Fixing device and image forming apparatus

Abstract

To provide an image forming apparatus that can achieve acceleration of fixing processing on thin paper without causing paper jam.SOLUTION: A fixing device has: a fuser 51 that includes a fixing member that is brought into contact with a toner image formed on a recording medium and applies heat and pressure to fix the toner image to the recording medium; and a separation unit 54 that includes a composite fan 540 in which a plurality of fans are arranged in series and separates the recording medium to which the toner image is fixed from the fixing member with air blown from the composite fan.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a fixing device and an image forming apparatus. [Background technology]

[0002] In an electrophotographic image forming apparatus, a toner image is formed on a sheet of paper, and the toner image on the sheet is fixed by a fixing device included in the image forming apparatus, thereby forming an image on the sheet. The fixing device performs a fixing process in which the toner image is fixed on the sheet of paper by conveying the sheet of paper while applying pressure and heat to the sheet of paper in a fixing nip formed by pressing fixing members such as two fixing rollers together.

[0003] Incidentally, the toner in the toner image formed on the paper becomes adhesive when heated while passing through the fixing nip. Therefore, the paper that has passed through the fixing nip may wrap around the surface of the fixing member that has come into contact with the toner image, causing a jam. To address this issue, an air separation technique is known that blows air toward the paper discharge side of the fixing nip to separate the paper from the fixing member.

[0004] In relation to this, the following prior art is disclosed in the following patent document: The passage of paper is detected by detecting the rotation of a rotating member that rotates by contacting paper that has passed through the fixing nip, and the amount of air blown for air separation is controlled according to the time from when the paper is sent to the fixing device to when the passage of the paper is detected. This optimizes the amount of air blown, preventing paper wrapping and jamming and stabilizing the transport position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Application No. 2017-142334 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as the paper transport speed increases, when a relatively thin paper sheet passes through the fixing section, the amount of air for air separation becomes insufficient, and the paper sheet cannot be separated from the fixing member, and the paper sheet may become wrapped around the fixing member, causing a jam. The prior art described in the above patent document cannot address such a problem.

[0007] The present invention has been made to solve such problems, and has an object to provide an image forming apparatus and a fixing device that can realize high-speed fixing processing for thin paper without causing jams. [Means for solving the problem]

[0008] The above-mentioned object of the present invention is achieved by the following means.

[0009] (1) A fixing device including a fixing member that comes into contact with a toner image formed on a recording medium and applies heat and pressure to the toner image to fix the toner image to the recording medium, and a separation unit including a composite fan having a plurality of fans arranged in series, which separates the recording medium on which the toner image has been fixed from the fixing member by air blown out from the composite fan, the separation unit further including a first duct that guides the air blown out by the composite fan to a predetermined blowing position, and the blowing out of a first fan arranged at the final stage of the plurality of fans arranged in series in the composite fan is a blowing direction of the air from the first duct intersects with a blowing direction of the air from the first duct, the first duct has a plurality of bending portions in the air flow path that change the flow direction of the air blown out from the first fan at least three times and guide the air to the predetermined blowing position, and an angle between the blowing direction of the air from the first duct and the flow direction of the air immediately before being changed to the blowing direction of the air from the first duct is smaller than an angle between the blowing direction of the first fan and the flow direction of the air after the flow direction of the air blown out from the first fan is changed for the first time. the fan is a sirocco fan, the composite fan includes a second fan disposed in series with the first fan, and a second duct that guides the air blown out from the second fan in a direction in which the first fan sucks in the air, and an angle formed between a plane perpendicular to a rotation axis of the second fan and a plane perpendicular to the rotation axis of the first fan is an acute angle. , fixing device.

[0010] (2) The fixing device according to (1) above, wherein the composite fans are arranged in a plurality of directions along a width direction of the recording medium, perpendicular to a transport direction of the recording medium.

[0011] (3) The fixing device according to (1) or (2), wherein the separation section blows the air blown out by the composite fan so as to directly hit the fixing member.

[0017] ( 4 ) The second fan is disposed at a position on the opposite side of the transport path of the recording medium with respect to the first fan. 1 ) The fixing device described in

[0019] ( 5 ) the second duct includes a wall parallel to a blowing direction of the air of the second fan, and a wall parallel to a suction direction of the air of the first fan into which the air blown out from the second fan flows, 1 )~( 4 13. The fixing device according to claim 12,

[0020] ( 6 the second fan is disposed such that a surface perpendicular to a rotation axis of the second fan faces an outer wall surface of a housing of the fixing unit and is parallel to the outer wall surface; Any of (1) through (5) The fixing device according to claim 1 .

[0021] (7) The air intake of the second fan However, for the second fan , on the opposite side of the fixing unit Opening The fixing device according to any one of the above (1) to (6).

[0022] ( 8 When the air is blown out from the composite fan, the first fan and the second fan operate simultaneously. 1 )~( 7 13. The fixing device according to claim 12,

[0023] ( 9 ) The first fan and the second fan are driven by the same power.1 )~( 8 13. The fixing device according to claim 12,

[0024] ( 10 ) an image forming unit for forming the toner image on the recording medium; and 9 and an image forming apparatus having the fixing device according to any one of claims 1 to 4. Effect of the Invention

[0025] The air blown out from a composite fan, which is made up of multiple fans arranged in series, separates the recording medium with the fused toner image from the fusing member, enabling high-speed fusing for thin paper without causing paper jams. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus. [Diagram 2] 1 is a block diagram showing a configuration of an image forming apparatus; [Diagram 3] FIG. 2 is a schematic diagram illustrating a configuration of a fixing unit. [Figure 4] FIG. 2 is a schematic diagram illustrating a configuration of a fixing unit. [Diagram 5] FIG. 2 is a perspective view illustrating a configuration of a fixing unit. [Figure 6] 4 is an explanatory diagram for explaining the air blowing direction of the first fan, the air flow direction in the first duct, and the air blowing direction from the first duct. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same elements are given the same reference numerals, and duplicated descriptions will be omitted. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios. In this specification, the angle formed by two directions or surfaces means the smaller angle of the angles formed by the two directions or surfaces.

[0028] Fig. 1 is a schematic diagram showing the configuration of an image forming apparatus 100. Fig. 2 is a block diagram showing the configuration of the image forming apparatus 100. Fig. 3 is a schematic diagram showing the configuration of a fixing section 50.

[0029] The image forming apparatus 100 can be connected to one or more terminals (not shown) for issuing various instructions, such as print instructions, to the image forming apparatus 100 via a network using the communication unit 130. The image forming apparatus 100 forms an image on a sheet of paper 900 based on a print job received from the terminal.

[0030] A print job is a general term for a print command to the image forming apparatus 100, and includes print data and print settings. The print data is data of a document to be printed, and may include various types of data, such as image data, vector data, and text data. Specifically, the print data may be Portable Document Format (PDF) data, Page Description Language (PDL) data, or Tagged Image File Format (TIFF) data. The print settings are settings related to image formation on paper 900, and may include various settings such as the number of pages, the number of copies, the paper type, color or monochrome selection, and page layout.

[0031] The image forming apparatus 100 includes a control unit 110, a storage unit 120, a communication unit 130, an operation display unit 140, an image reading unit 150, an image control unit 160, and an image forming unit 170. These components are communicatively connected to each other via a bus. The image forming apparatus 100 may be configured, for example, by an MFP (Multi Function Peripheral).

[0032] The control unit 110 includes a CPU (Central Processing Unit) and various memories, and controls the above-mentioned units and performs various arithmetic processing according to a program. The operation of the control unit 110 will be described in detail later.

[0033] The storage unit 120 is configured with a solid state drive (SDD) or a hard disc drive (HDD) or the like, and stores various programs and various data.

[0034] The communication unit 130 is an interface for communicating between the image forming apparatus 100 and an external device. A network interface conforming to standards such as Ethernet (registered trademark), SATA, and IEEE1394 is used as the communication unit 130. In addition, various local connection interfaces such as wireless communication interfaces such as Bluetooth (registered trademark) and IEEE802.11 are used as the communication unit 130.

[0035] The operation display unit 140 includes a touch panel, a numeric keypad, a start button, a stop button, and the like, and is used to display various information and input various instructions.

[0036] The image reading unit 150 has a light source such as a fluorescent lamp and an imaging element such as a CCD (Charge Coupled Device) image sensor. The image reading unit 150 shines light from the light source on a document set at a predetermined reading position, photoelectrically converts the reflected light by the imaging element, and generates image data from the electrical signal.

[0037] The image control unit 160 performs layout processing, screening, rasterization processing, etc. of print data included in a print job etc. received by the communication unit 130, and generates image data in a bitmap format. The image data is a CMYK value or RGB value for each pixel.

[0038] The image forming section 170 includes an image creating section 40, a fixing section 50, a paper feeding section 60, and a paper transport section 70.

[0039] (Image creation section 40) The image forming section 40 has image forming units 41Y, 41M, 41C, and 41K corresponding to the toners of the respective colors of Y (yellow), M (magenta), C (cyan), and K (black). Based on image data, the image forming units 41Y, 41M, 41C, and 41K form a toner image on the photoconductor drum 47 through processes of charging, exposure, and development. Exposure is performed by scanning the photoconductor drum 47 with a laser beam. The toner image formed on the photoconductor drum 47, which is an image carrier, is pressed against the photoconductor drum 47 and the primary transfer roller 48 via the intermediate transfer belt 42, and the intermediate transfer belt 42 is rotated and traveled by the driving force of the drive roller 45, so that the toner images are sequentially superimposed on the intermediate transfer belt 42 to form a color toner image. The intermediate transfer belt 42 travels in the sub-scanning direction (the direction of the straight arrow in FIG. 1). The color toner image formed on the intermediate transfer belt 42 is transferred onto the paper 900 being conveyed by the secondary transfer roller 43 and the opposing roller 44 being pressed against each other via the intermediate transfer belt 42 .

[0040] (Fixing unit 50) The fixing section 50 includes a fixing roller 51a, a fixing belt 51b, a heating roller 51c, a pressure roller 51d, a heater 51e, an air separating section 54, and a driving mechanism 55. The fixing section 50 constitutes a fixing device. The fixing belt 51b constitutes a fixing member. The fixing roller 51a, the fixing belt 51b, the heating roller 51c, the pressure roller 51d, and the heater 51e constitute a fixing unit 51. The air separating section 54 constitutes a separating section.

[0041] The fixing belt 51b is an endless belt, and is stretched by the heating roller 51c, the fixing roller 51a, and the like. The fixing belt 51b rotates in the clockwise direction in FIG. 3 by following the rotation of the fixing roller 51a, which is driven to rotate by the driving force of a driving motor (not shown). The fixing roller 51a and the pressure roller 51d are pressed against each other via the fixing belt 51b, thereby forming a fixing nip N between the fixing belt 51b and the pressure roller 51d. The paper 900 conveyed to the fixing unit 50 is heated at a predetermined fixing temperature in the fixing nip N and pressurized to fix (melt and fix) the toner image, and is conveyed by the rotation of the fixing belt 51b and the pressure roller 51d. The fixing temperature is set to, for example, 160 to 200° C. The fixing temperature can be varied depending on the type of paper 900, and the like. The fixing belt 51b is, for example, a PI (polyimide) base body having a thickness of 70 μm, the outer peripheral surface of which is covered with an elastic layer. The elastic layer is made of, for example, heat-resistant silicone rubber (hardness JIS-A30°) having a thickness of 200 μm.The heat-resistant resin is made of, for example, PFA (perfluoroalkoxy) having a thickness of 30 μm.

[0042] Heating roller 51c heats fixing belt 51b by conducting heat generated by built-in heater 51e to fixing belt 51b. Heating roller 51c is composed of, for example, a hollow metal (e.g., aluminum) core and a PFA or PTFE coating formed on the surface. The core is, for example, φ80 mm and 2.5 mm thick. The PFA or PTFE coating is 15 μm thick. Heater 51e is composed of multiple halogen lamps and is disposed in the internal space of the core of heating roller 51c.

[0043] Fixing roller 51a rotates in a clockwise direction in FIG. 3 by the driving force of a drive motor (not shown). The peripheral speed of fixing roller 51a is set to, for example, about 200 mm / s. Fixing roller 51a is indirectly heated by heater 51e via fixing belt 51b. Fixing roller 51a includes, for example, from the inside, a cylindrical metal core, an elastic layer formed on the surface of the core and made of a material such as silicone rubber or foamed silicone rubber, and a release layer such as fluororesin.

[0044] The pressure roller 51d pressurizes the fixing roller 51a through the fixing belt 51b. The pressure roller 51d includes, for example, from the inside, a cylindrical metal core, a foamed silicone rubber elastic layer formed on the surface of the core, and a release layer such as a fluororesin.

[0045] (Air separation section 54) The air separation unit 54 includes a composite fan 540 (see FIG. 4) in which a plurality of fans are arranged in series. "Arranged in series" means that two fans are arranged so that air blown out from one fan is drawn into the other fan. This increases the wind pressure (wind speed) in proportion to the number of fans arranged in series. The wind speed of the wind blown out from the composite fan 540 may be 10 to 80 m / sec. The plurality of fans included in the composite fan 540 of the composite fan 540 are preferably sirocco fans. The plurality of fans included in the composite fan 540 may be axial fans. In the following, as an example, the composite fan 540 will be described as being composed of two sirocco fans, a first fan 540a and a second fan 540b, which are connected in series. The first fan 540a and the second fan 540b are connected in series so that air blown out from the second fan 540b is drawn into the first fan 540a.

[0046] Air separating section 54 blows air blown out from composite fan 540 (i.e., air blown out from first fan 540a) from a predetermined blowing position (hereinafter also simply referred to as "blowing position") to a predetermined blowing position (hereinafter also simply referred to as "blowing position"), which will be described later. In this way, air separating section 54 separates paper 900 on which the toner image is fixed from fixing belt 51b.

[0047] The air separation section 54 will now be described in more detail.

[0048] Fig. 4 is a schematic diagram showing the configuration of fixing unit 50. Fig. 5 is a perspective view showing the configuration of fixing unit 50. Fig. 4 shows first fan 540a and second fan 540b as a partially cutaway view so that the blades of the sirocco fans can be seen.

[0049] As shown in FIG. 4, air blown out by the composite fan 540 (indicated by an outlined arrow in FIG. 4) is guided to a blowing position by a first duct 541. The air guided by the first duct is blown out from the blowing position, which is the output port of the first duct 541, toward a blowing position on the surface of the fixing belt 51b at a predetermined timing before or after the leading edge of the paper 900 passes through the fixing nip N so that the air hits the fixing belt 51b directly. The air that reaches the blowing position flows along the surface of the fixing belt 51b and enters between the fixing belt 51b and the leading edge of the paper 900 on the downstream side in the conveying direction on which the toner image is fixed, thereby separating the paper 900 from the fixing belt 51b. The blowing position can be appropriately set by experiment as a distance from the end of the paper 900 on the downstream side in the conveying direction at the fixing nip N, etc., from the viewpoint of the separation property of the paper 900 from the fixing belt 51b. The blowing position can be appropriately set by experimentation from the viewpoints of whether air can be blown to the blowing position without being obstructed and whether the paper 900 can be separated from the fixing belt 51b. The predetermined timing can be appropriately set by experimentation as the timing at which the paper 900 reaches a position at which air can be efficiently blown between the fixing belt 51b and the leading edge of the paper 900 on the downstream side in the transport direction on which the toner image is fixed.

[0050] When air is blown out from the composite fan 540, the first fan 540a and the second fan 540b are operated simultaneously at a predetermined timing. That is, the first fan 540a and the second fan 540b are controlled to rotate and stop at the same timing. This simplifies the control of the drive mechanism 55 by the control unit 110.

[0051] The first fan 540a and the second fan 540b are fans with the same specifications and are driven with the same electric power, which can increase the efficiency of the electric power relative to the volume of air blown out from the composite fan 540.

[0052] Of the multiple fans of the composite fan 540 arranged in series, the blowing direction d1 (see FIG. 6) of the first fan 540a arranged in the final stage is made to cross the blowing direction d4 (see FIG. 6) of the air from the first duct 541. This makes it possible to avoid the composite fan 540 being located on the transport path of the paper 900.

[0053] The second fan 540b is disposed on the opposite side of the transport path of the paper 900 to the first fan 540a. This makes it possible to avoid the second fan 540b being disposed on the transport path of the paper 900.

[0054] An acute angle is formed between a surface 540b1 perpendicular to the rotation axis of the second fan 540b and a surface 540a1 perpendicular to the rotation axis of the first fan 540a. This makes it possible to prevent interference between the positions of the fixing device 51 and the composite fan 540, and also makes it possible to suppress an increase in the size of the fixing unit 50.

[0055] Second fan 540b can be disposed such that surface 540b1 perpendicular to the rotation axis of second fan 540b faces and is parallel to outer wall surface 51f of the housing of fixation unit 51. This can prevent interference between the positions of fixation unit 51 and second fan 540b, and can bring first fan 540a and second fan 540b closer to each other.

[0056] An air inlet 540b2 of the second fan 540b is directed toward the opposite side of the fuser 51. This makes it possible to reduce the effect of the temperature of the fuser 51 on the combined fan 540.

[0057] The composite fan 540 includes a second duct 542 that guides air blown out from the air blowing direction O2 of the second fan 540b to the air suction direction I1 of the first fan 540a. The second duct 542 includes a wall 542b parallel to the air blowing direction O2 of the second fan 540b and a wall 542a parallel to the air suction direction I1 of the first fan 540a. This allows the air blown out from the second fan 540b to be sent in the air suction direction of the first fan 540a (a direction parallel to the rotation axis of the sirocco fan), thereby suppressing loss of air volume.

[0058] As shown in FIG. 5, a plurality of composite fans 540 (two in the example of FIG. 5) can be arranged along the width direction of the paper 900, which is perpendicular to the transport direction of the paper 900 (the direction indicated by the black arrow in FIG. 5). The air blown out from each of the multiple composite fans 540 is guided to a separate blowing position by each first duct 541, and is blown out from each blowing position toward a separate blowing position at the same timing. The multiple blowing positions to which the air blown out from the multiple composite fans 540 is blown out can be set so that they are equally distant from the end of the fixing nip N on the downstream side in the transport direction of the paper 900. A straight line connecting the multiple blowing positions that have been set is parallel to the rotation axis of the fixing roller 51a.

[0059] FIG. 6 is an explanatory diagram for explaining the direction in which air is blown out of first fan 540a, the direction in which air flows inside first duct 541, and the direction in which air is blown out of first duct 541. As shown in FIG.

[0060] The first duct 541 has a plurality of bent portions c1 to c3 in the air flow path, which change the flow direction of the air blown out from the first fan 540a a plurality of times and guide the air to the blowing position. The bent portions c1 to c3 can be configured as bends of the inner wall of the first duct 541 with respect to the flow direction of the air. As a result, as shown by the outline arrows in FIG. 6, the air blown out in the blowing direction d1 of the first fan 540a flows along the shape of the inside (inner wall) of the first duct 541, and the flow direction changes in this order to the flow direction d2 and the flow direction d3. And finally, the flow direction of the air changes to the blowing direction d4 of the air from the first duct 541. That is, the first duct 541 can change the flow direction of the air blown out in the blowing direction d1 of the first fan 540a a plurality of times and guide the air to the blowing position. As a result, the air flow direction is not changed significantly, so that loss of the air blowing volume can be suppressed and the volume occupied by the air separation section 54 can be reduced. Also, the angle θ1 between the blowing direction d4 of the air from the first duct 541 and the flow direction d3 of the air immediately before being changed to the blowing direction d4 is made smaller than the angle θ2 between the blowing direction d1 of the first fan 540a and the flow direction d2 after the flow direction of the air blown out from the first fan 540a is changed for the first time. As a result, the change in the air flow direction is made larger in the region with a smaller flow velocity (region with a larger cross-sectional area of ​​the flow path), so that loss of the air blowing volume can be suppressed.

[0061] The paper 900 on which the toner image has been fixed by the fixing unit 50 is discharged onto a paper discharge tray 90 as a printed matter.

[0062] The paper feed section 60 has a plurality of paper feed trays 61 and 62, and sends out the paper 900 stored in the paper feed trays 61 and 62 one by one to a downstream transport path.

[0063] Next, the operation of the control unit 110 will be described in detail.

[0064] When control unit 110 receives a print job via communication unit 130, image control unit 160 performs rasterization processing of the print data to generate image data, and image creating unit 40 forms a toner image on paper 900 based on the image data. Control unit 110 fixes the toner image on paper 900 to paper 900 by conveying paper 900 while applying pressure and heat at fixing nip N between fixing belt 51b and pressure roller 51d.

[0065] The control unit 110 sends a control signal to the drive mechanism 55 to operate the first fan 540a and the second fan 540b simultaneously with the same power, so that air is blown from the blowing position, which is the outlet of the first duct 541, to the blowing position on the surface of the fixing belt 51b. At this time, the control unit 110 operates the first fan 540a and the second fan 540b at the above-mentioned predetermined timing. This causes the paper 900 to be separated from the fixing belt 51b.

[0066] The control unit 110 discharges the paper 900 onto which the toner image has been fixed onto the paper discharge tray 90.

[0067] The above-described embodiment provides the following advantages.

[0068] The air blown out from a composite fan, which is made up of multiple fans arranged in series, separates the recording medium with the fused toner image from the fusing member, enabling high-speed fusing for thin paper without causing paper jams.

[0069] Furthermore, multiple pairs of composite fans are arranged along the width direction of the paper, which is perpendicular to the transport direction of the recording medium, so that air is blown uniformly across the width direction of the recording medium, making it possible to more effectively separate the recording medium from the fixing member.

[0070] Furthermore, the air blown out by the composite fan 540 is guided through the first duct 541 and is blown so as to directly hit the fixing member from the first duct 541. This allows the air to flow along the surface of the fixing member, improving the performance of separating the recording medium from the fixing member.

[0071] Furthermore, a first duct is provided to guide the air blown out by the composite fan to a predetermined blowing position, and the blowing direction of the first fan arranged at the final stage among the multiple fans arranged in series in the composite fan is made to intersect with the blowing direction of the air from the first duct. This makes it possible to avoid placing the composite fan 540 on the transport path of the paper 900.

[0072] Furthermore, the first duct has multiple bends in the air flow path that change the flow direction of the air blown out from the first fan multiple times and guide it to a specified blowing position. This prevents the air flow direction from changing significantly, suppressing loss of the air flow volume and reducing the size of the device.

[0073] Furthermore, the angle between the blowing direction of the air from the first duct and the flow direction of the air immediately before it is changed to the blowing direction of the air from the first duct is made smaller than the angle between the blowing direction of the first fan and the flow direction of the air after the flow direction of the air blown from the first fan is changed for the first time. This makes it possible to suppress loss of the blowing volume of air by making the change in the flow direction of the air larger in the area with a slower flow velocity.

[0074] Furthermore, each of the multiple fans is a sirocco fan. By using a sirocco fan that has a larger air volume than an axial fan, etc., it is possible to easily increase the volume of air for separating the recording medium from the fixing member.

[0075] Furthermore, the composite fan includes a second fan disposed in series with the first fan, and a second duct that guides the air blown out from the second fan in the direction of the air intake of the first fan, thereby preventing air leakage and reducing loss of the blowing volume.

[0076] Furthermore, the second fan is installed on the opposite side of the transport path of the recording medium from the first fan, which makes it possible to avoid placing the second fan on the transport path of the recording medium.

[0077] Furthermore, the angle between the plane perpendicular to the rotation axis of the second fan and the plane perpendicular to the rotation axis of the first fan is set to an acute angle, which prevents interference between the fixing unit and the composite fan and suppresses an increase in the size of the device.

[0078] Furthermore, the second duct is configured to include a wall parallel to the direction in which the second fan blows out air, and a wall parallel to the direction in which the first fan draws in air into which the air blown out from the second fan flows in. This makes it possible to suppress loss of air volume.

[0079] Furthermore, the second fan is disposed so that a surface perpendicular to the rotation axis of the second fan faces an outer wall surface of the housing containing the fixing unit and is parallel to the outer wall surface, thereby preventing interference between the fixing unit and the second fan and enabling the first fan and the second fan to be located close to each other.

[0080] In addition, the air intake of the second fan is directed toward the opposite side of the fuser, which reduces the effect of the fuser temperature on the composite fan.

[0081] Furthermore, when air is blown out from the composite fan, the first fan and the second fan are operated simultaneously, which simplifies the control of the drive mechanism of the composite fan by the control unit.

[0082] Furthermore, the first fan and the second fan are driven with the same power, which increases the power efficiency relative to the volume of air blown out from the composite fan.

[0083] The present invention is not limited to the above-described embodiments.

[0084] For example, in the embodiment, the recording medium is paper, but the recording medium is not limited to paper and may be a resin film or the like.

[0085] Furthermore, in the embodiment, an example has been described in which the composite fan is composed of two sirocco fans, but the composite fan may be composed of three or more sirocco fans or axial fans.

[0086] Furthermore, in the embodiment, an example has been described in which two composite fans are arranged in a direction perpendicular to the paper transport direction, but three or more composite fans may be arranged.

[0087] In the embodiment, the air blown out by the combined fan 540 is guided by the first duct 541 and is blown from the first duct 541 so as to directly hit the fixing member. However, the first duct 541 may not be provided and the air blown out by the combined fan 540 may be blown so as to directly hit the fixing member.

[0088] Furthermore, in the embodiments, a part or all of the processing executed by the program may be replaced with hardware such as a circuit. [Explanation of symbols]

[0089] c1, c2, c3 bending section, I1 Air intake direction, O2 air blowing direction, N fixing nip, 40 Imaging section, 50 Fixing section, 51 Fixing unit, 51a fixing roller, 51b Fixing belt, 51c heated roller, 51d Pressure roller, 51e heater, 51F exterior wall, 54 Air separation section, 55 Drive mechanism, 60 Paper feed section, 70 Paper transport section, 100 Image forming apparatus, 110 control section, 120 storage section, 130 Communications Department, 140 Operation display section, 150 Image reading unit, 160 Image control unit, 170 Image forming unit, 540 composite fan, 540a 1st fan, 540b 2nd fan, 541 1st Duct, 542 2nd Duct, 900 Paper.

Claims

1. a fixing unit including a fixing member that comes into contact with a toner image formed on a recording medium and applies heat and pressure to the toner image to fix the toner image to the recording medium; a separation unit including a composite fan in which a plurality of fans are arranged in series, and which separates the recording medium, on which the toner image is fixed, from the fixing member by air blown out from the composite fan; The separation unit further includes a first duct that guides the air blown out by the composite fan to a predetermined blowing position, a blowing direction of a first fan arranged in a final stage among the plurality of fans arranged in series in the composite fan intersects with a blowing direction of the air from the first duct, the first duct has a plurality of bent portions in a flow path of the air that changes a flow direction of the air blown out from the first fan at least three times and guides the air to the predetermined blowing position; an angle between a blowing direction of the air from the first duct and a flow direction of the air immediately before being changed to the blowing direction of the air from the first duct is smaller than an angle between a blowing direction of the first fan and a flow direction of the air after the flow direction of the air blown out from the first fan is initially changed, The fan is a sirocco fan, the composite fan includes a second fan disposed in series with the first fan, and a second duct that guides the air blown out from the second fan in a direction in which the air is sucked into the first fan, a plane perpendicular to the rotation shaft of the second fan and a plane perpendicular to the rotation shaft of the first fan form an acute angle.

2. The fixing device according to claim 1 , wherein the composite fan is arranged in a width direction of the recording medium, the width direction being perpendicular to a transport direction of the recording medium.

3. The fixing device according to claim 1 , wherein the separating section blows the air blown out by the composite fan so as to directly hit the fixing member.

4. The fixing device according to claim 1 , wherein the second fan is disposed at a position opposite to the first fan in a transport path of the recording medium.

5. The fixing device according to any one of claims 1 to 4, wherein the second duct includes a wall parallel to the air blowing direction of the second fan, and a wall parallel to the air suction direction of the first fan into which the air blown out from the second fan flows.

6. The fixing device according to any one of claims 1 to 5, wherein the second fan is arranged so that a surface perpendicular to the rotation axis of the second fan faces an outer wall surface of a housing of the fixing unit and is parallel to the outer wall surface.

7. 7. The fixing device according to claim 1, wherein the air inlet of the second fan opens on a side opposite to the fixing unit with respect to the second fan.

8. 8. The fixing device according to claim 1, wherein the first fan and the second fan operate simultaneously when the air is blown out from the composite fan.

9. 9. The fixing device according to claim 1, wherein the first fan and the second fan are driven by the same power.

10. an image forming unit for forming the toner image on the recording medium; A fixing device according to any one of claims 1 to 9, An image forming apparatus comprising:

Images