JP5347632B2 - Heating member, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a heating member wherein two cylinders having heating sources are arranged so as not to interfere with a member in a tube, and to provide a fixing device and an image formation device. <P>SOLUTION: Outer corner sections 76A, 78A of a gas inlet section 76 and a gas inlet section 78 are arranged in a concentric circle R of a core metal 62 of a heating roll 44 by mutually approaching an axis P of the gas inlet section 76 and an axis Q of the gas inlet section 78 of lamp heaters 48, 50, and outer corner sections 72A, 74A of a plate-shaped terminal 72 and a plate-shaped terminal 74 are arranged into a concentric circle S of the core metal 62 of the heating roll. Thus, interference between the lamp heaters 48, 50 and the inside of the core metal 62 (inner peripheral surface 62A of the core metal 62, key section 54, and C-shaped snap ring 64) is avoided. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a heating member, a fixing device, and an image forming apparatus.

  In general, in an image forming apparatus such as a copying machine or a printer that employs an electrophotographic method, the surface of the photosensitive drum is charged by a charging device, and then the surface of the photosensitive drum is irradiated with image light to form an electrostatic latent image. Then, the electrostatic latent image is developed by a developing device to form a toner image. Then, after the toner image is transferred onto the paper, the toner image on the paper is fixed by heating and pressing with a fixing device, thereby forming an image.

  The fixing device includes a heating roller incorporating a heater therein, and a pressure roller that presses the sheet against the heating roller. Then, the sheet holding the toner image is passed between the heating roller and the pressure roller, and the toner image is melted by heating and pressing to be fixed on the sheet.

  For example, the heating roller disclosed in Patent Document 1 includes a plurality of lamps, and the pinch seal portions of the adjacent lamps do not interfere with each other, and the straight tubular portions of the adjacent lamps are brought into contact or very close to each other. be able to.

JP 2005-216734 A

  SUMMARY OF THE INVENTION An object of the present invention is to obtain a heating member, a fixing device, and an image forming apparatus that are arranged so that two cylinders having a heat generation source do not interfere with members in a tube.

The invention according to claim 1 is a first cylindrical body provided with a heat source inside, a second cylindrical body arranged side by side with the first cylindrical body, and provided with a heat source inside, comprising 1 a cylindrical body and the tube body rotating around said second tubular member, wherein the first tubular body, said heat source provided at both ends of the first power supply portion shaped for supplying power A first gas introduction part that projects in the radial direction of the first cylinder from the outer peripheral surface of the first cylinder along the width direction and supplies gas to the first cylinder, and the second cylinder includes: Projecting in the radial direction of the second cylinder from the outer peripheral surface of the second cylinder along the width direction of the plate-like second power supply part that is provided at both ends and supplies power to the heat generation source, A second gas introduction part that is provided at a position that does not interfere with the introduction part and supplies gas into the second cylinder, the first gas introduction part and the second gas introduction part The first gas introduction unit, the second gas introduction unit, the first power supply unit, and the second power supply unit are arranged close to each other, and a gap is provided between the inner peripheral surface of the tube body. Has been placed.

According to a second aspect of the present invention, in the heating member according to the first aspect , the first gas introduction part and the second gas introduction part are arranged offset in the axial direction of the tubular body .

According to a third aspect of the present invention, in the heating member according to the first or second aspect, the heating member is fixed to the tubular body, and is attached to the tubular body and a gear key portion that protrudes to the inside of the tubular body. And a retaining member that protrudes to the inside of the tube, and includes the first gas introduction unit, the second gas introduction unit, the first power supply unit, and the second power. The supply unit is disposed with a gap between a second concentric circle that is a concentric circle of the tube and is in contact with the gear key portion, and a third concentric circle that is concentric with the tube and is in contact with the retaining member. Yes.

  According to a fourth aspect of the present invention, in the heating member according to the second or third aspect, the tube diameter of the second cylindrical body is larger than that of the first cylindrical body, and the heat generation area of the first cylindrical body is the first. It is a center part of the longitudinal direction of a cylinder, and the heat_generation | fever area | region of the said 2nd cylinder covers the whole area of the longitudinal direction of a 2nd cylinder.

  According to a fifth aspect of the present invention, in the heating member according to any one of the first to fourth aspects, a separation distance between the outer peripheral surface of the first cylindrical body and the outer peripheral surface of the second cylindrical body is 1 mm or more. is there.

  According to a sixth aspect of the present invention, in the fixing device, the heating member according to any one of the first to fifth aspects, and a pressure member that presses the transfer medium onto which the unfixed image is transferred to the heating member. And have.

  According to a seventh aspect of the present invention, in the image forming apparatus, a latent image forming unit that forms a latent image on an image carrier, a developing unit that develops the latent image, and the developed image is transferred to a transfer medium. And a fixing device according to claim 6 for fixing the image on the transfer medium.

According to invention of Claim 1 , while arrange | positioning so that a cylinder may not interfere with the member in a tubular body, the pipe diameter of a tubular body can be made as small as possible.
According to the second aspect of the present invention, it is possible to reliably prevent interference between the first gas introduction part and the second gas introduction part of the cylindrical body that are arranged close to each other in the pipe body.
According to the third aspect of the present invention, even if the keyway or the retaining member protrudes inside the tubular body, it can be arranged so as not to interfere with the tubular body.

  According to the fourth aspect of the present invention, the heating efficiency is increased and the standby time of the heating member can be shortened.

  According to the fifth aspect of the present invention, it is possible to avoid damage to the first and second cylinders caused by interference due to dimensional tolerances, vibrations, and the like of the first and second cylinders.

  According to the sixth aspect of the invention, the first cylinder or the second cylinder can be used properly according to the size of the transfer medium, which is economical.

  According to the seventh aspect of the present invention, the standby time of the image forming apparatus can be shortened.

1 is a schematic side view illustrating a configuration of an image forming apparatus according to an exemplary embodiment. FIG. 3 is a side sectional view showing a fixing unit according to the present embodiment. FIG. 2 is a schematic perspective view showing the inside of a fixing unit according to the present embodiment. It is a schematic perspective view which shows the structure of the heating roller which concerns on this embodiment. It is a schematic plan view which shows the structure of the heating roller which concerns on this embodiment. It is an enlarged view which shows the inside of the heating roller which concerns on this embodiment. It is a perspective view which shows the lamp heater in the heating roller which concerns on this embodiment. (A), (B) is sectional drawing which shows the modification of the metal core of the heating roller which concerns on this embodiment. It is an enlarged view which shows the inside of the metal core of FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below in detail based on examples shown in the drawings. First, an image forming apparatus 10 provided with a fixing device according to the present invention will be described with reference to FIG. The fixing device is configured as a fixing unit 40 that can be attached to and detached from the image forming apparatus main body 12.

<Image forming apparatus>

  As shown in FIG. 1, the image forming apparatus 10 has an opening / closing cover 14 rotatably attached to the image forming apparatus main body 12, and the image forming apparatus main body is opened by opening the opening / closing cover 14. The fixing unit 40 can be loaded in the inside 12.

  When the fixing unit 40 is loaded into the image forming apparatus main body 12, the connector 42 of the fixing unit 40 is coupled to the connector 16 of the image forming apparatus main body 12 at the same time so that power can be supplied to the fixing unit 40 and fixing is performed. Completion of loading of the unit 40 is detected. After the fixing unit 40 is loaded in the image forming apparatus main body 12, the image forming apparatus 10 becomes operable by closing the open / close cover 14.

  Further, the image forming apparatus main body 12 is provided with a process cartridge 18 in which an image forming unit is integrated into a unit. A photosensitive drum 20 that rotates in a certain direction is provided inside the process cartridge 18. Around the photosensitive drum 20, from the upstream side in the rotation direction, a charging roller 22 for charging the photosensitive drum 20, a developing roller 24 for developing the electrostatic latent image formed on the photosensitive drum 20, and a photosensitive roller A transfer roller 26 is provided for transferring the developed toner image on the body drum 20 to a sheet.

  Further, a cleaning member 28 for cleaning the surface of the photosensitive drum 20 after transfer is provided on the downstream side of the transfer roller 26 in the rotation direction of the photosensitive drum 20. The image forming apparatus main body 12 is provided with an exposure device 30 that irradiates the photosensitive drum 20 with image light between the charging roller 22 and the developing roller 24.

  A paper feed cassette 32 that accommodates paper is disposed in the lower part of the image forming apparatus main body 12 so that the paper can be pulled out. The paper feed cassette 32 takes out the paper one by one at the paper take-out position. A paper feed roller 34 for conveyance is provided.

  In addition, a plurality of conveying roller pairs 36 that convey the sheet supplied from the sheet feeding roller 34 to a position where the photosensitive drum 20 and the transfer roller 26 face each other are provided below the image forming apparatus main body 12. A fixing unit 40 is disposed (loaded) on the downstream side of the transfer roller 26 in the sheet conveyance direction, and a discharge unit for discharging the sheet after toner image fixing is disposed on the downstream side of the fixing unit 40. A paper portion 38 is provided.

  In such an image forming apparatus 10, the surface of the photosensitive drum 20 is charged by the charging roller 22, and image light is irradiated from the exposure device 30, whereby an electrostatic latent image is formed on the surface. This electrostatic latent image is developed by the developing roller 24, and a toner image is formed on the photosensitive drum 20.

  On the other hand, the paper is supplied from the paper supply cassette 32 by the paper supply roller 34, and is conveyed to a position where the photosensitive drum 20 and the transfer roller 26 face each other by the conveyance roller pair 36. Then, the toner image on the photosensitive drum 20 is transferred onto the paper by the transfer roller 26. The sheet on which the toner image has been transferred is conveyed to the fixing unit 40 and heated and pressed between the heating roller 44 and the pressure roller 46, whereby the toner image is melted and fixed on the sheet. . Thereafter, the paper on which the image is formed is discharged to the paper discharge tray 38.

<Fusing unit>

  Next, a fixing unit including the fixing device according to the present invention will be described.

  As shown in FIGS. 2 and 3, the fixing unit 40 includes a heating roller 44 that is heated to a predetermined temperature, and a pressure roller 46 that presses the sheet against the heating roller 44. .

  As an example, the pressure roller 46 is provided with a heat-resistant elastic body layer (silicon sponge, Asker C hardness 40 °) on a metal core 60 made of stainless steel or iron, and a release layer (film thickness) having a low friction coefficient on the surface layer. A tube made of 30 μm PFA) is provided.

  On the other hand, as an example, the heating roller 44 has a cylindrical cored bar 62 (meat) having the same diameter along the axial direction, provided with a release layer having a low friction coefficient (a tube made of PFA having a film thickness of 30 μm) on the surface. Lamp heaters (cylinders) 48 and 50 fixed to the apparatus main body 41 side of the fixing unit 40 are provided inside the heating roller 44. It is arranged (described later).

  As shown in FIG.4 and FIG.5, the bearing 58 is fitted by the both ends of the heating roller 44, and the heating roller 44 is rotatably supported. As shown in FIG. 2, a driving gear 52 that meshes with the driving gear 51 of the image forming apparatus main body 12 is provided at one end of the heating roller 44.

  A rectangular parallelepiped key portion 54 projects from the inner peripheral surface of the drive gear 52 and is fitted into a key groove 56 formed at one end portion of the core metal 62 of the heating roller 44. The gold 60 protrudes toward the inner peripheral surface 62A. As a result, the drive gear 52 is integrated with the heating roller 44 and cannot rotate with respect to the heating roller 44, and the rotational driving force is transmitted to the heating roller 44 via the driving gear 52.

  As described above, when the rotational driving force is transmitted from the driving gear 51 of the image forming apparatus main body 12 to the driving gear 52, the heating roller 44 rotates around the lamp heaters 48 and 50 at a constant speed in a predetermined direction. . That is, in the fixing unit 40, the heating roller 44 and the pressure roller 46 are rotationally driven at a constant speed in opposite directions.

<Heating roll>

  Here, the heating roller 44 will be described.

  In this embodiment, as shown in FIGS. 2 and 6, lamp heaters 48 and 50 are disposed in the cored bar 62 of the heating roller 44. As described above, by using the two lamp heaters 48 and 50 for the heating roller 44, a heat generation area corresponding to the paper size is secured, and a decrease in productivity when the paper is small is avoided.

  Further, a C-shaped retaining ring 64 for preventing the bearing 58 or the drive gear 52 from coming off can be attached to both ends of the cored bar 62. For this reason, mounting holes 66 are formed at both ends of the core metal 62, and mounting portions 64 A provided at both ends of the C-shaped retaining ring 64 are mounted in the mounting holes 66.

  Therefore, the mounting portion 64 </ b> A of the C-shaped retaining ring 64 protrudes toward the inner peripheral surface 62 </ b> A of the core metal 60. Here, since the drive gear 52 is provided on one end side of the metal core 62, a C-shaped retaining ring 64 is attached to the end surface of the drive gear 52, and the other end side of the metal core 62 is provided on the end surface of the bearing 58. A C-shaped retaining ring 64 is attached.

  On the other hand, as shown in FIG. 7, the lamp heaters 48 and 50 are provided with arc tubes 68 and 70 as tubular envelopes made of quartz glass, and the arc tubes 68 and 70 are arranged along the axial direction. A filament (not shown) is disposed, and halogen and an inert gas are enclosed.

  The lamp heater 48 has a tube diameter larger than that of the lamp heater 50, and the lamp heater 48 is provided with filaments having a dense winding pitch over substantially the entire axial direction of the arc tube 68. Is arranged at the center of the arc tube 70 with a dense winding pitch. That is, the heat generation area of the lamp heater 48 extends over the entire area of the arc tube 68 in the axial direction, but the heat generation area of the lamp heater 50 is the central portion of the arc tube 70 in the axial direction.

  The lengths of the lamp heaters 48 and 50 are set based on the maximum width of the conveyed paper. For example, when the maximum size of the conveyed paper is A3, the heat generation area of the lamp heater 48 is set to be slightly wider than the width dimension of the A3 size, and the heat generation area of the lamp heater 50 is A4 size. The dimension is set to be slightly wider than the width dimension.

  As a result, when the conveyed paper is A4 size, power is supplied to the lamp heater 50, and when the conveyed paper is A3 size, power is supplied to the lamp heater 48. Further, during the period from the operation stop state of the image forming apparatus 10 to the start of operation (standby time), power is supplied to the lamp heater 48 in order to shorten the standby time. Then, by setting the tube diameter of the lamp heater 48 to be larger than that of the lamp heater 50, the standby time of the image forming apparatus 10 is further shortened.

  On the other hand, plate terminals (power supply units) 72 and 74 connected to the filaments are provided at both ends of the arc tubes 68 and 70, respectively. The plate-like terminals 72 and 74 are thin metal plates such as nickel and stainless steel, seal the arc tubes 68 and 70, and via connectors 75 and 77 provided on the plate-like terminals 72 and 74. These are connected to a power source (not shown), and power can be supplied to the lamp heaters 48 and 50.

  Further, gas introducing portions 76 and 78 project from the outer peripheral surfaces of the arc tubes 68 and 70 along the radial direction thereof. The gas introduction portions 76 and 78 are provided for introducing halogen and inert gas into the arc tubes 68 and 70, and remain as traces on the outer peripheral surfaces of the arc tubes 68 and 70. Further, the projecting direction of the gas introducing portions 76 and 78 is set along the width direction of the plate terminals 72 and 74. That is, as shown in FIG. 6, the gas introducing portions 76 and 78 protrude along the lines L <b> 1 and L <b> 2 along the width direction of the plate-like terminals 72 and 74.

  As shown in FIG. 7, the gas introducing portions 76 and 78 are shifted in the axial direction between the arc tube 68 and the arc tube 70. Thus, when the lamp heater 48 and the lamp heater 50 are arranged side by side, the gas introduction part 76 and the gas introduction part 78 are prevented from interfering with each other.

  By using the lamp heater 48 and the lamp heater 50, the tube diameter of the heating roller 44 becomes larger than that in the case of one cylinder. Considering the downsizing and cost reduction of the image forming apparatus 10, it is necessary to make the diameter of the heating roller 44 as small as possible.

  As shown in FIG. 6, since the gas introduction part 76 or the gas introduction part 78 protrudes from the lamp heater 48 or the lamp heater 50, the gas introduction part 76 and the gas introduction part 78 are connected to the inner peripheral surface 62A of the core metal 62. The lamp heater 48 and the lamp heater 50 must be arranged so as not to interfere with each other.

  For this reason, first, the axis P of the gas introduction part 76 and the axis Q of the gas introduction part 78 are brought close to each other. Thereby, interference with the inside of the metal core 62 of the gas introduction part 76 and the gas introduction part 78 is avoided. Here, in consideration of the dimensional tolerance of the cored bar 62, the fourth dimension is provided on the concentric circle of the cored bar 62, and a gap (predetermined gap) H1 of the dimensional tolerance is provided from the inner peripheral surface 62A of the cored bar 62. In the virtual concentric circle R, the outer corner portions 76A and 78A of the gas introduction portion 76 and the gas introduction portion 78 are arranged. Thereby, interference with the gas introduction part 76 and the gas introduction part 78, and 62 A of inner peripheral surfaces of the metal core 62 is suppressed.

  On the other hand, since the projecting direction (axis P, Q) of the gas introduction part 76 or the gas introduction part 78 is along the width direction (L1, L2) of the plate-like terminal 72 or the plate-like terminal 74, the gas introduction part. If the axis P of 76 and the axis Q of the gas introduction part 78 are brought close to each other, the plate-like terminal 72 and the plate-like terminal 74 move in directions away from each other. For this reason, the lamp heater 48 and the lamp heater 50 must be arranged so that the outer corner portions 72A and 74A of the plate terminal 72 and the plate terminal 74 do not interfere with the inner peripheral surface 62A of the cored bar 62.

  Here, the plate-like terminal 72 or the plate-like terminal 74 is provided at both ends of the lamp heaters 48, 50, but at least one end of the cored bar 62 provided outside the lamp heaters 48, 50 is at least The drive gear 52 and the C-shaped retaining ring 64 are mounted. The key portion 54 of the drive gear 52 passes through a key groove 56 formed in the core metal 62, and the C-shaped retaining ring 64 passes through an attachment hole 66 formed in the core metal 62, respectively. Projects to the 62A side.

  That is, the lamp heaters 72 </ b> A and 74 </ b> A of the plate-like terminal 72 and plate-like terminal 74 do not interfere with the inner surface of the key portion 54 or the C-shaped retaining ring 64 protruding from the inner peripheral surface 62 </ b> A of the cored bar 62. 48 and the lamp heater 50 must be arranged.

  For this reason, in consideration of the dimensional tolerance of the key part 54 or the C-shaped retaining ring 64, the second virtual of the cored bar 62 is provided with a gap (predetermined gap) H2 of the dimensional tolerance from the inner surface of the key part 54. A concentric circle S and a plate-shaped terminal 72 and a plate-shaped terminal are provided in a third virtual concentric circle S of the metal core 62 provided with a gap (predetermined gap) H3 of the dimensional tolerance from the inner surface of the C-shaped retaining ring 64. 74 outer corner portions 72A and 74A are arranged.

  Accordingly, interference between the plate-like terminal 72 and the plate-like terminal 74 and the inner surface of the key portion 54 or the C-shaped retaining ring 64 is suppressed. Here, the second virtual concentric circle and the third virtual concentric circle are the same, but the outer angles of the plate-like terminal 72 and the plate-like terminal 74 are within the virtual concentric circle on the small diameter side of the second virtual concentric circle and the third virtual concentric circle. The portions 72A and 74A may be arranged.

  As described above, the axis P of the gas introduction part 76 and the axis Q of the gas introduction part 78 are brought close to each other, and the gas introduction part 76 and the outer corner part 76A of the gas introduction part 78 are within the fourth virtual concentric circle R of the cored bar 62. The lamp heaters 48 and 50 are arranged by arranging 78A and the outer corners 72A and 74A of the plate-like terminal 72 and the plate-like terminal 74 in the second virtual concentric circle S and the third virtual concentric circle S of the metal core 62. And the inside of the cored bar 62 (the inner peripheral surface 62A of the cored bar 62, the key portion 54, and the C-shaped retaining ring 64) are avoided. Make it smaller. Thereby, the tube diameter of the heating roll 44 becomes small.

  The separation distance t between the outer peripheral surface of the lamp heater 48 and the outer peripheral surface of the lamp heater 50 is set to 1 mm or more. This avoids damage to the lamp heaters 48 and 50 caused by interference due to dimensional tolerances, vibrations, and the like of the lamp heater 48 and the lamp heater 50.

  Although the lamp heater 48 is larger than the tube diameter of the lamp heater 50 here, the tube diameters of the lamp heater 48 and the lamp heater 50 may be the same. Here, the heat generating area of the lamp heater 48 extends over the entire area of the arc tube 68 in the axial direction, and the heat generating area of the lamp heater 50 is set at the center of the arc tube 70 in the axial direction. The heat generation area may be changed according to the specifications.

  Although the cylindrical cored bar 62 having the same diameter along the axial direction has been described here, the shape of the cored bar 62 is not limited to this. For example, as shown in FIG. 8A, a cored bar 82 having curling portions (protruding portions) 80 that are curved inward at both ends may be used.

  In this case, the inner diameter portion 80A of the curling portion 80 is disposed inside the key portion 54 or the C-shaped retaining ring 64 shown in FIG. Therefore, as shown in FIG. 9, in consideration of the dimensional tolerance of the inner diameter portion 80A of the curling portion 80, a core (a predetermined gap) H4 of the dimensional tolerance provided from the inner diameter portion 80A of the curling portion 80 is provided. In the first virtual concentric circle X of the gold 82, the outer corner portions 72A and 74A of the plate-like terminal 72 and the plate-like terminal 74 are arranged.

  Further, in addition to the cored bar 82 in which the curling part 80 is formed at both ends, as shown in FIG. 8B, a cored bar 86 in which a narrowed portion (projecting part) 84 is formed at both ends may be used. good.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 20 Photosensitive drum (image holding body)
24 Developing roller (developing means)
26 Transfer roller (transfer means)
30 Exposure device (latent image forming means)
40 Fixing unit (fixing means)
44 Heating roller (heating member)
46 Pressure roller (Pressure member)
48 Lamp heater (first cylinder)
50 Lamp heater (second cylinder)
54 Key part (gear key part)
62 Core (Heating cylinder)
64 C type retaining ring (Retaining member)
72 Plate terminal (first power supply unit)
74 Plate terminal (second power supply unit)
76 Gas introduction part (first gas introduction part)
78 Gas introduction part (second gas introduction part)
80 Curling part (protruding part)
82 Core (Heating tube)
84 Restriction (protrusion)
86 Core (Heating tube)
R 4th virtual concentric circle S 2nd virtual concentric circle S 3rd virtual concentric circle X 1st virtual concentric circle t separation distance

Claims (7)

A first cylinder provided with a heat source therein;
A second cylinder disposed side by side with the first cylinder and provided with a heat source therein;
A tube rotating around the first cylinder and the second cylinder;
With
The first cylindrical body is provided at both ends, and the radial direction of the first cylindrical body from the outer peripheral surface of the first cylindrical body along the width direction of the plate-shaped first power supply section that supplies power to the heat source. And a first gas introduction part for supplying gas into the first cylinder,
The second cylindrical body is provided at both ends, and the radial direction of the second cylindrical body from the outer peripheral surface of the second cylindrical body along the width direction of the plate-shaped second power supply section that supplies power to the heat generation source. And a second gas introduction part that is provided at a position that does not interfere with the first gas introduction part and supplies gas into the second cylinder,
The first gas introduction part and the second gas introduction part are arranged close to each other, and the first gas introduction part, the second gas introduction part, the first power supply part, and the second power supply part are A heating member disposed with a gap between the inner peripheral surface of the tubular body . 2. The heating member according to claim 1, wherein the first gas introduction part and the second gas introduction part are arranged offset in the axial direction of the tubular body. The heating member is fixed to the tube body, and a gear key portion that protrudes to the inside of the tube body,
  A retaining member that is a retaining member of a bearing or gear attached to the tubular body, and projects to the inside of the tubular body;
  With
  The first gas introduction part, the second gas introduction part, the first power supply part, and the second power supply part are concentric circles of the tubular body and are in contact with the gear key part, and the tubular body The heating member according to claim 1, wherein the heating member is disposed concentrically with a third concentric circle in contact with the retaining member.   The tube diameter of the second cylinder is larger than that of the first cylinder, the heat generation area of the first cylinder is a central portion in the longitudinal direction of the first cylinder, and the heat generation area of the second cylinder is the first. The heating member according to any one of claims 1 to 3, wherein the heating member extends over the entire length of the two cylinders.   The heating member according to any one of claims 1 to 4, wherein a separation distance between an outer peripheral surface of the first cylinder and an outer peripheral surface of the second cylinder is 1 mm or more. The heating member according to any one of claims 1 to 5,
A pressure member that presses a transfer medium onto which an unfixed image is transferred to the heating member;
A fixing device. A latent image forming apparatus for forming a latent image on an image carrier;
A developing device for developing the latent image;
A transfer device for transferring the developed image to a transfer medium;
The fixing device according to claim 6, wherein the image on the transfer medium is fixed.
An image forming apparatus.

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