JP2007206275A - Heat fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat fixing device and an image forming apparatus which are constituted in such a manner that vapor on the surface of a pressing rotator is removed, then, the force with which a recording material is gripped by the pressing rotator is maintained, and consequently failure in recording material conveyance and an image defect due to the failure are prevented. <P>SOLUTION: The heat fixing device 1 includes a heating element 20 having a heater 21, and the pressing rotator 25 that forms a fixing nip N together with the heating element 20, and the heat fixing device 1 conveys a recording material S with an unfixed image thereon through the fixing nip N, thereby fixing the unfixed image on the recording material S into a permanent image, wherein a duct means 33 is provided in which a path for a current of air is formed in the axial direction of the pressing rotator 25, and air is blown against the surface of the pressing rotator 25 from the duct means 33. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a heating body having a heater and a pressure rotating body such as a pressure roller that forms the heating body and a fixing nip portion, and passes a recording material holding an unfixed image to the fixing nip portion. The present invention relates to a heat fixing device that fixes an unfixed image on a recording material as a permanent image, and an image forming apparatus including the heat fixing device.

  Conventionally, a contact heating type fixing device has been widely used as a method of fixing an unfixed image formed on a sheet-like recording material such as recording paper in an image forming apparatus such as a copying machine, a printer, or a facsimile. In particular, in recent years, from the viewpoint of energy saving, a film heating type heat fixing device (hereinafter simply referred to as “film heat fixing device”) having high heat conduction efficiency and a fast rise in temperature has been widely used.

  This film heat fixing device is disclosed in, for example, Patent Documents 1, 2, and 3 and the like.

  The film heating and fixing device is a heat-resistant film that is brought into pressure contact with a heater (heat source) by a pressure roller as a pressurizing rotator and is slid and conveyed, and the fixing nip portion is formed between the heater and the pressure roller with the film interposed therebetween. Form. Then, a recording material carrying an unfixed image is introduced into the fixing nip portion and conveyed together with the film, whereby an unfixed image is formed by heat from a heater applied through the film and a pressing force of the fixing nip portion. It is fixed as a permanent image on the recording material.

  Such a film heat fixing device is used in image forming apparatuses such as a copying machine, a laser beam printer, a facsimile, a microfilm reader printer, an image display (display) device, and a recording machine.

  That is, in these image forming apparatuses, a latent image corresponding to target image information is formed on the image carrier by an appropriate image forming process means such as electrophotography, electrostatic recording, magnetic recording, etc., and this latent image is heated. A visible image (toner image) is formed using a toner made of a meltable resin or the like. Next, this toner image is transferred directly to the surface of a recording material (transfer material sheet, electrofax sheet, electrostatic recording sheet, printing paper, etc.) or via an intermediate transfer member, and is not fixed on the recording material surface. A toner image is formed. The film heat fixing device can be used as an image fixing device that heat-fixes the unfixed toner image as a permanently fixed image.

  As a heating element (heat source) having a low heat capacity and a high temperature rise, a ceramic heater having a low heat capacity and a high temperature rise is generally used. The ceramic heater has a heat-resistant, insulating, and heat-conductive ceramic material substrate and a heating resistor as a heating element that is formed on the substrate by means of printing, baking, etc. To generate heat.

  As this film heating and fixing apparatus, there is a system (film direct drive system) in which a film is transported between a pressure roller while applying tension using a film transport roller dedicated to transporting the film and a driven roller. Further, a system (pressure roller driving system) is known in which a film is loosely fitted to a support member that rotatably guides the film and the pressure roller is driven so that the film is driven to rotate with respect to the pressure roller. In recent years, the latter pressure roller drive system that does not require film tension management or offset control, and that can be reduced in size and cost is often employed.

  FIG. 6 is a cross-sectional view showing a schematic configuration of a laser beam printer which is an example of a conventional electrophotographic image forming apparatus.

  As shown in FIG. 6, in the image forming apparatus 1, a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 4 as an image carrier incorporated in a process cartridge 3 is uniformly formed by a charging roller 3a. Is charged. Next, the photosensitive drum 1 is irradiated with a laser L based on the obtained image information by the scanner 2, and a latent image is formed on the photosensitive drum 4. This latent image is developed by the developing roller 3b, which is a developer carrying member that carries and conveys the toner that constitutes the developing means, and becomes a toner image.

  On the other hand, the recording material S stacked on the recording material stacking plate 6 in the paper feed cassette 5 is fed while being separated one by one by the paper feed roller 7 and the separation pad 8, and the intermediate roller 9 and the transport roller 10. Is further conveyed downstream. On the conveyed recording material S, the toner image formed on the photosensitive drum 4 is transferred by the transfer roller 11.

  The recording material S on which the unfixed toner image is formed is conveyed further downstream, and the toner image is fixed by the film heat fixing device 12 having a heat source therein. Thereafter, the recording material S is discharged to the outside by the discharge roller 14 through the intermediate discharge roller 13.

  On the other hand, the transfer residual toner is removed from the photosensitive drum by a cleaning blade 3c constituting a cleaning unit, and the photosensitive drum is used for the next image formation.

  FIG. 7 is a schematic configuration diagram of the pressure roller driving type film heating and fixing device 12.

  With reference to FIG. 7, an outline of the pressure roller driving type film heating and fixing device 12 will be described.

  The film heating and fixing device 12 of this example uses a cylindrical film as a heat-resistant film as disclosed in, for example, Patent Documents 4 and 5, and rotates the film with a pressure roller as a pressure member. It is.

  The film heating and fixing device 12 includes a heating element 20 which is a horizontally long and thin plate-like heating element (hereinafter referred to as a “heater”) 21 having a vertical direction with respect to the drawing in FIG. A semicircular laterally long film guide / heater support 22 is provided.

  The heater 21 is supported at the center of the lower surface of the heater support 22 along the length of the support. For fixing the heater 21 to the heater support 22, there are methods using a heat-resistant adhesive or the like, or using a connector or a clip without bonding, but recently the latter which does not use equipment for drying the adhesive. This method is often adopted. The heater support 22 is loosely fitted on the inner periphery of the film 23 with a substantially semicircular outer cross section.

  At both ends of the heater support 22, flange members 24 that receive the end of the fixing film and restrict the movement of the fixing film 23 are disposed.

  The film heat fixing device 12 includes an elastic pressure roller 25 as a pressure member. The heater support 22 is urged toward the elastic pressure roller 25 by urging the flange member 24 with a spring member 26 that is a pressure means, and the fixing nip portion N is placed between the heater support 22 and the elastic pressure roller 25. Is forming. In other words, the elastic pressure roller 25 is heated to a required width by sandwiching the fixing film 23 between the heater support 22 and the lower surface of the heater 21 and pressing them against each other with a predetermined contact pressure against the roller elasticity. A fixing nip portion N as a portion is formed.

  The pressure roller 25 is rotationally driven in a counterclockwise direction indicated by an arrow by a driving unit (not shown). A rotational force acts on the film 23 by the pressure friction force in the fixing nip N between the outer surface of the roller 25 and the outer surface of the film 23 due to the rotation of the pressure roller 25. As a result, the film 23 rotates following the outer periphery of the heater support 22 in the clockwise direction indicated by an arrow while the inner surface of the film 23 slides in contact with the lower surface of the heater 21. The heater support 22 also serves as a guide for the rotating film 23.

  As the heater 21, a low-heat-capacity ceramic heater having a ceramic substrate and a heating resistor formed by printing and firing on the substrate surface as a basic component is generally used.

  The film 23 is rotated by the rotation of the pressure roller 25, and the heater 21 generates heat by energization and is adjusted to a predetermined temperature. In this state, the recording material S as a heated material on which the unfixed toner image T is formed and supported between the film 23 and the pressure roller 25 in the fixing nip portion N passes through the fixing inlet guide 32 and the toner image. It is introduced with the surface facing the film 23. By moving the fixing nip N together with the film 23, the recording material S is heated by the heater 21 through the film 23 in the fixing nip N, and the unfixed toner image T is softened and melted and fixed. The recording material S that has passed through the fixing nip N is separated from the surface of the film 23 and conveyed.

  In the film heating and fixing device 12, substantially no tension is applied to the film 23 except for the fixing nip portion N in the rotation state of the film 23 driven by the pressure roller 25. Therefore, the film shift movement force along the length of the heater support 22 accompanying the rotation of the film 23 is small, and the film shift movement control means can be simplified. Therefore, there are advantages such as easy assembling and cost reduction.

  In the recording material conveyance direction, on the downstream side of the fixing nip portion N, an upper discharge guide 28 for guiding the recording material and a lower discharge guide 30 are arranged to face each other. The upper discharge guide 28 holds a roller 27, and the lower discharge guide 30 holds a discharge roller 29. The roller 27 and the discharge roller 29 form a conveyance nip for nipping and conveying the recording material S.

  The interval formed by the upper discharge guide 28 and the lower discharge guide 30 is configured to be gradually narrowed in order to facilitate and stabilize the introduction of the recording material into the discharge nip formed by the roller 27 and the discharge roller 29. Yes.

  The flange member 24, the pressure roller 25, the upper discharge guide 28, and the lower discharge guide 30 are disposed on the frame 31.

The heated recording material is guided by an upper discharge guide 28 and a lower discharge guide 30, nipped and conveyed by a roller 27 and a discharge roller 29 that form a conveyance nip, and discharged outside the apparatus.
JP-A-63-313182 Japanese Patent Laid-Open No. 1-263679 Japanese Patent Laid-Open No. 2-157878 JP-A-4-44075 JP-A-4-204980

  However, the conventional film heat fixing apparatus has the following drawbacks.

  In the above configuration, when the recording material S which has been left in a high humidity environment for a long time and is sufficiently damp is used for printing, it is included in the recording material S at the fixing nip portion N between the pressure roller 25 and the fixing film 23. Moisture generated is instantly evaporated and water vapor is generated.

  On the other hand, as shown in FIG. 7, the pressure roller 25 is disposed in a space surrounded by a lower discharge guide 30, a fixing frame 31, and a fixing insertion guide 32.

  Here, since the toner T is placed on the printing surface of the recording material S, a film of the toner T is formed. Therefore, the water vapor from the recording material S is released to the pressure roller 25 side and drifts to the periphery. When continuous printing is performed, the water vapor fills around the lower discharge guide 30, the fixing frame 31, and the fixing insertion guide 32 surrounding the pressure roller 25.

  As a result, there is a problem that the pressure roller 25 is damp and the grip force between the recording material S and the pressure roller 25 is reduced, causing the recording material S to slip.

  In addition, since the recording material S slips and the conveyance of the recording material S is delayed, the conveyance speed of the pressure roller 25 becomes extremely slower than the conveyance speed of the image transfer unit, and the recording material S is loosened, whereby the inside of the image forming apparatus 1. This causes rubbing against the member and image defects. Further, the conveyance of the recording material S is delayed, so that the paper detection sensor provided in the conveyance path of the image forming apparatus 1 determines that the recording material S is not conveyed, and stops the apparatus. Jam sometimes occurred.

  In addition, in the image transfer portion where the transfer roller 11 is disposed and the fixing nip portion N of the pressure roller 25, the unfixed toner T transferred onto the recording material S is stopped by the conveyance of the recording material S being stopped. There was a problem that the image was disturbed by the impact, resulting in an image defect.

  Accordingly, an object of the present invention is to eliminate the water vapor adhering to the surface of the pressurizing rotator, maintain the grip force between the recording material and the pressurizing rotator, and eliminate the conveyance failure of the recording material and the accompanying image defects. And providing an image forming apparatus.

The above object is achieved by the heat fixing apparatus and the image forming apparatus according to the present invention. In summary, according to the first aspect of the present invention, a heating body having a heat source, a cylindrical film that rotates while being in contact with the heating body, and a fixing nip portion are formed together with the heating body via the film. And a pressure rotator for driving the film, heating and fixing the recording material holding an unfixed image through the fixing nip portion and fixing the unfixed image on the recording material as a permanent image. In the device
There is provided a heat fixing device provided with duct means having an air passage along the axial direction of the pressurizing rotator, and blowing air from the duct means to the surface of the pressurizing rotator.

  According to a second aspect of the present invention, the image forming means for forming an unfixed image on a recording material, and the heat fixing device for heat-fixing the unfixed image on the recording material are provided. An image forming apparatus is provided.

  According to the present invention, air is taken in from one end of the heat fixing device, and the air is discharged in the longitudinal direction of the pressurizing rotary body by the fixing duct means in which the air passage is formed in the axial direction of the pressurizing rotary body, and the pressurizing rotation Water vapor adhering to the body surface can be removed. Therefore, the rotating body for pressurization can convey the recording material without being dampened, and can prevent conveyance failure, jamming, and image failure.

  Embodiments of a heat fixing device and an image forming apparatus according to the present invention will be described below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.

Example 1
FIG. 1 shows a schematic configuration of an embodiment of the image forming apparatus of the present invention. In this embodiment, the image forming apparatus is an electrophotographic laser beam printer, and has the same configuration as the conventional laser beam printer described above with reference to FIG. Accordingly, members having the same configuration and function are denoted by the same reference numerals, and the overall configuration of the laser beam printer of this embodiment will be described below.

  Referring to FIG. 1, a laser beam printer 1 as an image forming apparatus according to the present embodiment includes a drum-shaped electrophotographic photosensitive member as an image carrier, that is, a photosensitive drum 4. It is rotated clockwise.

  The photosensitive drum 4 is uniformly charged by a charging roller 3a as a charging unit. The uniformly charged photosensitive drum 1 is irradiated with a laser L based on image information by an exposure device 2 such as a laser beam scanner as an exposure unit, and a latent image is formed on the photosensitive drum 4. This latent image is developed by the developing roller 3b, which is a developer carrying member that carries and conveys the toner that constitutes the developing means, and becomes a toner image.

  On the other hand, a sheet-like recording material S such as recording paper stacked on a recording material stacking plate 6 in the paper feeding cassette 5 is fed while being separated one by one by a paper feeding roller 7 and a separation pad 8. It is further conveyed downstream by the intermediate roller 9 and the conveying roller 10. On the conveyed recording material S, the toner image on the photosensitive drum 4 formed by the image forming unit as described above is transferred by the transfer roller 11.

  The recording material S on which the unfixed toner image is formed is conveyed further downstream, and the toner image is fixed by the film heat fixing device 12 having a heat source therein. Thereafter, the recording material S is discharged to the outside by the discharge roller 14 through the intermediate discharge roller 13.

  On the other hand, the transfer residual toner is removed from the photosensitive drum by a cleaning blade 3c constituting a cleaning unit, and the photosensitive drum is used for the next image formation.

  In this embodiment, the photosensitive drum 4, the charging unit 3 a, the developing unit 3 b, and the cleaning unit 3 c are unitized as one unit to constitute the process cartridge 3. The process cartridge 3 can be attached to and detached from the image forming apparatus main body by opening the openable / closable cartridge cover 15.

  In this embodiment, the process cartridge 3 has a configuration in which the photosensitive drum 4, the charging unit 3a, the developing unit 3b, and the cleaning unit 3c are integrated as a unit, but the present invention is not limited to this. The cartridge 3 may include at least one of the photosensitive drum 4 and at least one process unit, that is, a charging unit 3a, a developing unit 3b, a cleaning unit 3c, and the like.

  FIG. 2 is a schematic configuration diagram of the pressure roller driving type film heating and fixing device 12.

  Referring to FIG. 2, the overall structure of the film heat fixing device 12 of this embodiment is the same as that of the conventional film heat fixing device described with reference to FIG. Accordingly, members having the same configuration and function are denoted by the same reference numerals, and first, the overall configuration of the film heating and fixing apparatus of this embodiment will be described first.

  In this embodiment, the film heat fixing device 12 includes a heating body 20 and a pressure roller 25. The heating element 20 includes a horizontally long and thin plate-like heating element (heat source) whose longitudinal direction is the longitudinal direction with respect to the drawing, that is, a heater 21 and a horizontally long saddle type film guide / heater support 22 having a substantially semicircular cross section. I have.

  The heater 21 is supported at the center of the lower surface of the heater support 22 along the length of the support. The heater 21 can be fixed to the heater support 22 by using a heat-resistant adhesive or the like, or by using a connector or a clip without bonding. The heater support 22 is loosely fitted on the inner periphery of the film 23 with a substantially semicircular outer cross section.

  At both ends of the heater support 22, flange members 24 that receive the end of the fixing film and restrict the movement of the fixing film 23 are disposed.

  The film heat fixing device 12 includes an elastic pressure roller 25 as a pressure member that is a pressure rotating body. The heater support 22 is urged toward the elastic pressure roller 25 by urging the flange member 24 with a spring member 26 that is a pressure means, and the fixing nip portion N is placed between the heater support 22 and the elastic pressure roller 25. Is forming. In other words, the elastic pressure roller 25 is heated to a required width by sandwiching the fixing film 23 between the heater support 22 and the lower surface of the heater 21 and pressing them against each other with a predetermined contact pressure against the roller elasticity. A fixing nip portion N as a portion is formed.

  The pressure roller 25 is rotationally driven in a counterclockwise direction indicated by an arrow by a driving unit (not shown). A rotational force acts on the film 23 by the pressure friction force in the fixing nip N between the outer surface of the roller 25 and the outer surface of the film 23 due to the rotation of the pressure roller 25. As a result, the film 23 rotates following the outer periphery of the heater support 22 in the clockwise direction indicated by an arrow while the inner surface of the film 23 slides in contact with the lower surface of the heater 21. The heater support 22 also serves as a guide for the rotating film 23.

  As the heater 21, a ceramic heater having a low heat capacity is generally used which includes a ceramic substrate and a heating resistor formed by printing and firing on the substrate surface.

  The film 23 rotates by the rotation of the pressure roller 25, and the heater 21 generates heat by energization and is adjusted to a predetermined temperature. In this state, the recording material S as a heated material on which the unfixed toner image T is formed and supported between the film 23 and the pressure roller 25 in the fixing nip portion N passes through the fixing inlet guide 32 and the toner image. It is introduced with the surface facing the film 23. By moving the fixing nip N together with the film 23, the recording material S is heated by the heater 21 through the film 23 in the fixing nip N, and the unfixed toner image T is softened and melted and fixed. The recording material S that has passed through the fixing nip N is separated from the surface of the film 23 and conveyed.

  In the recording material conveyance direction, on the downstream side of the fixing nip portion N, an upper discharge guide 28 for guiding the recording material S and a lower discharge guide 30 are arranged to face each other. The upper discharge guide 28 holds a roller 27, and the lower discharge guide 30 holds a discharge roller 29. The roller 27 and the discharge roller 29 form a conveyance nip for nipping and conveying the recording material S.

  The interval formed by the upper discharge guide 28 and the lower discharge guide 30 is configured to be gradually narrowed in order to facilitate and stabilize the introduction of the recording material into the discharge nip formed by the roller 27 and the discharge roller 29. Yes.

  The flange member 24, the pressure roller 25, the upper discharge guide 28, and the lower discharge guide 30 are disposed on the frame 31.

  The heated recording material S is guided by an upper discharge guide 28 and a lower discharge guide 30, nipped and conveyed by a roller 27 and a discharge roller 29 that form a conveyance nip, and discharged outside the apparatus.

  Next, with reference to FIG. 3 and FIG. 4 as well, characteristic portions of the film heat fixing apparatus and the image forming apparatus of this embodiment will be described.

  Also in the film heat fixing apparatus of the present embodiment, the water contained in the recording material S is instantly evaporated by the heat of fixing at the fixing nip portion N to become water vapor. Since a film made of the toner T is stretched on the image forming surface side where the toner T of the recording material S is placed, most of the water vapor of the recording material S is on the non-image forming surface side, that is, the pressure roller 25 side. Released. For this reason, water vapor drifts around the pressure roller 25 and flows into the fixing frame 31, the inlet guide 32, and the lower discharge guide 30 that surround the pressure roller 25 depending on the rotation direction.

  Therefore, according to this embodiment, the fan 16 is provided on the side surface of the image forming apparatus 1 and rotated in the suction direction so that outside air outside the apparatus is taken into the apparatus.

  On the other hand, in the heat fixing device 12, duct means for forming an air passage extending along the longitudinal direction of the pressure roller 25, that is, a fixing duct 33 is provided, and air from the fan 16 is sent in.

The fixing duct 33 can be provided anywhere around the pressure roller 25. According to this embodiment, the recording material S is shown in FIG. 2 from the vertical line Lv passing through the center O ₂₅ of the pressure roller 25. Is disposed downstream in the conveying direction (left side in FIG. 2). Further, structurally, it is disposed in a space formed between the lower discharge guide 30, the pressure roller 25, and the fixing frame 31. That is, from the vertical line Lv passing through the center O ₂₅ of the pressure roller 33, on the downstream side in the conveyance direction of the recording material S (left side in FIG. 2) and from the horizontal line Lh passing through the center O ₂₅ of the pressure roller 33. It is disposed in a space formed by the lower discharge guide 30, the pressure roller 25, and the fixing frame 31 on the downstream side in the conveyance direction of the recording material S (left side in FIG. 2).

  Further, the fixing duct 33 is not limited to this, but in this embodiment, the fixing duct 33 is separated from the surface of the pressure roller 25 by a predetermined distance on the side facing the pressure roller 25 of the fixing duct 33, and The curved surface 34 is provided along the surface of the pressure roller 25. A large number of holes, that is, air outlets 35 are formed in the curved surface 34.

  As shown in FIG. 4, in this embodiment, the end 33 a of the fixing duct 33 on the same side as the fan 16 is an open air intake port, and the fixing duct 33 on the side opposite to the air intake port 33 a is formed. The end 33b is closed.

  Therefore, as shown in FIG. 3, the air sent by the fan 16 flows into the fixing duct 33 from the air intake port 33a of the fixing duct 33, and the inside of the fixing duct 33, that is, the longitudinal direction of the pressure roller 25, that is, , Flowing along the axial direction. The flowing air is closed at the opposite side 133 b of the air intake port 33 a of the fixing duct 33, so that the air taken in from one end through a large number of holes 35 provided in the vicinity of the pressure roller 125 of the fixing duct 133. And is blown onto the surface of the pressure roller 25. Thereby, the water vapor adhering to the surface of the pressure roller 25 can be removed.

  Therefore, the recording material S is conveyed by the pressure roller 25 without being slipped by the water vapor generated in the fixing nip portion N, and the image is fixed.

  Further, since air can be blown over the entire length in the longitudinal direction against the pressure roller 25, there is no pressure roller surface temperature difference due to the difference in the air volume in the lengthwise direction of the pressure roller 25. It is possible to prevent the fixing film from being broken due to the difference in thermal expansion of the pressure roller 25.

  Further, by providing the fixing duct 33 between the pressure roller 25 and the frame 31, the heat fixing device can be reduced in size.

  In this embodiment, the shape of the many holes 35 provided in the pressure roller vicinity surface 34 of the fixing duct 33 is shown as a round hole shape, but the same effect can be obtained when the hole shape is other than the round hole. Therefore, the shape is not limited.

  Further, in this embodiment, the fixing duct 33 is composed of separate parts from the lower discharge guide 30, the frame 31, and the fixing inlet guide 32, but the duct shape is changed to the lower discharge guide 30, the frame 31, and the fixing inlet guide 32. Therefore, the structure is not limited.

Example 2
With reference to FIG. 5, another embodiment of the film heat fixing device 12 of the present invention will be described.

  In addition, the same reference number is attached | subjected to what comprises the structure and function similar to Example 1, and description is abbreviate | omitted.

  According to this embodiment, in one embodiment, the shape of the hole 35 provided in the surface 34 of the fixing duct 33 facing the pressure roller 25 is set in the longitudinal direction of the pressure roller 25 as shown in FIG. The number of holes 35 is changed. In another embodiment, the size of the hole 35 is changed as shown in FIG. With this configuration, it becomes possible to blow air evenly on the surface of the pressure roller 25.

  In the present embodiment, as described above, the number of holes 35 and the size of the holes 35 are increased with respect to the air flow taken from outside the machine, or the number of holes is increased toward the downstream. The shape of was to be increased. However, since it varies depending on the air volume, the shape of the fixing duct, etc., it is not limited to the above embodiment.

  In the above embodiment, in the heat fixing apparatus 12 of the present invention, the pressing rotator 25 is described as a pressure roller, but other forms such as an endless belt may be used.

1 is a schematic sectional view showing an embodiment of an image forming apparatus according to the present invention. 1 is a schematic sectional view showing an embodiment of a film heating and fixing apparatus according to the present invention. It is a partial perspective view of a film heat fixing device. It is a partial perspective view of a film heat fixing device. It is a partial perspective view which shows the other Example of a film heating fixing apparatus. FIG. 11 is a schematic sectional view showing a conventional image forming apparatus. It is a schematic structure sectional view showing a conventional film heat fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film heating fixing apparatus 3a Charging roller (charging means)
3b Developing roller (developing means)
3c Cleaning blade (cleaning means)
4 Photosensitive drum (image carrier)
11 Transfer roller (transfer means)
12 Heat Fixing Device 16 Fan 20 Heating Body 21 Heater (Heat Source)
22 heater support 23 fixing film 25 pressure roller (rotating body for heating)
30 Lower discharge guide 31 Fixing frame 32 Fixing entrance guide 33 Fixing duct (duct means)
33a Air intake port 33b Reverse side of air intake port 35 hole S Recording paper (recording material)
T Toner N Fixing nip

Claims (7)

A heating body having a heat source; a cylindrical film that rotates while being in contact with the heating body; and a pressing rotator that forms a fixing nip portion together with the heating body via the film and drives the film In a heating and fixing apparatus that passes and conveys a recording material holding an unfixed image to a fixing nip portion, and fixes the unfixed image on the recording material as a permanent image.
A heating and fixing apparatus comprising: a duct unit that forms an air passage along an axial direction of the pressurizing rotary member, and air is blown from the duct unit to the surface of the pressurizing rotary member.   The discharge lower guide member for guiding the recording material from the fixing nip portion to the downstream side in the recording material conveyance direction, and a fixing frame member for attaching the lower discharge guide. The heat fixing apparatus according to 1.   3. The heat fixing apparatus according to claim 2, wherein the duct unit is provided between the pressure rotating body, the lower discharge guide, and the fixing frame member.   The duct means forms an air intake opening at one end, and the other end is a closed end. A plurality of holes are provided facing the pressurizing rotator, and the air taken in from the air intake is added to the air. The heat fixing device according to any one of claims 1 to 3, wherein the heat fixing device is ejected to the surface of the pressure rotating body.   The heat fixing apparatus according to claim 4, wherein the number of holes provided in the duct portion is changed in an axial direction of the pressing rotary body.   The heat fixing apparatus according to claim 4, wherein the size of the hole provided in the duct portion is changed in the axial direction of the pressing rotary body.   An image forming unit that forms an unfixed image on a recording material, and the heat fixing device according to any one of claims 1 to 6 for heat fixing the unfixed image to the recording material. An image forming apparatus.

Images