JP2010152399A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus having a fixing device which is free of nonuniform gloss and image displacements. <P>SOLUTION: The image forming apparatus includes a first fixing section for heating and fixing a transfer material carrying an unfixed toner image; and a conveying means for the transfer material, which is disposed downstream of the first fixing section separately from the first fixing section. The conveying means includes a first conveying belt for conveying the transfer material; a second conveying belt for conveying the transfer material while sandwiching it between the first conveying belt and the second conveying belt itself; and a cooling means for cooling the transfer material via the first or second conveying belt. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a thermal fixing device using an electrophotographic system such as a copying machine, a printer, and a FAX.

  In recent years, in electrophotographic image forming apparatuses, the use of oil-containing fixing devices has progressed, and the number of wax-containing toners has increased. However, when the transfer material passes through the heat fixing portion and then the wax cools down, it comes into contact with something and the cooling state or surface state of the wax existing on the surface of the toner image changes. A problem that appears as uneven luster occurs.

  In order to prevent this problem, 1) a technique for delicately managing the contact state between the conveyance (paper discharge) member and the transfer material so as to prevent the roller and the guide plate from contacting as much as possible before the wax cools down. (See, for example, Patent Document 1).

  Also, 2) a technique for lowering the temperature at a position where the transfer material is separated from the fixing belt has been proposed (see, for example, Patent Document 2 and Patent Document 3).

JP 2003-20149 A JP 2002-99173 A JP 2004-233520 A

  However, the technique disclosed in Patent Document 1 has a drawback in that the transfer material conveyance performance deteriorates. Further, the structure of Patent Document 2 lacks stability in terms of adhesion between the belt and the transfer material, and gloss unevenness is liable to occur. Even in the structure of Patent Document 3, the belt is in contact with each other and has a weak pressure region (belt There is a problem that image misalignment is likely to occur at a portion where no pressing member is provided from the inside.

  The present invention provides a fixing device having a structure that is set to an overheating condition that does not cause a gloss change in a toner image, separated from a belt in a uniform cooling state, can avoid uneven gloss, and is less likely to cause image misalignment. An object of the present invention is to provide an image forming apparatus having

  The problems of the present invention are solved by the following means.

1. A first fixing unit that heats and fixes a transfer material carrying an unfixed toner image;
The transfer material conveying means disposed separately from the first fixing unit on the downstream side of the first fixing unit;
The conveying means is
A first conveyor belt for conveying the transfer material;
A second conveying belt for nipping and conveying the transfer material with the first conveying belt;
An image forming apparatus comprising: a cooling unit that cools the transfer material via the first conveyance belt or the second conveyance belt.

  2. 2. The image forming apparatus according to 1, wherein the cooling unit is a cooling fin.

3. The first fixing unit includes a heating unit;
The heating unit and the first conveying belt or the second conveying belt that cools the transfer material by the cooling unit are both disposed on the side where the unfixed toner image carried on the transfer material is present. 3. The image forming apparatus as described in 1 or 2 above.

  After the wax on the transfer material is once melted and made uniform, it is separated from the belt in a uniformly cooled state, so even if it contacts the transport member in the subsequent transfer material transport path, The uneven gloss due to the change is eliminated, and the conveyance of the transfer material and the improvement of the uneven gloss are reliably achieved. In the second fixing unit, since both surfaces of the transfer material are supported by the belt from the entrance to the exit of the transfer material, the adhesion between the belt and the transfer material can be secured, so uneven gloss due to poor adhesion between the transfer material and the belt. Can be prevented. In addition, the toner image is surely fixed by the first fixing device, and the second fixing device does not dissolve the toner image so much and raises the surface temperature of the transfer material only to the temperature at which the wax is dissolved. Image displacement does not occur when there is an area where the pressure is weak while there is a pressure (a portion without a pressing member from within the belt).

1 is a schematic diagram illustrating an example of an overall configuration of an image forming apparatus. FIG. 2 is an enlarged cross-sectional view of a main part of the fixing device in FIG. 1.

  First, an image forming apparatus equipped with the fixing device according to the present invention will be described.

  In the description of the embodiment of the present invention, the technical scope of the present invention is not limited by the terms used in this specification.

  FIG. 1 is a schematic diagram illustrating an example of the overall configuration of the image forming apparatus.

  In FIG. 1, 10 is a photoconductor, 11 is a scorotron charger as charging means, 12 is a writing device as image writing means, 13 is a developing device as developing means, and 14 is for cleaning the surface of the photoconductor 10. A cleaning device, 15 a cleaning blade, 16 a developing sleeve, and 20 an intermediate transfer belt. The image forming unit 1 includes a photoconductor 10, a scorotron charger 11, a developing device 13, a cleaning device 14, and the like. Since the mechanical configuration of the image forming unit 1 for each color is the same, in FIG. Reference numerals are given to configurations of only the (yellow) series, and reference symbols are omitted for the constituent elements of M (magenta), C (cyan), and K (black).

  The arrangement of the image forming means 1 for each color is in the order of Y, M, C, K with respect to the running direction of the intermediate transfer belt 20, and each photoconductor 10 contacts the stretched surface of the intermediate transfer belt 20. The contact point rotates in the same direction as the traveling direction of the intermediate transfer belt 20 and at the same linear speed.

  The intermediate transfer belt 20 is stretched around a driving roller 21, an earth roller 22, a tension roller 23, a static elimination roller 27, and a driven roller 24. The belt unit 3 includes these rollers, the intermediate transfer belt 20, a transfer device 25, a cleaning device 28, and the like. Configure.

  The intermediate transfer belt 20 is driven by rotation of the driving roller 21 by a driving motor (not shown).

  The photosensitive member 10 is formed by forming a photosensitive layer such as a conductive layer, an a-Si layer, or an organic photosensitive member (OPC) on the outer periphery of a cylindrical metal base formed of, for example, an aluminum material, and the conductive layer is grounded. In the state, it rotates counterclockwise as indicated by the arrow in FIG.

  An electrical signal corresponding to the image data from the reading device 80 is converted into an optical signal by the image forming laser, and is projected onto the photoconductor 10 by the writing device 12.

  The developing device 13 is a developing sleeve formed of a cylindrical non-magnetic stainless steel or aluminum material that maintains a predetermined interval with respect to the peripheral surface of the photoconductor 10 and rotates in the reverse direction at the closest position to the rotation direction of the photoconductor 10. 16.

The intermediate transfer belt 20 is an endless belt having a volume resistivity of 10 ⁶ to 10 ¹² Ω · cm. For example, the intermediate transfer belt 20 may be an engineering plastic such as modified polyimide, thermosetting polyimide, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride, and nylon alloy. A semiconductive seamless belt having a thickness of 0.04 to 0.10 mm, in which a conductive material is dispersed.

  A transfer unit 25 has a function of transferring a toner image formed on the photoreceptor 10 onto the intermediate transfer belt 20 by applying a direct current having a polarity opposite to that of the toner. As the transfer unit 25, a transfer roller can be used in addition to the corona discharger.

  Reference numeral 26 denotes a transfer roller which can be brought into contact with and released from the earth roller 22 and retransfers the toner image formed on the intermediate transfer belt 20 onto the transfer material P.

  A cleaning device 28 is provided to face the driven roller 24 with the intermediate transfer belt 20 interposed therebetween. After the toner image is transferred to the transfer material P, the intermediate transfer belt 20 has the charge of the residual toner weakened by the neutralizing roller 27 to which an AC voltage superimposed with a DC voltage having the same or opposite polarity as that of the toner is applied. The toner remaining on the peripheral surface is cleaned. A fixing device 4 includes a first fixing unit F1 and a second fixing unit F2. Details will be described later.

  7 is a transport path, 70 is a paper feed roller, 71 is a timing roller, 72 is a paper cassette, and 73 is a transport roller.

  Reference numeral 81 denotes a conveyance (paper discharge) roller, and 82 denotes a paper discharge tray. Reference numeral 85 denotes an operation panel.

  Reference numeral 9 denotes an ADU mechanism.

  B1 is a control unit that is a control unit for each drive unit, image forming process, fixing temperature, and the like.

  Hereinafter, the image forming process (image forming process) will be described with reference to FIG.

  When the image recording is started, the photosensitive drum 10 of the yellow (Y) image forming means 1 is rotated in the direction indicated by the arrow by starting a driving motor for the photosensitive drum (not shown), and at the same time, the photosensitive member 10 is charged by the charging roller 11. Application of a potential is started.

  After the photoconductor 10 is applied with a potential, the exposure optical system 12 starts image writing with an electric signal corresponding to the first color signal, that is, Y image data, and the Y of the document image is formed on the surface of the photoconductor 10. An electrostatic latent image corresponding to the image is formed.

  The latent image is reversed and developed in a non-contact state by the developing device 13, and a yellow (Y) toner image is formed according to the rotation of the photoreceptor 10.

  The Y toner image formed on the photoreceptor 10 as an image forming body by the image forming process is transferred onto the intermediate transfer belt 20 by the transfer unit 25.

  Next, the intermediate transfer belt 20 is synchronized with the Y toner image, and a potential is applied by the charging action of the scorotron charger 11 by the magenta (M) image forming means 1, and the M color signal, Image writing is performed by an electrical signal corresponding to the M image data, and the M toner image formed on the photoreceptor 10 by non-contact reversal development by the developing device 13 is transferred by the M transfer unit 25 to Overlaid from above the Y toner image.

  A similar process is used to synchronize with the superimposed toner images of Y and M, and corresponding to the C image data based on the C color signal formed on the photoreceptor 10 by the cyan (C) image forming means 1. A C toner image is formed by being superimposed on the Y, M, and Y toner images by the C transfer unit 25, and is further synchronized with the Y, M, and C superimposed toner images. K) The toner image corresponding to the K image data based on the K color signal formed on the photoconductor 10 by the image forming means 1 is transferred onto the Y, M, C, A toner image of K is superimposed and formed on the toner image, and a superimposed color toner image of Y, M, C, and K is formed on the intermediate transfer belt 20, respectively.

  Further, the toner remaining on the surface of the photoreceptor 10 of each color after the primary transfer is removed by the cleaning unit 14, and the photoreceptor 10 in the previous image formation by a uniform exposure device before charging, not shown. The history is canceled and the next image forming cycle is started.

  The intermediate transfer belt 20 carrying the superimposed toner image is sent in the direction of arrow F, and the transfer material P is sent out by a feed roller 70 from a paper feed cassette 72 which is a transfer material storage means, and a transport roller 73. Then, the toner image is conveyed to the timing roller 71, synchronized with the toner image on the intermediate transfer belt 20, and fed to the transfer area S of the transfer roller 26 by driving the timing roller 71.

  The transfer material P superimposed on the intermediate transfer belt 20 is nipped and transferred between the earth roller 22 and the transfer roller 26 in the transfer region S. The first fixing unit F1 of the fixing device 4 is sandwiched and pressed by the heating roller 40 and the pressure roller 40b to be fixed. In the case of single-sided printing, the transfer material P is sent to the second fixing unit F2 by the conveyance switching valve 92 in a one-dot chain line state, and is subjected to heat and cooling processing and discharged from the discharge roller 81 to the discharge tray. . In the case of double-sided printing, the transfer material P is transported to the paper reversing path 90 by the transport switching valve 92 in the state indicated by the solid line after the fixing section F1, is reversed by the ADU mechanism section, and passes through the transport path 90b. The toner is conveyed to the timing roller 71, synchronized with the toner image on the intermediate transfer belt 20, and fed to the transfer area S of the transfer roller 26 by driving the timing roller 71. Hereinafter, the same as in the case of single-sided printing. Paper is discharged in the process.

  Here, the fixing device according to the present invention will be described.

  FIG. 2 is an enlarged cross-sectional view of a main part of the fixing device in FIG.

  Reference numeral 4 denotes a fixing device. As shown in FIG. 2, a fixing roller 40 heated by a halogen heater 40a and a pressure roller 40b that can be pressurized and released by a pressure mechanism (not shown) contain wax. A first fixing unit F1 that sandwiches and presses a toner image formed of toner and fixes the toner image on a transfer material, a belt unit 4a in which a belt 41 is stretched between a heating roller 42, a separation roller 43, and a tension roller 44, and heating. The heating roller 42 and the heating roller 46 of the two belt units of the belt unit 4b in which the belt 45 is stretched around the roller 46, the separation roller 47, and the tension roller 48, and the separation roller 43 and the separation roller 47 are mutually connected via the belt. The second fixing unit F2 is configured to press and heat-treat after the transfer material is sandwiched and conveyed between the belt and heat-treated.

  In FIG. 2, the fixing roller 40 of the first fixing unit has a heat resistant silicone rubber layer 402, which is an elastic body, lined on a cylindrical cored bar 401 made of aluminum, and is separated from the outer periphery of the heat resistant silicone rubber layer 402. A predetermined temperature is generated by a halogen heater 40a, which is a heat source, which is made of a configuration in which a thin PFA resin layer 403, which is a mold layer, is coated, and is disposed in a hollow portion of the fixing roller 40 via a support contact piece (not shown) During the operation of image formation and fixing processing, it is rotated in the direction of arrow W by obtaining power from a drive unit (not shown). The temperature is detected by a non-contact temperature sensor 404 installed at a predetermined distance from the surface of the fixing roller 40 and transmitted to the control unit B1. The control unit B1 turns the halogen heater 40a on and off. Thus, the surface temperature of the fixing roller 40 is controlled to be a specified temperature.

  The pressure roller 40b is made of a structure in which a heat-resistant silicone rubber is lined on a cylindrical rigid core bar made of aluminum, and a PFA resin thin layer as a release layer is coated on the surface layer. Is brought into contact with the fixing roller 40 to form a nip portion T, which is pressed by the fixing roller 40 and rotates. When the image is not formed by the fixing roller 40 and the pressure roller 40b, the pressure bonding is automatically released.

  The configuration of the first fixing unit F1 is not limited to this. Even in a fixing configuration having a so-called belt, there is a region where the belt is in contact with the other party and the pressure is weak (the portion without the pressing member from the inside of the belt). Any other configuration may be used as long as the toner is fixed and the toner is sufficiently fixed to the transfer material.

  The heating rollers 42 and 46 and the separation rollers 43 and 47 in the post heat treatment section (second fixing section F2) are coupled to each other via a bearing that slides in a radial direction so that they can be pressed against each other via the belts 41 and 45. Are supported by a fixing device frame (not shown). The belts 41 and 45 are formed by lining a silicone rubber with a thickness of 0.1 to 0.5 μm on the outer surface of a PI (polyimide) belt substrate having a thickness of 50 to 100 μm, and further releasing a toner thereon. A good PFA resin is applied and fired to 15 to 50 μm. The heating rollers 42 and 46 are obtained by applying a fluororesin to the surface of an aluminum cylinder. Temperature sensors 42b and 46b for detecting the belt surface temperature are provided in the vicinity of the nip portion H, and the control unit B1 is a heating unit based on the information. The halogen heaters 42a and 46a are turned on and off. The separation rollers 43 and 47 have a small diameter so that the curvature is large, and the outer shape is in the range of 10 to 25 mm. In addition, the separation roller 43 obtains power from a drive source (not shown) and rotates in the direction of the arrow, so that the separation roller 47 pressed through the belt also frictionally rotates, so that the belts 41 and 45 travel at the same speed. . The heating rollers 42 and 46 are heated by halogen heaters 42a and 46a. Separation rollers 43 and 47 are made of a cylindrical product made of stainless steel.

  The transfer material P is pressed by the heating rollers 42 and 46, and the wax layer covering the toner image fixed by the first fixing unit is heated again and melted. Since the melted wax easily leaks, the wax layer is melted. In addition, the toner image surface becomes uniform. The surface temperature of the transfer material is equal to or lower than the crystallization temperature of the wax in the process of becoming uniform with no gloss change and being sandwiched and conveyed between the belts 41 and 45 cooled from the inside by the cooling fins 41a and 45a. The transfer material is separated by the curvature while the wax is substantially solidified at the separation rollers 43 and 47. 51 and 55 are cleaning rollers for cleaning the excess wax on the belts 41 and 45 while heating, anodizing the aluminum cylinder, and having halogen heaters 51a and 55a in the internal space.

  The fixing device according to the embodiment of the present invention is configured as described above.

  The toner used in the present invention will be described below.

  As long as the toner used in the present invention contains a wax, a conventionally known toner can be used. Examples of the wax include conventionally known paraffin waxes, polyolefin waxes, modified products thereof (for example, oxides and graphs and processed products), higher fatty acids, and metal salts thereof, amide waxes, ester waxes, and the like. Waxes can be used, but for example, higher fatty acid ester waxes are preferably used. The wax content of the toner according to the present invention is preferably 7 to 20% by mass. By setting it to 7% or more, the separation performance of the transfer material from the fixing roller can be secured in the first fixing unit, and by setting it to 20% or less, the storage performance as toner can be secured. Polymerized toner is an example of a toner whose wax content can be easily adjusted. The toner according to the present invention is preferably a polymerized toner because the wax content can be easily adjusted.

  The melting point of the wax contained in the toner is preferably 60 to 90 ° C. When the melting point is 60 ° C. or more, the storage performance as a toner is secured, and when the melting point is 90 ° C. or less, the separation performance of the transfer material from the fixing roller can be secured in the first fixing unit F1. The toner can be easily melted in the second fixing portion F2. Further, the value of the difference (Tw−TK) between the melting point Tw of the wax and the crystallization temperature TK is preferably 25 ° C. or less, and more preferably 10 ° C. or less. Since the value of (Tw−TK) is small, it is not necessary to increase the cooling means in the second fixing unit F2, which will be described later, and it can be made more compact. Here, the melting point of the wax refers to the temperature at the peak of the peak showing the maximum endotherm in the DSC curve at the time of temperature rise in the differential scanning calorimetry (DSC), and the crystallization temperature of the wax is the difference. In the DSC curve at the time of temperature drop in scanning calorimetry (DSC), it means the temperature at the peak of the peak showing the maximum heat generation. Further, the softening point Tm of the temperature toner measured using a Koka flow tester is preferably 95 to 115 ° C., and the difference between Tm and Tw (Tm−Tw) is preferably 20 ° C. or more. (Tm−Tw) is more preferably 30 ° C. or higher. When the softening point is 95 ° C. or higher, the storage performance as a toner is secured, and when the softening point is 115 ° C. or lower, fixing can be designed compactly in the first fixing portion F1. Further, (Tm−Tw) is 20 ° C. or higher, so that it is easier to melt only the wax in the second fixing unit F2.

  As described above, in a general fixing device, the transfer material is fixed at the first fixing unit F1, and then transferred to the post heat treatment unit, and the toner image becomes something in the process of cooling the wax. When the contact state of the wax and the contact surface of the toner image change due to contact, there arises a problem of uneven glossiness. However, in the present invention, the belt surface temperature Tb of the portion where the transfer material starts to contact the belt occurs. And Tw ≦ Tb, where Tw is the surface temperature Ts of the transfer material where the transfer material has started to be separated, Tw is the melting point of the wax contained in the toner, TK is the crystallization temperature of the wax, and Tm is the softening point of the toner. The above problem can be avoided by managing the conditions ≦ Tw + (Tm−Tw) / 2 and Ts <TK.

  That is, after the fixing process in the first fixing unit F1, in the post-heat treatment unit that is the second fixing unit F2, the heating condition is set so that no gloss change appears in the toner, and only the wax on the image surface is melted. After the layer became uniform, it became a uniform gloss, and was transported while being cooled by being sandwiched between two belts. When the temperature became below the crystallization temperature of the wax at the separation roller, The transfer material leaves and is further conveyed downstream. In other words, after the wax is once melted in the post-heat treatment portion to be in a uniform state, it is cooled while being in close contact with the belt while being in a uniform state, and thus the transfer material that has come out of the second fixing portion F2. The gloss of the upper toner image is uniform. In addition, since the conditions of the cooling means and the like are set so that the surface temperature of the transfer material coming out of the second fixing portion F2 is equal to or lower than the crystallization temperature of the wax, a member for guiding or conveying the transfer thereafter Even when touched, uneven glossiness is less likely to occur. In the post-heat treatment portion, the toner constituents other than wax hardly dissolve, so that there is no image shift even if there is an area where there is no member for backing up the belt from the inside.

  A styrene acrylic toner (softening point Tm = 110 ° C.) prepared by a polymerization method containing 13% by mass of a higher fatty acid ester wax having Tw = 80 ° C. and TK = 60 ° C. is used. , C toners are stacked and fixed at the first fixing unit F1, and then, after passing through the paper reversing path, M toner and C toner are stacked on the entire second surface and fixed at the first fixing unit F1. The printed image was passed through the second fixing unit. ON / OFF control of the halogen lamps 42a and 46a is set so that the detection temperature of the temperature sensors 42b and 46b is 90 to 95 ° C., and a radiation detection type temperature sensor is installed at the position 43a of the second fixing unit. When the conditions of the cooling fins 41a and 45a are determined so that the paper surface detection temperature Ts is 50 to 55 ° C., the pair of transport rollers is placed downstream of the radiation detection type temperature sensor at the position 43a. Even when the paper was transported by providing it, gloss unevenness did not occur. In addition, the increase in glossiness was 5 or less compared to the case where the double-sided printed image fixed by the first fixing unit F1 was taken out so as not to damage the image.

Comparative Example 1
A styrene acrylic toner (softening point Tm = 110 ° C.) prepared by a polymerization method containing 13% by mass of a higher fatty acid ester wax having Tw = 80 ° C. and TK = 60 ° C. is used. , C toners are stacked and fixed by the first fixing unit, and then, after passing through the paper reversing path, M toner and C toner are stacked on the entire second surface and fixed by the first fixing unit F1. The image was passed through the second fixing unit F2. The ON / OFF control of the halogen lamps 42a and 46a is set so that the detection temperature of the temperature sensors 42b and 46b is 110 to 115 ° C., and a radiation detection type temperature sensor is installed at the position 43a of the second fixing unit F2. When the conditions of the cooling fins 41a and 45a were determined so that the surface detection temperature Ts of the paper would be 70 to 75 ° C. when installed, the pair of transport rollers immediately after the radiation detection type temperature sensor at the position 43a. When the paper is transported with the slab, gloss unevenness occurs at the transport roller contact portion.

Comparative Example 2
A styrene acrylic toner (softening point Tm = 110 ° C.) prepared by a polymerization method containing 13% by mass of a higher fatty acid ester wax having Tw = 80 ° C. and TK = 60 ° C. is used. , C toners are stacked and fixed at the first fixing unit F1, and then, after passing through the paper reversing path, M toner and C toner are stacked on the entire second surface and fixed at the first fixing unit F1. The print image was passed through the second fixing unit F2. ON / OFF control of the halogen lamps 42a and 46a is set so that the detection temperature of the temperature sensors 42b and 46b is 90 to 95 ° C., and a radiation detection type temperature sensor is installed at the position 43a of the second fixing unit F2. When the conditions of the cooling fins 41a and 45a were determined so that the paper surface detection temperature would be 70 to 75 ° C. when installed, a pair of conveyance rollers was provided immediately after the radiation detection type temperature sensor at the position 43a. When the paper is conveyed, uneven gloss occurs at the conveyance roller contact portion.

Comparative Example 3
A styrene acrylic toner (softening point Tm = 110 ° C.) prepared by a polymerization method containing 13% by mass of a higher fatty acid ester wax having Tw = 80 ° C. and TK = 60 ° C. is used. , C toners are stacked and fixed at the first fixing unit F1, and then, after passing through the paper reversing path, M toner and C toners are stacked on the entire second surface and fixed at the first fixing unit. The image was passed through the second fixing unit F2. ON / OFF control of the halogen lamps 42a and 46a is set so that the detection temperature of the temperature sensors 42b and 46b is 110 to 115 ° C., and a radiation detection type temperature sensor is installed at the position 43a of the second fixing unit. When the conditions of the cooling fins 41a and 45a are determined so that the sheet surface detection temperature is 50 to 55 ° C., a pair of conveyance rollers is provided immediately after the radiation detection type temperature sensor at the position 43a. Even when the paper was transported, gloss unevenness did not occur. However, compared with the case where the double-sided printed image fixed by the first fixing unit F1 is taken out so as not to damage the image, the increase in glossiness is 10 or more, and the cooling fin contact length is not increased. Since the surface temperature of the sheet cannot be reduced below TK, the second fixing unit has to be enlarged.

  Therefore, as shown in the embodiment, the occurrence of uneven gloss can be avoided by maintaining the condition of Tw ≦ Tb ≦ Tw + (Tm−Tw) / 2.

DESCRIPTION OF SYMBOLS 1 Image forming means 4 Fixing device 4a, 4b Belt unit 40 Fixing roller 40a, 42a, 46a, 51a Halogen heater 41, 45 Belt 42, 46 Heating roller 42b, 46b, 43a Temperature sensor 43, 47 Separation roller 44, 48 Tension roller 41a, 45a Cooling fins 51, 55 Cleaning roller

Claims (3)

A first fixing unit that heats and fixes a transfer material carrying an unfixed toner image;
The transfer material conveying means disposed separately from the first fixing unit on the downstream side of the first fixing unit;
The conveying means is
A first conveyor belt for conveying the transfer material;
A second conveying belt for nipping and conveying the transfer material with the first conveying belt;
An image forming apparatus comprising: a cooling unit that cools the transfer material via the first conveyance belt or the second conveyance belt.   The image forming apparatus according to claim 1, wherein the cooling unit is a cooling fin. The first fixing unit includes a heating unit;
The heating unit and the first conveying belt or the second conveying belt that cools the transfer material by the cooling unit are both disposed on the side where the unfixed toner image carried on the transfer material is present. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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