JP2010266705A - Fixing and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus where productivity is not reduced even for paper of a plurality of longitudinal direction sizes. <P>SOLUTION: A cooling means at an fixing end and a cooling means for cooling recording paper after fixing to prevent adhesion of delivered paper are achieved with one cooling fan. Further, the cooling region is controlled in the longitudinal direction according to the size of the paper. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixing device of an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile, and in particular, has a heating rotating member and a pressure rotating member that form a fixing region by a pressing region that presses while rotating with respect to each other. The present invention also relates to a fixing device that heats and fixes the unfixed toner image when a transfer material on which the unfixed toner image is formed passes through the fixing region, and a conveyance device downstream of the fixing device.

  Conventionally, as a fixing method for fixing an unfixed toner image on a sheet (transfer material) in the image forming apparatus, heat that heats and melts the unfixed toner image on the sheet to fix it on the sheet from the standpoint of safety and fixability. A fixing method is generally used. In recent years, a belt heating type heating apparatus has been put into practical use from the viewpoint of quick start and energy saving. That is, a heat-resistant resin belt (hereinafter referred to as a fixing belt) as a heating member is sandwiched between, for example, a ceramic heater as a heating body and a pressure roller as a pressure member, and a pressure nip portion (hereinafter referred to as fixing). A recording material on which an unfixed toner image is formed and supported between the fixing belt and the pressure roller of the fixing nip portion, and is conveyed while being held together with the fixing belt. An unfixed toner image is fixed on the surface of the recording material with the pressure of the fixing nip portion while applying heat from the ceramic heater through the fixing belt. This belt heating type heating apparatus does not require energization of the heater in standby, and after the image forming apparatus receives the print signal, the recording material reaches the heating apparatus even if the heater is energized. It is possible to make it heatable. Therefore, from the viewpoint of energy saving, the belt heating type heating device is an excellent heat fixing device that does not waste energy. Furthermore, a fixing method is also proposed in which a pressure member is arranged through a belt so as to face the heating roller. Regardless of which fixing method is used, when the paper is fixed in the fixing region, the surface of the heating roller passing through the paper passing region has a substantially uniform temperature distribution.

  However, when small size paper having a width smaller than the maximum size paper is continuously fixed in the fixing area, the temperature of the surface of the heating roll passing through the non-sheet passing area excessively increases. This is because when small-size paper is continuously passed, heat is partially stored in the non-paper passing area where the paper does not pass, as much as there is no heat removal by the paper. This phenomenon is called the temperature rise at the end of the fixing device or the temperature rise at the non-sheet passing portion. If the temperature rise at the end of the fixing device becomes high, the temperature rise limits of the fixing member components and the pressure roller are exceeded. Lead to damage of the parts.

  If the image density is high, the temperature of the paper discharged onto the paper output tray is still high, so the toner on the image surface is not completely cooled, and the toner of the recording paper loaded on the paper output tray is adjacent. It sticks to the paper to be printed and is called “paper discharge adhesion”, which is a problem.

  In order to prevent such temperature rise of the non-sheet passing portion, a cooling fan is provided in the fixing device, and the temperature rise is suppressed by blowing air to the heating roller and pressure roller of the non-sheet passing portion. A configuration for cooling the sheet downstream of the apparatus is known. Patent Document 1 is known as a description of the prior art.

  The technology described in this publication differs by adjusting the length in the width direction of the blower opening according to the width of the paper used when the cooling air is blown from the cooling fan to the non-sheet passing area side. The temperature rise of the non-sheet passing portion is prevented even for paper of different sizes.

Japanese Patent Laid-Open No. 2003-076209

  Even in the prior art of Patent Document 1, paper of various sizes is supported in the width direction depending on the shape of the guide duct that guides the cooling air, but the loss of cooling air volume is caused by the bent duct shape. Therefore, it was necessary to secure the airflow by increasing the airflow of the cooling fan or increasing the size of the cooling fan. Even if the bent part of the duct shape was abolished and it was going to be formed with a smooth curved surface, it was necessary to increase the space of the duct, which eventually led to an increase in the size of the apparatus.

  In the prior art, as shown in FIG. 12, two fixing end cooling fans 1A are arranged near both ends of the fixing device 101A in order to cool the longitudinal end portion of the fixing film (heating) 20A in the fixing device 101A. Yes. The air Z1 sent from the fixing end cooling fan 1A hits the fixing belt 20A, then passes upward (downstream in the conveying direction), becomes air Z2, and is exhausted outside the apparatus by the external exhaust fan 102A. Further, the sheet after fixing is stacked as a recording sheet 103A on the sheet discharge tray. In recent years, the conveying path of 101A after fixing has been shortened, the speed has been increased, and the time to discharge has been shortened. At this time, there is a problem in that the high-temperature recording paper 103A is stacked on the paper discharge tray 102A, the toner cannot be fully agglomerated, and the stacked papers stick to each other. For this reason, an image cooling fan 104A for cooling the recording paper is disposed after the fixing device 101A, and the cooling air S1 is exhausted outside the apparatus by the external exhaust fan 102A.

  Here, as shown in FIG. 13, when the longitudinal direction (Y1) of the paper has a short width (Q1), the fixing end cooling fan 1A cools R1 at both ends, and the image cooling fan 104A cools R1 + P1 + R1. R1 portions at both ends of the image cooling fan 104A are unnecessary cooling air.

  Further, as shown in FIG. 14, when the longitudinal direction (Y1) of the paper is wide (Q2), the fixing end cooling fan 1A cools the R2 portion at both ends, so that the T2 portion becomes unnecessary cooling air.

  As described above, the fixing end cooling fan 1A is out of the sheet area, and the image cooling fan 104A supplies cooling air to the excess area even though the area to be cooled differs from the sheet area. For this reason, the image forming apparatus is equipped with a total of three fans, one for fixing edge cooling fan 1A at both ends for cooling outside the paper area and one for cooling image area by image cooling fan 104A. Yes.

  As described above, the cost for the installation of three or more inefficient fans, such as the fan cost, electrical wiring, and controller board mounting area, increases, making it difficult to mount on costly low-speed machines. This is a big problem at present.

In order to solve the above-described problems, the image forming apparatus of the present invention forms a fixing region by the press contact regions that are pressed against each other while rotating, and the transfer material on which an unfixed toner image is formed passes through the fixing region. A fixing member that heat-fixes an unfixed toner image and having a heat source in at least one of a pair of rotating members, and a conveyance roller that conveys a transfer material downstream of the fixing member;
In order to cool a predetermined region of the fixing member, a non-sheet-passing area cooling duct having a blower opening formed facing the fixing member;
An image cooling duct having a blower opening facing the transfer material to cool the transfer material after fixing downstream of the fixing member, cooling air to the non-sheet passing area cooling duct and the image cooling duct. A cooling device having a cooling fan for blowing air, an exhaust duct for discharging cooled air, and an exhaust fan,
An image forming apparatus characterized in that the position of the non-sheet passing area cooling duct and the image cooling duct is moved in the direction perpendicular to the transfer material conveyance direction (transfer material longitudinal direction) in accordance with a plurality of transfer material widths. It is.

  According to the present invention, one cooling fan is used as the cooling means for the fixing end and the cooling means for cooling the recording paper after fixing and preventing the adhesion of the discharged paper. Furthermore, by controlling the cooling area in the longitudinal direction according to the size of the paper, it is possible to provide an image forming apparatus that does not reduce the productivity even with a plurality of paper of a longitudinal size.

1 is a cross-sectional view of an image forming apparatus in an embodiment. 1 is a cross-sectional view or a perspective view of a fixing device according to an embodiment. FIG. 3 is an explanatory diagram of an end portion temperature raising and cooling configuration of the fixing device in the embodiment. 1 is a perspective view of an image forming apparatus in an embodiment. FIG. 3 is an explanatory diagram of a cooling air flow of a fixing end portion and a recording paper in the first embodiment. FIG. 3 is an explanatory diagram of a cooling shutter in the first embodiment. FIG. 3 is an explanatory diagram of a driving configuration of a cooling shutter in the first embodiment. FIG. 3 is an explanatory diagram of a cooling effect in the first embodiment. FIG. 3 is an explanatory diagram of a cooling device arrangement in the first embodiment. Explanatory drawing of the cooling device in Example 2. FIG. FIG. 6 is an explanatory diagram of a recording paper cooling air blocking configuration in Embodiment 3. FIG. 6 is an explanatory diagram of a cooling end air flow and a recording sheet cooling air flow of a conventional configuration. The top view of cooling airflow description of the conventional structure. The top view of cooling airflow description of the conventional structure.

  Next, specific examples (examples) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.

"Main body configuration"
First, the image forming process will be described with reference to FIG. The printer as the image forming apparatus is a photosensitive drum 51a (yellow), 51b (magenta), 51c that is four image carriers arranged in parallel to form toner images of colors of yellow, magenta, cyan, and black. (Cyan), 51d (black), and an intermediate transfer belt 103 arranged in a manner of longitudinally cutting the photosensitive drums 51a to 51d. Around the photosensitive drums 51a to 51d, a charger, a developing device, and a cleaner (not shown) are arranged, and these are unitized as process cartridges (image forming units) 52a to 52d. The photosensitive drums 51a to 51d are each charged by a charger, and the color separated yellow, magenta, cyan, and black light images are exposed by the exposure device 53, and the photosensitive drums 51a to 51d are exposed to yellow, magenta, and cyan. , A black latent image is formed, and each latent image is developed by a developing unit to form yellow, magenta, cyan, and black toner images on the photosensitive drums 51a to 51d. Transcript. The transfer material P is stored in the feeding cassette 54. The feeding cassette 54 can be pulled out in the front direction in the figure. For example, the feeding cassette 54 can be pulled out to the front side of the apparatus in order to replenish the transfer material P or to perform jam processing when a jam occurs in the feeding cassette 54. It is a possible configuration. The transfer material P is fed one by one from the feed cassette 54 by a pickup roller (feed / conveying means) 55, and after the timing is adjusted by a registration roller 56, the transfer material P is transferred to a secondary transfer outer roller 57 and an intermediate transfer belt. The toner image on the intermediate transfer belt 106 is secondarily transferred by being conveyed to a nip portion constituted by the secondary transfer outer roller 58 in 103. Thereafter, the transfer material P onto which the toner image has been secondarily transferred is conveyed to the fixing device 101b, where it is fixed by receiving heat and pressure, whereby the toner of each color is melted and mixed and fixed to the transfer material P. After the print image is formed, it passes through a transport roller 105b provided downstream of the fixing device 101, and is discharged to the discharge tray 102b by the discharge transport means 59.

  Note that a cooling means for cooling the heat of the fixing belt 10 and the recording paper after fixing, which is a feature of the present embodiment, is disposed in the left Q portion of the fixing device.

"Fixing device configuration"
FIG. 2A is a cross-sectional view of the fixing device in this embodiment. The fixing device of this example is a heating device of a fixing belt heating method and a pressure rotating body driving method (tensionless type).

  Reference numeral 20 denotes a fixing belt as a first rotating body (first fixing member), which is a cylindrical member (endless belt-like or sleeve-like) formed by providing an elastic layer on the belt-like member.

  Reference numeral 22 denotes a pressure roller as a second rotating body (second fixing member).

  Reference numeral 17 denotes a heater holder having a substantially semi-circular cross-sectional saddle shape heat resistance and rigidity as a heating body holding member, and 16 is a fixing heater as a heating body (heat source). It is arranged along. The fixing belt 20 is loosely fitted to the heater holder 17 and is biased at the end by the fixing flange 50 as shown in the perspective view of FIG.

  The pressure roller 22 is formed by forming a silicone rubber layer having a thickness of about 3 mm on a stainless steel core by injection molding and coating a PFA resin tube having a thickness of about 40 μm thereon. The pressure roller 22 is disposed such that both ends of the core bar are rotatably supported by bearings between a side plate (not shown) and a front side plate of the apparatus frame 24. On the upper side of the pressure roller 22, the fixing belt unit composed of the fixing heater 16, the heater holder 17, the fixing belt 20, etc. is arranged in parallel with the pressure roller 22 with the heater 16 facing downward, and both ends of the heater holder 17. Is biased in the axial direction of the pressure roller 22 with a force of 98 N (10 kgf) on one side and a total pressure of 196 N (20 kgf) by a pressure mechanism (not shown), so that the downward surface of the fixing heater 16 is passed through the fixing belt 20. A fixing nip portion 27 having a predetermined width necessary for heat fixing is formed by pressing the elastic layer of the pressure roller 22 against the elasticity of the elastic layer with a predetermined pressing force. The pressurization mechanism has a pressure release mechanism, and is configured to release the pressurization and remove the recording material P at the time of jam processing or the like.

  Reference numerals 23 and 26 denote an entrance guide and a fixing paper discharge roller assembled to the apparatus frame 24. The entrance guide 23 is a transfer material so that the recording material P that has passed through the secondary transfer nip is accurately guided to the fixing nip portion 27 that is a pressure contact portion between the fixing belt 20 and the pressure roller 22 in the fixing heater 16 portion. To play a leading role. The entrance guide 23 of the present embodiment is formed of polyphenylene sulfide (PPS) resin.

  The pressure roller 22 is driven to rotate at a predetermined peripheral speed in the direction of the arrow by a driving means (not shown). A rotational force acts on the cylindrical fixing belt 20 by the frictional force at the fixing nip portion 27 between the outer surface of the pressure roller 22 and the fixing belt 20 due to the rotation of the pressure roller 22, and the fixing belt 20 While the inner surface of the fixing heater 16 is in close contact with the downward surface and slides, the outer periphery of the heater holder 17 is driven and rotated in the direction of the arrow. Grease is applied to the inner surface of the fixing belt 20 to ensure slidability between the heater holder 17 and the inner surface of the fixing belt 20.

  The pressure roller 22 is rotationally driven, and accordingly, the cylindrical fixing belt 20 is driven and rotated, and the fixing heater 16 is energized. The fixing heater 16 is heated to a predetermined temperature. In the adjusted state, the recording material P carrying an unfixed toner image is guided and introduced along the entrance guide 23 between the fixing belt 20 and the pressure roller 22 of the fixing nip 27, and the fixing nip 27 2, the toner image carrying surface side of the recording material P is in close contact with the outer surface of the fixing belt 20 and is nipped and conveyed together with the fixing belt 20 through the fixing nip portion 27. In this nipping and conveying process, the heat of the fixing heater 16 is applied to the recording material P via the fixing belt 20, and the unfixed toner image t on the recording material P is heated and pressurized on the recording material P and melted and fixed. The The recording material P that has passed through the fixing nip 27 is separated from the fixing belt 20 by the curvature, and is discharged by the fixing discharge roller 26.

"Cooling system"
A method of cooling the surface of the fixing belt of the fixing device in a plurality of sizes of recording paper in the longitudinal direction (Y) will be described with reference to FIG.

  3A, air Z1 from a cooling fan (not shown) is sent to the upper portion of the fixing belt to cool the fixing film 20 in the R portion outside the area Q of the recording paper.

  The non-sheet-passing area cooling air intake duct 2 is a non-sheet-passing area that is a fixing area where small-size paper (paper having a narrower width than the maximum-size paper) passes through the fixing area Q continuously. This is a duct for cooling the region R.

The non-sheet passing area cooling air intake duct 2 is provided in the vicinity of both ends of the fixing belt 20 in the longitudinal direction, and suppresses the temperature rise of the fixing belt 20 or the non-sheet passing portion of the fixing device.
FIG. 3-B shows a shutter mechanism at the fan outlet.

  A shutter 3 is disposed at the duct exit on the fixing belt side. The shutter 3 is held by a shutter frame 8 and is opened and closed by a pulse motor and a driving gear. A duct opening 9 is provided in the shutter frame. The shutter position is opened to a position corresponding to each paper size by detecting the edge position 4 determined by the paper size by the sensor 5. As a result, it is possible to provide an optimum opening width for the size of the paper to be passed, and to blow with the optimum width.

  Here, the features of the present embodiment will be described with reference to FIGS. 3-A and C. The shutter 3 and the non-sheet passing area cooling intake duct 2 are integrated with each other and move according to the size of the recording sheet. Further, the end wall 107 of the non-sheet-passing area cooling intake duct does not move but is disposed in the vicinity of the end of the fixing film 20.

"Thermistor"
In FIG. 3C, 19 and 18 are two thermistors of main and sub as first and second temperature detecting means. The main thermistor 19 as the first temperature detecting means is disposed on the fixing heater 16 that is a heating body, and in contact with the back surface of the fixing heater 16 in this embodiment, detects the temperature of the back surface of the fixing heater 16.

  The sub-thermistor is in elastic contact with the inner surface of the fixing belt 20 above the heater holder 17 and detects the temperature of the inner surface of the fixing belt 20.

  The main thermistor 19 is disposed near the longitudinal center of the fixing belt 20, and the sub-thermistor 18 is disposed near the end of the fixing heater 16. The main thermistor 19 is disposed in contact with the back surface of the fixing heater 16 and the inner surface of the fixing belt 20.

  The outputs of the main thermistor 19 and the sub-thermistor 18 are connected to a control circuit unit (CPU) 21 via A / D converters 64 and 65, respectively. The control circuit unit 21 outputs the outputs of the main thermistor 19 and the sub-thermistor 18. Based on the above, the temperature control content of the fixing heater 16 is determined, and energization to the fixing heater 16 is controlled by the heater drive circuit unit 28 as a power supply unit (heating means).

"Cooling system configuration"
FIG. 4 is a perspective view of the image forming apparatus, and the cooling air sent from the intake fan 1b outside the recording paper area passes through the opening G1 (\\\\) of the fixing end cooling duct 110 to enter the fixing apparatus 101. b is sent to the fixing belt 20 of b. Further, the cooling air in the recording paper area is downstream of the fixing device 101b and the conveying roller 105b from an opening H (////) formed by the first image cooling duct portion 108 and the second image cooling duct portion 109. Therefore, the toner surface side of the recording paper after fixing is arranged to be cooled.

  Next, in FIG. 5 to FIG. 11, a configuration that cools the fixing film edge outside the image area and the recording paper after fixing the image area variably according to the size of the recording paper with one cooling fan, which is a feature of this configuration. explain.

  First, FIG. 5-A is a perspective view of the vicinity of the paper discharge tray 102b from the fixing device 101b, and FIG. 5-B is a cross-sectional view illustrating the flow of cooling air from the cooling fan 1b.

  Of the air sent from the cooling fan 1b, the cooling air E1 outside the area of the recording paper P3 is directed toward the downstream end of the fixing film 20 of the fixing device 101b (on the side facing the second transfer portion 112). After being guided to the units 110 and 111 and cooled outside the area of the recording sheet P3 of the cooling port fixing film, it is converted into air E2 and exhausted from the air fan 102b to the outside. The reason why the cooling air is applied to the downstream portion of the fixing film 20 is to prevent the air that has finished cooling the fixing film from flowing to the second rotating portion 112 and to exhaust the air reliably from the mechanical fan 102b. .

  Next, the cooling air F in the area of the recording paper P3 is guided by the image cooling duct portions 108 and 109, and the toner surface side of the recording paper is cooled from the opening H in the vicinity of the downstream of the fixing device 101b and the conveying roller 105b. Then, the air is exhausted from the air fan 102b. The reason why the cooling air F is sent to the vicinity of the downstream side of the conveying roller 105b is that the conveying roller 105b directly contacting the recording paper is cooled to increase the cooling efficiency to the recording paper, and the cooling air F is upstream. This is because the exhaust from the mechanical fan 102b is surely performed without escaping.

<Duct structure>
The variable moving configuration of the cooling duct will be described with reference to FIGS.

  6, 7, 8-(A) shows a case where the width of the recording paper is small, and FIGS. 6, 7, 8-(B) show a case where the width of the recording paper is large.

  First, in FIG. 6, the cooling duct is composed of two parts, a first cooling duct 113 (dotted line) and a second cooling duct 114 (solid line). The first cooling duct 113 has an image cooling duct portion 108 and a fixing end portion cooling duct portion 110. The second cooling duct 114 has an image cooling duct portion 109 and a fixing end portion cooling duct portion 111. The first cooling duct 113 (dotted line) and the first cooling duct 114 (solid line) are overlapped with each other so as to form an area of the recording paper P3 (J1 · J2) to form openings H1 and H2. Outside the recording paper region, openings G1 and G2 are formed by movable fixing end cooling duct portions 110 and 111 and fixed walls 107 that do not move.

  The first cooling duct 113 (dotted line) and the second cooling duct 114 are provided with gear portions (115, 116), and the drive from the shutter opening / closing motor is transmitted from the drive gear 117, and the opening portion is recorded on the recording paper. H1 サ イ ズ H2 can be selected according to the size. Further, when the fixing end cooling duct portions 110 and 111 that move and the fixed wall 107 that does not move are the largest, there is a gap between the fixing end cooling duct portions 110 and 111 and the fixed wall 107 as shown in FIG. The cooling air does not flow from the G1 part. This is because the area larger than the fixing film is not a heat source and does not need to be cooled, so the air from the cooling fan is efficiently supplied to the recording paper, and the air sent outside the fixing area is in other parts. It is for preventing it from flowing into.

  Next, in FIG. 7, the first cooling duct 113 (dotted line) and the second cooling duct 114 perform a moving operation by transmitting drive from the drive motor 120 to the gear 121 → the gear 121.

  Thus, when the size of FIG. 8-A is large according to the width of the recording paper P3 as shown in FIG. 8, the cooling air is supplied to the fixing film 20 outside the recording paper area as E3 at the width R3. In the recording paper region, the cooling air F3 is sent directly to the recording paper P3 with a width Q3. If the size shown in FIG. 8B is small, the cooling air E4 is supplied to the fixing film 20 outside the recording paper area with a width R4, and the cooling air F4 is directly supplied to the recording paper P3 within the recording paper area. Sent in Q4.

  FIG. 9 is a cross-sectional view (A) and a perspective view (B) of the cooling fan 1b, the ducts 113 and 114, the fixing device 102b, and the conveying roller 105b of this embodiment. The cooling fan 1b and the ducts 113 and 114 are supported by the image forming apparatus separately from the fixing device 102b. When the fixing device 102b is replaced, only the fixing device can be removed.

  As described above, in this configuration, the region outside the recording paper can be cooled by the overheated fixing film, and the inside of the recording paper can be cooled by the toner of the recording paper after fixing, thereby preventing the paper discharge adhesion. This makes it possible to reduce the cost significantly by using only one fan, which used to be two at the fixing end and one for recording paper.

  In the working system 1, a cooling fan having almost the same size as the heating area of the fixing film was used, but a method using a fan having a width smaller than the heating area of the fixing film and further reducing the cost is shown in FIG. explain.

  First, in FIG. 10-A, the width V5 of the cooling fan 1C is smaller than the width W5 of the fixing film 20, but a regulating wall 122 is provided in the first cooling duct 113 and the second cooling duct 114, and the cooling fan 1C has a small width. Even so, the air is sent uniformly to the width W5 of the large fixing film 20.

As shown in FIG. 10-B, the moving first cooling duct 113 and second cooling duct 114 are moved.
By providing the fixed duct 123 that does not move between the cooling fan 1d and the regulating wall 124 in the fixed duct 123, the width of the cooling fan 1d can be reduced.

  As described above, even if the width of the cooling fan is smaller than the fixing region, the width of the cooling fan is reduced and the cost is accelerated by moving the regulating wall or the X1 direction (the cooling fan is moved away) in the duct. Note that the cross flow fan is used in Conventional Example 1 because the size in the width direction is necessary, but a cheaper axial fan, sirocco fan, or the like can be used if the configuration of Conventional Example 2 is used.

  FIG. 11 shows a configuration when it is not desired to cool the recording sheet after fixing. The fixing film cooling air blowing opening G is the same as that of the working systems 1 and 2. However, if the amount of toner on the thin paper is small, and if it is desired to reduce the curl of the discharged paper, the first shielding shutter 125 and the second shielding shutter 126 that shield the recording paper cooling opening H are overlapped in the longitudinal direction. The drive motor 127 can control the opening and closing of the opening.

1b Cooling fan
101b Fixing device E1 / F Cooling air
102b Mechanical fan P3 recording paper
108 ・ 109 Image cooling duct
105b Transport roller
113 1st cooling duct
114 Second cooling duct
110/111 Fixing edge cooling duct
107 Fixed wall G1, G2, H, H1 opening

Claims (10)

At least one of a pair of rotating members that forms a fixing region by a pressure contact region that is pressed against each other while rotating, and that heat-fixes the unfixed toner image when the transfer material on which the unfixed toner image is formed passes through the fixing region. A fixing member having a heat source on one side, and a conveyance roller for conveying a transfer material downstream of the fixing member;
In order to cool a predetermined region of the fixing member, a non-sheet-passing area cooling duct having a blower opening formed facing the fixing member;
An image cooling duct having a blower opening facing the transfer material to cool the transfer material after fixing downstream of the fixing member, cooling air to the non-sheet passing area cooling duct and the image cooling duct. A cooling device having a cooling fan for blowing air, an exhaust duct for discharging cooled air, and an exhaust fan,
An image forming apparatus characterized in that the position of the non-sheet passing area cooling duct and the image cooling duct is moved in the direction perpendicular to the transfer material conveyance direction (transfer material longitudinal direction) in accordance with a plurality of transfer material widths. .   2. The image forming apparatus according to claim 1, wherein the non-sheet passing area cooling duct and the image cooling duct form a variable size cooling duct.   The size-variable cooling duct is made into two bodies, and the non-sheet-passing area cooling duct is moved in the longitudinal direction of the transfer material according to a plurality of transfer material widths. The image forming apparatus according to claim 1, wherein the image cooling duct cools a transfer material having a transfer material width.   4. The image forming apparatus according to claim 1, further comprising a first driving unit configured to move the longitudinal direction of the transfer material of the variable size cooling duct. 5.   The image forming apparatus according to claim 1, wherein the cooling fan is disposed between the fixing device and the paper discharge roller on the toner adhesion surface side of the transfer material.   6. The cooling air is exhausted to the downstream surface of the fixing member, the non-sheet passing area cooling duct, and the image area cooling duct to the downstream side of the conveying roller. The image forming apparatus described in 1. The image forming apparatus according to claim 1, wherein the variable size duct and the cooling fan are disposed in the main body of the image forming apparatus and are not fixed to the fixing device.   The image forming apparatus according to claim 1, wherein the pre-cooling fan includes a single fan.   The image according to any one of claims 1 to 8, further comprising a blocking shutter that selectively blocks the opening of the image area cooling duct according to the thickness, one side, and usage environment of the transfer material. Forming equipment.   The image forming apparatus according to claim 1, further comprising a second driving unit that selectively drives the blocking shutter.