amount of fixer is reduced, the disturbed toner will scatter and land on the ejection head of the inkjet head. There is a problem that it ends up. If the toner adheres to the discharge port of the liquid in which the toner swells and dissolves, the discharge port may be clogged. In addition, when applying a fixer from above a toner image carried on a recording medium, it is necessary to apply a lot of liquid to reach the contact portion between the toner and the recording medium for reliable fixing. However, when a large amount of liquid is applied, there is a need for heating for drying, which causes problems such as an increase in required power amount and time required for fixing.

  In addition, with the technology that applies a fixer and changes the toner to a film on an intermediate transfer member and transfers it to a recording medium, in order to form an image, it functions to form a toner film without heating the fixer. However, since the fixing solution is applied to the toner on the intermediate transfer member, the fixing solution is mixed into the image forming unit in contact with the intermediate transfer member. Indicates a function of forming a toner film at the use environment temperature of the image forming apparatus, and therefore, there is a problem that other members in the apparatus may be adversely affected.

  As a technology for the fixer to function at the operating environment temperature of the image forming apparatus, in the image forming apparatus adopting a liquid developing method using toner and a carrier liquid, a fixing liquid having a good affinity with the carrier liquid is previously applied to the recording medium. In addition, a technique has been proposed in which a carrier liquid existing between toners of a toner layer formed by liquid development is allowed to flow, and the toner layer is dissolved and swelled to be fixed on a recording medium (for example, see Patent Document 3). ). In this technique, image disturbance due to the application of the fixing liquid can be suppressed, but there is a possibility that the image may be disturbed when the fixing liquid acts on the carrier liquid, and the fixing liquid is at the operating environment temperature of the image forming apparatus. In order to function, there exists a problem that it may have a bad influence with respect to the other member in a machine. In addition, regarding this technology, there is a recognition that applying a fixing solution before transferring an image increases the fixing time compared to applying a fixing solution after transferring an image, and the fixing solution has an affinity with a liquid developer. It can be recognized that it is important that the toner image is not applicable to a toner image formed by developing means that is not liquid developing. The fixing solution is applied to the recording medium by a member carrying the fixing solution on the surface thereof.

  Since the liquid is applied to the recording medium before the recording medium carries the toner image, image disturbance due to the liquid application can be suppressed, but it is necessary to apply a large amount of liquid to the recording medium and heat for drying. As a technology that is expected to increase the amount of power consumption and fixing time due to the necessity of toner, recording is performed by flying and landing toner on a recording medium, which is called toner jet, direct toning, toner projection, etc. A technique that employs a method of directly recording an image on a medium has been proposed (see, for example, [Patent Document 4]). In this technology, by applying a coating liquid containing a softening agent that dissolves or swells the resin contained in the toner to the recording medium before the landing of the toner, the scattering of the toner at the time of landing in the direct recording method is reduced. It aims to promote the establishment. That is, by applying a coating liquid containing a softening agent to the surface of the recording medium in advance, the adhesion between the toner and the printing surface when the toner collides increases, and the repulsive force when the toner collides is reduced. However, the aim is to suppress and improve toner scattering. The coating liquid applied to the recording medium before the toner adheres is absorbed by the fibers on the surface of the recording paper, and the fibers become soft due to moisture absorption, thereby reducing dust at the time of toner landing. However, in order to dissolve and swell the toner and affect the fixability, it is necessary that a considerable amount of the coating solution contacts the toner. If the flying toner only adheres to the recording medium, only a very small amount of the coating liquid on the surface of the recording medium comes into contact with the toner, so that the coating liquid does not seep into the toner layer and toner scattering is reduced. It is not practical to secure the fixability as well. This technique also includes a technique in which a liquid is applied to the intermediate transfer member in advance, and the image is formed by flying toner and transferred to the recording medium in contact with the recording medium. In this case, the penetration of the liquid into the toner layer is promoted. However, there is a problem that it may have an adverse effect on the components in the machine. Such a coating solution is applied to the recording medium by a member carrying the coating solution on its surface.

  As described above, while using a liquid that improves the fixability in order to reduce the power required for heating during fixing, problems caused by using such a liquid, that is, image disturbance, power consumption for drying, and fixing time No technology has yet been proposed that enables image formation without being limited to application to liquid development, while avoiding adverse effects on in-machine members, avoiding deterioration of the function of such liquids . Further, for example, in a configuration in which the liquid applied to the recording medium is applied to the recording medium by a member that supports the liquid applied to the recording medium, when the amount of liquid carried on the surface of the member is uneven, recording is performed. Unevenness is also caused in the amount of liquid applied to the medium, which may cause fixing unevenness.

  The present invention uses a fixing liquid while reducing the power required for heating during fixing by making the toner constituting the toner image into a state suitable for fixing to a recording medium using a fixing liquid. For liquid development while avoiding image distortion, power consumption for drying, increase in fixing time, adverse effects on in-machine members, and unevenness in the amount of fixer applied to the recording medium. An object of the present invention is to provide an image forming apparatus such as a copying machine, a facsimile machine, and a printer that can perform image formation without limitation.

  In order to achieve the above object, a first aspect of the present invention provides a fixing liquid containing a plasticizer for swelling and softening a toner constituting a toner image so that the toner is suitable for fixing on a recording medium. Fixing liquid applying means for applying to the recording medium before carrying, a recording medium coated with the fixing liquid by the fixing liquid applying means, and a toner image on a toner image carrier to the fixing liquid on the recording medium. The transfer means for transferring while contacting, the toner constituting the toner image on the recording medium transferred by the transfer means, and the fixing liquid are heated to fix the toner image on the recording medium with the toner in the above state. The fixing liquid application means has a coating member for applying the fixing liquid carried on the surface of the recording medium on the surface to which the toner image is transferred by the transfer means, Whether the application member In an image forming apparatus having a fixing solution removing means for removing the fixing solution.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the application member is a rotating body that applies the fixing liquid to a recording medium by rotating in a predetermined direction, and the fixing liquid removing unit includes: In the predetermined direction, the application member is positioned downstream of the position where the fixing solution is applied to the recording medium, and the fixing solution is applied to the application member by a supply unit that supplies the fixing solution to the application member. The fixing liquid is removed from the application member at a position upstream of the supply position.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the fixing liquid removing unit includes the coating member in an area including a maximum width of a recording medium to which the fixing liquid is applied by the coating member. The fixing solution is removed from the substrate.

  According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the fixing liquid removing unit has an end abutting against the application member and supplying the fixing liquid from the application member. It has a fixing liquid removing member that is scraped off.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the image forming apparatus further includes a foreign matter removing unit that removes a foreign matter different from the fixing solution from the coating member, and the fixing solution is removed. The means also serves as the foreign matter removing means, and removes the foreign matter together with the fixing liquid from the application member.

  According to a sixth aspect of the present invention, in the image forming apparatus according to any one of the first to fifth aspects, the plasticizer has a function of bringing the toner into the state at an ambient temperature where the image forming apparatus is used. It is characterized by being manifested when the temperature rises above the ambient temperature.

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the plasticizer is a single unit before being used as the fixing liquid at an environmental temperature in which the image forming apparatus is used. It is a solid in the state of.

  According to an eighth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, the toner image carrier that carries the toner image transferred onto the recording medium by the transfer means is a photoconductor. It is characterized by that.

  According to a ninth aspect of the present invention, in the image forming apparatus according to any one of the first to eighth aspects, the toner image carrier carrying the toner image transferred onto the recording medium by the transfer means is carried on the photoconductor. And an intermediate transfer member to which the toner image is transferred.

  According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to seventh aspects, a toner image carrier that carries a toner image transferred to a recording medium by the transfer means is a toner carrier. It is an intermediate transfer member on which a carried toner is transferred to form a toner image.

  According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the first to tenth aspects, the fixing unit includes a roller-shaped fixing member and performs fixing by a roller fixing method. And

  The present invention relates to a fixing solution for applying a fixing solution containing a plasticizer for swelling and softening toner constituting a toner image to a state suitable for fixing on a recording medium onto a recording medium before carrying the toner image. A transfer means for transferring the toner image on the toner image carrier onto the recording medium coated with the fixing liquid by the fixing liquid applying means while contacting the fixing liquid on the recording medium; Fixing means for fixing the toner image to the recording medium by heating the toner constituting the toner image on the recording medium transferred by the means and the fixing liquid to bring the toner into the state and fixing the toner image to the recording medium. The coating unit has a coating member for coating the fixing liquid carried on the surface of the recording medium on the side where the toner image is transferred by the transfer unit, and the fixing unit removes the fixing liquid from the coating member. Liquid removal means Since the image forming apparatus has a relatively simple configuration, the fixing solution can be applied to the recording medium to reduce the cost and improve the fixing property, and the fixing solution is not limited to liquid development. By using it efficiently, the temperature required for fixing is reduced and energy is saved for heating, while securing the fixability, while avoiding problems with the in-machine members by using the fixing solution, and fixing solution applied to the recording medium. Accordingly, it is possible to provide an image forming apparatus capable of avoiding unevenness in the amount, and thereby performing good image formation.

  The application member is a rotating body that applies the fixing liquid to the recording medium by rotating in a predetermined direction, and the fixing liquid removing unit applies the fixing liquid to the recording medium in the predetermined direction. A position downstream of the position and upstream of a position where the fixing liquid is applied to the application member by a supply unit that supplies the fixing liquid to the application member; If the liquid is removed, the fixing liquid can be applied to the recording medium with a relatively simple configuration to reduce the cost and improve the fixing performance, and the fixing liquid is not limited to liquid development. By using it efficiently, the temperature required for fixing is reduced and energy is saved for heating, while ensuring fixability, avoiding problems with internal members by using a fixer, and recording media After the fixing liquid is applied to the fixing member, the fixing liquid applied to the recording medium is stabilized by removing the fixing liquid from the coating member before the fixing liquid is supplied by the supplying means, due to the stable supply of the fixing liquid to the applying member by the supplying means. It is possible to avoid unevenness in the amount of liquid, thereby providing an image forming apparatus that can perform good image formation.

  If the fixing solution removing means removes the fixing solution from the coating member in a region including the maximum width of the recording medium to which the fixing solution is applied by the coating member, the fixing solution can be configured with a relatively simple configuration. Can be applied to a recording medium to reduce costs and improve fixability, and is not limited to liquid development, but by using a fixer with high efficiency, the temperature required for fixing can be reduced and energy saving for heating can be achieved. While avoiding the problem, it is possible to avoid problems with the in-machine members due to the use of the fixer and to avoid unevenness in the amount of the fixer applied to the recording medium by using a recording medium having a different width. Thus, an image forming apparatus capable of performing good image formation can be provided.

  If the fixing liquid removing unit has a fixing liquid removing member whose end is in contact with the coating member and scrapes the fixing liquid from the coating member, the fixing liquid is applied to the recording medium with a relatively simple configuration. The cost can be reduced and the fixing property can be improved, and the fixing is not limited to liquid development, and the fixing solution is used efficiently to reduce the temperature required for fixing and to save energy for heating. It is possible to avoid problems with in-machine members due to the use of the fixing liquid while ensuring the performance, and to avoid unevenness in the amount of the fixing liquid applied to the recording medium with a relatively simple configuration. Thus, an image forming apparatus capable of performing good image formation can be provided.

  A foreign matter removing unit that removes foreign matter different from the fixing solution from the coating member, and the fixing solution removing unit also serves as the foreign matter removing unit and removes the foreign matter together with the fixing solution from the coating member. For example, the fixing solution can be applied to the recording medium with a relatively simple configuration to reduce costs and improve the fixing property, and is not limited to liquid development, and the fixing solution can be fixed with high efficiency. Is applied to a recording medium by using a fixer to avoid problems with in-machine members and adhering foreign matter to the coating member, while maintaining the fixability while reducing the temperature required for heating. It is possible to avoid unevenness in the amount of the fixing solution, thereby providing an image forming apparatus that can perform good image formation.

  The plasticizer has a relatively simple configuration if the function of bringing the toner into the state does not appear at the environmental temperature at which the image forming apparatus is used, but appears when the temperature exceeds the environmental temperature. Can be applied to recording media to reduce costs and improve fixability, and is not limited to liquid development, but by using a fixer, the temperature required for fixing can be reduced and energy savings can be saved. While securing the fixability, it is possible to avoid problems with in-machine members by using the fixer and to avoid unevenness in the amount of fixer applied to the recording medium with high accuracy. An image forming apparatus capable of performing formation can be provided.

  If the plasticizer is solid in a single state before being used as the fixer at the environmental temperature at which the image forming apparatus is used, the fixer can be applied to the recording medium with a relatively simple configuration and the cost can be reduced. In addition to liquid development, the fixing solution can be used to reduce the temperature required for fixing and to save energy for heating while ensuring fixing properties. By using a fixer, it is possible to avoid problems with in-machine members by using a plasticizer selected as an indicator that it is solid in a single state before being used as a fixer. It is possible to avoid unevenness in the amount of the fixing solution applied to the medium, and thus it is possible to provide an image forming apparatus capable of performing good image formation.

  If the toner image carrier carrying the toner image transferred to the recording medium by the transfer means is a photoconductor, the structure can be simplified and the cost can be reduced. The fixing solution can be applied to the recording medium with the structure to reduce the cost and improve the fixability, and is not limited to the liquid development, but the fixing solution can be used to reduce the temperature required for fixing and While securing the fixability while saving energy, it is possible to avoid problems with in-machine members by using the fixer and to avoid unevenness in the amount of fixer applied to the recording medium. An image forming apparatus capable of image formation can be provided.

  If the toner image carrier carrying the toner image transferred to the recording medium by the transfer means is an intermediate transfer member to which the toner image carried on the photoconductor is transferred, the photoconductor and the photoconductor are contacted. It is possible to prevent the fixing liquid from adhering to other members and the problems caused by this, and to apply the fixing liquid to the recording medium with a relatively simple configuration to reduce costs and improve the fixability. At the same time, without being limited to liquid development, the use of a fixer solution reduces the temperature required for fixing and saves energy for heating while ensuring fixability, while using the fixer to cause problems with internal components. And an unevenness in the amount of the fixing liquid applied to the recording medium can be avoided, thereby providing an image forming apparatus capable of performing good image formation.

  If the toner image carrier carrying the toner image transferred to the recording medium by the transfer means is an intermediate transfer member on which the toner carried on the toner carrier is transferred to form a toner image, the intermediate transfer member It is possible to prevent the fixing liquid from adhering to other members and the problems caused by this, and to apply the fixing liquid to the recording medium with a relatively simple configuration to reduce the cost and improve the fixability. At the same time, without being limited to liquid development, the use of a fixer solution reduces the temperature required for fixing and saves energy for heating while ensuring fixability, while using the fixer to cause problems with internal components. And an unevenness in the amount of the fixing liquid applied to the recording medium can be avoided, thereby providing an image forming apparatus capable of performing good image formation.

  If the fixing means has a roller-shaped fixing member and fixing is performed by a roller fixing method, uniform heating and improvement of fixing performance can be achieved with a relatively simple configuration. The fixing solution can be applied to the recording medium with a simple structure to reduce the cost and improve the fixability, and the temperature required for fixing can be reduced by using the fixing solution without being limited to liquid development. While ensuring the fixability while saving energy with respect to heating, it is possible to avoid problems with in-machine members by using the fixer and to avoid unevenness in the amount of fixer applied to the recording medium. Therefore, it is possible to provide an image forming apparatus that can perform better image formation.

1 is a schematic front view of an image forming apparatus to which the present invention is applied. FIG. 2 is a block diagram of a part of a control system that controls the fixing device shown in FIG. 1. FIG. 6 is a conceptual diagram showing that the minimum fixing temperature is lowered by a plasticizer that exhibits a function of swelling and softening toner by heating. It is a figure showing the experimental result which shows that smear property improves with the plasticizer which expresses the function to swell and soften the toner by heating. FIG. 6 is a conceptual diagram showing that the manner in which the fixing liquid adheres to the toner differs depending on whether the toner is transferred in contact with a recording medium or transferred in a non-contact manner. FIG. 4 is a conceptual diagram showing that a fixing solution attached to a toner when heated and brought into contact with a recording medium swells and softens the toner by heating and is in a state suitable for fixing. FIG. 2 is a schematic configuration diagram of a part of the fixing liquid application unit illustrated in FIG. 1 and a control system that controls the fixing liquid application unit. FIG. 8 is a schematic plan view of a part of the fixing solution applying unit shown in FIG. 7. FIG. 8 is a correlation diagram showing that the amount of fixing liquid applied to a recording medium changes depending on the presence or absence of the fixing liquid removing means shown in FIG. 7. FIG. 8 is a correlation diagram showing that the amount of fixing liquid applied to the recording medium changes depending on the presence or absence of the foreign matter removing means shown in FIG. 7. It is a schematic front view of a part of an image forming apparatus having another configuration to which the present invention is applied. It is a schematic front view of a part of an image forming apparatus having another configuration to which the present invention is applied.

  FIG. 1 shows an outline of an image forming apparatus to which the present invention is applied. The image forming apparatus 100 is a multifunction peripheral of a copying machine, a printer, and a facsimile machine, and can perform full-color image formation. Other image forming apparatuses, that is, a monochrome machine, a copying machine, a printer, It may be a single facsimile, or another multifunction device such as a multifunction device of a copying machine and a printer. When used as a printer, the image forming apparatus 100 performs an image forming process based on an image signal corresponding to image information received from the outside. This is the same when the image forming apparatus 100 is used as a facsimile.

  The image forming apparatus 100 forms an image on a sheet-like recording medium as a transfer medium, in addition to plain paper generally used for copying or the like, OHP sheets, cardboard, postcards and other thick paper, and envelopes. It is possible to do. The image forming apparatus 100 is also a double-sided image forming apparatus capable of forming an image on both sides of a transfer sheet S as a recording material as a recording medium as a sheet as a recording medium.

  The image forming apparatus 100 is a photosensitive member that is a latent image carrier as a drum-like image carrier capable of forming an image as an image corresponding to each color separated into yellow, magenta, cyan, and black. A tandem structure in which the photoconductive drums 20Y, 20M, 20C, and 20BK are arranged in parallel along the extending direction of the transfer belt 11 and arranged in parallel, in other words, a tandem system is adopted.

  The photoreceptor drums 20Y, 20M, 20C, and 20BK are rotatably supported by a frame (not shown) of the main body 99 that functions as a printer unit of the image forming apparatus 100, and are toner images as an intermediate transfer belt that is an intermediate transfer member. They are arranged in this order from the upstream side of the A1 direction, which is the moving direction of the transfer belt 11 as the carrier, and is the counterclockwise direction in FIG. Y, M, C, and BK added after the numerals of the respective symbols indicate members for yellow, magenta, cyan, and black.

  Each of the photosensitive drums 20Y, 20M, 20C, and 20BK has an image forming unit 60Y as an image forming device for forming yellow (Y), magenta (M), cyan (C), and black (BK) images, respectively. It is provided in 60M, 60C and 60BK.

  The photosensitive drums 20Y, 20M, 20C, and 20BK are rotated on the outer peripheral surface side, that is, on the image forming surface side of the endless transfer belt 11 that is configured as an endless belt disposed substantially in the center of the main body 99. The axes are parallel to each other and are arranged in a predetermined pitch at equal intervals in the A1 direction that is the moving direction of the transfer belt 11.

  The transfer belt 11 is movable in the direction of the arrow A1 while facing the photosensitive drums 20Y, 20M, 20C, and 20BK. The visible image, that is, the toner image formed on each of the photoconductive drums 20Y, 20M, 20C, and 20BK is superimposed and transferred to the transfer belt 11 that moves in the direction of the arrow A1, and is then collectively transferred to the transfer sheet S. It has become. Therefore, the image forming apparatus 100 is an intermediate transfer type image forming apparatus. Therefore, the image forming apparatus 100 is a tandem indirect transfer type electrophotographic apparatus.

  The lower portion of the transfer belt 11 faces each of the photosensitive drums 20Y, 20M, 20C, and 20BK. The facing position, which is the opposed portion, is on the respective photosensitive drums 20Y, 20M, 20C, and 20BK. A primary transfer portion 58 is formed as a primary transfer region for transferring the toner image to the transfer belt 11.

  In the superimposing transfer to the transfer belt 11, the toner images formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are transferred to the same position on the transfer belt 11 while the transfer belt 11 moves in the A1 direction. As described above, voltage application by the primary transfer rollers 12Y, 12M, 12C, and 12BK disposed at positions facing the photosensitive drums 20Y, 20M, 20C, and 20BK across the transfer belt 11 causes the A1 direction upstream. The timing is shifted toward the downstream side.

  In the main body 99, the image forming apparatus 100 is opposed to image forming units 60Y, 60M, 60C, and 60BK that are image forming stations serving as four image forming apparatuses, and above the photosensitive drums 20Y, 20M, 20C, and 20BK. The transfer belt unit 10 is an intermediate transfer unit as a primary transfer unit that is an intermediate transfer device including the transfer belt 11, and is disposed on the right side of the transfer belt 11 in FIG. The secondary transfer device 5 as a secondary transfer unit, which is a transfer means as the secondary transfer means, and a latent image forming means disposed opposite to the lower side of the image forming units 60Y, 60M, 60C, 60BK. And an optical scanning device 8 as an exposure device as a writing device as an optical unit which is an optical writing unit.

  The image forming apparatus 100 is also transferred below the optical scanning device 8 in the main body 99 toward the secondary transfer portion 57 as a secondary transfer region between the transfer belt 11 and the secondary transfer device 5. A sheet feeding device 61 serving as a sheet feeding device, which is a sheet feeding tray serving as a sheet feeding unit capable of stacking a large number of sheets S, and a transfer sheet S conveyed from the sheet feeding device 61 as an image. The registration roller pair 4 serving as a transport roller that feeds toward the secondary transfer unit 57 at a predetermined timing in accordance with the toner image formation timing by the forming units 60Y, 60M, 60C, and 60BK, and the leading edge of the transfer paper S is a registration roller A sensor (not shown) for detecting that the pair 4 has been reached.

  The image forming apparatus 100 also includes a fixing device 6 as a fixing unit as a roller fixing type fixing unit for fixing the toner image on the transfer sheet S on which the toner image is transferred in the main body 99, and a registration roller pair. Fixing as a fixing liquid applying means for applying a fixing liquid described later onto the transfer sheet S sent from 4 to the secondary transfer section 57, that is, the transfer sheet S before the toner image is transferred and carried on the secondary transfer section 57. A fixing liquid coating device 41 which is a liquid coating unit, a paper discharge roller 7 which is a paper discharge device as a pair of paper discharge rollers which are a discharge roller for discharging the fixed transfer paper S to the outside of the main body 99, and a transfer belt unit. 10, toner bottles 9 </ b> Y, 9 </ b> M, 9 </ b> C, and 9 </ b> BK filled with yellow, cyan, magenta, and black toners and disposed above the main body 99 and discharged. And a main body 99 externally stacking the discharged transfer sheet S, the sheet discharge tray 17 formed by internal sheet discharge portion by chromatography La 7.

  The image forming apparatus 100 also includes a duplex unit 51 attached to the right side of the main body 99 in the drawing, and a reading device 98 that is an image reading device that is positioned above the main body 99 and reads a document. ing.

  The image forming apparatus 100 is also formed in the main body 99 from the lower side to the upper side on the right side in the figure, and the secondary transfer unit 57, the registration roller pair 4, the fixing device 6, and the paper discharge roller 7 are arranged in the middle. A sheet conveyance path 81 through which the transfer sheet S fed from the sheet feeding device 61 enters, and a sheet conveyance from the duplex unit 51 on the upstream side of the registration roller pair 4 in the conveyance direction of the transfer sheet S in the sheet conveyance path 81. A sheet feeding path 82 that merges with the path 81, and a sheet refeeding conveyance path 83 that branches from the sheet conveyance path 81 toward the duplex unit 51 on the downstream side of the fixing device 6 in the conveyance direction of the transfer sheet S in the sheet conveyance path 81. have.

  In the main body 99, the image forming apparatus 100 also includes a driving device (not shown) that rotationally drives the photosensitive drums 20Y, 20M, 20C, and 20BK, a CPU as a calculation unit that controls the overall operation of the image forming apparatus 100, and storage. The control unit 91 includes a memory serving as a storage unit as a unit, and a power source as a power supply unit (not shown) that is fed from an external power source and feeds the components included in the image forming apparatus 100.

The image forming apparatus 100 also includes a start switch (not shown) for instructing image formation start on the outer surface of the main body 99, a paper type input key as a paper type input unit for inputting the thickness of the transfer paper S, and the like. 100 operation and operation modes can be designated, and an operation panel (not shown) including a liquid crystal display device (not shown) as display means for performing predetermined display is provided.
As shown in FIG. 1, the image forming apparatus 100 is an in-body paper discharge type image forming apparatus in which the paper discharge tray 17 is located above the main body 99 and below the reading device 98.

  In addition to the transfer belt 11, the transfer belt unit 10 is driven as primary transfer rollers 12Y, 12M, 12C and 12BK as primary transfer bias rollers, and a plurality of rollers around which the transfer belt 11 is wound. A driving roller 72 as a member, a cleaning facing roller 74 as a stretching roller, stretching rollers 33 and 34 as supporting rollers for stretching the transfer belt 11 together with the driving roller 72 and the cleaning facing roller 74, and the transfer belt 11 And a tension roller 75 that abuts against the transfer belt 11 from the outside and applies a predetermined tension to the transfer belt 11 together with the cleaning counter roller 74.

  The transfer belt unit 10 is also provided with a cleaning device 13 as a belt cleaning device, which is an intermediate transfer member cleaning device that is disposed facing the transfer belt 11 at a position facing the cleaning counter roller 74 and cleans the surface of the transfer belt 11. A belt drive device as a drive system (not shown) that drives the drive roller 72 to rotate, and a primary transfer bias is applied to the primary transfer rollers 12Y, 12M, 12C, and 12BK, together with the primary transfer rollers 12Y, 12M, 12C, and 12BK. The image forming apparatus includes a power supply and bias control means (not shown) constituting biasing means (not shown) constituting each transfer device.

  The cleaning facing roller 74, the stretching rollers 33 and 34, and the tension roller 75 are driven rollers that rotate with the transfer belt 11 that is rotationally driven by the driving roller 72. The primary transfer rollers 12Y, 12M, 12C, and 12BK press the transfer belt 11 from the back surface thereof toward the photosensitive drums 20Y, 20M, 20C, and 20BK to form primary transfer nips. The primary transfer nip is formed in a portion of the transfer belt 11 that extends substantially horizontally between the cleaning facing roller 74 and the stretching roller 33. The cleaning facing roller 74, the stretching roller 33, and the tension roller 75 have a function of stabilizing the primary transfer nip.

  In each primary transfer nip, a primary transfer electric field is formed between the photosensitive drums 20Y, 20M, 20C, and 20BK and the primary transfer rollers 12Y, 12M, 12C, and 12BK due to the influence of the primary transfer bias. . The toner images of the respective colors formed on the photosensitive drums 20Y, 20M, 20C, and 20BK are primarily transferred onto the transfer belt 11 due to the influence of the primary transfer electric field and nip pressure.

The driving roller 72 is in contact with the secondary transfer device 5 via the transfer belt 11 to form a secondary transfer portion 57.
The cleaning facing roller 74 has a function as a tension roller as a pressure member that applies a predetermined tension suitable for transfer to the transfer belt 11 together with the tension roller 75.

  In FIG. 1, the cleaning device 13 is disposed on the lower left side of the transfer belt unit 10, specifically, below the cleaning counter roller 74. Although not shown, the cleaning device 13 houses a brush roller and a cleaning blade as a cleaning member disposed so as to contact the transfer belt 11 at a position facing the cleaning counter roller 74 and a cleaning member therein. 1 and a waste toner collection bottle disposed on the front side of the case in FIG.

  The cleaning device 13 cleans the transfer belt 11 by scraping and removing foreign matters such as residual toner on the transfer belt 11 with a cleaning member. The foreign matter removed from the transfer belt 11 is stored in a waste toner collection bottle as a waste toner bottle. The waste toner collection bottle can be taken out to the front side of the paper in FIG. 1 with the front panel opened, and can be replaced with a new one when the foreign matter inside becomes full. Note that cleaning devices 71Y, 71M, 71C, and 71BK, which will be described later, similarly have replaceable waste toner collection bottles.

  Although not shown in detail in the secondary transfer device 5, a secondary transfer roller that is a transfer member that is disposed to face the drive roller 72 and is in contact with the transfer belt 11, and the secondary transfer roller to the transfer belt 11. And a spring serving as a biasing means that forms a secondary transfer portion 57 that is a nip between the secondary transfer roller and the transfer belt 11. The secondary transfer roller is applied with a voltage having a polarity opposite to that of the toner by a power source, and transfers the toner image on the transfer belt 11 to the transfer sheet S not only by pressure contact with the transfer belt 11 by a spring but also by bias. The secondary transfer roller also has a sheet conveying function for conveying the transfer sheet S on which the toner image is transferred to the fixing device 6. The spring causes the transfer sheet S fed to the secondary transfer unit 57 to be in close contact with the transfer belt 11, and the toner image carried on the transfer belt 11 is transferred to the fixing liquid by the fixing liquid applying device 41 of the transfer sheet S. It is provided for transferring while being brought into contact with the coated surface in a pressure contact manner.

  Although not shown, the optical scanning device 8 includes a light source such as a semiconductor laser, a polygon mirror, an F-θ lens, a reflection mirror, and the like, and the light source emits light based on data corresponding to an image to be formed. By controlling the rotation of the polygon mirror and controlling the rotation of the polygon mirror, each surface of the photoconductive drums 20Y, 20M, 20C, and 20BK is irradiated while scanning with laser light, and each color of yellow, magenta, cyan, and black is applied. A corresponding electrostatic latent image is formed.

  The sheet feeding device 61 accommodates a plurality of transfer sheets S in a state of a stack of transfer sheets, and is disposed below the optical scanning device 8 below the main body 99. In the present embodiment, the sheet feeding device 61 includes a plurality of sheet feeding cassettes 25 arranged in two stages so that a plurality of transfer sheets S can be stacked in a bundle of sheets in the vertical direction. The transfer roller S loaded on the uppermost transfer sheet S is separated from a feeding roller 24 as a paper feed roller that contacts the upper surface of the uppermost transfer paper S, and only one of the transfer sheets S fed by the paper feed roller 24 is separated. Further, a separation roller (not shown) that further conveys and an opening / closing detection sensor (not shown) that detects that the paper feed cassette 25 is opened and closed with respect to the main body 99 are provided. The uppermost transfer sheet S is fed toward the registration roller pair 4 by being driven to rotate counterclockwise at the above timing.

  In the sheet feeding device 23, the feeding roller 24 is selectively driven to rotate counterclockwise in the figure, and the separation roller acts so that the uppermost of the transfer sheets S stacked in the sheet feeding cassette 25 is actuated. The transfer paper S is put into the paper transport path 81 and fed toward the registration roller pair 4 so that the transported transfer paper S is stuck and stopped while being sandwiched between the rollers of the registration roller pair 4. It has become.

  The duplex unit 51 includes a manual sheet feeding device 53 disposed on the outer surface side, a part of the sheet feeding path 82 disposed across the duplex unit 51 from the manual sheet feeding device 53, and refeeding. The reversal conveyance path 21 that reverses and conveys the transfer paper S that has passed through the paper conveyance path 83 toward the paper feed path 82, and the transfer paper S that is disposed in the reverse conveyance path 21 is conveyed toward the paper feed path 82. And a conveying roller 23.

  The manual paper feeder 53 includes a manual feed tray 27 as a manual paper feed tray on which the transfer paper S can be stacked, and a paper feed roller that contacts the upper surface of the uppermost transfer paper among the transfer paper S stacked on the manual feed tray 27. And a separation roller (not shown) for separating the transfer paper fed by the feed roller 28 one by one.

  In the manual sheet feeding device 53, the feeding roller 28 is rotated in the clockwise direction in the drawing, and the separation roller acts to feed the uppermost transfer sheet S toward the registration roller pair 4 to be conveyed. The transfer sheet S is abutted and stopped while being sandwiched between the rollers of the registration roller pair 4.

  The fixing device 6 includes a fixing roller 65 as a roller-shaped fixing member, and a roller-shaped pressurization for forming a fixing nip 62 as a fixing portion that is a pressure-contacting portion that presses against the fixing roller 65 and presses the transfer sheet S. A pressure roller 63 serving as a member, and a heater 66 that is disposed inside the fixing roller 65 and is a halogen heater serving as a fixing heat source as a heating means for heating the fixing roller 65 to heat the fixing nip 62 to a predetermined temperature. And a non-contact type thermistor 68 as temperature detecting means which is disposed in the vicinity of the outer peripheral surface of the fixing roller 65 and detects the temperature of the fixing roller 65 as a fixing member temperature detecting means.

  As shown in FIG. 2, the fixing device 6 is also detected by a PWM drive circuit 92a as a heating drive means for driving the heater 66, a target control temperature of the fixing roller 65 set to a temperature described later, and a thermistor 68. Heating for controlling the temperature of the fixing roller 65 by controlling the power applied to the heater 66 through the PWM drive circuit 92a based on the information of the temperature deviation between the temperature of the fixing roller 65 and the energizing time per unit time (= DUTY). And a fixing temperature controller 92b as a temperature controller which is a fixing temperature control means as a drive control means.

  The PWM drive circuit 92 a and the fixing temperature controller 92 b are realized as one function of the control unit 91. In this respect, the control unit 91 functions as a fixing temperature control unit. The control unit 91 functioning as a fixing temperature control unit substantially controls the temperature of the fixing nip 62 by controlling the temperature of the fixing roller 65.

  The fixing device 6 passes the transfer paper S carrying the toner image between the fixing nips 62, and the fixing roller 65 comes into contact with the image surface carrying the toner image of the transfer paper S so that the action of heat and pressure is performed. As a result, the toner constituting the carried toner image is melted and pressure-bonded to be fixed on the surface of the transfer paper S.

As shown in the figure, the transfer sheet S entering the fixing nip 62 has already been applied with the fixing liquid by the fixing liquid applying device 41 on the surface carrying the toner. However, the illustration of the fixing solution is omitted in FIG.
The remainder of the fixing device 6 will be described later.

  The yellow, cyan, magenta, and black toners in the toner bottles 9Y, 9M, 9C, and 9BK are polymerized toners that are rotated by driving means (not shown) to discharge the toner, and are not shown by a pipe (not shown). A predetermined replenishment amount is supplied to the developing devices 80Y, 80M, 80C, and 80BK provided in the image forming units 60Y, 60M, 60C, and 60BK, as will be described later, through the configured conveyance path.

  Although not shown in detail, the reading device 98 includes a contact glass for placing an original, a light source for irradiating light on the original placed on the contact glass, and a first light that reflects light reflected on the original from the light source. A first traveling body that travels in the left-right direction in FIG. 1, a second traveling body that includes a second reflector that reflects light reflected by the reflector of the first traveling body, and a second traveling body. An image forming lens for forming an image of light from the body, a reading sensor for receiving the light passing through the image forming lens and reading the contents of the document are provided.

  The image forming units 60Y, 60M, 60C, and 60BK have the same configuration. The image forming units 60Y, 60M, 60C, and 60BK are primary transfer rollers as process means around the photosensitive drums 20Y, 20M, 20C, and 20BK along the rotation direction B1 that is clockwise in FIG. 12Y, 12M, 12C, 12BK, a cleaning device 71Y, 71M, 71C, 71BK as a cleaning unit, a neutralizing device (not shown) as a neutralizing unit, and a charging roller (not shown) as a charging unit for AC charging And developing devices 80Y, 80M, 80C, and 80BK as developing units that perform development using a developer that is a two-component developer including toner and a magnetic carrier.

  These are well-known configurations. For example, the developing devices 80Y, 80M, 80C, and 80BK are not illustrated in detail, but development as a developer carrying member facing the photosensitive drums 20Y, 20M, 20C, and 20BK is performed. A roller, a screw that stirs while conveying the developer, a toner concentration sensor as a toner concentration sensor that detects the toner concentration in the developer, and in the toner bottles 9Y, 9M, 9C, and 9BK according to the output of the toner concentration sensor The developing roller has a magnet fixed to the apparatus main body side and a sleeve rotatably supported on the outside of the magnet. is doing.

  The photosensitive drum 20Y, the cleaning device 71Y, the charge eliminating device, the charging device 79Y, and the developing device 80Y are integrated to form a process cartridge. The components around the photoconductive drums 20M, 20C, and 20BK are similarly integrated to form a process cartridge. These process cartridges are detachable in the direction of the rotation axis of the photosensitive drums 20Y, 20M, 20C, and 20BK on the front side in FIG. 1 with the front panel opened. Making a process cartridge in this way is very preferable because it can be handled as a replacement part, so that the maintainability is remarkably improved.

  In the image forming apparatus 100 having such a configuration, image formation is performed by performing the following image forming processes in the image forming units 60Y, 60M, 60C, and 60BK, respectively, by pressing a start switch or the like. That is, when a signal indicating that a color image is to be formed is input, data corresponding to the image to be formed is acquired and input to the control unit 91 as appropriate, for example, by reading a document in the reading device 98. At the same time, the driving roller 72 is driven, the transfer belt 11, the cleaning facing roller 74, the stretching rollers 33 and 34, and the tension roller 75 are driven to rotate, and the photosensitive drums 20Y, 20M, 20C, and 20BK are driven to rotate in the B1 direction. Is done.

  The surface of each of the photosensitive drums 20Y, 20M, 20C, and 20BK is uniformly charged by the charging rollers of the charging devices 79Y, 79M, 79C, and 79BK that are supplied with power from the power source in accordance with the rotation in the B1 direction. The electrostatic latent image corresponding to each color of yellow, magenta, cyan and black is written by exposure scanning of the laser beam from the optical scanning device 8 driven by the control means 91 based on the data corresponding to the image to be formed. This electrostatic latent image is developed by developing devices 80Y, 80M, 80C, and 80BK with yellow, magenta, cyan, and black toners to be visualized, and magenta, cyan, and black toner images. A monochromatic image constituted by the above is formed.

  The yellow, magenta, cyan, and black toner images obtained by development are sequentially rotated in the A1 direction by primary transfer rollers 12Y, 12M, 12C, and 12BK to which a voltage having a polarity opposite to that of the toner is applied by a power source. The transfer image is transferred to the same position on the transfer belt 11, and a composite color image is formed on the transfer belt 11.

  On the other hand, with the input of a signal indicating that a color image should be formed, one of the paper feed roller 24 corresponding to each paper feed cassette 25 and the paper feed roller 28 corresponding to the manual feed tray 27 is selected and rotated. The transfer sheet S is fed out and separated and conveyed one by one, and the conveyed transfer sheet S stops in a state where it abuts against the registration roller pair 4. In the case of double-sided image formation, the transfer sheet S on which an image is fixed on one side of the fixing device 6 as described later is abutted against the registration roller pair 4 while being reversed through the reverse conveyance path 21. Stop in the state.

  The registration roller pair 4 rotates and the registration roller pair 4 rotates in accordance with the timing when the combined color image superimposed on the transfer belt 11 moves to the secondary transfer portion 57 as the transfer belt 11 rotates in the A1 direction. The fixing sheet is fed onto the surface of the transfer sheet S sent out by the fixing liquid application device 41 on the side to which the composite color image, which is a toner image, is transferred by the secondary transfer unit 57.

  The transfer sheet S to which the fixing liquid is applied is brought into close contact with the secondary transfer roller urged toward the transfer belt 11 at the secondary transfer unit 57, and the secondary transfer is performed by the nip pressure and the power source. The toner image is secondarily transferred onto the transfer sheet S by the action of a voltage having a polarity opposite to that of the toner constituting the composite color image applied to the roller, and is recorded.

  The transfer sheet S is conveyed by the secondary transfer device 5 and the transfer belt 11 rotating in the A1 direction, and sent to the fixing device 6, where the fixing device 6 is a fixing unit between the fixing roller 65 and the pressure roller 63. When passing through the nip 62, the carried toner image, that is, the synthesized color image is fixed by the action of heat and pressure and the action of the fixing liquid described later.

  The transfer sheet S on which the composite color image has been fixed, which has passed through the fixing device 6, is discharged out of the main body 99 through the discharge roller 7 and stacked on the discharge tray 17 at the top of the main body 99. In the case of double-sided image formation, the transfer sheet S fixed on one side is conveyed again toward the registration roller pair 4 through the refeed path 83 and the reverse conveyance path 21.

  In the photosensitive drums 20Y, 20M, 20C, and 20BK, transfer residual toner remaining after the transfer is removed by the cleaning devices 71Y, 71M, 71C, and 71BK, discharged by the discharging device, and then discharged by the charging devices 79Y, 79M, 79C, and 79BK. Used for charging.

  The surface of the transfer belt 11 after passing the secondary transfer portion 57 after the secondary transfer is cleaned by a cleaning member provided in the cleaning device 13 to prepare for the next transfer.

A fixing solution used to perform such image formation will be described.
The fixing liquid is a plasticizer for swelling and softening the toner constituting the toner image transferred and carried on the transfer paper S in the secondary transfer unit 57 to a state suitable for fixing to the transfer paper S. It contains a surfactant for improving the permeability of the fixing solution between the toners constituting the toner image, and a solvent that functions as a diluent for these plasticizer and surfactant.

  The plasticizer employs a solid plasticizer that exhibits a softening function when heated. When heat is applied, in the image forming apparatus 100, the image forming apparatus 100 is heated when fixing by the fixing device 6. When the temperature exceeds about 50 ° C. or lower. Such an environmental temperature is, for example, an office temperature, or a temperature in the main body 99 excluding the temperature of the fixing device 6 during the temperature raising operation and the ambient atmosphere.

  Therefore, even if the plasticizer adheres to the configuration of the image forming apparatus 100 excluding the fixing device 6, for example, adheres to the transfer belt 11 and the secondary transfer roller in the secondary transfer unit 57, the function does not appear. It is possible to prevent or suppress the occurrence of in-flight contamination due to adhesion to such a configuration.

  On the other hand, when the temperature is raised by heating by the fixing device 6 and exceeds the environmental temperature, the function of swelling and softening the toner and making it suitable for fixing onto the transfer paper S is exhibited. This function will be described with reference to FIG.

  FIG. 3 is a conceptual diagram showing that the lower limit temperature of the temperature at which the toner is suitable for fixing, that is, the lower limit fixing temperature is lowered by the plasticizer. In the figure, the storage elastic modulus is a value indicating the hardness of the toner, and means that if the storage elastic modulus is high, the toner is hard and low, and the toner is soft. If the storage elastic modulus is K or less, the toner is fixed to the transfer paper S and can be fixed. Therefore, the temperature when the storage elastic modulus is K is the fixing lower limit temperature. In the figure, the solid plasticizer means a plasticizer used in the fixing solution used in the image forming apparatus 100. This is because the plasticizer is a solid in a single state before being used as a fixing solution at the environmental temperature. In the same figure, the liquid plasticizer means a liquid in a single state at the environmental temperature.

  As shown in the figure, when the fixing liquid containing the solid plasticizer is applied to the toner, the lower limit fixing temperature becomes T1 lower than the lower limit fixing temperature T2 when the fixing liquid is not used. Therefore, the target control temperature of the fixing roller 65 can be set lower than when the fixing liquid is not used, and the power consumption of the fixing device 6 and the image forming apparatus 100 can be reduced.

  The figure also shows that the liquid plasticizer shown has the ability to soften the toner at a temperature lower than T1, for example, ambient temperature included in the environmental temperature, and includes a solid plasticizer. Liquids do not function at temperatures where such liquid plasticizers have a function to soften toner, and unlike fixers containing such liquid plasticizers, it has been shown that they have little softening ability at such ambient temperatures. . Therefore, if a fixing liquid containing a liquid plasticizer is used for the scale, the inside of the apparatus is contaminated. However, in the image forming apparatus 100, the inside of the apparatus is not contaminated by using the fixing liquid containing the solid plasticizer. Whether the plasticizer having the function of lowering the storage elastic modulus of the toner is solid or liquid as a single substance at an ambient temperature such as room temperature or not, and whether or not internal contamination can occur when the plasticizer is used as a fixing liquid. Therefore, the plasticizer constituting the fixing solution used in the image forming apparatus 100 is based on the fact that it is a single solid at ambient temperature.

A solid plasticizer is a compound containing an ethylene oxide group — (CH ₂ CH ₂ O) — or a propylene oxide group — (CH (CH ₃ ) CH ₂ O) — in the molecular chain, and is generally a glycol ether or glycol fatty acid. Among what are called esters, the material is solid at room temperature and has a melting point of 40 ° C. or higher, desirably 50 ° C. or higher.

Specifically, polyoxyethylene glycols represented by the compound (1) are desirable.
_{HO- (CH 2 CH 2 O)} n-OH ··· (1)
n is preferably 10 or more and 100 or less. When n is less than 10, it does not become solid at room temperature, and when n is greater than 100, the molecule becomes too large, and the plastic ability when heat is applied is low and the toner is difficult to soften. Specific examples of suitable materials include polyethylene glycol # 1000, polyethylene glycol # 1540, polyethylene glycol # 2000, polyethylene glycol # 4000, polyethylene glycol # 6000, polyethylene glycol # 8000, and the like.

Alternatively, polyoxyethylene polyoxypropylene glycols represented by the compound (2) are also desirable.
_{HO- (CH 2 CH 2 O)} n (CH (CH 3) CH 2 O) m-OH ··· (2)
n is preferably 10 or more and 200 or less. m is preferably 5 or more and 50 or less. When n is less than 10, it does not become a solid at room temperature, and when n is greater than 200, the molecule becomes too large, the plastic ability when heat is applied is low, and the toner is difficult to soften. When m is less than 5, it does not become solid at room temperature, and when m is greater than 50, the molecule becomes too large, and the plastic ability when heat is applied is low and the toner is difficult to soften. Specific examples of suitable materials include Emulgen 290 from Kao Corporation, Epan 450, Epan 750, Epan 785 from Daiichi Kogyo Seiyaku.

Alternatively, polyoxyethylene alkyl ethers represented by the compound (3) are desirable.
R—O— (CH ₂ CH ₂ O) n—OH (3)
n is preferably 10 or more and 100 or less. When n is less than 10, it does not become solid at room temperature, and when n is greater than 100, the molecule becomes too large, and the plastic ability when heat is applied is low and the toner is difficult to soften.
R is a linear alkyl group or a branched alkyl group, and the number of carbon atoms is preferably 10 or more and 22 or less. If it has less than 10 carbon atoms, it is soft as a solid, and there are safety problems such as skin irritation and eye irritation. When the number of carbon atoms is larger than 22, the plastic ability when heat is applied is low, and the toner is difficult to soften. Specific examples of suitable materials include Emulgen 350, Emulgen 420, and Emulgen 4085 from Kao Corporation, EMALEX 611, EMALEX 620, EMALEX 710, EMALEX 720 from Japan Emulsion Co., Ltd., and the like.

Further, polyoxyethylene fatty acid esters and polyoxyethylene fatty acid diesters represented by the compound (4) and the compound (5) are desirable.
R-COO- (CH2CH2O) n-OH (4)
R-COO- (CH2CH2O) n-COO-R '(5)
n is preferably 10 or more and 100 or less. When n is less than 10, it does not become solid at room temperature, and when n is greater than 100, the molecule becomes too large, and the plastic ability when heat is applied is low and the toner is difficult to soften. R and R ′ are normal alkyl groups or branched alkyl groups, and the number of carbon atoms is preferably 10 or more and 22 or less. If it has less than 10 carbon atoms, it is soft as a solid, and there are safety problems such as skin irritation and eye irritation. When the number of carbon atoms is larger than 22, the plastic ability when heat is applied is low, and the toner is difficult to soften. As specific materials, Emanon 3199V and Emanon 3299RV of Kao Corporation, EMALEX 820, EMALEX 830 of Japan Emulsion Co., Ltd., and the like are suitable.

  The surfactant is used to improve the permeability of the fixing liquid into the toner layer. A nonionic surfactant is suitable as the surfactant. Specifically, polyoxyethylene alkyl ethers and acetylene surfactants are desirable. Specifically, polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene alkyl (12-14) ether (12E.O.), and polyoxyethylene alkyl (12-14) ether. As acetylene-based surfactants such as BT-12 of the company, acetylene glycol is excellent, and Olphine 1010 and Olphin 4051F manufactured by Nissin Chemical Industry Co., Ltd. are suitable.

  Water is suitable for the diluent that is the solvent for these materials. Since city water contains many impurities such as calcium ions and magnesium ions, water from which these metal ions have been removed to some extent is desirable. However, the water does not need to be distilled water, and water obtained by removing impurity ions with an ion exchange membrane, so-called ion exchange water is suitable.

The heating temperature for fixing the toner image on the transfer sheet S coated with the fixing liquid containing the solid plasticizer, that is, the target control temperature of the fixing roller 65 will be described.
Since such a fixing solution is used, the fixing lower limit temperature is lowered as described above, but the fixing lower limit temperature is generally set to a temperature that ensures a predetermined smear property. The smear property is an index related to toner contamination when the recording medium after heat fixing is rubbed. The lower the numerical value representing the toner contamination concentration, the lower the toner contamination concentration, that is, the less toner contamination, and the better the fixing property. If the smear ID obtained as described below is 0.40 or less, it is allowed for practical use. Accordingly, the temperature of the fixing roller 65 at which the storage elastic modulus is K or less and the smear ID is 0.40 or less is set as the target control temperature of the fixing roller 65.

  As shown in FIG. 4, the image forming apparatus 100 has improved smearing properties under the same temperature condition as compared with an image forming apparatus that does not use a fixing solution and has a fixing configuration only with heat fixing. The figure shows a case in which a smear test result, which is a friction test result, is performed by an image forming apparatus 100 in which a fixing solution is applied to the transfer paper S in advance before the toner image is transferred and an image forming apparatus only for heat fixing. Shows a comparison. The fixing solution is a solution in which polyethylene glycol # 2000 is used as a solid plasticizer and Olfine 4051F is used as a surfactant, and these are diluted with ion-exchanged water as a solvent to 25 wt% and 0.5 wt%, respectively. .

  This smear test was conducted using a smear tester (friction tester type I, JIS L0823, friction element diameter: 15φ). A white cotton cloth (JIS L0803 cotton No. 3) of about 25 × 25 mm was attached to the friction element with a double-sided tape so that the fiber direction was horizontal with the moving direction of the friction element. Then, the evaluation image was rubbed 5 times in a continuous motion. The evaluation images are a halftone image with an image area ratio of 55% and a 100% solid image. The white cotton cloth is peeled off, and the image density at any three locations on the friction mark where the image is adhered is measured using a spectrometer (X-Rite, 938 Spectrodensitometer), and the average value is smeared. ID. As described above, the lower the smear ID, the smaller the contamination by the toner when rubbing the fixed image.

  Accordingly, in the image forming apparatus 100, smearing is ensured even when the target control temperature of the fixing roller 65, that is, the set temperature is 121 ° C., and in the image forming apparatus only for heat fixing, the smear is not set unless the set temperature is 139 ° C. It can be seen that the property is not secured.

  In the image forming apparatus 100, based on the test result, the fixing temperature setting, in other words, the target control temperature is set to 121 ° C. This temperature is 18 ° C. lower than the lower limit fixing temperature in an image forming apparatus with only thermal fixing. Therefore, the image forming apparatus 100 saves power and is an image forming apparatus with a low environmental load. In this embodiment, as described above, a fixing solution containing 25 wt% and 0.5 wt% of Olphine 4051F as a solid plasticizer and Olfin 4051F as a solid plasticizer is employed. By adjusting this, the temperature for ensuring smearing can be changed, and the fixing set temperature is not limited to this.

  In the image forming apparatus 100, the smearing property is improved, and the fixing set temperature can be set to a very low temperature as compared with the conventional one, and the smearing property is ensured at such a very low fixing set temperature. Stable fixing and image formation are not simply because a fixing solution containing such a solid plasticizer is used, but such a fixing solution is applied in advance to the transfer paper S before carrying a toner image. In addition, the toner image on the transfer belt 11 is transferred to the surface of the transfer sheet S on which the fixing liquid is applied while being brought into contact with the secondary transfer device 5, and then fixed by heating or the like in the fixing device 6. It is because it is doing. The reason for this will be described below.

  First, when the toner image on the transfer belt 11 is transferred to the transfer paper S to which the fixing liquid is applied, the fixing liquid previously applied to the transfer paper S is apparent as shown in FIG. However, the surface of each of the toners becomes a fixing liquid until the vicinity of the surface of the toner image in contact with the transfer belt 11 by soaking in between the many toners constituting the toner image transferred on the transfer paper S by capillary action. Covered. In particular, a large amount of fixing liquid adheres to the toner near the surface of the transfer paper S. Since the capillary phenomenon is intensified by transferring the toner image on the transfer belt 11 while being in contact with the transfer paper S, the capillary phenomenon occurs between the toners rather than simply transferring from the transfer belt 11 to the transfer paper S by electrostatic flight. Soaks in the fixer. The capillary phenomenon is particularly intensified by transferring the transfer sheet S while being brought into pressure contact with the transfer belt 11 as in the present embodiment, and such penetration is favorably generated.

  Next, when the transfer sheet S carrying the toner image in which the fixing liquid is soaked between the toners and the toner surface is covered with the fixing liquid is heated in the fixing nip 62, the plasticizer in the fixing liquid is heated together with the toner. As shown in FIG. 6, it functions to swell and soften the toner by penetrating into the toner resin in the toner. Since pressure is also applied at the fixing nip 62, the penetration of the fixing liquid into the toner layer is further promoted, and the anchor effect on the transfer sheet S is efficiently generated in the softened toner, so that the toner is fixed to the transfer sheet S. Is done. When heating is performed from the surface side of the toner image as in the present embodiment, heat is not easily transmitted to the vicinity of the interface between the transfer paper S and the toner image as compared to the surface of the toner image. Since the toner adheres well to the toner close to the surface of the transfer paper S, the function is exhibited when the plasticizer reaches a temperature at which the above-described function is exhibited, and the fixing is performed with high efficiency. In particular, in this embodiment, since heating is performed from the toner image side, the amount of heat absorbed by the transfer paper S is small compared to heating only from the back side of the transfer paper S, and the temperature rise efficiency of the plasticizer that requires heating is increased. Therefore, the function of the plasticizer is quickly exhibited. Note that heating from the back side of the transfer sheet S may be performed, that is, a heating unit that heats the pressure roller 63 may be used in combination, but in this case, transfer is performed within a range where power saving is achieved. It is preferable to use heating from the paper S side together.

  As described above, in the image forming apparatus 100, the fixing liquid that exhibits the function at a temperature lower than the conventional fixing set temperature is applied in advance to the transfer paper S, and the fixing liquid applied in advance is used as the toner image. When transferring the toner, the toner adheres efficiently to the toner on the surface of the transfer paper S by contact transfer, so that the toner on the surface of the transfer paper S is suitable for fixing at a lower temperature and with a smaller amount of heat. Thus, fixing is performed satisfactorily. The fixing liquid preliminarily applied to the transfer paper S efficiently adheres to the toner on the surface of the transfer paper S by contact transfer when transferring the toner image. The fixing liquid is supplied from the surface side of the toner image. This also contributes to reducing the supply amount of the fixing solution and reducing the power and time required for heating to dry the fixing solution. Since the capillary transfer phenomenon is utilized by performing contact transfer, the amount of the fixing liquid that needs to be attached to the transfer paper S in advance is smaller than when transferring toner by flying and landing on the transfer paper S. This also contributes to reducing the power and time required for heating to dry the fixing solution.

  Further, since the fixing liquid is applied before the toner image is transferred, the toner image is not disturbed when the fixing liquid is applied, and a good fixed image can be obtained. Further, since the function of the fixing solution is manifested when the temperature is raised for fixing, even if the fixing solution adheres to the transfer belt 11 or the like, there is no influence. This technique is not limited to application to liquid development.

  In addition, the deterioration of transferability due to voids is avoided by making the fixer liquid instead of foam. In-machine contamination due to the fixing liquid adhering to the photosensitive drums 20Y, 20M, 20C, 20BK, the transfer belt 11, and the members in contact therewith is due to the fact that the fixing liquid develops its function by increasing the temperature. In addition to the adhesion itself, for example, the function of such a member may be deteriorated, and a residual toner, scattered toner, or the like may be fixed on the member. Since the fixing liquid is not supplied to the toner images on 20M, 20C, 20BK and the transfer belt 11, it is suppressed or prevented.

The configuration of the fixer coating device 41 will be described with reference to FIGS.
The fixing liquid coating device 41 is a coating roller 44 that is a roller-like rotating body that is a coating member serving as a fixing liquid coating member that applies and fixes the fixing liquid to the transfer paper S transported in the paper transport path 81. A counter roller 45 disposed opposite to the application roller 44 with the paper conveyance path 81 interposed therebetween, a motor 46 as a driving means for rotationally driving the application roller 44, and a fixing liquid storage unit that stores a fixing liquid. Liquid chamber 47.

  The fixing liquid application device 41 is also a supply member that is immersed in the fixing liquid contained in the liquid chamber 47 and is driven to rotate by the application roller 44 to carry the fixing liquid on the surface and supply the carried fixing liquid to the application roller 44. Supply roller 48, fixing solution removing means 49 for removing the fixing solution from the application roller 44, and a driver (not shown) of the motor 46.

  The application roller 44, the opposing roller 45, and the supply roller 48 are long in the direction perpendicular to the paper surface in FIG. 7, and in the left-right direction of the paper surface in FIG. .

  The application roller 44 is disposed on the side of the sheet conveyance path 81 where the toner image is transferred to the transfer sheet S in the secondary transfer portion 57, and the surface of the transfer sheet S, that is, the periphery of the transfer sheet S is arranged on the same side. Apply the fixer supported on the surface.

  The counter roller 45 is driven to rotate by the application roller 44 or rotated by the transfer sheet S conveyed between the application roller 44 and the application roller 44 by the rotational drive. The counter roller 45 is a glass bead roller having a diameter of 25 mm, in which chloroprene is wound around a stainless metal core, and glass beads having a diameter of 100 μm are fixed on the surface thereof with an epoxy adhesive.

  Both the application roller 44 and the supply roller 48 have a diameter of 25 mm and employ a roller in which chloroprene is wound around a stainless steel core. The hardness of the roller is 35 degrees according to JIS-A. The application roller 44 and the supply roller 45 are in a state of being pressed against each other by 20N on one side between the shafts at both ends in the direction perpendicular to the paper surface in the figure, which is the longitudinal direction.

  The center of the application roller 44 and the counter roller 45 are arranged at the same height. The supply roller 48 has its center at a position 10 mm lower than the center of the application roller 44. The supply roller 48 is immersed in a fixing solution stored in the liquid chamber 47 at a depth of 5 mm. Since the center of the application roller 44 and the center of the supply roller 48 are offset, when the transfer sheet S enters the nip between the application roller 44 and the opposing roller 45, the gap between the application roller 44 and the supply roller 45 is reduced. The effect on the applied pressure is reduced.

  The application roller 44 is driven by the control means 91 via the driver by the motor 46, so that the application roller 44 is driven in a predetermined direction, specifically in the direction of the arrow shown in FIG. Is rotated. In this respect, the control means 91 functions as a fixing liquid application control means for controlling the application of the fixing liquid to the transfer paper S by the fixing liquid application device 41 and applies the fixing liquid to the transfer paper S by the application roller 44. It functions as a fixing liquid application member drive control means for controlling.

  The control unit 91 functioning as the fixing liquid application member drive control unit passes the transfer sheet S fed from the registration roller pair 4 toward the secondary transfer unit 57 through the nip portion between the application roller 44 and the opposing roller 45. At this timing, the motor 46 is driven so that the fixing liquid is applied to the transfer paper S, and the application roller 44 is rotated. Therefore, the control means 91 functioning as the fixing liquid application member drive control means measures the timing based on the drive timing of the registration roller pair 4 and sends a signal relating to the drive control of the motor 46 to the driver. Based on the above, the drive of the motor 46 is turned ON / OFF, and thereby the application of the fixing liquid onto the transfer paper S by the application roller 44 is turned ON / OFF. As a result, the fixing liquid supplied to the application roller 44 by the supply roller 48 is conveyed to the nip portion between the application roller 44 and the opposing roller 45 by the rotation of the application roller 44, and is transferred onto the transfer paper S in this nip portion. Applied.

  Thus, when the application roller 44 is driven to rotate by the motor 46 and the fixing liquid is applied to the transfer paper S, the supply roller 48 is driven to rotate by the application roller 44 to carry a fixed amount of the fixing liquid in the liquid chamber 47 on the peripheral surface. In other words, it is held and transported to a portion facing the coating roller 44 along with the driven rotation, and is supplied to the coating roller 44 at the facing portion. The liquid chamber 47 and the supply roller 48 constitute a supply unit 56 as a fixer supply unit that supplies the fixing solution to the application roller 44. Details of the fixer removing means 49 will be described later.

  Since the image forming apparatus 100 includes the fixing liquid application device 41, the fixing liquid is applied to the transfer sheet S before the toner image is transferred. Since the toner does not adhere to the application roller 44, the toner adhering to the application roller 44 will not adhere to the transfer sheet S again, and image defects will not occur.

  The fixing liquid removing unit 49 has an end that is in contact with the application roller 44, and scrapes the fixing liquid carried on the surface of the application roller 44, that is, the peripheral surface, from the application roller 44 when the application roller 44 rotates. The blade 49a is a fixing liquid removing blade as a fixing liquid removing member to be removed, and a support unit (not shown) that supports the blade 49a at a fixed position.

  The blade 49a is downstream of the nip portion between the application roller 44 and the opposing roller 45, which is the position where the application roller 44 applies the fixing liquid to the transfer paper S in the rotation direction of the application roller 44 shown in FIG. At a position upstream of the facing portion between the application roller 44 and the supply roller 48, which is a position where the fixing liquid is applied to the application roller 44 by the supply roller 56, specifically the supply roller 48. The fixing liquid is removed from the application roller 44 at the contact position.

  The blade 49a is an elastic blade that is long in the direction perpendicular to the paper surface in FIG. 7 and in the left-right direction of the paper surface in FIG. 8 and has this direction as the longitudinal direction, and is composed of urethane, nitrile, silicon, polyurethane foam, porous rubber, etc. A material selected from rubber and natural rubber is used as the material. The blade 49a is in contact with the application roller 44 at the tip edge portion, and the fixing liquid on the application roller 44 is removed by setting the linear pressure in the longitudinal direction to 0.2 N / cm.

  The width L3 of the transfer sheet S shown in FIG. 8 indicates the maximum width of the transfer sheet S on which the image forming apparatus 100 can form an image in the longitudinal direction of the application roller 44, the opposing roller 45, the supply roller 48, and the blade 49a. . As shown in the figure, the width L2 in the longitudinal direction of the blade 49a is larger than the width L3 and smaller than the width L1 in the longitudinal direction of the coating roller 44 and the opposing roller 45, and in the longitudinal direction, The arrangement region of the blade 49a includes the passage region of the transfer sheet S having the width of L3, and is also included in the arrangement region of the application roller 44 and the counter roller 45. Although not clear from the figure, the width of the supply roller 48 in the longitudinal direction is also L1, and the position of the supply roller 48 in the longitudinal direction coincides with the position of the application roller 44 and the opposing roller 45 in the longitudinal direction. Further, FIG. 8 shows a case where the transfer sheet S is passed through the nip portion between the application roller 44 and the counter roller 45 with respect to the center in the longitudinal direction.

  As a result, the fixing liquid removing unit 49 applies the fixing liquid at the above-described contact position in the area including the maximum width L3 of the transfer sheet S on which the image forming apparatus 100 can form an image. The fixing liquid is removed from the roller 44.

  Therefore, no matter what size of the transfer sheet S is passed through the nip portion between the coating roller 44 and the counter roller 45, the fixing liquid is supplied to the peripheral surface of the coating roller 44 that has passed through the nip portion by the supply means 56. The fixing solution is removed from the peripheral surface by the fixing solution removing means 49 in a region corresponding to the region where the blade 49a is disposed. For this reason, the portion of the peripheral surface corresponding to the arrangement region has a uniform amount of fixing solution, and the amount of fixing solution is reset, so that even if the fixing solution is supplied by the supply unit 56 thereafter, The portion corresponding to the arrangement region is in a state where the fixing solution is uniformly carried.

  That is, when the fixing roller 44 is applied to the transfer paper S, the amount of the fixing liquid carried differs between the passing portion and the non-passing portion of the transfer paper S in the longitudinal direction. Unevenness occurs. At this time, if the fixing liquid is supplied by the supply means 56 in a state where such unevenness is generated, even if the fixing liquid is supplied, the unevenness is not completely eliminated, and the amount of the fixing liquid carried is More non-passing parts than passing parts. Therefore, when the width of the transfer sheet S to be passed next is larger than the width of the transfer sheet S passed through the previous time, the fixing liquid is supplied also in the previous non-passing portion. In this case, the amount of the fixing solution applied in the toner is larger than the amount of the fixing solution applied in the passage portion. Uneven application of the fixing solution can cause unevenness in fixing properties. That is, when the coating amount on the transfer paper S is increased, wrinkles or the like are generated on the transfer paper S in the increased area, affecting the transferability and fixing properties of the toner onto the transfer paper S, and causing image deterioration and the like. obtain. However, when the blade 49a is provided and reset by the blade 49a as described above, the portion corresponding to the arrangement region is in a state where a fixed amount of the fixing liquid is uniformly carried.

  Therefore, even when the width of the transfer sheet S to be passed next is larger than the width of the transfer sheet S that has been passed through the previous time, there is no uneven application of the fixing liquid in the width direction of the transfer sheet S, and It is possible to prevent unevenness of fixing property due to coating unevenness.

  Here, when 100 sheets of A4 size plain paper (RICOPY PPC paper TYPE 6200 manufactured by Ricoh Co., Ltd.) are continuously passed in the vertical direction, the same A4 size plain paper is passed in the horizontal direction. Comparison of the amount of fixing solution applied (A4 size per sheet) on the area corresponding to the non-sheet passing portion in the area corresponding to the sheet passing portion in the A4 size lateral direction by the presence or absence of the blade 49a As a result, the result is shown in FIG. When the blade 49a is provided, the amount of the fixing solution applied is 170 mg from the initial stage. However, when the blade 49a is not provided, the amount applied is 255 mg, and the amount applied is increased. As described above, the fixing liquid is supplied one after another by the supply roller 48 in the non-sheet passing portion in the A4 vertical direction, and the fixing liquid on the application roller 44 increases. When the sheet is passed in the A4 horizontal direction after the sheet is passed, the increased fixing liquid on the above-described region is applied to the transfer paper S, and the coating amount is increased.

  In the above description, the sheet passing is performed based on the center, but even when the sheet passing is performed based on the end portion, the arrangement region of the blade 49a is the transfer sheet S having the maximum width in the longitudinal direction. The same advantages can be obtained as long as the configuration includes the passage region and the coating roller 44 and the counter roller 45.

The fixing liquid removing unit 49 also serves as a foreign substance removing unit that removes foreign substances different from the fixing liquid from the application roller 44. This point will be described below.
Since the application roller 44 applies the fixing liquid while being in contact with the transfer paper S, the paper dust of the transfer paper S adheres to the surface of the application roller 44 after application. Further, when toner scattering occurs in the image forming apparatus 100, the scattered toner may adhere to the application roller 44. In this way, the application roller 44 becomes soiled over time due to the adhesion of foreign matters different from the fixing liquid, such as paper dust and scattered toner. Therefore, the fixing liquid removing unit 49 is also caused to function as a foreign substance removing unit that removes such foreign substances different from the fixing liquid from the application roller 44.

  Specifically, the blade 49a, which is a fixing solution removing blade as a fixing solution removing member, is used as a foreign matter removing member that not only removes the fixing solution but also removes the paper dust and scattered toner on the coating roller 44 described above. To function as a foreign matter removal blade.

  FIG. 10 shows the application amount of the fixing liquid applied on the transfer paper S when the number of sheets to be passed is increased with and without the blade 49a functioning as a foreign matter removing member (A4 size equivalent to one sheet). ). In the case where the blade 49a is provided, the amount of the fixing solution applied remains substantially flat around 170 mg even when the number of sheets to be passed is increased. On the other hand, when the blade 49a is not provided, the amount of the fixer applied decreases according to the number of sheets to be passed. When the application amount of the fixing solution is about 50 mg, the coating unevenness becomes large and the fixing property of the image is deteriorated. If the coating unevenness occurs and the fixing property is deteriorated, the smear ID described with reference to FIG. 4 exceeds 0.4 and fixing failure may occur. This is because paper dust or the like adheres and accumulates on the application roller 44 when the number of sheets to be passed increases, and the amount of fixing liquid supplied from the supply roller 48 when foreign matter such as paper powder on the application roller 44 increases. As a result, the amount of the fixing liquid applied to the transfer paper S decreases.

  In this regard, if the blade 49a is provided as a foreign matter removing blade as a foreign matter removing member, cleaning is performed to remove foreign matters such as paper dust on the coating roller 44, and the amount of fixing liquid applied to the transfer paper S is kept constant. It becomes possible. In addition, by causing the blade 49a, which is a fixing solution removing blade as a fixing solution removing member, to function as a foreign matter removing blade as a foreign matter removing member, the foreign matter applied together with the fixing solution without adding another configuration to the blade 49a. Thus, the application roller 44 can be cleaned while avoiding an increase in size and cost.

  In the image forming apparatus 100 having the above-described configuration, when A4-size plain paper (RICOPY PPC paper TYPE 6200 manufactured by Ricoh) is used as the transfer paper S, the fixing solution per sheet is as shown in FIGS. A constant amount, specifically 170 mg, is applied uniformly and stably over the entire transfer paper S over time. In consideration of heating by the fixing nip 62, this amount does not require drying.

  When the paper conveyance path 81 is formed by a guide member such as a guide plate that guides the conveyance of the transfer paper S, the paper conveyance path 81 is downstream of the fixing liquid coating device 41 in the conveyance direction of the transfer paper S, particularly by fixing. A guide member is provided only on the back side of the transfer sheet S in the upstream side of the fixing device 6 where the fixer dries, and the application surface of the transfer sheet S on which the fixer is applied, in other words, carries toner. A guide member is not provided on the image surface side so that the guide member does not come into contact with the fixing liquid or the toner image to disturb the application state of the fixing liquid or the toner image.

  Here, the control means 91 applies, to the transfer paper S before carrying the toner image, a fixer containing a plasticizer for swelling and softening the toner into a state suitable for fixing to the transfer paper S in the memory. The toner image on the transfer belt 11 is transferred to the fixing liquid coating apparatus 41 to be applied and the transfer paper S coated with the fixing liquid by the fixing liquid coating apparatus 41 while being in contact with the fixing liquid on the transfer paper S 2. The toner constituting the toner image on the transfer paper S transferred by the secondary transfer means 5 and the secondary transfer means 5 and the fixing liquid are heated to apply the toner to fix the toner image on the transfer paper S. Using the fixing device 6, the fixing liquid coating device 41 is coated using a coating roller 44 for coating the surface of the transfer sheet S on which the toner image is transferred by the transfer unit 5, and coating the fixing liquid carried on the surface. A constant for removing the fixing liquid from the roller 44. Fixing method using a liquid removal means 49, fixing program for executing an image forming method, and stores the image forming program. In this respect, the control unit 91 or the memory functions as a fixing program storage unit and an image forming program storage unit. Such a fixing program and an image forming program are not limited to a memory provided in the control unit 91, but also a semiconductor medium (for example, ROM, non-volatile memory), an optical medium (for example, DVD, MO, MD, CD-R). , A magnetic medium (for example, a hard disk, a magnetic tape, a flexible disk, etc.) can be stored in other storage media, and when such a memory and other storage media store such a fixing program and an image forming program, the fixing program And a computer-readable recording medium storing an image forming program.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

For example, the shape of the applying member that is a rotating body is not limited to a roller shape, and may be a belt shape or the like. The shape of the fixing solution removing member is not limited to the blade shape as long as the fixing solution can be removed from the coating member.
The supporting means that supports the fixing liquid removing member may include a contacting / separating means using, for example, a solenoid or the like that contacts and separates the fixing liquid removing member from the coating member. The removing member may be separated from the applying member. Such control can be performed, for example, by a control unit such as a control unit that functions as a fixing liquid application control unit.
The supply means for supplying the fixing liquid to the application member is not limited to the configuration having the liquid chamber.
The fixing solution removing unit and the foreign matter removing unit may be independent of the fixing solution applying unit.

  Even if the image forming apparatus to which the present invention is applied is a tandem type, it is possible to adopt a direct transfer system as shown in FIG. 11 instead of the indirect transfer system described above. In this image forming apparatus, the above-described image forming apparatus 100, that is, a quadruple tandem intermediate transfer system, and a photoconductor that is a photoconductor as a toner image carrier that carries a toner image to be transferred onto the transfer paper S. The image forming apparatus 100 has the same configuration as that provided in the image forming apparatus including the transfer belt 11 that is an intermediate transfer body to which the toner images carried on the drums 20Y, 20M, 20C, and 20BK are transferred. The same reference numerals as those used for the components provided are assigned, and illustrations are omitted as appropriate, and descriptions thereof are also omitted as appropriate.

  In an image forming apparatus employing this direct transfer method, specifically, a quadruple tandem direct transfer method, the toner image carrier carrying the toner image transferred to the transfer paper S is the photosensitive drums 20Y, 20M, 20C, and 20BK. In this process, a sheet conveying belt 11 ′ as a recording medium conveying member is provided instead of the transfer belt 11 described above, and the fixing solution is applied by the fixing solution applying device 41 in the process of being conveyed by the sheet conveying belt 11 ′. The toner images of the respective colors formed at the image stations 60BK, 60C, 60M, and 60Y are sequentially transferred onto the transfer sheet S by the primary transfer rollers 12Y, 12M, 12C, and 12BK as transfer means, and then transferred by the fixing device 6. Fix it.

  The fixer application device 41 shown in the figure has substantially the same configuration as the fixer application device 41 shown in FIGS. 7 and 8, and the application roller 44 and the opposing roller 45 are arranged in the vertical direction. They are arranged in parallel and differ in that the blade 49a is in contact with the coating roller 44 from below. However, the contact position of the blade 49a with the application roller 44 in the rotation direction of the application roller 44 is the same as in the above example. The supply roller 48 has its center at a position 10 mm lower than the center of the application roller 44. The supply roller 48 is immersed in a fixing solution stored in the liquid chamber 47 at a depth of 5 mm. Since the center of the application roller 44 and the center of the supply roller 48 are offset, when the transfer sheet S enters the nip between the application roller 44 and the opposing roller 45, the gap between the application roller 44 and the supply roller 45 is reduced. The effect on the applied pressure is reduced.

  In addition, the image forming apparatus to which the present invention is applied adopts a quadruple tandem intermediate transfer system and includes a transfer belt 11 as an intermediate transfer body. Instead of the photoconductors such as 20M, 20C, and 20BK, a configuration in which the toner carried on the toner carrying member is transferred and the toner image is directly formed on the surface thereof may be employed.

  An example of such an image forming apparatus is shown in FIG. In this image forming apparatus, components similar to those already provided in the image forming apparatus 100 described above are denoted by the same reference numerals as those provided in the image forming apparatus 100, and appropriately illustrated. Is omitted, and the description is omitted as appropriate.

  This image forming apparatus adopts a method called toner jet, direct toning, toner projection, etc., which records an image directly on the transfer belt 11 by causing the toner to fly and land on the transfer belt 11. The image forming units 60Y, 60M, 60C, and 60BK include toner carriers 93Y, 93M, 93C, and 93BK that carry yellow, magenta, cyan, and black toners. Toner is ejected to toner transfer means 94Y, 94M, 94C, 94BK and toner injection means control means 94Y, 94M, 94C, 94BK to cause the toner carried on the transfer belt 11 to fly, and an image is formed on the transfer belt 11. Toner forming means control means 94Y, 94M to be formed 94C, and has the toner control means 95Y having a toner passage hole (not shown) passing toner flying from 94BK, 95M, 95C, and 95BK.

  The image forming apparatus to which the present invention is applied is not a so-called tandem type image forming apparatus, and forms a toner image of each color sequentially on one photosensitive drum, and sequentially superimposes the color toner images to obtain a color image. The present invention can be similarly applied to a so-called one-drum type image forming apparatus.

  In addition, in recent years, in accordance with demands from the market, color image forming apparatuses, such as color copiers and color printers, have increased in number, but image forming apparatuses can only form monocolor images. It may be.

The developer may be a two-component developer or a one-component developer.
The fixing unit provided in the image forming apparatus to which the present invention is applied is not a fixing unit adopting the roller fixing method provided in the above-described embodiment, but a belt fixing method provided with an endless belt-like fixing belt as a fixing member. The fixing means employed may be used. The fixing means adopting the roller fixing method has an advantage that uniform heating can be realized with a relatively simple configuration, and the fixing means adopting the belt fixing method has an advantage that power consumption is relatively small. is there.

  The image forming apparatus may not be a copier, a printer, and a facsimile machine, but may be a single unit thereof, or may be a multi-function machine of another combination such as a copier and printer. .

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

5 Transfer means 6 Fixing means 11 Intermediate transfer body 12Y, 12M, 12C, 12BK as toner image carrier Transfer means 20Y, 20M, 20C, 20BK Photoconductor as toner image carrier 41 Fixing liquid application means 44 Application member 49 Fixing Liquid removal means, foreign matter removal means 49a Fixing liquid removal member, foreign matter removal member 56 Supply means 65 Roller-like fixing member 93Y, 93M, 93C, 93BK Toner carrier 100 Image forming apparatus L3 Maximum width of recording medium S Recording medium

Japanese Patent No. 4224076 Japanese Patent No. 4354164 JP 2007-121652 A JP 2009-39977 A

Claims (11)

Fixing liquid application means for applying a fixing liquid containing a plasticizer for swelling and softening the toner constituting the toner image to a state suitable for fixing to the recording medium on the recording medium before carrying the toner image;
Transfer means for transferring the toner image on the toner image carrier to the recording medium coated with the fixing liquid by the fixing liquid application means while being in contact with the fixing liquid on the recording medium;
Fixing means for heating the toner constituting the toner image on the recording medium transferred by the transfer means and the fixing liquid to fix the toner image on the recording medium by setting the toner in the state;
The fixing solution application unit has an application member that applies the fixing solution carried on the surface of the recording medium on the surface of the recording medium on which the toner image is transferred by the transfer unit;
An image forming apparatus having a fixing solution removing means for removing the fixing solution from the coating member. The image forming apparatus according to claim 1.
The application member is a rotating body that applies the fixer to a recording medium by rotating in a predetermined direction.
The fixing liquid removing means is a position downstream of the position where the application member applies the fixing liquid to the recording medium in the predetermined direction, and the supply means supplies the fixing liquid to the application member. An image forming apparatus, wherein the fixing liquid is removed from the coating member at a position upstream of a position where the fixing liquid is supplied to the coating member. The image forming apparatus according to claim 1 or 2,
The image forming apparatus, wherein the fixing solution removing unit removes the fixing solution from the coating member in a region including a maximum width of a recording medium to which the fixing solution is applied by the coating member. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus according to claim 1, wherein the fixing liquid removing unit has a fixing liquid removing member whose end is in contact with the coating member and scrapes the fixing liquid from the coating member. The image forming apparatus according to any one of claims 1 to 4,
A foreign matter removing means for removing foreign matter different from the fixing liquid from the coating member;
The image forming apparatus according to claim 1, wherein the fixing solution removing unit also serves as the foreign matter removing unit, and removes the foreign matter together with the fixing solution from the coating member. The image forming apparatus according to any one of claims 1 to 5,
2. The image forming apparatus according to claim 1, wherein the plasticizer does not exhibit a function of bringing the toner into the state at an environmental temperature at which the image forming apparatus is used, but is expressed at a temperature higher than the environmental temperature. The image forming apparatus according to any one of claims 1 to 6,
The image forming apparatus, wherein the plasticizer is solid in a single state before being used as the fixing liquid at an environmental temperature in which the image forming apparatus is used. The image forming apparatus according to any one of claims 1 to 7,
An image forming apparatus, wherein a toner image carrier carrying a toner image transferred to a recording medium by the transfer means is a photoconductor. The image forming apparatus according to any one of claims 1 to 8,
An image forming apparatus, wherein the toner image carrier carrying a toner image transferred to a recording medium by the transfer means is an intermediate transfer member to which a toner image carried on a photosensitive member is transferred. The image forming apparatus according to any one of claims 1 to 7,
An image forming apparatus characterized in that a toner image carrier carrying a toner image transferred to a recording medium by the transfer means is an intermediate transfer body on which the toner carried on the toner carrier is transferred to form a toner image. . The image forming apparatus according to any one of claims 1 to 10,
The image forming apparatus, wherein the fixing unit includes a roller-shaped fixing member and performs fixing by a roller fixing method.

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