JP2010256839A - Transfer-fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer-fixing device and an image forming apparatus that are low in energy consumption, do not generate a defective fixing image and a gloss-irregular image, and have high fixability. <P>SOLUTION: This transfer-fixing device 66 for transferring and fixing a toner image T on a transfer-fixing side of a recording medium P includes a transfer-fixing member 27 carrying the toner image T, a pressing member 68 that presses against the transfer-fixing member 27 to form a nip, a heat transmission plate 68b that is heated by a heater 68a and heats the transfer-fixing side of the recording medium P while guiding the recording medium P conveyed toward the nip, and a biasing member 91 for biasing the recording medium P guided by the heat transmission plate 68b against the heat transmission plate 68b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a transfer fixing device for transferring and fixing a toner image on a recording medium, and an image forming apparatus using an electrophotographic system such as a copying machine, a printer, a facsimile, or a composite machine including the same. , About.

2. Description of the Related Art Conventionally, in image forming apparatuses such as copiers and printers, a technique using a transfer fixing device that simultaneously performs a transfer process and a fixing process is known (see, for example, Patent Document 1 and Patent Document 2).
An image forming apparatus provided with such a transfer fixing device is less likely to cause a decrease in image quality even when a recording medium having a rough surface is used, compared to an image forming apparatus that performs a transfer process and a fixing process separately. There are advantages.

Specifically, in an image forming apparatus that performs a transfer process and a fixing process separately, when a recording medium with a rough surface is used, an intermediate transfer body such as an intermediate transfer belt cannot follow the surface characteristics of the recording medium. A small gap is formed between the recording medium and the recording medium. For this reason, abnormal discharge occurs in the portion where the minute gap is formed, and the image carried on the intermediate transfer member is not normally transferred onto the recording medium, and the image becomes rough as a whole.
On the other hand, in an image forming apparatus provided with a transfer and fixing device, heat is applied to a toner image simultaneously with transfer, so that the toner is softened and melted to form a block-like lump having viscoelasticity. Therefore, even if a minute gap is formed between the fixing member and the recording medium using a recording medium having a rough surface, the image is transferred as a lump to that portion. Therefore, the image is good and has a high image quality without being distorted.

  Further, the image forming apparatus provided with the transfer fixing device is not fixed on the recording medium conveyed to the nip portion (the contact position between the transfer fixing member and the pressure member) where the transfer / fixing process is performed. Since the toner image is not carried, restrictions on the transport path of the recording medium are reduced as compared with an image forming apparatus that performs the transfer process and the fixing process separately. That is, an image forming apparatus that performs a transfer process and a fixing process separately is not fixed on a recording medium conveyed to a nip portion (a contact position between a fixing member and a pressure member) in which the fixing process is performed. Since the toner image is carried, restrictions are imposed on the conveyance path from the transfer unit to the fixing unit so as not to contact the unfixed toner image. Therefore, the image forming apparatus provided with the transfer fixing device has a high degree of design freedom with respect to the recording medium conveyance path, and can improve the conveyance of the recording medium.

The above-described conventional transfer fixing apparatus heats and melts the toner image by heating the transfer fixing member carrying the toner image, so that the transfer fixing member becomes thicker for a longer life or a large tandem. When the circumference of the transfer and fixing member becomes long because it is installed in the image forming apparatus of the mold, the thermal efficiency of the transfer and fixing member is lowered. For this reason, the energy consumption in the transfer fixing apparatus has been increased.
Further, in the conventional transfer fixing device, in addition to the above-described heating process of the transfer fixing member, a cooling process for cooling the transfer fixing member after the transfer / fixing process is performed in order to reduce thermal damage of the image forming unit. There were many cases. Since such a heating / cooling cycle is repeated, energy consumption in the transfer and fixing device is large.

  The inventor of the present application has conducted research to solve such problems, and as a result, the heating of the transfer fixing member is minimized, and the amount of heat necessary for heating and melting the toner is immediately before being conveyed to the nip portion. In addition, they learned how to supplement the recording medium by heating it efficiently. In order to realize such a measure, a heat transfer member that contacts the transfer fixing surface of the recording medium and transmits heat is provided upstream of the nip portion in the conveyance direction of the recording medium and in the vicinity of the nip portion. It is conceivable to provide it. However, in that case, if the distance between the heat transfer member and the nip portion is not close to some extent, the heat of the surface of the recording medium (transfer fixing surface) heated by the heat transfer member is diffused inside the recording medium, It has also been found that there is a problem that the toner image has insufficient fixability. Such a problem becomes particularly noticeable when cardboard is used as the recording medium. Further, if the adhesion force and the adhesion time between the heat transfer member and the recording medium are not secured to some extent, temperature unevenness occurs on the surface of the recording medium that is heated immediately before being conveyed to the nip portion. In such a case, poor fixing or uneven gloss will occur in the output image after the transfer / fixing process.

  The present invention has been made to solve the above-described problems, and provides a transfer fixing device and an image forming apparatus that have low energy consumption and good fixability without causing defective fixing images and uneven gloss images. There is to do.

  A transfer fixing device according to a first aspect of the present invention is a transfer fixing device for transferring and fixing a toner image onto a transfer fixing surface of a recording medium, the transfer fixing member carrying the toner image, and the transfer fixing device. A pressure member that forms a nip portion where the recording medium is conveyed in pressure contact with the fixing member, and is heated by the heating body and guides the recording medium conveyed toward the nip portion, while the recording medium A heat transfer plate that heats the transfer fixing surface; and a biasing member that biases the recording medium guided by the heat transfer plate toward the heat transfer plate.

  According to a second aspect of the present invention, in the transfer fixing device according to the first aspect, the urging member is a brush-like member that contacts a recording medium guided by the heat transfer plate. It is.

  According to a third aspect of the present invention, there is provided the transfer fixing device according to the second aspect, wherein the brush-like member includes a plate-like member that prevents the bristles from being caught in the nip portion. It is provided on the pressure member side.

  According to a fourth aspect of the present invention, there is provided the transfer fixing device according to the second or third aspect, wherein the brush-like member has hollow bristles and is guided to the heat transfer plate. The recording medium is configured to blow air through the bristles.

  According to a fifth aspect of the present invention, there is provided the transfer fixing device according to any one of the second to fourth aspects, wherein the brush-like member is moved in a conveying direction of the recording medium at a contact position with the recording medium. One or a plurality of brush-like rollers rotating in the same direction.

  According to a sixth aspect of the present invention, there is provided the transfer fixing device according to the fifth aspect, wherein the brush roller has a linear velocity equal to a conveyance speed of the recording medium at a contact position with the recording medium. It is rotationally driven as described above.

  According to a seventh aspect of the present invention, there is provided the transfer fixing device according to the fifth or sixth aspect, wherein the brush-shaped roller is disposed upstream of the brush-shaped roller with respect to a recording medium conveyance direction. And a guide member for guiding the recording medium.

  According to an eighth aspect of the present invention, in the transfer fixing device according to the fifth aspect of the present invention, the brush roller is slidably contacted with the brush bristles of the brush roller. A cleaning member is provided.

  A transfer fixing device according to a ninth aspect of the present invention is the transfer fixing device according to any one of the fifth to eighth aspects, wherein the brush roller is disposed so as to be in sliding contact with the pressure member. It is a thing.

  A transfer fixing device according to a tenth aspect of the present invention is the transfer fixing device according to any one of the fifth to ninth aspects, wherein the brush roller is a cylindrical member having flexibility on an outer peripheral surface thereof. Is covered.

  The transfer fixing device according to an eleventh aspect of the present invention is the transfer fixing apparatus according to the tenth aspect, wherein the cylindrical member is formed of a low friction material.

  A transfer fixing apparatus according to a twelfth aspect of the present invention is the transfer fixing apparatus according to the tenth or eleventh aspect of the present invention, further comprising heating means for heating the cylindrical member.

  A transfer fixing device according to a thirteenth aspect of the present invention is the transfer fixing apparatus according to the first aspect of the present invention, wherein the urging member is moved from the heat transfer plate side to the recording medium guided by the heat transfer plate. In addition, a suction mechanism for sucking together is used.

  A transfer fixing device according to a fourteenth aspect of the present invention is the transfer fixing apparatus according to any one of the first to thirteenth aspects, wherein the urging member conveys a recording medium guided by the heat transfer plate. It is controlled so that only the direction front end portion and the conveyance direction rear end portion are urged toward the heat transfer plate.

  A transfer fixing device according to a fifteenth aspect of the present invention is the transfer fixing device according to any one of the first to fourteenth aspects, wherein the biasing member is a thickness of a recording medium guided by the heat transfer plate. The condition for urging the recording medium toward the heat transfer plate is variably controlled according to the size or type.

  According to a sixteenth aspect of the present invention, in the transfer fixing device according to any one of the first to fifteenth aspects, the heat transfer plate is formed in a convex shape on the guided recording medium side. And a recording medium conveyance speed at a position before reaching the guide surface is lower than a recording medium conveyance speed at a position after reaching the guide surface. It is a thing.

  The transfer fixing device according to a seventeenth aspect of the present invention is the transfer fixing device according to any one of the first to sixteenth aspects, wherein the heat transfer plate is formed in a concave shape on the side of the guided recording medium. And a recording medium conveyance speed at a position before reaching the guide surface is greater than a recording medium conveyance speed at a position after reaching the guide surface. Is.

  A transfer fixing device according to an eighteenth aspect of the present invention is the transfer fixing apparatus according to any one of the first to seventeenth aspects, wherein the heat transfer plate is moved in a conveyance direction of the recording medium at a contact position with the recording medium. And a metal layer covered on the outer peripheral surface of the elastic roller rotating in the same direction.

  An image forming apparatus according to a fifteenth aspect of the present invention includes the transfer fixing apparatus according to any one of the first to fourteenth aspects.

  The present invention provides a heat transfer plate for heating the transfer fixing surface of a recording medium while guiding the recording medium conveyed to the nip portion between the transfer fixing member and the pressure member, and the recording medium guided by the heat transfer plate A transfer fixing device and an image forming apparatus that have low energy consumption and good fixability without causing defective fixing images and uneven gloss images are provided. Can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. It is an enlarged view showing a part of the transfer fixing device. It is the figure which looked at the heating apparatus installed in a transfer fixing apparatus in the width direction. It is the figure which looked at a part of another heating apparatus in the width direction. It is an enlarged view showing a part of another transfer fixing device. It is an enlarged view which shows a part of another heating apparatus. It is an enlarged view which shows a part of transfer fixing apparatus in Embodiment 2 of this invention. It is an enlarged view which shows a part of transfer fixing apparatus in Embodiment 3 of this invention. It is a block diagram which shows a part of image forming apparatus in Embodiment 4 of this invention. It is an enlarged view which shows a part of transfer fixing apparatus in Embodiment 5 of this invention. It is a block diagram which shows a part of image forming apparatus in Embodiment 6 of this invention. It is a block diagram which shows a part of transfer fixing apparatus in Embodiment 7 of this invention. It is a figure which shows the pressurization mechanism of a brush-shaped roller. It is a block diagram which shows a part of transfer fixing apparatus in Embodiment 8 of this invention. It is a block diagram which shows a part of transfer fixing apparatus in Embodiment 9 of this invention. It is a block diagram which shows a part of transfer fixing apparatus in Embodiment 10 of this invention. It is sectional drawing which looked at the brush-like roller in the width direction. It is a block diagram which shows a part of transfer fixing apparatus in Embodiment 11 of this invention. It is a block diagram which shows a part of transfer fixing apparatus in Embodiment 12 of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

Embodiment 1 FIG.
A first embodiment of the present invention will be described in detail with reference to FIGS.
First, the configuration and operation of the entire image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is an apparatus main body of a color copying machine as an image forming apparatus, 2 is a writing section (exposure section) that emits laser light based on input image information, and 20Y, 20M, 20C, and 20BK are colors (yellow, magenta). , Cyan, black), 21 is a photosensitive drum (image carrier) accommodated in each of the process cartridges 20Y, 20M, 20C, and 20BK, 22 is a charging unit that charges the photosensitive drum 21, 23Y, 23M, 23C, and 23BK are developing devices that develop the electrostatic latent image formed on the photosensitive drum 21, and 24 is a transfer bias that transfers the toner image formed on the photosensitive drum 21 to the transfer fixing belt 27. A roller 25 indicates a cleaning device that collects untransferred toner on the photosensitive drum 21.

  Reference numeral 27 denotes a transfer fixing belt as a transfer fixing member onto which a plurality of color toner images are transferred, 29 denotes a cleaning device (belt cleaning device) for cleaning the transfer fixing belt 27 after the transfer / fixing process, and 32Y, 32M. , 32C, 32BK are toner replenishing units for replenishing the developing devices 23Y, 23M, 23C, 23BK with toner of each color, 51 is a document conveying unit for conveying the document D to the document reading unit 55, and 55 is image information of the document D. A document reading section to be read, 61 is a paper feed section for storing a recording medium P such as transfer paper, 66 is a transfer fixing device for transferring and fixing a toner image on the recording medium P, and 67 is a recording medium immediately before the transfer / fixing process. A heating device for heating P, 68 is a pressure roller as a pressure member that presses against the transfer fixing belt 27 to form a nip portion, and 85 is a temperature distribution in the width direction of the transfer fixing belt 27. Rubbing roller to equalize, 91 denotes a brush-like member as an urging member for urging the heating apparatus 67 P the recording medium.

Here, the transfer fixing device 66 includes a transfer fixing belt 27 as a transfer fixing member, a heating device 67 as a heating unit, a pressure roller 68 as a pressure member, a leveling roller 85, and a brush-like member as a biasing member. 91, etc.
The process cartridges 20Y, 20M, 20C, and 20BK are obtained by integrating the photosensitive drum 21, the charging unit 22, and the cleaning device 25, respectively. Then, image formation of each color (yellow, magenta, cyan, black) is performed on the photosensitive drum 21 in each of the process cartridges 20Y, 20M, 20C, and 20BK.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
First, the document D is transported from the document table in the direction of the arrow in the drawing by the transport roller of the document transport unit 51 and placed on the contact glass 53 of the document reading unit 55. Then, the document reading unit 55 optically reads the image information of the document D placed on the contact glass 53.

  Specifically, the document reading unit 55 scans the image of the document D on the contact glass 53 while irradiating light emitted from the illumination lamp. Then, the light reflected by the document D is imaged on the color sensor via the mirror group and the lens. The color image information of the document D is read for each RGB (red, green, blue) color separation light by the color sensor, and then converted into an electrical image signal. Further, an image processing unit (not shown) performs color conversion processing, color correction processing, spatial frequency correction processing, and the like on the basis of RGB color separation image signals, so that yellow, magenta, cyan, and black are processed. Get color image information.

  Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 2. Then, laser light (exposure light) based on the image information of each color is emitted from the writing unit 2 toward the photosensitive drums 21 of the corresponding process cartridges 20Y, 20M, 20C, and 20BK.

On the other hand, the four photosensitive drums 21 rotate in the clockwise direction in FIG. First, the surface of the photosensitive drum 21 is uniformly charged at a position facing the charging unit 22 (a charging process). Thus, a charged potential is formed on the photosensitive drum 21. Thereafter, the surface of the charged photosensitive drum 21 reaches the irradiation position of each laser beam.
In the writing unit 2, laser light corresponding to the image signal is emitted from the light source corresponding to each color. The laser light is incident on the polygon mirror 3 and reflected, and then passes through the lenses 4 and 5. The laser light after passing through the lenses 4 and 5 passes through different optical paths for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  The laser beam corresponding to the yellow component is reflected by the mirrors 6 to 8 and then irradiated onto the surface of the photosensitive drum 21 of the first process cartridge 20Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 21 by the polygon mirror 3 that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 21 charged by the charging unit 22.

  Similarly, the laser beam corresponding to the magenta component is reflected by the mirrors 9 to 11 and then irradiated to the surface of the photosensitive drum 21 of the second process cartridge 20M from the left side of the paper, thereby causing an electrostatic latent image corresponding to the magenta component. An image is formed. The cyan component laser light is reflected by the mirrors 12 to 14 and then irradiated on the surface of the photosensitive drum 21 of the third process cartridge 20C from the left side of the paper, thereby forming an electrostatic latent image of the cyan component. The black component laser light is reflected by the mirror 15 and then irradiated on the surface of the photosensitive drum 21 of the fourth process cartridge 20BK from the left side of the paper, thereby forming an electrostatic latent image of black component.

Thereafter, the surface of the photosensitive drum 21 on which the electrostatic latent images of the respective colors are formed reaches positions facing the developing devices 23Y, 23M, 23C, and 23BK, respectively. Then, the respective color toners are supplied from the developing devices 23Y, 23M, 23C, and 23BK onto the photosensitive drum 21, and the latent image on the photosensitive drum 21 is developed (this is a developing step).
Thereafter, the surface of the photosensitive drum 21 after the development process reaches a position facing the transfer and fixing belt 27 stretched and supported by the plurality of roller members 28A to 28C and 85, respectively. Here, a transfer bias roller 24 is installed at each facing position so as to contact the inner peripheral surface of the transfer fixing belt 27. Then, at the position of the transfer bias roller 24, the images (toner images) of the respective colors formed on the photosensitive drum 21 are sequentially superimposed and transferred onto the transfer and fixing belt 27 (first transfer step). .

Then, the surface of the photosensitive drum 21 after the first transfer process reaches a position facing the cleaning device 25. Then, the untransferred toner remaining on the photosensitive drum 21 is collected by the cleaning device 25 (this is a cleaning process).
Thereafter, the surface of the photosensitive drum 21 passes through a static elimination unit (not shown), and a series of image forming processes on the photosensitive drum 21 is completed.

On the other hand, the surface of the transfer fixing belt 27 (transfer fixing member) on which the toner images of the respective colors on the photosensitive drum 21 are transferred and carried are run in the direction of the arrow in the drawing, and the pressure roller 68 (pressure member). ) Is reached (the nip portion). Here, unlike the conventional one, the transfer fixing device 66 in the first embodiment is not provided with a device for directly heating the transfer fixing belt 27 itself (or even if it is installed, the heating amount). There are few devices.)
The toner image carried on the transfer fixing belt 27 is transferred and fixed to the transfer fixing surface (front surface) of the recording medium P at the nip portion between the transfer fixing belt 27 and the pressure roller 68 ( Transfer / fixing process). Specifically, the transfer fixing surface of the recording medium P is heated by the heating device 67 immediately before the nip portion, and the toner image is heated and melted by the heat of the transfer fixing surface at the nip portion, and the toner is pressed by the pressure of the nip portion. The image is fixed on the transfer fixing surface. The configuration and operation of the transfer fixing device 66 will be described in more detail later with reference to FIGS.
Thereafter, the surface of the transfer fixing belt 27 reaches the position of the belt cleaning unit 29. Then, deposits such as residual toner on the transfer fixing belt 27 are collected by the belt cleaning device 29, and a series of transfer fixing processes on the transfer fixing belt 27 is completed.

Here, the recording medium P transported to the nip portion of the transfer fixing device 66 is transported from the paper feed unit 61 via the transport guide 63, the registration roller 64, the heating device 67, and the like.
Specifically, the transfer paper P fed by the paper feed roller 62 from the paper feed unit 61 that stores the recording medium P passes through the conveyance guide 63 and is guided to the registration roller 64. The recording medium P that has reached the registration roller 64 is conveyed toward the nip portion between the transfer fixing belt 27 and the pressure roller 68 in synchronization with the toner image on the transfer fixing belt 27. At this time, the recording medium P conveyed toward the nip portion is guided to the heat transfer plate 67b (see FIG. 2) of the heat transfer device 67 and is directed toward the heat transfer plate 67b by the brush-like member 91. While being energized, only the transfer fixing surface of the recording medium P is heated by the heating device 67 (heat transfer plate 67b).
Thereafter, the recording medium P on which the full-color image has been transferred and fixed passes through the paper discharge conveyance path, and is discharged as an output image outside the apparatus main body 1 by the paper discharge roller 80, and a series of image forming processes is completed. In the image forming apparatus according to the first embodiment, the conveyance speed (or process linear speed) of the recording medium P is set to about 300 mm / second.

The toner used in Embodiment 1 is preferably suitable for low-temperature fixing. Specifically, the softening point (1/2 outflow temperature) of the toner is preferably about 100 ° C.
As the toner binder resin, one having the following composition can be used.
For example, homopolymers of styrene such as polyester, polystyrene, poly p-chlorostyrene, polyvinyltoluene and the like; and styrene-p-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers. Styrene-vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate Copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, Styrene-vinyl ethyl ether Copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Examples thereof include styrenic copolymers such as polymers.
Moreover, the following resin can also be mixed and used. Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or fat Examples thereof include cyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin, and paraffin wax. Among these, those containing a polyester resin are preferred in order to obtain sufficient fixing properties. In particular, the crystalline polyester resin is sufficiently softened and melted at the time of paper contact, and can form an image with high color reproducibility as well as fixing strength. The polyester resin is obtained by condensation polymerization of alcohol and carboxylic acid, and the alcohol used is polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butane. Diols such as diol, neopentyl glycol, 1,4-butenediol, 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyexethylenated bisphenol A, polyoxypropylenated bisphenol A, etc. And a divalent alcohol simple substance obtained by substituting these with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, and other divalent alcohol simple substance.
Examples of the carboxylic acid used to obtain the polyester resin include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, Adipic acid, sebacic acid, malonic acid, divalent organic acid monomers in which these are substituted with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, acid anhydrides thereof, lower alkyl esters and linolenic acid Dimers and other divalent organic acid monomers can be mentioned.
In order to obtain a polyester resin to be used as a binder resin, it is also preferable to use not only a polymer with only the above bifunctional monomer but also a polymer containing a component with a trifunctional or higher polyfunctional monomer. It is. Examples of the polyhydric alcohol monomer having three or more valences that are such polyfunctional monomers include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sarbitane, pentaesitol, dipenta. Esitol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol , Trimethylolethane, trimethylolpropane, 1.3.5-trihydroxymethylbenzene, and others.
Examples of the trivalent or higher polyvalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2 -Methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, embol trimer acid, acid anhydrides thereof, and the like.

Further, the toner used in the first exemplary embodiment can contain a release agent for the purpose of improving the release property of the toner on the surface of the transfer fixing belt 27 in the transfer fixing step. As the release agent, all known ones can be used, and in particular, defree fatty acid type carnauba wax, montan wax, oxidized rice wax, and ester wax can be used alone or in combination. As the carnauba wax, those having fine crystallinity, an acid value of 5 or less, and a particle diameter of 1 μm or less when dispersed in a toner binder are preferable. The montan wax generally refers to a montan wax refined from minerals, and like a carnauba wax, it is microcrystalline and preferably has an acid value of 5 to 14. The oxidized rice wax is obtained by air-oxidizing rice bran wax, and the acid value is preferably 10-30. When the acid value of each wax is less than the respective range, the low temperature fixing temperature rises and the low temperature fixing becomes insufficient. On the contrary, when the acid value exceeds each range, the cold offset temperature rises and the low-temperature fixing becomes insufficient. The added amount of the wax is 1 to 15 parts by weight, preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin. If it is less than 1 part by weight, the releasing effect is thin and the desired effect is difficult to obtain. On the other hand, if the amount exceeds 15 parts by weight, problems such as significant spent on the carrier occur.
Further, as an external additive, for the purpose of improving the fluidity of the toner, silica, titanium oxide, alumina, and the like, and if necessary, fatty acid metal salts, polyvinylidene fluoride, and the like may be added.
In particular, since the transfer fixing device 66 can sufficiently heat the toner, even if a relatively large amount of an additive such as submicron large particle size silica is used, the fixing property and the fixing temperature are not affected. Therefore, an external additive prescription considering fluidity and transferability is possible.

Next, referring to FIGS. 2 and 3, the characteristic transfer fixing device 66 in the first embodiment will be described in detail.
FIG. 2 is an enlarged view showing a part of the transfer fixing device 66. FIG. 3 is a view of the heating device 67 as viewed from the X direction in FIG. 2 in the width direction.
As shown in FIG. 2, the transfer fixing device 66 includes a transfer fixing belt 27 as a transfer fixing member, a heating device 67 (heating means), a pressure roller 68 as a pressure member, and a brush-like member 91 as an urging member. , Etc.

  Here, the transfer fixing belt 27 as a transfer fixing member is an endless belt having a multilayer structure in which an elastic layer and a release layer are sequentially formed on a base layer. The base layer is formed of a polyimide resin having a layer thickness of 80 μm. The elastic layer is for following the irregularities on the surface of the recording medium P, and is formed of silicone rubber having a layer thickness of 160 μm. The release layer is for securing release properties with respect to the toner and paper powder on the belt surface, and is formed of a fluororesin having a layer thickness of 7 μm.

The pressure roller 68 has a surface layer (release layer) formed on a cylindrical cored bar made of aluminum or the like, and rotates in the clockwise direction in FIG. The pressure roller 68 is brought into pressure contact with the roller member 28A via the transfer fixing belt 27 by a pressure mechanism (not shown). In this way, a desired nip portion is formed between the pressure roller 68 and the transfer fixing belt 27.
As the surface layer of the pressure roller 68, PTFE (polytetrafluoroethylene), PFA (tetrafluoroethylene barfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer), or the like is used. be able to.

The heating device 67 is disposed in the vicinity of the entrance side of the nip portion in the transfer fixing device 66. The heating device 67 includes a heating body 67a, a heat transfer plate 67b, an electrode 67c, and the like.
The heating element 67a is sandwiched between the heat transfer plate 67b and the electrode 67c. In the first embodiment, as the heating element 67a, a resistance heating element whose resistance rapidly increases when a predetermined Curie point is reached is used. Specifically, a positive temperature coefficient thermistor made of a barium titanate semiconductor ceramic body is used as the heating body 67a. In the first embodiment, as shown in FIG. 3, ten heating elements 67a (positive characteristic thermistors) are arranged in parallel in the width direction.
The heat transfer plate 67b (heat transfer member) is a stainless steel plate having a plate thickness of 0.2 mm. The heat transfer plate 67b extends from the vicinity of the registration roller 64 to the vicinity of the nip portion, and functions as a guide plate (guide plate) that guides the recording medium P conveyed toward the nip portion. Further, the heat transfer plate 67b contacts the transfer fixing surface (front surface) of the recording medium P conveyed toward the nip portion, and heat generated by the heating body 67a is recorded on the recording medium P (transfer fixing surface). It has the function of transferring heat to Furthermore, the AC power supply 71 is connected to the heat transfer plate 67b, and functions as one of the electrodes.

An AC power supply 71 is connected to the electrode 67c and the heat transfer plate 67b that sandwich the heating body 67a, and a voltage of AC 100 volts is applied to both ends of the heating body 67a when the switch 72 is connected. Thereby, an electric current flows in the heating body 67a, and the heating body 67a generates heat. Further, the heat of the heating body 67a is transmitted from the heat transfer plate 67b to the transfer fixing surface of the recording medium P.
In the first embodiment, as the material of the heat transfer plate 67b, heat conductivity is high, heat capacity in the same volume is low, and relatively inexpensive copper is used. Therefore, heating efficiency is high and relatively inexpensive. A heating device 67 can be provided.

Here, it is preferable to use a heating body 67a having a Curie point lower than the ignition point of the recording medium P. As a result, the heating body 67a is prevented from malfunctioning due to its self-temperature control function, causing the temperature to rise above the ignition point of the recording medium P.
Specifically, in the first embodiment, the Curie point of the heating body 67a is set to 200 ° C. Thereby, when the temperature of the heating body 67a exceeds 200 ° C., the resistance between the electrode 67c and the heat transfer plate 67b rapidly increases, and the current flowing in the heating body 67a decreases. Specifically, when the temperature of the heating body 67a is 210 ° C., the current flowing in the heating body 67a decreases to ½, and when the temperature of the heating body 67a is 220 ° C., the current flowing in the heating body 67a is ¼. To drop.
The heating element 67a configured in this manner is heated to 190 to 200 ° C. after 6 seconds with 1200 watts of power, and thereafter does not increase to 210 ° C. or more by the self-temperature control function. When the heating body 67a is controlled at 210 ° C. or lower, it is controlled to a desired temperature by PID control or the like using a temperature sensor (not shown). Even if the control circuit fails, safety cannot be ensured because it cannot exceed 210 ° C. as described above. Moreover, in this Embodiment 1, since the several heating body 67a is arranged in parallel in the width direction, each self-temperature control is performed by the several heating body 67a, and the temperature nonuniformity of the width direction is 10 degreeC. It can be:

  As described above, the heating device 67 configured in this way heats only the transfer fixing surface (front surface) of the recording medium P immediately before the transfer / fixing process. In other words, the heating device 67 causes the recording medium P to nip before the temperature of the back surface of the recording medium P (the back surface with respect to the transfer fixing surface) rises (before heat is transferred from the front surface to the back surface). The transfer fixing surface is heated so as to be conveyed to the section.

The inventor of the present application made a recording when the recording medium P (thick paper 300 g paper) was brought into contact with a copper plate (thickness 1 mm) heated to 160 ° C. for 60 msec and then conveyed (running) in the air at an ambient temperature of 40 ° C. The temperature fluctuation of the transfer fixing surface of the medium P was simulated. As a result, the recording medium P heated to about 140 ° C. by the copper plate is only 110 m. For 10 msec (corresponding to a conveying distance of 3 mm when the conveying speed is 300 mm / sec.) In the air at an atmospheric temperature of 40 ° C. It was found that the temperature decreased until. Therefore, in order to increase the heating efficiency of the recording medium P before the transfer and fixing step, it is necessary to place a heat transfer member (heat transfer plate) for heating the recording medium as close to the nip as possible.
In the first embodiment, the heat transfer plate 67b is formed in a plate shape, the tip thereof is as close as possible to the nip portion, and the length in the transport direction is set as long as possible. The heating efficiency of the previous recording medium P can be improved.

  The inventor of the present application sets the heating temperature of the heat transfer plate 67b to 140 to 200 ° C. without installing the brush-like member 91, and the recording medium P (made by Ricoh Company, “ The temperature fluctuation of the transfer fixing surface of the copy paper 6200 ") was confirmed. As a result, it was found that the temperature drop on the transfer and fixing surface of the recording medium P was 15 ° C. or less at 0 to 60 msec after being sent from the heat transfer plate 67b.

Here, the heat transfer plate 67b in Embodiment 1 has a guide surface (a surface in contact with the recording medium P) for guiding the recording medium P covered with nickel plating containing fluororesin particles. Yes. Specifically, 30 vol% PTFE (polytetrafluoroethylene) is dispersed in a nickel plating film. Such a coating has a hardness in a precipitated state of about Hv300, is harder than a normal resin coating, and is excellent in slipping property, wear resistance, and releasability. Therefore, it is possible to reduce the problem of toner and paper powder adhering to the heat transfer plate 67b and to improve the durability of the heat transfer plate 67b.
The guide surface of the heat transfer plate 67b (the surface that contacts the recording medium P) can be covered with diamond-like carbon (DLC) or graphite-like carbon (GLC) having high wear resistance.

The heating device 67 in the first embodiment heats the transfer and fixing surface so that the temperature of the transfer and fixing surface of the recording medium P is higher than the surface temperature of the transfer and fixing belt 27. That is, the toner image T carried on the transfer fixing belt 27 is heated and melted by the heat received from the recording medium P at the nip portion.
In the first embodiment, the transfer fixing surface of the recording medium P is heated, and the temperature for obtaining sufficient gloss on the output image can be set independently, so the temperature of the transfer fixing belt 27 (fixing setting) Temperature) can be lowered. Further, since the recording medium P is heated immediately before the transfer / fixing process, the adhesion between the toner T and the recording medium P is not increased more than necessary without being heated excessively.
That is, according to the configuration of the first embodiment, it is possible to perform low-temperature fixing, reduce the warm-up time of the apparatus, and improve energy saving. In addition, since heat transfer to the transfer fixing belt 27 can be suppressed, durability of the transfer fixing belt 27 can be improved. Furthermore, since the heating temperature of the transfer fixing belt 27 is reduced, thermal deterioration of the transfer fixing belt 27 can be suppressed.

  Further, the transfer fixing device 66 according to the first embodiment presses (biases) the recording medium P guided to the nip portion by the heat transfer plate 67b against the heat transfer plate 67b by the brush-like member 91 (biasing member). ) Is configured as follows. With this configuration, in order to improve the adhesion force and the adhesion time of the recording medium P to the heat transfer plate 67b, the surface of the recording medium P is reliably raised to the target temperature by the heat transfer plate 67b and fixed. Defects can be suppressed.

Here, the brush-like member 91 is a recording medium P on which brush bristles 91 a made of heat-resistant polyimide fibers (diameter 0.2 mm) and planted at a density of 50 fibers / cm ² are guided to the heat transfer plate 67 ^b . Are configured to be in point contact or line contact at a plurality of locations. By reducing the contact area with the recording medium P as much as possible and pressing the recording medium P against the heat transfer plate 67b, the heat is transferred to the brush-like member 91 side, thereby preventing the heating efficiency of the recording medium P from being reduced. In addition, it is possible to suppress a problem that the transportability of the recording medium P is lowered.

  In addition, the bristle 91a of the brush-like member 91 can be a loop-like one, a tip-like one, a hollow structure, or the like in addition to the straight-haired one. In particular, when a hollow bristle 91a (outer diameter of about 0.24 mm) is used, a fan is installed on the lower surface side of the brush-like member 91, and the bristle is applied to the recording medium P guided by the heat transfer plate 67b. By blowing air through 67b (hollow part), the recording medium P can be urged to the heat transfer plate 67b even by the force of air, and the fall of the brush bristles 67b can be prevented.

  In addition, since the bristles 91a of the brush-like member 91 are formed of a magnetic material (for example, SUS304) and the magnet is installed on the heat transfer plate 67b side, the bristles 91a are attracted to the magnetic force by the magnet. Moreover, the fall of the bristle 91a can be prevented. That is, the brush bristles 91b are repeatedly brought into contact with the recording medium P to cause the hair to fall down, and the force that biases the recording medium P to the heat transfer plate 67b is weakened, thereby preventing the recording medium P from being heated poorly. Can do.

As described above, the transfer fixing device 66 according to the first embodiment minimizes the heating of the transfer fixing belt 27, and the recording medium immediately before the amount of heat necessary for heating and melting the toner is conveyed to the nip portion. It supplements by heating P efficiently. However, in this case, the transfer and fixing belt 27 receives a large amount of heat from the heated recording medium P and has a non-uniform distribution, and is the width direction of the transfer and fixing belt 27 (the direction orthogonal to the recording medium conveyance direction). ) Causes temperature unevenness, and it becomes easy to generate defective fixing images such as uneven fixing and offset.
On the other hand, in the first embodiment, as shown in FIG. 2, a leveling roller 85 is provided to equalize the temperature distribution in the width direction of the surface of the transfer fixing belt 27 after passing through the nip portion. Yes.
The leveling roller 85 is a roller member disposed on the downstream side in the running direction of the transfer fixing belt 27 with respect to the nip portion, and stretches and supports the transfer fixing belt 27 together with the three roller members 28A to 28C. The leveling roller 85 is a heat pipe, and makes the temperature distribution in the width direction of the surface of the transfer and fixing belt 27 uniform by efficiently convection of heat inside the heat pipe. Accordingly, even when the recording medium P immediately before being conveyed to the nip portion is heated by the heating device 67 with the heating of the transfer fixing belt 27 being minimized, fixing defects such as uneven fixing and offset occur. Can be suppressed.

  Note that the heating device 67 is not limited to that of the first embodiment, and may be configured as shown in FIG. 4, for example. FIG. 4 is a view of a part of the heating device 67 as viewed in the width direction. The heating device 67 shown in FIG. 4 includes a plurality of heating bodies 67a sandwiched between two divided electrodes 67c and a heat transfer plate 67b. An AC power supply 71 is connected to each of the two divided electrodes 67c, and an AC voltage is applied between the two. As a result, current flows from one electrode 67c to the other electrode 67c through the heating body 67a, the heat transfer plate 67b, and the heating body 67a (current flow in the direction of the arrow), and the heating body 67a is heated. Will be. When such a configuration is adopted, the voltage applied to the heating body 67a is reduced, and the heat capacity of the heating body 67a can be reduced. Thereby, the control responsiveness of the heating device 67 can be enhanced by effectively utilizing the PTC characteristics.

  Moreover, as shown in FIG. 5, the heating apparatus 67 can also be comprised. As shown in FIG. 5, the heat transfer plate of the heating device 67 is divided into a first heat transfer plate 67b1 and a second heat transfer plate 67b2. The first heat transfer plate 67b1 bends from the upper surface to the side surface of the heating body 67a, and further bends from a position reaching the lower surface of the heating body 67a to extend to the vicinity of the nip portion so as to become the guide surface of the recording medium P. Has been. The second heat transfer plate 67b2 extends from the lower surface of the heating body 67a to the vicinity of the registration roller 64. An insulating material 67d is installed between the first heat transfer plate 67b1 and the second heat transfer plate 67b2. An AC power supply 71 is connected to the first heat transfer plate 67b1 and the second heat transfer plate 67b2. Even when the heating device 67 configured as described above is used, the same effect as in the first embodiment can be obtained.

Further, as shown in FIG. 5, a plate-like member 91 b (regulating member) that prevents the brush bristles 91 a from being caught in the nip portion is installed at the end portion on the pressure roller 68 side. You can also. Specifically, the plate-like member 91 b is a stainless steel plate having a thickness of 0.3 mm, and is curved according to the curvature of the pressure roller 68. The gap between the plate-like member 91b and the pressure roller 68 can be set to about 1 mm.
With such a configuration, a problem that the bristles 91a of the brush-like member 91 fall down and are caught in the pressure roller 68 is prevented.

In the first embodiment, the heat transfer plate 67b is formed of copper. However, as shown in FIG. 6, the heat transfer plate 67b is formed by stacking a plurality of foils 67b11 to 67b13 made of a high thermal conductivity material. You can also. At this time, it is preferable to select a material that is easily adsorbed to the recording medium P by electrostatic force or the like for the plurality of foils 67b11 to 67b13.
With such a configuration, as shown in FIG. 6, even when the surface of the recording medium P is uneven, the heat transfer member 67 b easily follows the uneven shape, and the adhesion to the recording medium P is improved. Therefore, the heating efficiency for the recording medium P is improved, and the temperature unevenness of the recording medium P is reduced.

  As described above, according to the first embodiment, recording is performed while guiding the recording medium P conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b for heating the transfer fixing surface of the medium P is provided, and a brush-like member 91 (biasing member) for urging the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b is provided. Therefore, the energy consumption is low, and it is possible to suppress the occurrence of poor fixing images and uneven gloss images and obtain good fixing properties.

In the first embodiment, a resistance heating element (positive characteristic thermistor) is used as the heating element 67a of the heating device 67 so that the heat transfer plate 67b is heated by the heating element 67a. On the other hand, the heat transfer plate 67b may be formed of a metal material whose magnetic permeability decreases when reaching a predetermined Curie point, and the heat transfer plate 67b can be heated by electromagnetic induction. In such a case, the same effect as in the first embodiment can be obtained.
Specifically, the heating device includes a heat transfer plate made of a magnetic shunt alloy such as nickel or iron and having a thickness of about 0.3 mm, an induction coil (heating body) facing the heat transfer plate, and the like. With such a configuration, when a high frequency voltage of 20 kHz is applied to the induction coil, the heat transfer plate is heated by electromagnetic induction and heat is transferred to the transfer fixing surface of the recording medium P. In the heat transfer plate, the ratio of the nickel component in the magnetic shunt alloy is set to about 40%, and when the temperature reaches 200 ° C. (Curie point), the magnetic permeability rapidly decreases and is heated by electromagnetic induction. Disappear. Specifically, the heat transfer plate configured in this manner is heated to 190 to 200 ° C. after 3 seconds with 1200 watts of power, and then heated to 210 ° C. or more by the self-temperature control function. Absent.

  In the first embodiment, the brush-like member 91 is used as an urging member that urges the recording medium P toward the heat transfer plate 67b. However, a spring material may be used as the urging member. In that case, in order to reduce the friction with the recording medium P, it is preferable to coat the sliding surface of the spring material with a low friction material such as a fluororesin.

Embodiment 2. FIG.
A second embodiment of the present invention will be described in detail with reference to FIG.
FIG. 7 is an enlarged view showing a part of the transfer fixing device in the second embodiment, and corresponds to FIG. 2 in the first embodiment. The transfer fixing device according to the second embodiment is formed with a convex shape on the side of the recording medium P on which the heat transfer plate 67b of the heating device 67 is guided, and recording at positions before and after reaching the heat transfer plate 67b. The difference from the first embodiment is that the medium conveyance speed is different.

  Similarly to the first embodiment, the transfer fixing device 66 according to the second embodiment is also connected to a heating device 67 that heats the recording medium P immediately before the transfer / fixing process, from the vicinity of the registration roller 64 to the vicinity of the nip portion. A heat transfer plate 67b is provided which extends to the point and functions also as a guide plate. A brush-like member 91 as an urging member is installed at a position facing the heat transfer plate 67b.

Here, as shown in FIG. 7, the heat transfer plate 67b of the heating device 67 in the second embodiment is provided with a guide surface made of a curved surface formed in a convex shape on the guided recording medium P side. Yes. Specifically, the heat transfer plate 67b is curved with a curvature of about 300R.
Further, the conveyance speed of the recording medium P at a position before reaching the guide surface is configured to be lower than the conveyance speed of the recording medium P at a position after reaching the guide surface. Specifically, the linear velocity on the outer peripheral surface of the registration roller 64 is set to be reduced by about 1% from the linear velocity of the roller member 28A at the position of the nip portion.

  With such a configuration, since the recording medium P is pulled toward the nip portion and conveyed along the convex heat transfer plate 67b, the adhesion of the recording medium P to the heat transfer plate 67b is further increased. The heating efficiency for the recording medium P is improved. Specifically, when the inventor of the present application measured by thermography, the heat transfer plate 67b in the second embodiment was used, compared with the case where the heat transfer plate 67b in the first embodiment was used. It was confirmed that the surface temperature of the recording medium P heated by the hot plate 67b rose by 5 to 10 ° C.

  The heat transfer plate 67b is preferably formed in accordance with the shape of the pressure roller 68 when the pressure roller 68 is formed in a thumb shape. Specifically, when the outer diameter of the central portion in the width direction of the pressure roller 68 is 0.1 mm smaller than the outer diameter of both end portions in the axial direction, the width direction of the heat transfer plate 67b (the surface of FIG. The curvature at the center of the vertical direction can be 250R (the curvature at both ends in the width direction is 300R).

  As described above, according to the second embodiment, as in the first embodiment, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the member 91 (biasing member) is provided, energy consumption is low, and generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 3 FIG.
A third embodiment of the present invention will be described in detail with reference to FIG.
FIG. 8 is an enlarged view showing a part of the transfer fixing device in the third embodiment, and corresponds to FIG. 2 in the first embodiment. The transfer and fixing device according to the third embodiment is formed in a concave shape on the side of the recording medium P on which the heat transfer plate 67b of the heating device 67 is guided, and the recording medium at a position before and after reaching the heat transfer plate 67b. This is different from the first embodiment in that there is a difference in the conveyance speed.

  Similarly to the first embodiment, the transfer fixing device 66 according to the third embodiment is also connected to a heating device 67 that heats the recording medium P immediately before the transfer / fixing process, from the vicinity of the registration roller 64 to the vicinity of the nip portion. A heat transfer plate 67b is provided which extends to the point and functions also as a guide plate. A brush-like member 91 as an urging member is installed at a position facing the heat transfer plate 67b.

Here, as shown in FIG. 8, the heat transfer plate 67b of the heating device 67 in the third embodiment is provided with a guide surface made of a curved surface formed in a concave shape on the side of the recording medium P to be guided. . Specifically, the heat transfer plate 67b is curved with a curvature of about 300R in the opposite direction to that of the second embodiment.
Further, the conveyance speed of the recording medium P at a position before reaching the guide surface is configured to be higher than the conveyance speed of the recording medium P at a position after reaching the guide surface. Specifically, the linear velocity on the outer peripheral surface of the registration roller 64 is set to be increased by about 1% from the linear velocity of the roller member 28A at the position of the nip portion.

  With such a configuration, since the recording medium P is clogged on the nip side and conveyed along the concave heat transfer plate 67b, the adhesion of the recording medium P to the heat transfer plate 67b is further increased, and the recording medium Heating efficiency for P is improved. Specifically, when the inventor of the present application measured by thermography, the heat transfer plate 67b in the third embodiment was used, compared with the case where the heat transfer plate 67b in the first embodiment was used. It was confirmed that the surface temperature of the recording medium P heated by the hot plate 67b rose by 5 to 10 ° C.

  As described above, according to the third embodiment, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member), as in each of the above embodiments. A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the member 91 (biasing member) is provided, energy consumption is low, and generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 4 FIG.
A fourth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 9 is an enlarged view showing a part of the transfer fixing device according to the fourth embodiment, and corresponds to FIG. 7 in the second embodiment. The transfer fixing apparatus according to the fourth embodiment is different from that according to the second embodiment in that the contact operation of the brush-like member 91 with respect to the recording medium P is performed.

The transfer fixing device 66 according to the fourth embodiment also has a heating device 67 that heats the recording medium P immediately before the transfer / fixing process, from the vicinity of the registration roller 64 to the vicinity of the nip portion, as in the above embodiments. A heat transfer plate 67b is provided which extends to the point and functions also as a guide plate. A brush-like member 91 as an urging member is installed at a position facing the heat transfer plate 67b.
Furthermore, the heat transfer plate 67b is formed in a convex shape as in the second embodiment. Further, the linear velocity on the outer peripheral surface of the registration roller 64 is set to be reduced by about 1% from the linear velocity of the roller member 28A at the position of the nip portion.

Here, the brush-like member 91 (biasing member) in the fourth embodiment is a front end portion and a rear end portion (a front end portion and a rear end portion in the transport direction) of the recording medium P guided by the heat transfer plate 67b. .) Is controlled to be biased toward the heat transfer plate 67b.
Specifically, as shown in FIGS. 9A and 9B, the brush-like member 91 is configured to be movable in the vertical direction by the rotation of the cam 92. When the leading end of the recording medium P being transported (the leading end in the transport direction) reaches the position facing the brush-shaped member 91, the brush-shaped member 91 is moved upward as shown in FIG. The tip of the recording medium P is positively pressed against the heat transfer plate 67b. Thereafter, when the central portion (central portion in the transport direction) of the recording medium P reaches the position facing the brush-like member 91, the brush-like member 91 is moved downward as shown in FIG. The operation of positively pressing the central portion of the heat transfer plate against the heat transfer plate 67b is stopped. Finally, when the rear end portion (rear end portion in the transport direction) of the recording medium P reaches the position facing the brush-like member 91, the brush-like member 91 is again moved upward as shown in FIG. Thus, the rear end portion of the recording medium P is positively pressed against the heat transfer plate 67b.

  With such a configuration and control, the problem that the back surface of the recording medium P is rubbed with the bristles 91a of the brush-like member 91 and a large amount of paper dust is generated is reduced. Further, the problem that the first surface of the recording medium P during double-sided printing is rubbed with the brush bristles 91a and the image formed on the first surface is damaged is reduced. Specifically, when the present inventor has made 1000 sheets and confirmed the amount of generated paper dust, when the brush-like member 91 is contacted / separated (the configuration / operation in the fourth embodiment). )), The amount of paper dust generated was significantly reduced as compared with the case where the brush-like member 91 was not contacted / separated (the configuration / operation in the second embodiment). In addition, instead of the operation of completely separating the brush-like member 91 from the recording medium P, the operation of reducing the contact force of the brush-like member 91 with respect to the recording medium P by half is the same as that of the fourth embodiment. As with, the amount of paper dust generated was greatly reduced.

  As described above, according to the fourth embodiment, as in the above-described embodiments, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the member 91 (biasing member) is provided, energy consumption is low, and generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 5 FIG.
A fifth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 10 is an enlarged view showing a part of the transfer fixing device according to the fifth embodiment, and corresponds to FIG. 2 in the first embodiment. The transfer fixing device in the fifth embodiment is different from that in the third embodiment in which the suction members 95 and 96 are used as the urging members, and the brush-like member 91 is used as the urging member. To do.

Similarly to the embodiments described above, the transfer fixing device 66 according to the fifth embodiment is also connected to a heating device 67 that heats the recording medium P immediately before the transfer / fixing process, from the vicinity of the registration roller 64 to the vicinity of the nip portion. A heat transfer plate 67b is provided which extends to the point and functions also as a guide plate.
Further, the heat transfer plate 67b is formed in a concave shape as in the third embodiment. Further, the linear velocity on the outer peripheral surface of the registration roller 64 is set to be increased by about 1% from the linear velocity of the roller member 28A at the position of the nip portion.

In the fifth embodiment, the recording medium guided to the heat transfer plate 67b is used as the biasing member that biases the recording medium P guided to the nip portion by the heat transfer plate 67b toward the heat transfer plate 67b. Suction mechanisms 95 and 96 for sucking P together with air from the heat transfer plate 67b side are used.
Specifically, the suction mechanism (biasing member) includes a duct 96 that covers the upper portion of the heating device 67, and a suction fan 95 installed at the suction port of the duct 96. Further, a through hole having a diameter of 30 μm is formed in the heat transfer plate 67b for each range of 25 mm × 25 mm. With such a configuration, when the suction fan 95 is operated, the recording medium P is sucked (biased) toward the heat transfer plate 67b.

  In the fifth embodiment, the suction mechanism 95, 96 is used to urge the recording medium P toward the heat transfer plate 67b without contacting the recording medium P. The problem of paper dust from the back is less likely to occur. However, in the case where the adhesion between the recording medium P and the heat transfer plate 67b is ensured by energizing only the front and rear end portions of the recording medium P to the heat transfer plate 67b, as in the fourth embodiment, The suction fan 95 is configured so as to urge only the front end portion and the rear end portion (the front end portion and the rear end portion in the transport direction) of the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. On / off control can be performed.

  As described above, according to the fifth embodiment, recording is performed while guiding the recording medium P conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b for heating the transfer and fixing surface of the medium P is provided, and suction mechanisms 95 and 96 (bias) for sucking and biasing the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Member), the energy consumption is low, and it is possible to suppress the occurrence of defective fixing images and uneven gloss images and obtain good fixability.

Embodiment 6 FIG.
A sixth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 11 is a configuration diagram illustrating a part of the image forming apparatus according to the sixth embodiment. The image forming apparatus according to the sixth embodiment is different from that of the first embodiment in which four photosensitive drums 21 are installed in that one photosensitive drum 21 is installed.

  Similarly to the embodiments described above, the transfer fixing device 66 according to the sixth embodiment also has a heating device 67 that heats the recording medium P immediately before the transfer / fixing process, and from the vicinity of the registration roller 64 to the vicinity of the nip portion. A heat transfer plate 67b is provided which extends to the point and functions also as a guide plate. Further, an urging member (brush-like member 91) is installed at a position facing the heat transfer plate 67b.

As shown in FIG. 11, the image forming apparatus according to the sixth embodiment has a writing unit (not shown) corresponding to each color (yellow, magenta, cyan, black) around one photosensitive drum 21. A charging unit (not shown), developing devices 23Y, 23M, 23C, and 23BK, a cleaning device 25, and the like are disposed. Then, images (toner images) of the respective colors are formed on the photosensitive drum 21 so as to overlap each other, and the color image is transferred onto the transfer fixing belt 27 at a position facing the transfer bias roller 24.
After that, the toner image T carried on the transfer fixing belt 27 is transferred onto the recording medium P heated by the heating device 67 at the position of the nip portion with the pressure roller 68 as in the above embodiments.・ Fixed.

  As described above, according to the sixth embodiment, as in the above-described embodiments, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the member 91 (biasing member) is provided, energy consumption is low, and generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 7 FIG.
A seventh embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 12 is a configuration diagram showing a part of the transfer and fixing device according to the seventh embodiment, and corresponds to FIG. 2 in the first embodiment. The transfer fixing device in the seventh embodiment is different from that in the first embodiment in that a brush-like roller 191 is used as a brush-like member (biasing member).

Referring to FIG. 12, similarly to the first embodiment, the transfer fixing device 66 according to the seventh embodiment also includes a registration roller 64 and a heating device 67 that heats the recording medium P immediately before the transfer / fixing process. A heat transfer plate 67b that extends from the vicinity of the nip to the vicinity of the nip portion and functions also as a guide plate is provided. In addition, a brush-like member 191 as an urging member is installed at a position facing the heat transfer plate 67b.
Here, unlike the non-rotating plate-like brush-like member 91 in the first embodiment, the brush-like member in the seventh embodiment is the same as the conveyance direction of the recording medium P at the contact position with the recording medium P. This is a brush-like roller 191 that rotates in the direction (rotates clockwise in FIG. 12).

  In the transfer fixing device 66 according to the seventh embodiment, the recording medium P guided to the nip portion by the heat transfer plate 67b is pressed (biased) against the heat transfer plate 67b by the brush-like roller 191 (biasing member). It is configured. With this configuration, in order to improve the adhesion force and the adhesion time of the recording medium P to the heat transfer plate 67b, the surface of the recording medium P is reliably raised to the target temperature by the heat transfer plate 67b and fixed. Defects can be suppressed.

Referring to FIGS. 12 and 13, a brush roller 191 as an urging member has heat resistance in which a brush cloth in which polyimide fibers, aramid fibers, etc. are planted is spirally wound on a core metal. A roller-shaped member that rotates in the clockwise direction of FIG. Then, the recording medium P that has passed the position of the registration roller 64 is guided by the heat transfer plate 67b and the guide member 65, and is urged by the brush roller 191 and pressed against the heat transfer plate 67b immediately before the nip portion. However, after being heated by the heat transfer plate 67b, it is fed into the nip portion.
The brush-like roller 191 according to the seventh embodiment has an outer diameter of 30 mm, a bristle length of the bristle of 10 mm, an original thickness of the bristle of brush is 1330 T / 120 F, and the density of the bristle is 100,000- It is set to 150,000 / inch ^2. Further, the brush bristles of the brush roller 191 are not limited to those described above, and fluorine resin, heat-resistant resin or metal, or those whose surfaces are coated with a low wear material, or the like is used. You can also. By imparting heat resistance to the brush-shaped roller 191, it is possible to reduce a problem that the bristles of the brush-shaped roller 191 are thermally deteriorated by the heat of the heat transfer plate 67 b.

The brush roller 191 is preferably driven to rotate so that the linear velocity at the position of contact with the recording medium P is equal to or higher than the conveyance speed of the recording medium P. That is, it is preferable that the brush roller 191 rotate in the clockwise direction in FIG. 12 at a speed equal to or higher than the conveyance speed of the recording medium P.
With such a configuration, when the recording medium P enters the contact position between the brush-like roller 191 and the heat transfer plate 67b, it is possible to prevent a problem that the transportability is lowered due to being caught by the brush-like roller 191. In the seventh embodiment, the linear velocity at the contact position of the brush roller 191 with the recording medium P is set to be 1 to 3% faster than the conveyance speed of the recording medium P.

  Here, in the seventh embodiment, as shown in FIG. 12, the recording medium P is transported in a substantially horizontal direction from the left to the right, and a heat transfer plate 67b is disposed above the recording medium P. A brush-like roller 191 is disposed in the case. As described above, by arranging the brush-like roller 191 in the gravity direction of the recording medium P, a force due to the reaction in the direction of lifting the recording medium P acts on the brush-like roller 191, and therefore the recording medium P and the brush-like roller 191. Contact force increases, and the transportability of the recording medium P is improved. In the seventh embodiment, the conveyance direction of the recording medium P is set to a substantially horizontal direction. However, even in an image forming apparatus in which the conveyance direction of the recording medium P is set to an oblique direction, the gravity of the recording medium P By arranging the brush-like roller 191 in the direction in which the component force in the direction acts, it is possible to obtain substantially the same effect as described above.

Further, the brush-like roller 191 as an urging member makes point contact or line contact at a plurality of locations with the recording medium P guided by the heat transfer plate 67b. By suppressing the contact area with the recording medium P as much as possible and pressing the recording medium P against the heat transfer plate 67b, the heat is transferred to the brush-like roller 191 side, thereby preventing the heating efficiency of the recording medium P from being reduced. In addition, it is possible to suppress a problem that the transportability of the recording medium P is lowered.
In the seventh embodiment, the pressure width (nip width) of the brush-like roller 191 in pressure contact with the heat transfer plate 67b is set to be 3 to 12 mm (corresponding to a pressure pressure of about 3 to 5 kgf). To do.)

Here, in the seventh embodiment, the brush-like roller 191 (biasing member) transfers the recording medium P to the heat transfer plate 67b according to the thickness (or type) of the recording medium P guided by the heat transfer plate 67b. The condition for energizing the head is variably controlled.
The transfer fixing device 66 according to the seventh embodiment is provided with pressure mechanisms 192 to 194 that change the urging force against the recording medium P urged toward the heat transfer plate 67b by the brush roller 191. The apparatus main body 1 is provided with detection means for detecting the paper thickness of the recording medium P to be passed. Then, the pressurization mechanisms 192 to 194 are variably controlled based on the information about the paper thickness of the recording medium P acquired by the detection means.
Note that the paper thickness of the recording medium P to be passed can be detected by installing a paper thickness sensor in the conveyance path of the recording medium P, or input to the operation unit of the apparatus main body 1 by the user. You may judge based on the information regarding the recording medium P. FIG.

  Specifically, referring to FIG. 13, the pressurizing mechanism includes a lever 192, a cam 193, a tension spring 194, a drive motor (not shown), and the like, and a brush-like roller for the heat transfer plate 67b. The relative position of 191 is variable. The lever 192 is held on the side plate of the apparatus main body so as to be rotatable about the support shaft 192a. A brush-like roller 191 is rotatably held at one end side of the lever 192, and one hook portion of a tension spring 194 is connected to the other end side. The other hook portion of the tension spring 194 is connected to the side plate of the apparatus main body. A cam 193 connected to a drive motor (not shown) is engaged with the center of the lever 192. With this configuration, when the cam 193 is rotationally driven by a drive motor (not shown) and the posture of the cam 193 is determined, the lever 192 rotates around the support shaft 192a by the spring force of the tension spring 194. (The lever 192 rotates while being in contact with the cam 193), and the position of the brush roller 191 is varied in the vertical direction.

Specifically, FIG. 13A shows a state in which the brush roller 191 is in contact with the heat transfer plate 67b with a predetermined pressure width (nip width). In this state, by changing the posture of the cam 193 in the rotation direction by a predetermined angle, the pressing width (the urging force against the recording medium P) is increased or decreased. The pressurizing mechanisms 192 to 194 (pressurizing width variable mechanism) have a thickness (paper thickness) of the recording medium P when the thickness (paper thickness) of the recording medium P guided by the heat transfer plate 67b is thick. The biasing force (pressurization width) is controlled to be larger than when the pressure is thin.
A thicker recording medium (thick paper) has a heat transfer surface (front surface) heated by the heat transfer plate 67b than the thin recording medium (thin paper). Therefore, the degree of temperature decrease on the transfer and fixing surface until reaching the nip portion is large. On the other hand, in the case of thin paper, since the heating efficiency by the heat transfer plate 67b is higher than that of thick paper, if the temperature control of the heat transfer plate 67b is performed based on the thick paper, the thin paper will be excessively heated. It will heat up or curl due to temperature rise.
Therefore, by performing the above-described control, even when the recording medium P having a different thickness (paper thickness) is passed, the temperature of the recording medium P immediately before the transfer fixing process heated by the heat transfer plate 67b. Thus, a stable transfer-fixed image can be formed without any variation. This is based on the fact that the pressure width (biasing force) of the brush roller 191 with respect to the heat transfer plate 67b affects the amount of heat given to the recording medium P from the heat transfer plate 67b.

  In the seventh embodiment, since the pressure width of the brush roller 191 against the heat transfer plate 67b is varied according to the thickness of the recording medium P, in the transfer fixing process regardless of the thickness of the recording medium P. The temperature of the transfer and fixing surface of the recording medium P when fed into the nip portion can be optimized. Further, since the recording medium P can be heated with a minimum amount of heat necessary for obtaining a good transfer-fixed image, the energy efficiency of the entire apparatus can be improved. Furthermore, since the sheet is heated with the minimum amount of heat when passing the thin paper, it is possible to prevent a problem that the thin paper is curled after the heating.

In the seventh embodiment, the urging condition of the brush roller 191 (the urging member), which is variably controlled according to the thickness (or type) of the recording medium P, is the brush roller with respect to the heat transfer plate 67b. The pressure width was 191. On the other hand, the urging condition of the brush-like roller 191 that is variably controlled according to the thickness (or type) of the recording medium P can be set to the rotation speed of the brush-like roller.
Specifically, the drive motor of the brush roller 191 is a variable speed drive motor so that the rotation speed of the brush roller 191 can be varied. When the thickness (paper thickness) of the recording medium P guided by the heat transfer plate 67b is thick, the rotational speed of the brush roller 191 is faster than when the recording medium P is thin (paper thickness). Control to be. As a result, when passing thick paper, the thick paper is positively urged to the heat transfer plate 67b by the brush-like roller 191 having a large number of rotations, so that an effect substantially equivalent to the above-described effect can be obtained. .

Here, FIG. 13B shows a state in which the brush roller 191 is completely separated from the heat transfer plate 67b and the pressure roller 68 by the operation of the separation mechanisms 192 to 194 described above.
In the seventh embodiment, when no paper is passed (when the recording medium P does not pass between the heat transfer plate 67b and the brush roller 191), the heat transfer plate 67b, the pressure roller 68, and the guide are used. Control is performed such that the brush-shaped roller 191 is relatively separated from the member 65 (the state shown in FIG. 13B).
As a result, the brush roller 191 comes into contact with the heat transfer plate 67b only at the minimum necessary timing, so that heat is transmitted from the heat transfer plate 67b to the brush roller 191 and the brush roller 191 is thermally deteriorated. Defects are reduced. Further, since the brush roller 191 is deformed by contacting the heat transfer plate 67b, the pressure roller 68, and the guide member 65 only at the minimum necessary timing, the brush bristles of the brush roller 191 have a long time. It is possible to reduce the problem that the hair fall is not restored due to the deformation.

12 and 13A, in the transfer fixing device 66 according to the seventh embodiment, the brush roller 191 is located upstream of the brush roller 191 with respect to the conveyance direction of the recording medium P. A guide member 65 that abuts against the brush bristles and guides the recording medium P is provided. Specifically, the guide member 65 is disposed such that the downstream end W thereof is in contact with the brush bristles of the brush roller 191.
With such a configuration, the brush bristles of the brush-like roller 191 come into contact with the heat transfer plate 67b after the contact with the guide member 65 is released. That is, a state where the brush bristles of the brush-like roller 191 are not densely formed is formed by the guide member 65 on the upstream side in the conveyance direction of the contact position between the brush-like roller 191 and the heat transfer plate 67b. Therefore, the recording medium P fed to the contact position between the brush-shaped roller 191 and the heat transfer plate 67b is smoothly conveyed without receiving a large resistance due to the brush bristles of the brush-shaped roller 191.

  As described above, according to the seventh embodiment, as in each of the embodiments described above, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the roller 191 (brush-like member) is provided, energy consumption is low, generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 8 FIG.
The eighth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 14 is a configuration diagram showing a part of the transfer fixing device according to the eighth embodiment, and corresponds to FIG. 12 in the seventh embodiment. In the transfer fixing device according to the eighth embodiment, a brush roller 191 as an urging member is in contact with the pressure roller 68, and a cleaning member 200 that is in sliding contact with the brush roller 191 is provided. Is different from that of the seventh embodiment.

  Referring to FIG. 14, the transfer fixing device 66 according to the eighth embodiment is also connected to a heating device 67 that heats the recording medium P immediately before the transfer / fixing step, as with the seventh embodiment, and a registration roller 64. A heat transfer plate 67b that extends from the vicinity of the nip portion to the vicinity of the nip portion and functions also as a guide plate is provided. Further, a brush roller 191 as an urging member (brush member) is installed at a position facing the heat transfer plate 67b.

Here, unlike in the seventh embodiment, the brush-like roller 191 in the eighth embodiment is disposed so as to be in sliding contact with the pressure roller 68 (pressure member). Specifically, the brush bristles of the brush-shaped roller 191 are configured to be in sliding contact with the outer peripheral surface of the pressure roller 68.
With such a configuration, the surface of the pressure roller 68 is cleaned by the brush roller 191. Specifically, since the background contamination toner adheres to the transfer fixing belt 27, when the size in the width direction of the recording medium P passing through the nip portion between the transfer fixing belt 27 and the pressure roller 68 is small, There is a possibility that the background dirt toner on the transfer and fixing belt 27 attached outside the size area adheres to the pressure roller 68. As described above, even if the surface of the pressure roller 68 is contaminated with toner, the pressure roller 68 is cleaned by the brush roller 191 that is in sliding contact with the surface of the pressure roller 68. A problem that the back surface of the recording medium P becomes dirty is suppressed. In addition, since the brush roller 191 also serves as a cleaning unit for the pressure roller 68 in this way, the transfer fixing device 66 can be manufactured at a lower cost than when the cleaning unit for the pressure roller 68 is provided separately from the brush roller 191. Downsizing and downsizing.

In addition, the transfer fixing device 66 according to the eighth embodiment is provided with a cleaning member 200 that cleans the brush-like roller 191 in sliding contact with the brush bristles of the brush-like roller 191. Specifically, the cleaning member 200 is arranged so as to bite into the bristles of the brush roller 191 at a position downstream of the brush roller 191 in the rotation direction with respect to the sliding contact position between the brush roller 191 and the pressure roller 68. This is a flicker bar (bar-shaped member) provided.
Thus, by providing the cleaning member 200, paper dust attached to the brush-like roller 191 (paper dust released from the recording medium P at the contact position with the heat transfer plate 67b) or the pressure roller 68 is provided. The toner (which is the above-described background dirt toner) and the like removed from the brush-like roller 191 is removed from the brush-like roller 191. Then, the paper dust and toner removed from the brush roller 191 fall in the direction of gravity and are collected on the tray 201.
In the eighth embodiment, the cleaning member 200 is a flicker bar, but a plate-like blade or scraper may be used as the cleaning member.

  As described above, according to the eighth embodiment, as in the above-described embodiments, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the roller 191 (brush-like member) is provided, energy consumption is low, generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 9 FIG.
A ninth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 15 is a configuration diagram showing a part of the transfer fixing device according to the ninth embodiment, and corresponds to FIG. 12 in the seventh embodiment. The transfer fixing apparatus according to the ninth embodiment is different from that of the seventh embodiment in that two brush-like members are provided.

  Referring to FIG. 15A, similarly to the seventh embodiment, the transfer fixing device 66 in the ninth embodiment also includes a heating device 67 that heats the recording medium P immediately before the transfer / fixing step. A heat transfer plate 67b is provided which extends from the vicinity of the registration roller 64 to the vicinity of the nip portion and also functions as a guide plate. In addition, a brush-like roller as an urging member (brush-like member) is installed at a position facing the heat transfer plate 67b.

Here, different from the seventh embodiment, a plurality of brush rollers 191A and 191B (biasing members) are installed in the transfer fixing device 66 in the ninth embodiment.
Specifically, as shown in FIG. 15A, on the upstream side in the transport direction (the upstream side in the transport direction of the recording medium P guided by the heat transfer plate 67b), the first brush roller 191A having a large outer diameter. At the downstream side in the transport direction (the downstream side in the transport direction of the recording medium P guided by the heat transfer plate 67b) and the nip portion (the nip portion between the pressure roller 68 and the transfer fixing belt 27). A second brush-like roller 191B having a small outer diameter is installed at a position close to (.). The two brush-shaped rollers 191A and 191B are both in contact with the heat transfer plate 67b and rotate clockwise in FIG. 15A, and the recording medium P guided by the heat transfer plate 67b is directed toward the heat transfer plate 67b. Energize.
With such a configuration, the recording medium P is urged toward the heat transfer plate 67b by the second brush roller 191B having a small outer diameter in the vicinity of the nip portion between the pressure roller 68 and the transfer fixing belt 27. Therefore, the surface of the recording medium P is sufficiently heated up to the vicinity of the nip portion.

  In the transfer fixing device 66 shown in FIG. 15A, a second brush roller 191B having a small outer diameter is installed in the vicinity of the nip portion between the pressure roller 68 and the transfer fixing belt 27. On the other hand, as shown in FIG. 15B, a plate-like brush-like member 91 can be installed in the vicinity of the nip portion between the pressure roller 68 and the transfer fixing belt 27. Specifically, the transfer fixing device 66 shown in FIG. 15B has a brush roller 191 installed upstream in the transport direction (upstream in the transport direction of the recording medium P guided by the heat transfer plate 67b). A plate-like brush-like member 91 is provided at a position downstream of the conveyance direction (on the downstream side of the conveyance direction of the recording medium P guided by the heat transfer plate 67b) and close to the nip portion. Even in such a configuration, the recording medium P is directed toward the heat transfer plate 67b by the plate-like brush member 91 in the vicinity of the nip portion between the pressure roller 68 and the transfer fixing belt 27. Since it can be energized, the surface of the recording medium P is sufficiently heated up to the vicinity of the nip portion.

  As described above, according to the ninth embodiment, as in the above-described embodiments, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member). A heat transfer plate 67b for heating the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a plurality of recording media P guided by the heat transfer plate 67b are urged toward the heat transfer plate 67b. Since the brush-shaped rollers 191A and 191B (brush-shaped members) are provided, energy consumption is low, and generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 10 FIG.
A tenth embodiment of the present invention will be described in detail with reference to FIGS.
FIG. 16 is a configuration diagram showing a part of the transfer fixing device according to the tenth embodiment, and corresponds to FIG. 12 in the seventh embodiment. FIG. 17 is a cross-sectional view of the brush-like roller 191 viewed in the width direction.
The transfer fixing apparatus according to the tenth embodiment is different from the seventh embodiment in that a flexible cylindrical member 191c is covered on the outer peripheral surface of the brush-like roller 191.

  Referring to FIG. 16, the transfer fixing device 66 according to the tenth embodiment also has a registration roller 64 in addition to the heating device 67 that heats the recording medium P immediately before the transfer / fixing step, as in the seventh embodiment. A heat transfer plate 67b that extends from the vicinity of the nip portion to the vicinity of the nip portion and functions also as a guide plate is provided. Further, a brush roller 191 as an urging member (brush member) is installed at a position facing the heat transfer plate 67b.

  Here, the brush-like roller 191 in the tenth embodiment is different from that in the seventh embodiment, and a cylindrical member 191c having flexibility is covered on the outer peripheral surface thereof. Specifically, as shown in FIG. 17, the brush-shaped roller 191 has a cylindrical member 191c having flexibility so that the bristle 191b (brush cloth) is wound on the cored bar 191a and further covers the bristle 191b. Is provided. The cylindrical member 191c is a thin heat-resistant tubular member formed of a low friction material such as a fluorine compound, and is integrally rotated together with the core metal 191a and the brush bristles 191b in the clockwise direction in FIG. The The brush-shaped roller 191 configured as described above forms a nip by being pressed against the heat transfer plate 67b in a state where the cylindrical member 191c and the brush bristles 191b are deformed.

Here, also in the tenth embodiment, the distance from the contact position between the heat transfer plate 67b and the brush-like member 191 (cylindrical member 191c) to the nip portion between the pressure roller 68 and the transfer fixing belt 27. Is formed to be as short as possible.
Further, in order to ensure a sufficient heating time for the recording medium P at the contact position between the heat transfer plate 67b and the brush-like member 191 (cylindrical member 191c), the cylindrical member 191c and the brush bristles 191b are slightly contacted. It is configured to be sufficiently deformed by contact force (about 3 to 5 kgf).
As shown in FIG. 17, flanges 191 d for preventing the cylindrical member 191 c from falling off from the brush-like roller 191 and axial displacement are press-fitted at both ends of the brush-like roller 191.

Thus, by covering the outer peripheral surface of the brush-shaped roller 191 with the flexible cylindrical member 191c, even when the thin recording medium P such as coated paper is passed through, the transmission is performed. The recording medium P can be satisfactorily heated without impairing the smoothness of the surface of the recording medium P at the contact position between the hot plate 67b and the brush-like roller 191.
Specifically, as in the seventh embodiment, when the brush bristles of the brush roller 191 are in sliding contact with the recording medium P fed into the contact position between the heat transfer plate 67b and the brush roller 191, the coated paper When passing through the thin recording medium P as described above, irregularities may be formed on the surface of the recording medium P, and the smoothness of the recording medium P may be impaired. On the other hand, in the tenth embodiment, since the flexible cylindrical member 191c is covered on the outer peripheral surface of the brush roller 191, the brush hair 191b of the brush roller 191 is attached to the recording medium P. The cylindrical member 191c of the brush-like roller 191 does not make direct point contact or line contact, but makes surface contact with the recording medium P almost uniformly. Therefore, the recording medium P can be heated satisfactorily without impairing the smoothness of the surface of the recording medium P.

Further, as in the seventh embodiment, the brush bristles of the brush roller 191 are in direct sliding contact with the recording medium P fed to the contact position between the heat transfer plate 67b and the brush roller 191. In some cases, there is a possibility that the brush hair of the brush-like roller 191 may come off or cut off due to long-term use. If the dropped bristle adheres to the recording medium P, parts of the apparatus main body 1 or the like, an abnormal image may be generated on the output image or the apparatus main body 1 may break down.
On the other hand, in the tenth embodiment, since the cylindrical member 191c is covered on the outer peripheral surface of the brush-like roller 191, the problem that the brush hair 191b of the brush-like roller 191 falls off or is reduced. The

  Further, the brush-like roller 191 in the tenth embodiment has a gap formed by the brush bristles 191b on the inner peripheral surface side of the cylindrical member 191c, so that the bristles 191b are made of heat-resistant aramid fibers or the like. The thermal conductivity of the surface of the brush roller 191 can be made extremely small. In such a case, unnecessary heat transfer from the heat transfer plate 67b to the brush roller 191 can be reduced, so that the energy efficiency of the heating device 67 can be improved.

In the tenth embodiment, since the cylindrical member 191c that is deformable with a thin film is provided on the outer periphery of the flexible brush bristles 191b, the flexibility of the surface of the brush roller 191 is ensured. Therefore, the brush-shaped roller 191 is easily deformed even if it comes into contact with the heat transfer plate 67b with a relatively low pressure, and a good nip width (8 to 12 mm) between both the members 67b and 191. Nip) is formed. Note that heating at the nip is heating only the recording medium P that does not include heating of the toner image, so that the pressure of the brush roller 191 against the heat transfer plate 67b is about 50 to 200 g / cm ² is sufficient. . If the pressure applied by the brush roller 191 to the heat transfer plate 67b is set to be larger than the above upper limit value, curling or wrinkling may occur when the thin recording medium P is passed. There is sex.
In the tenth embodiment, since the flexibility of the surface of the brush roller 191 is ensured, the curvature of the brush roller 191 is provided downstream of the contact position between the brush roller 191 and the heat transfer plate 67b. The separation part when the recording medium P is sent out from the contact position between the brush-like roller 191 and the heat transfer plate 67b can be improved.

Here, the transfer fixing device 67 according to the tenth embodiment also does not pass through the recording medium P between the heat transfer plate 67b and the brush-shaped roller 191 when the paper is not passed through, as in the seventh embodiment. At this time, the brush-shaped roller 191 is controlled to be separated from the heat transfer plate 67b (the movement of the brush-shaped roller 191 to the position indicated by the broken line in FIG. 16).
As a result, the brush roller 191 comes into contact with the heat transfer plate 67b only at the minimum necessary timing, so that heat is transmitted from the heat transfer plate 67b to the brush roller 191 and the brush roller 191 is thermally deteriorated. Defects are reduced. Further, since the brush roller 191 contacts and deforms the heat transfer plate 67b only at the minimum necessary timing, the cylindrical member 191c and the brush hair 191b of the brush roller 191 are restored by deformation for a long time. It is possible to reduce the trouble that does not happen.

Further, the transfer fixing device 67 according to the tenth embodiment is a position above the heating device 67 (a position indicated by a broken line in FIG. 16 and away from the conveyance path of the recording medium P) by a movable mechanism (not shown). ) Can be moved automatically. If a jam of the recording medium P occurs in the conveyance path between the registration roller 64 and the nip portion (the nip portion between the pressure roller 68 and the transfer fixing belt 27), the state is indicated. It is detected by a jam detection sensor, and the brush roller 191 is controlled to move downward and to move the heating device 67 upward. Thereafter, the user performs jam processing for taking out the recording medium P jammed at the position.
This facilitates the user's jam handling operation and eliminates the problem of continuing to heat the recording medium P, which has been stopped due to jamming, by the heating device 67.

  In the tenth embodiment, since the cylindrical member 191c of the brush roller 191 is formed of a low friction material, the durability of the brush roller 191 due to sliding with the heat transfer plate 67b can be improved. it can. On the other hand, since the grip force of the recording medium P at the contact position with the heat transfer plate 67b is reduced, the transportability of the recording medium P is reduced. In the tenth embodiment, the resist roller 64 and the nip portion (the nip portion between the pressure roller 68 and the transfer fixing belt 27) are provided in order to suppress such a decrease in the transportability of the recording medium P. The length of the conveyance path between them is set to be shorter than the length in the conveyance direction of the minimum size recording medium P that can be used in the apparatus 1. That is, the transportability of the recording medium P is determined by the transport force by the registration roller 64 and the transport force by the pressure roller 68 and the transfer fixing belt 27 without being substantially affected by the surface property of the brush roller 191. Will be.

  As described above, according to the tenth embodiment, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member), as in the above embodiments. A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the roller 191 (brush-like member) is provided, energy consumption is low, generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 11 FIG.
The eleventh embodiment of the present invention will be described in detail with reference to FIG.
FIG. 18 is a configuration diagram showing a part of the transfer and fixing device in the eleventh embodiment, and corresponds to FIG. 16 in the tenth embodiment. The transfer fixing apparatus according to the eleventh embodiment is different from that according to the tenth embodiment in that the cylindrical member 191c covered by the brush-like roller 191 is directly heated.

  Referring to FIG. 18, similarly to the tenth embodiment, the transfer fixing device 66 in the eleventh embodiment also includes a registration roller 64 and a heating device 67 that heats the recording medium P immediately before the transfer / fixing step. A heat transfer plate 67b that extends from the vicinity of the nip portion to the vicinity of the nip portion and functions also as a guide plate is provided. Further, a brush roller 191 as an urging member (brush member) is installed at a position facing the heat transfer plate 67b. Further, the brush-like roller 191 is provided with a flexible cylindrical member 191c on the outer peripheral surface thereof so as to cover the brush bristles 191b, as in the tenth embodiment.

Here, the transfer fixing device 66 according to the eleventh embodiment is provided with heating means 211 and 212 for heating the cylindrical member 191c of the brush roller 191. Specifically, the heating means includes a heater 211 disposed at a position facing the outer peripheral surface of the brush-shaped roller 191, and a reflecting plate 212 that reflects light emitted from the heater 211 toward the outer peripheral surface of the brush-shaped roller 191. And is composed of. The outer peripheral surface (cylindrical member 191c) of the brush-like roller 191 is heated by the radiant heat of the heater 211 and is conveyed to the contact position between the brush-like roller 191 and the heat transfer plate 67b. Heat.
In the eleventh embodiment, in order to increase the heating efficiency of the cylindrical member 191c, a metal belt having good heat conduction and heat resistance is used as the cylindrical member 191c. Specifically, the cylindrical member 191c is a metal belt made of stainless steel having a thickness of about 0.1 mm.
Further, the heating means 121 and 122 are disposed on the upstream side in the rotation direction of the brush roller 191 with respect to the contact position between the brush roller 191 and the heat transfer plate 67b.

  With such a configuration, in addition to the effects described in the tenth embodiment, the recording medium P is heated from the back surface side (the back surface when the transfer fixing surface is the front surface). It is possible to obtain an effect of reducing a decrease in heating efficiency of the recording medium P when a thick paper is passed or a low temperature environment.

  As described above, according to the eleventh embodiment, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member) as in the above embodiments. A heat transfer plate 67b that heats the transfer and fixing surface of the recording medium P while guiding the recording medium P to be guided is provided, and a brush shape that urges the recording medium P guided by the heat transfer plate 67b toward the heat transfer plate 67b. Since the roller 191 (brush-like member) is provided, energy consumption is low, generation of defective fixing images and uneven gloss images can be suppressed, and good fixability can be obtained.

Embodiment 12 FIG.
The twelfth embodiment of the present invention will be described in detail with reference to FIG.
FIG. 19 is a configuration diagram showing a part of the transfer fixing device according to the twelfth embodiment, and corresponds to FIG. 16 in the tenth embodiment. The transfer and fixing apparatus according to the twelfth embodiment is different from the tenth embodiment in that a metal layer 217a covered on the outer peripheral surface of the elastic roller 217 is used as a heat transfer plate.

Referring to FIG. 19, similarly to the tenth embodiment, the transfer fixing device 66 according to the twelfth embodiment also includes a registration roller 64 and a heating device 67 that heats the recording medium P immediately before the transfer / fixing step. A heat transfer plate that also functions as a guide plate that guides the recording medium P from the vicinity of to the vicinity of the nip portion is provided.
Here, the heat transfer plate in the twelfth embodiment is the outer peripheral surface of the elastic roller 217 that rotates in the same direction as the recording medium conveyance direction (counterclockwise in FIG. 19) at the contact position with the recording medium P. The metal layer 217a is covered with the metal layer 217a. Further, a brush-like roller 191 as an urging member (brush-like member) is installed at a position facing the heat transfer plate 217b (elastic roller 217). Further, the brush-like roller 191 is provided with a flexible cylindrical member 191c on the outer peripheral surface thereof so as to cover the brush bristles 191b, as in the tenth embodiment.

The elastic roller 217 is configured similarly to the brush roller 191 in the eleventh embodiment. That is, the elastic roller 217 (brush-shaped roller) is provided with a cylindrical member 217a (metal layer) having flexibility so that the bristle (brush cloth) is wound on the core metal and further covers the brush bristle. ing. Here, the cylindrical member 217a (metal layer) covered on the outer peripheral surface of the elastic roller 217 (brush roller) is a metal belt made of stainless steel having a thickness of about 0.1 mm.
In the twelfth embodiment, the exciting coil 218 is used as a heating body for heating the elastic roller 217 (the metal layer 217a as a heat transfer plate). And the metal layer 217a as a heat exchanger plate is electromagnetically heated by applying a high frequency alternating voltage to the exciting coil 218 from a power supply unit (not shown). Thus, the heating efficiency of the heat transfer plate 217a (metal layer) is improved by using electromagnetic induction heating for heating the heat transfer plate 217a (metal layer).

With such a configuration, the recording medium P fed to the contact position between the elastic roller 217 and the brush-shaped roller 191 is sent out from the contact position by the rotation of both rollers 191 and 217, and the pressure roller Thus, the toner is smoothly conveyed (guided) toward the nip portion between 68 and the transfer fixing belt 27. Since the elastic roller 217 and the brush-like roller 191 are in contact with each other at a constant speed, wear due to friction between both the rollers 191 and 217 is reduced.
Further, since both the elastic roller 217 and the brush-like roller 191 have the surface flexibility secured and the surface hardness is almost the same, the nip between the elastic roller 217 and the brush-like roller 191 is flat. Shape. Therefore, even when the recording medium P having a small thickness is passed, a problem that the recording medium P that has passed through the nip between the elastic roller 217 and the brush roller 191 is curled by heat is suppressed.

  As described above, according to the twelfth embodiment, the sheet is conveyed to the nip portion between the transfer fixing belt 27 (transfer fixing member) and the pressure roller 68 (pressure member) as in the above embodiments. A heat transfer plate 217b (metal layer) for heating the transfer and fixing surface of the recording medium P while guiding the recording medium P is provided, and the recording medium P guided by the heat transfer plate 217b (elastic roller 217) is provided as a heat transfer plate. Since the brush-like roller 191 (brush-like member) that urges toward 217b is provided, energy consumption is low, and it is possible to obtain a good fixability by suppressing the occurrence of defective fixing images and uneven gloss images. it can.

  It should be noted that the present invention is not limited to the above-described embodiments, and within the scope of the technical idea of the present invention, the embodiments can be modified as appropriate in addition to those suggested in the embodiments. Is clear. In addition, the number, position, shape, and the like of the constituent members are not limited to the above embodiments, and can be set to a number, position, shape, and the like that are suitable for carrying out the present invention.

1 image forming apparatus body (apparatus body),
27 transfer fixing belt (transfer fixing member),
28A-28C roller member,
66 transfer fixing device,
67 heating device,
67a heating element,
67b, 67b1, 67b2 heat transfer plate,
67c electrode,
67d insulation,
68 Pressure roller (pressure member),
91 brush-like member (biasing member),
91a brush hair,
91b plate-like member,
92 cams,
95 Suction fan (biasing member, suction mechanism),
96 Duct (suction mechanism), P Recording medium.

JP-A-2005-37879 JP 2002-99159 A

Claims (19)

A transfer fixing device for transferring and fixing a toner image to a transfer fixing surface of a recording medium,
A transfer fixing member carrying a toner image;
A pressure member that forms a nip portion to which the recording medium is conveyed in pressure contact with the transfer fixing member;
A heat transfer plate that is heated by a heating body and that heats the transfer-fixing surface of the recording medium while guiding the recording medium conveyed toward the nip portion;
A biasing member that biases the recording medium guided by the heat transfer plate toward the heat transfer plate;
A transfer fixing device comprising:   The transfer fixing device according to claim 1, wherein the urging member is a brush-like member that contacts a recording medium guided by the heat transfer plate.   The transfer fixing device according to claim 2, wherein the brush-like member includes a plate-like member on a side of the pressure member that prevents the brush hair from being caught in the nip portion.   3. The brush-like member according to claim 2, wherein the brush-like member has hollow bristles and is configured to blow air onto the recording medium guided by the heat transfer plate via the bristles. Item 4. The transfer fixing device according to Item 3.   5. The brush-like member according to claim 2, wherein the brush-like member is one or a plurality of brush-like rollers that rotate in the same direction as the conveyance direction of the recording medium at a contact position with the recording medium. Transfer fixing device.   The transfer fixing device according to claim 5, wherein the brush roller is rotationally driven so that a linear velocity at a contact position with the recording medium is equal to or higher than a conveyance speed of the recording medium.   7. A guide member for contacting the bristle of the brush-like roller and guiding the recording medium is provided upstream of the brush-like roller with respect to the conveyance direction of the recording medium. The transfer fixing device according to 1.   8. The transfer fixing device according to claim 5, further comprising a cleaning member that slides in contact with the brush bristles of the brush roller to clean the brush roller.   The transfer fixing device according to claim 5, wherein the brush roller is disposed so as to be in sliding contact with the pressure member.   The transfer fixing device according to claim 5, wherein the brush-like roller has a cylindrical member having flexibility on an outer peripheral surface thereof.   The transfer fixing device according to claim 10, wherein the cylindrical member is made of a low friction material.   The transfer fixing apparatus according to claim 10, further comprising a heating unit configured to heat the cylindrical member.   The transfer fixing device according to claim 1, wherein the urging member is a suction mechanism that sucks a recording medium guided by the heat transfer plate together with air from the heat transfer plate side.   The biasing member is controlled so as to bias only the leading end portion and the trailing end portion in the transport direction of the recording medium guided by the heat transfer plate toward the heat transfer plate. The transfer fixing device according to claim 1.   The biasing member is variably controlled under a condition for biasing the recording medium toward the heat transfer plate according to a thickness or a type of the recording medium guided by the heat transfer plate. The transfer fixing device according to claim 1. The heat transfer plate comprises a guide surface made of a curved surface formed in a convex shape on the side of the recording medium to be guided,
The recording medium conveyance speed at a position before reaching the guide surface is configured to be lower than the recording medium conveyance speed at a position after reaching the guide surface. Item 16. The transfer fixing device according to Item 15. The heat transfer plate comprises a guide surface formed of a curved surface formed in a concave shape on the side of the recording medium to be guided,
The recording medium conveyance speed at a position before reaching the guide surface is configured to be higher than the recording medium conveyance speed at a position after reaching the guide surface. Item 17. The transfer fixing device according to any one of Items 16 above.   18. The heat transfer plate is a metal layer covered on an outer peripheral surface of an elastic roller that rotates in the same direction as the recording medium conveyance direction at a position in contact with the recording medium. The transfer fixing apparatus according to any one of the above.   An image forming apparatus comprising the transfer fixing device according to claim 1.

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