JP2011081238A - Film heating fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost, and speed up by improving efficiency of a heat quantity supplied to a sheet. <P>SOLUTION: In a film heating fixing device, a space is provided inside a film approximately in the sheet introduction direction (paper passing upstream side) from a heat nip part by film guide member inside the film, and a domain for conveying the sheet at a prescribed spacing from the film outside is provided by a sheet guide member facing to the film on the film outside. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a heating element having a heater and a heat-resistant film that slides on the heater surface, and a pressure roller that forms a heating nip portion with the heating element, and heats a sheet holding an unfixed image. The present invention relates to a heat fixing device that passes and conveys to a nip portion and fixes an unfixed image on a sheet, and an image forming apparatus using the heat fixing device.

  Conventionally, a contact heating type fixing device has been widely used as a method for fixing an unfixed image formed on a sheet in an image forming apparatus such as a copying machine, a printer, or a facsimile. Particularly in recent years, from the viewpoint of energy saving, a film heating type heat fixing device having high heat conduction efficiency and a rapid rise in temperature has been widely used.

  This film heating type heat fixing device is disclosed in Japanese Patent Laid-Open No. 4-44075, etc., and a heat resistant film (film) is brought into pressure contact with a heater by a pressure roller to be slid and conveyed, and the film is sandwiched between them. By introducing a sheet carrying an unfixed image into the press nip formed by the heater and the pressure roller and transporting it together with the film, the heat from the heater applied through the film and the press nip The unfixed image is fixed on the sheet by the applied pressure.

  Such film heating type heating means include, for example, electrophotography, electrostatic recording, image forming apparatuses such as copying machines, laser beam printers, facsimiles, microfilm reader printers, image display (display) devices, and recording machines. Indirect (transfer) method on the surface of a sheet (transfer material sheet, electrofax sheet, electrostatic recording sheet, printing paper, etc.) using toner made of heat-meltable resin or the like by an appropriate image forming process means such as magnetic recording Alternatively, it can be used as an image fixing apparatus that heat-fixes an unfixed toner image corresponding to target image information formed by a direct method.

  As a heating element with a low heat capacity and a high temperature rise, a heat-resistant, insulating, and heat-conductive ceramic material substrate and a heating resistance portion as an energization heating portion provided on the substrate by means of printing, baking, etc. are provided. A ceramic heater is used that is a basic structural body and that generates heat by supplying electric power to the heat generating resistor portion and has a low heat capacity and a high temperature rise as a whole.

  The film heating system heat fixing device is configured to transport a film between a pressure roller while applying tension using a dedicated film transport roller and a driven roller (film direct drive system). And, a method (pressure roller driving method) is known in which the film is driven to rotate with respect to the pressure roller by loosely fitting the support member that guides the film in a rotatable manner and driving the pressure roller. In recent years, the latter pressure roller driving system that does not require film tension management or offset control and can be reduced in size and cost is often employed.

  FIG. 7 is a schematic configuration diagram of an example of a pressure roller driving type film heat fixing device.

  The outline of the pressure roller driving type film heating and fixing apparatus will be described below with reference to FIG. This example heating means uses a cylindrical film as a heat-resistant film disclosed in JP-A-4-44075, etc., and the film is rotated and driven by a pressure roller as a pressure means. This is a free-type device (a device that drives a film without applying tension to the film).

  Reference numeral 14 denotes a horizontally long and thin plate-like heating element (hereinafter referred to as a heater) whose longitudinal direction is perpendicular to the drawing.

  Reference numeral 10 denotes a horizontally long saddle type film guide / heater support having a substantially semicircular cross section. A heater 14 is fixedly supported by a heat resistant adhesive or the like along the length of the support at the center of the lower surface of the heater support 10. is there. The heater support 10 has a substantially semicircular outer shape in cross section and the outer periphery of the film 10 is loosely fitted.

  Reference numeral 90 denotes a cylindrical (endless belt-like), thin heat-resistant film (hereinafter referred to as a fixing film or film), which is loosely fitted on the heater support 10 on which the heater 14 is supported.

  Reference numeral 15 denotes a flange member that receives the film end portions respectively disposed at both ends of the heater support 10 and restricts the movement of the film 90.

  Reference numeral 11 denotes an elastic pressure roller as a pressure member, which sandwiches the lower surface of the heater 14 of the heater support 10 and the film 90 and presses them against each other with a predetermined contact pressure against the roller elasticity. A heating nip portion N as a heating portion is formed.

  The pressure roller 11 is rotationally driven in a counterclockwise direction indicated by an arrow by a driving unit (not shown). The rotation force acts on the film 90 by the pressure friction force in the heating nip portion N between the outer surface of the roller 11 and the outer surface of the film 90 due to the rotation of the pressure roller 11, and the film 90 has its inner surface on the lower surface of the heater 14. While sliding in contact, the outer periphery of the heater support 10 is rotated in the clockwise direction indicated by the arrow. The heater support 10 also serves as a guide for the rotating film 90.

  In general, a low-heat-capacity ceramic heater having a ceramic substrate and a heating resistor printed and fired on the substrate surface as a basic component is used as the heater 14.

  In the state where the film 90 is rotated by the rotation of the pressure roller 11 and the heater 14 generates heat by energization and the temperature is adjusted to a predetermined temperature, the film 90 in the heating nip portion N is interposed between the pressure roller 11. The toner image surface of the sheet P as a heated material on which the unfixed toner image T is formed and supported is introduced to the film 90 side through the introduction guide member 80, and the heating nip portion N is moved together with the film 90. In the heating nip portion N, the sheet P is heated by the heater 14 through the film 90, and the unfixed toner image T is softened and fused. The sheet P passing through the heating nip N is separated from the surface of the film 90 and conveyed.

  In this apparatus, in the rotation state of the film 90 driven by the pressure roller 11, substantially no tension is applied to the film 90 except for the portion of the heating nip portion N. Therefore, the heater support is accompanied by the rotation of the film. There are advantages such that the film-side movement force along the length of the body 10 is small and the film-side movement control means can be simplified, easy assembling and cost reduction can be achieved.

  Reference numeral 8 denotes a pressing means that biases the flange member 15 to bias the heater support 10 and form a heating nip portion N with the elastic pressure roller 11.

  Reference numeral 8b denotes a pressure release member which is pivotally supported by the frame 30 and is configured to be held at a position where the pressure means is rotated by being rotated.

  Reference numeral 51 denotes a roller for nipping and conveying the heated sheet, and reference numeral 50 denotes a discharge upper guide for holding the roller 51 and guiding the upper side of the sheet.

  A discharge roller 41 forms a discharge nip with the roller 51, and a discharge lower guide 40 guides the lower side of the sheet on which the discharge roller 41 can be disposed. The upstream side of the discharge nip of the interval formed by the upper discharge guide 50 and the lower discharge guide 40 is configured to gradually narrow in order to facilitate and stabilize the introduction into the discharge nip.

  Reference numeral 60 denotes a paper discharge tray on which the heat-fixed sheets are stacked.

  The heated sheet P is nipped and conveyed between the roller 51 and the discharge roller 41 through the upper discharge guide 50 and the lower discharge guide 40, and is discharged to the paper discharge tray 60.

  Reference numeral 30 denotes a frame in which the flange member 15, the pressure roller 11, the upper discharge guide 50, and the lower discharge guide 40 are disposed.

JP-A-4-44075

  In recent years, there has been an increasing demand for higher speeds for small and low-cost image forming apparatuses. In order to increase the power supply per unit time and to increase the pressure heating time as a measure for increasing the speed, the heating nip region has been expanded.

  In the above conventional example, as shown in FIG. 7, the heat fixing device of the film heating method having high heat conduction efficiency and quick rise in temperature causes the heater 14 to generate heat to a higher temperature due to the increase in power supply, and the width is narrow. The heater support 10 and the pressure roller 11 in the non-sheet passing portion when the small size sheet is passed may melt. In order to avoid melting, expensive heat-resistant materials had to be used.

  Further, the pressure is increased to enlarge the heating nip region. Due to the increased pressure, it is becoming difficult to treat jammed paper when a jam occurs. Due to the high pressure, the sheet P is torn during jam processing, and the torn sheet P remains in the apparatus, causing further jamming, and the torn sheet P is a residue that causes a failure of the apparatus main body. Things are happening frequently. As a countermeasure against this, pressure releasing means for releasing the pressure means has also been adopted in small and low cost image forming apparatuses. When the configuration as shown in FIG. 7 is employed in a small and low-cost image forming apparatus, the release member 8b pressurizing means is configured to be held at a position where it can be opened. Since abnormal heat generation may lead to failure, it is necessary to detect the opening, and the cost has been increased by adding a configuration such as a dedicated sensor.

  The object of the present invention is to increase the power supply per unit time even if the speed is increased by increasing the ability to efficiently supply heat to the sheet and fix the sheet-like unfixed toner in the film heat fixing device. An object of the present invention is to provide a high-speed and low-cost image forming apparatus without increasing the pressure for expanding the heating nip area.

In order to achieve the above object, in the present invention,
A sheet having a heater having a heat generating portion, a heating member having a heat-resistant film that slides on the heater surface, and a pressure roller that forms the heating member and a heating nip, and holding an unfixed image In the heating and fixing apparatus that passes and conveys the toner to the heating nip portion and fixes the unfixed image on the sheet,
The film guide member inside the film provides a space in the film substantially in the sheet introduction direction (upstream side of the sheet) from the heating nip portion, and the sheet guide member facing the film outside the film provides a space outside the film. The predetermined interval is an area for sheet conveyance.

  Therefore, by providing an area for heating the sheet that passes through the vicinity of the film with residual heat before passing through the heating nip, the unfixed image on the sheet is semi-melted (preliminarily fixed), and in the heating nip, An unfixed image can be fixed on a sheet with a small amount of heat.

  Preliminary fixing is performed by preheating with the remaining heat of the film of the fixing device, so that the amount of heat generated by the heater is efficiently supplied to the sheet, and the ability to fix unfixed toner on the sheet is improved. As a result, it could be introduced into a high-speed film heating and fixing device without any special increase in power.

  By providing the preliminary fixing area, it is not necessary to increase the pressure applied to the heating nip portion, and the sheet P is torn during jam processing, and the torn sheet P remains in the apparatus, causing further jamming or tearing. The residue of the sheet P does not induce the failure of the apparatus main body. There is no cost increase due to the addition of configuration.

  An interval X formed by the outer peripheral portion of the film in the preliminary fixing region and the sheet guide member facing the film is preferably 0 ≦ X ≦ 3 mm. Therefore, efficient fixing properties could be obtained by setting the interval to 3 mm or less.

  When the sheet passing direction area of the heating nip portion is N, the sheet passing direction area PH formed by the sheet outer periphery and the sheet guide member facing the film is preferably PH ≧ N. Therefore, an efficient fixing property can be obtained by setting the preliminary fixing area to be larger than the heating nip area.

  The film guide member may be a rib-shaped resin material. Therefore, the heat transfer rate from the film to the film guide member can be reduced, and an efficient fixing property can be obtained.

  The film guide member may be a wire metal. Therefore, by setting the film guide member to a low heat capacity, the heat exchange of the guide portion can be immediately brought into an equilibrium state, the heat transfer rate of the remaining heat from the film can be further improved, and an efficient fixing property can be obtained. It was.

A sheet having a heater having a heat generating portion, a heating member having a heat-resistant film that slides on the heater surface, and a pressure roller that forms the heating member and a heating nip, and holding an unfixed image In the heating and fixing apparatus that passes and conveys the toner to the heating nip portion and fixes the unfixed image on the sheet,
The film guide member inside the film provides a space inside the film substantially in the sheet introduction direction (upstream side of the sheet) from the heating nip portion, and has a sheet guide member facing the film outside the film. The guide member is biased toward the outside of the film.

  Accordingly, by providing an area for heating the sheet that is passed through the film with residual heat before passing through the heating nip portion, the unfixed image on the sheet is semi-melted (preliminary fixing), and the heating nip portion Can fix an unfixed image on a sheet with a small amount of heat. By making contact with light pressure, preliminary fixing can be performed without affecting the characteristics of the sheet such as stiffness, so that desired fixing properties can be stably obtained.

  Preliminary fixing is performed by preheating with the remaining heat of the film of the fixing device, so that the amount of heat generated by the heater is efficiently supplied to the sheet, and the ability to fix unfixed toner on the sheet is improved. As a result, it could be introduced into a high-speed film heating and fixing device without any special increase in power.

By providing the preliminary fixing area, it is not necessary to increase the pressure applied to the heating nip portion, and the sheet P is torn during jam processing, and the torn sheet P remains in the apparatus, causing further jamming or tearing. The residue of the sheet P does not induce the failure of the apparatus main body. There is no cost increase due to the addition of configuration. The biasing force F of the preliminary fixing region formed by the sheet guide member toward the outer peripheral portion of the film is preferably 0 ≦ X ≦ 500 gf. Therefore, an efficient fixing property could be obtained at a light pressure of 500 gf or less.

  When the sheet passing direction region of the heating nip portion of the preliminary fixing region is N, the biasing region PH formed by the outer peripheral portion of the film and the sheet guide member facing the film is preferably PH ≧ N. Therefore, an efficient fixing property can be obtained by setting the preliminary fixing area to be larger than the heating nip area.

  The image forming apparatus may include the film heat fixing device, and the sheet may be conveyed while fixing the unfixed toner image by the image heating unit.

  As described above, according to the present invention, in the film heating and fixing device, the amount of heat is efficiently supplied to the sheet, and the ability to fix the sheet-like unfixed toner is increased. Thus, it is possible to provide a high-speed and low-cost image forming apparatus without increasing the supply power and without increasing the pressure for expanding the heating nip region.

Schematic of the image forming apparatus according to the first embodiment Enlarged model of the film heating and fixing device according to the first embodiment The partially broken perspective view of the film heating fixing device part which is 1st embodiment Enlarged model of the film heating and fixing device according to the first embodiment The enlarged model figure of the film heat fixing device part which is the second embodiment The partially broken perspective view of the film heating fixing device part which is 2nd embodiment Enlarged model view of film heating and fixing unit of conventional image forming device

Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified. Absent.
(First embodiment)
(1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this example is a laser beam printer using an electrophotographic process.

  Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a drum) as a first image carrier. The surface of the drum 1 is uniformly charged by the primary charger 2 during the rotation process.

  Next, rotation is performed by scanning exposure with the laser beam 1 modulated in accordance with the time-series electric digital pixel signal of the target image information output from the laser scanner 3 on the charging processing surface of the rotating drum 1. An electrostatic latent image corresponding to the target image information is formed on the surface of the drum 1.

  Subsequently, the electrostatic latent image is developed with the negative toner T by the developing device 4 to be reversely developed (toner adheres to the laser exposure portion) to be visualized.

  On the other hand, a sheet P as a sheet is separated and fed from the sheet feeding cassette 20 by the sheet feeding roller 21, and passes through a registration roller pair 22 to a transfer portion which is a pressure nip portion between the drum 1 and the transfer roller 5. The toner images on the surface of the rotary drum 1 are sequentially transferred to the surface of the transfer material P by being conveyed and introduced at this timing.

  The transfer paper P that has passed through the transfer portion is separated from the surface of the rotary drum 1 and is conveyed and introduced into an image fixing device 7 as a heating device described in the next section (2), and undergoes a fixing process for the transferred toner image. The paper is discharged to the paper discharge tray 60 as a print by the discharge means.

  After the transfer paper is separated, the surface of the rotary drum 1 is cleaned by the cleaning device 23 after removing residual contaminants such as transfer residual toner, and is used repeatedly.

  In the printer of this example, four process devices including a drum 1, a primary charger 2, a developing device 4, and a cleaning device 23 are collectively configured as a process cartridge 24 that can be attached to and detached from the printer main body and can be replaced.

(2) Film heating and fixing device 7
2, 3, and 4, the film guide member 91 is fixed to the heater support 10, and a space K is provided in the film 90 from the heating nip portion N substantially in the sheet introduction direction (upstream side of the sheet). FIG. 6 is an enlarged model view and a partially broken perspective view of a film heating / fixing apparatus 7 part provided with a region passing through a predetermined interval X as a preheating part PH (preliminary fixing part).

  This example apparatus 7 has a tension-free type film heating type heating means and a sheet discharge means, similar to the heating apparatus of FIG. 7, and common constituent parts common to the apparatus of FIG. A description thereof will be omitted.

The heater 14 as a heating element is a ceramic heater, and is a thin film such as TaSiO ₂ , AgPd, TA ₂ N, RuO ₂ , and nichrome formed on a heat-resistant, insulating, and high thermal conductivity alumina substrate by screen printing, for example. An overcoat such as heat-resistant glass is applied to the surface having the heat generating resistance portion and facing the inner surface of the film 90.

  The film 90 which is a heat resistant film is a single layer film having heat resistance, toner releasability and toughness, or a composite layer film subjected to desired surface treatment or lamination treatment. The film 90 in this example is a polyimide (PI) film, which is a heat-treated 50 μm Zno single-layer film or a composite layer film subjected to release treatment with tetrafluoroethylene (PTFE).

  The flange member 15 receives the film end portions respectively disposed at both end portions of the heater support 10 and restricts the movement of the film 90. The longitudinal position that restricts the rotation of the film of the flange member 15 is located outside the sheet conveyance region.

  In the heating nip portion N, the heater 14 and the pressure roller 11 are in a pressure contact state with a predetermined pressure (for example, A4 width and a total pressure of 10 to 20 kg) with the film 90 interposed therebetween.

  The film guide member 91 is fixed to the heater support 10 so that a space K can be formed from the heating nip portion N in the film 90 in the substantially sheet introduction direction (upstream side of the sheet). The film 90 having the space K as an air heat insulation layer inside the upstream side has residual heat by heating at the heating nip portion N, so that heat can be applied to the sheet P as a preheating portion PH (preliminary fixing portion). It has become.

  Reference numeral 81 denotes a sheet guide member that guides the sheet while maintaining the distance from the upstream outer side of the film 90 at a predetermined interval X.

  The sheet guide member 81 allows the preheating unit PH (preliminary fixing unit) to be conveyed while being maintained at a predetermined distance X from the film 90.

  Reference numeral 80 denotes an introduction guide member that conveys the sheet to a preheating unit PH (preliminary fixing unit) formed by the film 90 and the sheet guide member 81.

  When the pressure roller 11 is rotationally driven in the counterclockwise direction indicated by the arrow from the non-designated device main body drive system to the pressure roller gear, the cylindrical film 90 is heated at the heating nip portion N by the surface friction force of the pressure roller 11. The inner surface rotates while closely contacting the surface (lower surface) of the heater 14.

  In the state where the film 90 is driven to rotate and the heater 14 is heated to a predetermined temperature (for example, 150 deg or more) by energizing the heat generating resistor portion, the film 90 heated by the heating nip portion N has a preheated portion PH ( A preliminary fixing portion).

  A sheet P carrying an unfixed toner image T as a material to be heated passes through the introduction guide member 80 and is introduced into the preheating portion PH (preliminary fixing portion). In the introduced sheet P, the residual heat of the film 90 causes the toner image T on the sheet P to be semi-softened and melted.

  In the preheating portion PH, the toner image T on the sheet P is semi-softened and melted and then introduced into the heating nip portion N. The sheet P introduced in the heating nip portion N receives the heat of the heater 14 through the film 90 in close contact with the outer surface of the film 90. The toner image T on the sheet P is softened and melted by the heat and fixed.

  In the preheating unit PH, the remaining heat that is normally transmitted to and consumed by the heater support 10 is efficiently used by the heat insulation effect of the space K inside the film 90 to heat the unfixed toner image T on the sheet P. The ability to fix the sheet-like unfixed toner can be improved even with the same amount of supplied heat.

  Therefore, it is possible to increase the speed without increasing the supply power per unit time and without increasing the pressure for expanding the heating nip region.

  At this time, the effect was great when the distance X formed by the outer peripheral portion of the film 90 of the preheating portion PH and the sheet guide member 81 was 0 ≦ X ≦ 3 mm. Therefore, efficient fixing properties could be obtained by setting the interval to 3 mm or less.

  In addition, the effect was great when the relationship between the heating nip portion N and the preheating portion PH was PH ≧ N. Therefore, efficient fixing properties can be obtained by setting the preheating portion PH to be equal to or larger than the heating nip portion N region.

  The film guide member 91 may be a rib-shaped resin material. Therefore, the heat transfer rate from the film to the film guide member can be reduced, and an efficient fixing property can be obtained.

  The film guide member 19 may be a wire metal. Therefore, by setting the film guide member to a low heat capacity, the heat exchange of the guide portion can be immediately brought into an equilibrium state, the heat transfer rate of the remaining heat from the film can be further improved, and an efficient fixing property can be obtained. It was.

(Embodiment 2)
FIG. 5 and FIG. 6 are an enlarged model view and a partially broken perspective view of a part of the film heat fixing device 7 according to the second embodiment.

  In this embodiment, a film guide member 91 is fixed to the heater support 10, and a space K is provided in the film 90 from the heating nip portion N in a substantially sheet introduction direction (upstream side of paper passing). A region that passes while being nipped and conveyed by the urging force is provided as a preheating unit PH (preliminary fixing unit). The difference between the first embodiment and the first embodiment is that variation in the preliminary fixing performance of the preheating unit PH can be suppressed by nipping and conveying due to sheet characteristics such as stiffness.

  The reference numerals in FIGS. 5 and 6 are the same as those in the first embodiment shown in FIGS.

  The sheet guide member 82 is movable toward the film 90 so that the sheet P can be nipped and conveyed with the film 90.

  The urging member 83 urges the sheet guide member 82 toward the film 90 with a predetermined urging force F.

  In the preheating portion PH, the toner image T on the sheet P is semi-softened and melted and then introduced into the heating nip portion N. The sheet P introduced in the heating nip portion N receives the heat of the heater 14 through the film 90 in close contact with the outer surface of the film 90. The toner image T on the sheet P is softened and melted by the heat and fixed.

  In the preheating unit PH, the remaining heat that is normally transmitted to and consumed by the heater support 10 is efficiently used by the heat insulation effect of the space K inside the film 90 to heat the unfixed toner image T on the sheet P. The ability to fix the sheet-like unfixed toner can be improved even with the same amount of supplied heat.

  In the case of this embodiment, since the film 90 and the sheet guide member 82 are nipped and conveyed, variations in the pre-fixing performance of the pre-heating unit PH can be suppressed by sheet characteristics such as stiffness, so that the supplied power is not increased. In addition, more stable fixing performance could be obtained.

  Therefore, it is possible to increase the speed without increasing the supply power per unit time and without increasing the pressure for expanding the heating nip region.

  At this time, it was possible to obtain a great effect when the urging force F of the preheating portion PH portion formed by the sheet guide member 82 toward the outer peripheral portion of the film 90 of the preheating portion PH was 0 ≦ X ≦ 500 gf. Therefore, an efficient fixing property could be obtained at a light pressure of 500 gf or less.

  In addition, the effect was great when the relationship between the heating nip portion N and the preheating portion PH was PH ≧ N. Therefore, efficient fixing properties can be obtained by setting the preheating portion PH to be equal to or larger than the heating nip portion N region.

  The film guide member 91 may be a rib-shaped resin material. Therefore, the heat transfer rate from the film to the film guide member can be reduced, and an efficient fixing property can be obtained.

  The film guide member 19 may be a wire metal. Therefore, by setting the film guide member to a low heat capacity, the heat exchange of the guide portion can be immediately brought into an equilibrium state, the heat transfer rate of the remaining heat from the film can be further improved, and an efficient fixing property can be obtained. It was.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Primary charger 3 Laser scanner 4 Developer 7 Film heating fixing apparatus 8 Pressurizing means 80 Entrance guide member 81 Guide member 90 Film (heat resistant film)
91 Film guide member 10 Heater support 11 Pressure roller 14 Heater (heating element)
15 Flange member 30 Frame 40 Lower discharge guide 41 Ejection roller 50 Ejection upper guide 51 Roller 60 Ejection tray N Heating nip part PH Preheating part (preliminary fixing part)
P sheet T toner X distance K space F biasing force

Claims (11)

A sheet having a heater having a heat generating portion, a heating member having a heat-resistant film that slides on the heater surface, and a pressure roller that forms the heating member and a heating nip, and holding an unfixed image In the heating and fixing apparatus that passes and conveys the toner to the heating nip portion and fixes the unfixed image on the sheet,
A space is provided inside the film in the sheet introduction direction (upstream side of the sheet) from the heating nip portion by the film guide member inside the film, and a predetermined distance from the outside of the film by the sheet guide member facing the film outside the film. The heating and fixing apparatus is characterized in that the interval is set as an area for sheet conveyance.   2. The heat fixing device according to claim 1, wherein an interval X formed by the sheet outer peripheral portion and the sheet guide member facing the film satisfies 0 ≦ X ≦ 3 mm.   The sheet passing direction region PH formed by a sheet guide member facing the outer peripheral portion of the film and the film is PH ≧ N, where N is a sheet passing direction region of the heating nip portion. The heat fixing apparatus according to 1.   The heat fixing apparatus according to claim 1, wherein the film guide member is a rib-shaped resin material.   The heat fixing apparatus according to claim 1, wherein the film guide member is a wire metal. A sheet having a heater having a heat generating portion, a heating member having a heat-resistant film that slides on the heater surface, and a pressure roller that forms the heating member and a heating nip, and holding an unfixed image In the heating and fixing apparatus that passes and conveys the toner to the heating nip portion and fixes the unfixed image on the sheet,
The film guide member inside the film provides a space inside the film in the sheet introduction direction (upstream side of the sheet) from the heating nip portion, and has a sheet guide member facing the film outside the film, the sheet guide A heat fixing device characterized in that a member is urged toward the outside of the film.   6. The heat fixing apparatus according to claim 5, wherein an urging force F formed by the sheet guide member toward the outer peripheral portion of the film satisfies 0 ≦ X ≦ 500 gf.   The sheet passing direction region PH formed by a sheet guide member facing the film outer peripheral portion and the film is PH ≧ N, where N is a sheet passing direction region of the heating nip portion. The heat fixing device according to 6.   9. The heat fixing apparatus according to claim 6, wherein the film guide member is a rib-shaped resin material.   The heat fixing apparatus according to claim 6, wherein the film guide member is a wire metal.   An image forming apparatus using the heat fixing apparatus according to claim 1.

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