JP2011047995A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device in which a heating roller or the like is efficiently heated by a heater, and also temperature near a position corresponding to the end of a first width area (maximum paper passing area) on the heating roller or the like is efficiently raised. <P>SOLUTION: The fixing device includes: a first hollow rotating body 9a which can rotate centering a first rotary shaft I; the heater 910 which heats the first rotating body 9a from the inside; a second rotating body 9b which forms a fixing nip N9 in which a sheet type material to be transferred T is conveyed with the first rotating body 9a; a first width area 901a which is formed on the first rotating body 9a and through which the material to be transferred T having the maximum width in a conveying width direction orthogonal to a conveying direction D1 passes; and heat shielding members 920 which are arranged near positions corresponding to first width area ends 901e being the ends of the first width area 901a in the direction of the first rotary shaft I inside the first rotating body 9a, and intercept radiant heat going from the heater 910 to the ends 902 of the first rotating body 9a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fixing device and an image forming apparatus including the fixing device.

  Conventionally, as an apparatus for forming (printing) an image on a sheet, an image forming apparatus such as a copier, a printer, a facsimile, or a complex machine of these is known. In the image forming apparatus, a charging step for charging the surface of the photosensitive drum, an exposure step for irradiating the charged photosensitive drum with laser light to form an electrostatic latent image on the surface of the photosensitive drum, and the surface of the photosensitive drum A developing process for developing the toner by attaching toner to the electrostatic latent image formed thereon, a transferring process for transferring the toner image formed from the toner attached to the surface of the photosensitive drum to the paper, and the toner transferred to the paper An image is formed on the paper by sequentially performing each of the fixing steps for fixing the image on the paper.

  Among the above steps, in the fixing step, in order to fix the toner constituting the toner image transferred onto the paper onto the paper, it is necessary to apply heat to the toner to melt the toner. Conventionally, as a fixing device that performs a fixing process, a heating roller, a pressure roller that forms a fixing nip on which a sheet on which a toner image is transferred by the heating roller, and a heating roller are heated from the inside of the heating roller are heated. A fixing device including a heater is used.

In recent years, it has been desired to efficiently use the energy radiated from the heater disposed inside the heating roller in order to save energy.
In order to efficiently use energy, a fixing device is known in which the heat capacity of the heating roller is reduced by reducing the thickness of the heating roller (see, for example, Patent Document 1). According to the fixing device including the heating roller having a small heat capacity, the time required for warming up the fixing device can be shortened, so that energy saving can be coped with.

JP 2003-177624 A

  With the recent increase in printing speed, it is desired to further shorten the time required for warming up the fixing device. In general, when the temperature near the end of the first width region (maximum paper passing region) through which the maximum width paper passes in the transport width direction orthogonal to the paper transport direction is greater than or equal to the image forming apparatus. It is designed to start printing. In the fixing device described in Patent Document 1, no special contrivance is made at both ends of the heating roller in the axial direction, and heat from the heater disposed inside dissipates from both ends of the heating roller in the axial direction. Cheap. Therefore, the heating roller cannot be heated efficiently. Therefore, it is desirable to efficiently raise the temperature in the vicinity of the end of the first width region (maximum sheet passing region) in the heating roller so that the temperature distribution of the heating roller is made uniform efficiently.

According to the present invention, the heating roller or the like can be efficiently heated by the heater, and the temperature in the vicinity of the position corresponding to the end of the first width region (maximum sheet passing region) in the heating roller or the like can be efficiently increased. It is an object of the present invention to provide a fixing device that can be heated.
Another object of the present invention is to provide an image forming apparatus including the fixing device.

  The present invention includes a hollow first rotating body that is rotatable about a first rotating shaft, a heater that is disposed inside the first rotating body and that heats the first rotating body from the inside, and the first A fixing nip that is disposed opposite to the rotating body and forms a sheet-like material to be transferred is formed by the first rotating body and is rotatable about a second rotating shaft that is parallel to the first rotating shaft. A second rotator, a first width region formed in the first rotator and through which a transfer material having the maximum width in the transport width direction orthogonal to the transport direction passes, and the first rotator are disposed inside the first rotator. A heat shielding member, disposed in the vicinity of a position corresponding to an end of the first width region, which is an end of the first width region in the first rotation axis direction, from the heater to an end of the first rotating body; And a heat shielding member that shields radiant heat toward the portion.

  Moreover, it is preferable that the outer edge of the said heat shielding member is arrange | positioned facing the vicinity of the position corresponding to the said 1st width area | region edge part in the internal peripheral surface of a said 1st rotary body.

  Moreover, it is preferable that the said heat-shielding member has a light reflection surface formed inside in the said 1st rotating shaft direction.

  Moreover, it is preferable that the said heat shielding member has a concave curved surface part inside the said 1st rotating shaft direction.

  The heat shielding member reflects light from the heater and at least a part of the light from the heater at a position corresponding to the end of the first width region on the inner peripheral surface of the first rotating body. It is preferable to reflect toward the vicinity.

  The first rotating body is preferably a cylindrical rotating roller.

  Moreover, it is preferable that the first rotating body is an annular and flexible rotating belt.

  The present invention also provides one or more image carriers on which electrostatic latent images are formed on the surface, and a developer for developing a toner image on the electrostatic latent images formed on the one or more image carriers. The present invention relates to an image forming apparatus comprising: a transfer unit that directly or indirectly transfers a toner image formed on the image carrier to a sheet-like transfer material; and the fixing device.

According to the present invention, the heating roller or the like can be efficiently heated by the heater, and the temperature in the vicinity of the position corresponding to the end portion of the first width region (maximum sheet passing region) in the heating roller or the like can be efficiently increased. It is possible to provide a fixing device that can raise the temperature to a low temperature.
According to the present invention, an image forming apparatus including the fixing device can be provided.

FIG. 3 is a diagram for explaining an arrangement of each component in the printer 1 of the first embodiment. 1 is a perspective view showing a fixing device 9 according to a first embodiment. FIG. 3 is a longitudinal sectional view of the fixing device 9 according to the first embodiment when viewed from the direction of a first rotation axis I. 3 is a longitudinal sectional view of the fixing device 9 according to the first embodiment when viewed from a conveyance direction D1 of a sheet T. FIG. FIG. 5 is a partially enlarged vertical sectional view of the fixing device 9 shown in FIG. 4. It is a figure which shows the temperature distribution of the vicinity of the position corresponding to the 1st width area | region edge part 901e in the heating roller 9a of 1st Embodiment. FIG. 6 is a longitudinal sectional view of a fixing device 9 according to a second embodiment viewed from a first rotation axis I direction. FIG. 6 is a longitudinal sectional view of the fixing device 9 according to the second embodiment when viewed from a conveyance direction D1 of the paper T.

<First Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
With reference to FIG. 1, the overall structure of a printer 1 as a first embodiment of an image forming apparatus of the present invention will be described. FIG. 1 is a diagram for explaining the arrangement of components in the printer 1 according to the first embodiment.

As shown in FIG. 1, a printer 1 as an image forming apparatus includes an apparatus main body M and an image forming unit GK that forms a predetermined toner image on a sheet T as a sheet-like transfer material based on predetermined image information. And a paper supply / discharge unit KH that supplies the paper T to the image forming unit GK and discharges the paper T on which the toner image is formed.
The outer shape of the apparatus main body M is configured by a case body BD as a casing.

  As shown in FIG. 1, the image forming unit GK includes a photosensitive drum 2 as an image carrier (photosensitive member), a charging unit 10, a laser scanner unit 4 as an exposure unit, a developing device 16, and a toner cartridge. 5, a toner supply unit 6, a drum cleaning unit 11, a static eliminator 12, a transfer roller 8, and a fixing device 9.

  As shown in FIG. 1, the paper feed / discharge unit KH includes a paper feed cassette 52, a manual paper feed unit 64, a transport path L for paper T, a registration roller pair 80, and a paper discharge unit 50.

Hereinafter, each configuration of the image forming unit GK and the paper supply / discharge unit KH will be described in detail.
First, the image forming unit GK will be described.
In the image forming unit GK, in order from the upstream side to the downstream side along the surface of the photosensitive drum 2, charging by the charging unit 10, exposure by the laser scanner unit 4, development by the developing device 16, transfer by the transfer roller 8, Static elimination by the static eliminator 12, cleaning by the drum cleaning unit 11, and fixing by the fixing device 9 are performed.

  The photosensitive drum 2 is made of a cylindrical member and functions as a photosensitive member or an image carrier. The photosensitive drum 2 is disposed so as to be rotatable in the direction of an arrow about an axis extending in a direction orthogonal to the conveyance direction of the paper T in the conveyance path L. An electrostatic latent image can be formed on the surface of the photosensitive drum 2.

  The charging unit 10 is disposed to face the surface of the photosensitive drum 2. The charging unit 10 uniformly charges the surface of the photosensitive drum 2 to be negative (minus polarity) or positive (plus polarity).

  The laser scanner unit 4 functions as an exposure unit, and is disposed away from the surface of the photosensitive drum 2. The laser scanner unit 4 includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  The laser scanner unit 4 scans and exposes the surface of the photosensitive drum 2 based on image information input from an external device such as a PC (personal computer). By scanning exposure with the laser scanner unit 4, the charge on the exposed portion of the surface of the photosensitive drum 2 is removed. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 2.

  The developing device 16 is provided corresponding to the photosensitive drum 2 and is disposed to face the surface of the photosensitive drum 2. The developing device 16 attaches a single color (usually black) toner to the electrostatic latent image formed on the photoconductive drum 2 to form a single color toner image on the surface of the photoconductive drum 2. The developing device 16 includes a developing roller 17 disposed opposite to the surface of the photosensitive drum 2, a stirring roller 18 for stirring the toner, and the like.

  The toner cartridge 5 is provided corresponding to the developing device 16 and stores toner supplied to the developing device 16.

  The toner supply unit 6 is provided corresponding to the toner cartridge 5 and the developing device 16, and supplies the toner contained in the toner cartridge 5 to the developing device 16. The toner supply unit 6 and the developing device 16 are connected by a toner supply path (not shown).

  The transfer roller 8 transfers the toner image developed on the surface of the photosensitive drum 2 to the paper T. A transfer bias for transferring the toner image formed on the photosensitive drum 2 to the paper T is applied to the transfer roller 8 by a transfer bias applying unit (not shown).

  The transfer roller 8 is brought into contact with or separated from the photosensitive drum 2. Specifically, the transfer roller 8 is configured to be movable between a contact position where the transfer roller 8 is in contact with the photosensitive drum 2 and a spaced position where the transfer roller 8 is separated from the photosensitive drum 2. Specifically, the transfer roller 8 is disposed at the contact position when the toner image developed on the photosensitive drum 2 is transferred to the paper T, and is disposed at the separation position in other cases.

  A sheet T conveyed on the conveyance path L is sandwiched between the photosensitive drum 2 and the transfer roller 8. The sandwiched paper T is pressed against the surface of the photosensitive drum 2. A transfer nip N is formed between the photosensitive drum 2 and the transfer roller 8. In the transfer nip N, the toner image developed on the photosensitive drum 2 is transferred onto the paper T.

  The static eliminator 12 is disposed to face the surface of the photosensitive drum 2. The static eliminator 12 irradiates the surface of the photosensitive drum 2 with light, thereby neutralizing the surface of the photosensitive drum 2 after the transfer is performed (removing the electric charge).

  The drum cleaning unit 11 is disposed to face the surface of the photosensitive drum 2. The drum cleaning unit 11 removes toner and deposits remaining on the surface of the photosensitive drum 2, and transports the removed toner and the like to a predetermined recovery mechanism for recovery.

  The fixing device 9 melts and presses the toner constituting the toner image transferred onto the paper T and fixes the toner on the paper T. The fixing device 9 includes a heating rotator (heating roller) 9a heated by a heater, and a pressure rotator (pressure roller) 9b pressed against the heating rotator 9a. The heating rotator 9a and the pressure rotator 9b sandwich and pressurize the paper T on which the toner image has been transferred, and convey the paper T. By transporting the paper T while being sandwiched between the heating rotator 9a and the pressure rotator 9b, the toner transferred onto the paper T is melted and pressurized, and is fixed to the paper T. Details of the fixing device 9 will be described later.

Next, the paper supply / discharge unit KH will be described.
As shown in FIG. 1, in the lower part of the apparatus main body M, a single paper feed cassette 52 that stores paper T is disposed. The paper feed cassette 52 is configured to be drawable in the horizontal direction from the front side (right side in FIG. 1) of the apparatus main body M. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. In the paper feed cassette 52, the paper T is stored in a state of being stacked on the placement plate 60. The paper T placed on the placement plate 60 is sent out to the transport path L by the cassette paper feed unit 51 arranged at the paper feed side end of the paper feed cassette 52 (the right end in FIG. 1). The cassette paper feed unit 51 includes a double feed prevention mechanism including a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 63 for feeding the paper T to the transport path L one by one. Prepare.

  A manual paper feed unit 64 is provided on the front surface (right side in FIG. 1) of the apparatus main body M. The manual paper feed unit 64 is provided mainly for supplying the apparatus main body M with a paper T of a size and type different from the paper T set in the paper feed cassette 52. The manual paper feed unit 64 includes a manual feed tray 65 that forms a part of the front surface of the apparatus main body M in the closed state, and a paper feed roller 66. The lower end of the manual feed tray 65 is attached to the vicinity of the paper feed roller 66 so as to be rotatable (openable and closable). The paper T is placed on the open manual feed tray 65. The paper feed roller 66 feeds the paper T placed on the open manual feed tray 65 to the manual feed path La.

  A paper discharge unit 50 is provided on the upper side of the apparatus main body M. The paper discharge unit 50 discharges the paper T to the outside of the apparatus main body M by the third roller pair 53. Details of the paper discharge unit 50 will be described later.

  The conveyance path L for conveying the paper T is a first conveyance path L1 from the cassette paper feeding unit 51 to the transfer nip N, a second conveyance path L2 from the transfer nip N to the fixing device 9, and a discharge from the fixing device 9. A third conveyance path L3 to the section 50, a manual conveyance path La that joins the paper supplied from the manual sheet feeding unit 64 to the first conveyance path L1, and a third conveyance path L3 from the upstream side to the downstream side. And a return transport path Lb that reverses the paper and returns it to the first transport path L1.

Moreover, the 1st junction part P1 and the 2nd junction part P2 are provided in the middle of the 1st conveyance path L1. A first branch portion Q1 is provided in the middle of the third transport path L3.
The first joining part P1 is a joining part where the manual feed path La joins the first transport path L1. The second junction P2 is a junction where the return conveyance path Lb merges with the first conveyance path L1.
The first branch portion Q1 is a branch portion where the return transport path Lb branches from the third transport path L3, and includes a first roller pair 54a and a second roller pair 54b. One roller of the first roller pair 54a and one roller of the second roller pair 54b are combined.

  In the middle of the first transport path L1 (specifically, between the second junction P2 and the transfer roller 8), a sensor for detecting the paper T, correction of skew (oblique paper feeding) of the paper T, and image A registration roller pair 80 is arranged to synchronize with the formation of the toner image in the forming unit GK. The sensor is disposed immediately before the registration roller pair 80 in the transport direction of the paper T (upstream in the transport direction). The registration roller pair 80 conveys the paper T by performing the above-described correction and timing adjustment based on detection signal information from the sensor.

The return conveyance path Lb is a conveyance path that is provided so that the opposite surface (non-printing surface) to the surface that has already been printed faces the photosensitive drum 2 when performing duplex printing on the paper T.
According to the return conveyance path Lb, the sheet T conveyed from the first branching section Q1 to the paper discharge section 50 side by the first roller pair 54a is reversed and returned to the first conveyance path L1 by the second roller pair 54b. , And can be conveyed to the upstream side of the registration roller pair 80 disposed on the upstream side of the transfer roller 8. A predetermined toner image is transferred onto the non-printing surface by the photosensitive drum 2 on the paper T that has been turned upside down by the return conveyance path Lb.

  A paper discharge unit 50 is formed at the end of the third transport path L3. The paper discharge unit 50 is disposed on the upper side of the apparatus main body M. The paper discharge unit 50 opens toward the front side of the apparatus main body M (the right side in FIG. 1, the manual paper feed unit 64 side). The paper discharge unit 50 discharges the paper T conveyed on the third conveyance path L3 to the outside of the apparatus main body M by the third roller pair 53.

On the opening side of the paper discharge unit 50, a paper discharge stacking unit M1 is formed. The paper discharge stacking unit M1 is formed on the upper surface (outer surface) of the apparatus main body M. The paper discharge stacking unit M1 is a part formed by the upper surface of the apparatus main body M being depressed downward. The bottom surface of the paper discharge stacking unit M1 constitutes a part of the top surface of the apparatus main body M. In the paper discharge stacking unit M1, sheets T formed with a predetermined toner image and discharged from the paper discharge unit 50 are stacked and stacked.
A paper detection sensor is disposed at a predetermined position on each conveyance path.

  Hereinafter, with reference to the drawings, a configuration related to a characteristic part in the printer 1 of the first embodiment will be described. FIG. 2 is a perspective view showing the fixing device 9 of the first embodiment. FIG. 3 is a longitudinal side view of the fixing device 9 according to the first embodiment as viewed from the first rotation axis I direction. FIG. 4 is a longitudinal front view of the fixing device 9 according to the first embodiment as viewed from the sheet conveyance direction. FIG. 5 is a partially enlarged longitudinal front view of the fixing device 9 shown in FIG.

  As shown in FIGS. 2 and 3, the fixing device 9 according to the first embodiment includes a heating roller 9a as a first rotating body, a pressure roller 9b as a second rotating body, a heater 910, and a heat shielding member. 920, and a first thermistor 970 and a second thermistor 980 as non-contact temperature detection sensors.

  As shown in FIGS. 3 and 4, the heating roller 9a is a hollow cylindrical rotating roller. The heating roller 9a is configured to be rotatable around a first rotation axis I extending in a conveyance width direction (second direction) D2 orthogonal to the conveyance direction D1 of the paper T. For example, the heating roller 9a has a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) having a thickness of about 30 μm on the outer peripheral surface of a cylindrical metal roller such as Al (aluminum) having a thickness of about 1 mm. It is configured by providing a release layer made of a heat-resistant coat or film made of a fluororesin such as PTFE (polytetrafluoroethylene). The heating roller 9a is rotatably supported by a case body BD of the apparatus main body M in the printer 1 and other members via a bearing member (not shown).

As shown in FIGS. 3 and 4, the pressure roller 9b is disposed so as to face the outer peripheral surface of the pressure roller 9b so as to contact the outer peripheral surface of the heating roller 9a. The pressure roller 9b is formed shorter than the heating roller 9a in the first rotation axis I direction (second direction) D2. The midpoint of the pressure roller 9b in the second rotation axis J direction and the midpoint of the heating roller 9a in the first rotation axis I are substantially coincident.
The pressure roller 9b is configured to be rotatable about a second rotation axis J parallel to the first rotation axis I of the heating roller 9a. For example, the pressure roller 9b is provided with an elastic layer such as silicone rubber having a thickness of about 5.5 mm and an Asker C hardness of 15 to 60 on the outer peripheral surface of a core metal such as aluminum or iron having a diameter of about 14 mm. Further, the elastic layer is formed by providing a release layer made of a fluororesin such as PFA or PTFE having a thickness of about 50 μm on the surface of the elastic layer.

Further, as shown in FIG. 4, the pressure roller 9b is configured such that a roller shaft 931 parallel to the second rotation axis J protrudes from both end portions in the second rotation axis J direction (second direction D2). The roller shaft 931 is rotatably supported by the case body BD of the apparatus main body M in the printer 1 and other members.
A pressure roller drive unit (not shown) such as an electric motor is connected to the roller shaft 931 of the pressure roller 9b as a second rotating body drive unit that rotationally drives the pressure roller 9b. When the pressure roller 9b is rotationally driven at a predetermined speed by the pressure roller driving unit, the heating roller 9a that contacts the outer peripheral surface of the pressure roller 9b is driven and rotated. As a result, a fixing nip N9 is formed between the pressure roller 9b and the heating roller 9a to sandwich the paper T on which the toner image is transferred.

  As shown in FIGS. 3 and 4, the heater 910 heats the heating roller 9a from the inside to heat the fixing nip N9 that is a contact portion between the heating roller 9a and the pressure roller 9b. The heater 910 is composed of, for example, a halogen heater. The heater 910 is disposed along the first rotation axis I of the heating roller 9a inside the heating roller 9a. The heater 910 is attached to the case body BD of the apparatus main body M and other members of the printer 1 via support members (not shown) at both ends in the longitudinal direction protruding from both ends in the first rotation axis I direction of the heating roller 9a. Fixed. The heater 910 heats the paper T that is nipped and conveyed between the heating roller 9a and the pressure roller 9b via the heating roller 9a. As a result, the paper T on which the toner image is transferred is conveyed to the fixing nip N9 and passed therethrough, whereby the toner TN on the paper T is melted and fixed on the paper T.

When the sheet T conveyed to the fixing nip N9 is conveyed after passing through the sheet passing area in the fixing device 9, the toner image is fixed. The “sheet passing area” means that the sheet T conveyed to the fixing nip N9 in the conveyance width direction (second direction) D2 orthogonal to the conveyance direction D1 of the sheet T is sandwiched between the heating rotating belt 9a and the pressure roller 9b. It is an area that passes through. The sheet passing area is formed (set) corresponding to the maximum size (maximum width) of paper that can be used in the printer 1 with reference to the center in the transport width direction D2 of the heating roller 9a and the pressure roller 9b.
In the fixing device 9 of the present embodiment, the maximum sheet passing area is set as a sheet passing area in which the sheet T having the maximum width (the maximum length in the first rotation axis I direction) in the transport width direction D2 is transported to the fixing nip N9. To do. For example, the A4 size paper T is transported to the fixing nip N9 in a state where the long side of the A4 size paper T is parallel to the first rotation axis I direction (transport width direction D2) of the heating roller 9a (A4 size lateral direction). The maximum sheet passing area is formed (set) as described above. The maximum sheet passing area is set for each printer.

  Specifically, as shown in FIGS. 2 and 4, a first width region 901a is formed in the heating roller 9a. On the outer peripheral surface of the heating roller 9a, when a paper T having the maximum width, for example, an A4 size paper T is conveyed to the fixing nip N9 in the horizontal direction, the first width serving as the maximum paper passing region through which the paper T passes is provided. Region 901a is formed (set). On the outer peripheral surface of the pressure roller 9b, a second width region 901b that is the maximum sheet passing region corresponding to the first width region 901a of the heating roller 9a is formed (set).

When the paper T having the maximum width passes, positions corresponding to both ends of the paper T in the first rotation axis I direction are first width region end portions 901e and 901e. That is, the paper T is transported through the first width area 901a as an area inside the first width area end portions 901e and 901e.
The first width region end portions 901e and 901e are in the vicinity of both end portions 902 and 902 of the heating roller 9a in the first rotation axis I direction (conveyance width direction D2), and from the both end portions 902 and 902 to the first rotation axis I. It is formed (set) at a position separated by a predetermined distance inside the direction.

As shown in FIGS. 4 and 5, the heat shielding member 920 is disposed inside the heating roller 9a. The heat shielding member 920 is disposed in the vicinity of the position corresponding to the first width region end portions 901e and 901e of the first width region 901a inside the heating roller 9a. The “corresponding position” is a position on the radially inner side of the heating roller 9a (first rotating body) with respect to the first width region end 901e. The vicinity of “the vicinity of the corresponding position” refers to a range within 10 mm in the first rotation axis I direction (conveying width direction D2) of the heating roller 9a with respect to the “corresponding position”.
The heat shielding member 920 shields radiant heat from the heater 910 toward the end 902 of the heating roller 9a in the first rotation axis I direction.

  The heat shielding member 920 is fixed by a cylindrical support member 925. The support member 925 is disposed so as to straddle the inside and the outside of the heating roller 9a through openings 903 formed at both ends of the heating roller 9a in the first rotation axis I direction. One end of the support member 925 is fixed to the heat shielding member 920. The other end of the support member 925 is fixed to the case body BD of the apparatus main body M in the printer 1 and other members.

  As shown in FIGS. 3 and 5, the heat shielding member 920 has a dome shape. When viewed from the first rotation axis I direction (second direction D2) of the heating roller 9a, the heating roller 9a is formed in a wide ring shape (doughnut shape) having a circular hole at the center. The outer edge 921 of the heat shielding member 920 is disposed to face the vicinity of the position corresponding to the first width region end 901e on the inner peripheral surface of the heating roller 9a. The inner peripheral edge 923 of the heat shielding member 920 is disposed in the vicinity of the heater 910 so as to face the outer peripheral surface of the heater 910. The outer edge 921 is located on the inner side in the first rotation axis I direction than the inner peripheral edge 923.

  The heat shielding member 920 has a light reflection surface 922 formed of a concave (curved surface) curved surface inside the first rotation axis I direction (second direction D2) of the heating roller 9a. Specifically, the curved surface portion of the heat shielding member 920 is formed to extend inward in the first rotation axis I direction from the center in the radial direction of the heating roller 9a toward the inner peripheral surface of the heating roller 9a. Yes.

  The heat shielding member 920 (light reflecting surface 922) is made of a light metal such as SUS or aluminum, for example. The light reflecting surface 922 is formed by coating a concave curved surface with a heat reflecting film (for example, a gold film). As a result, the heat shielding member 920 reflects the light from the heater 910, and a part of the light from the heater 910 has a first width on the inner peripheral surface of the heating roller 9a as indicated by the dotted arrow in FIG. Reflected toward the vicinity of the position corresponding to the region end 901e. The heat shielding member 920 shields the radiant heat from the heater 910 from moving toward the end 902 of the heating roller 9a in the first rotation axis I direction.

  As shown in FIG. 4, the first thermistor 970 as a non-contact type temperature detection sensor is disposed in close proximity to the central portion of the surface of the heating roller 9a in the first rotation axis I direction (second direction D2). The The first thermistor 970 detects the temperature of the central portion in the direction of the first rotation axis I on the surface of the heating roller 9a. The second thermistor 980 is disposed opposite to and close to the position corresponding to the first width region end 901e near both ends of the heating roller 9a in the first rotation axis I direction. The second thermistor 980 detects the temperature at or near the position corresponding to the first width region end 901e near both ends in the first rotation axis I direction on the surface of the heating roller 9a.

  A thermostat 990 is electrically connected to the first thermistor 970 and the second thermistor 980. The thermostat 990 is at or near the temperature corresponding to the temperature at the center of the heating roller 9a detected by the first thermistor 970 in the first rotation axis I direction and the first width region end 901e detected by the second thermistor 980. The amount of heat generated by the heater 910 is automatically adjusted so that the heating roller 9a is maintained at a predetermined temperature necessary for fixing by changing the electric resistance value based on the temperature of the heater.

Next, the operation of the printer 1 of the first embodiment will be briefly described with reference to FIG.
First, a case where single-sided printing is performed on the paper T stored in the paper feed cassette 52 will be described.
The paper T accommodated in the paper feed cassette 52 is sent out to the first transport path L1 by the forward feed roller 61 and the paper feed roller pair 63, and then the registration rollers via the first junction P1 and the first transport path L1. Transported to pair 80.
In the registration roller pair 80, skew correction of the paper T and timing adjustment with the toner image are performed.

The paper T discharged from the registration roller pair 80 is introduced between the photosensitive drum 2 and the transfer roller 8 through the first conveyance path L1. A toner image is transferred onto the paper T between the photosensitive drum 2 and the transfer roller 8.
Thereafter, the paper T is discharged from between the photosensitive drum 2 and the transfer roller 8 and is passed through the second conveyance path L2 to the fixing nip N9 between the heating roller 9a and the pressure roller 9b in the fixing device 9. be introduced. Then, the toner TN is melted in the fixing nip N9, and the toner TN is fixed to the paper T.

Next, the paper T is conveyed to the paper discharge unit 50 through the third conveyance path L3 by the first roller pair 54a, and is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1 by the third roller pair 53.
In this way, single-sided printing of the paper T stored in the paper feed cassette 52 is completed.

  When single-sided printing is performed on the paper T placed on the manual feed tray 65, the paper T placed on the manual feed tray 65 is sent out to the manual feed path La by the paper feed roller 66, and then the first joining portion. It is conveyed to the registration roller pair 80 via P1 and the first conveyance path L1. Subsequent operations are the same as the one-side printing operation of the paper T accommodated in the paper feed cassette 52 described above, and a description thereof will be omitted.

Next, the operation of the printer 1 when performing duplex printing will be described.
In the case of single-sided printing, as described above, the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1, and the printing operation is completed.
On the other hand, when performing double-sided printing, the paper T on which single-sided printing has been performed is reversed from the time of single-sided printing and conveyed again to the registration roller pair 80 via the return conveyance path Lb. Then, double-sided printing is performed on the paper T.

  More specifically, the operation is the same as the above-described single-sided printing operation until the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 by the third roller pair 53. Thus, in the case of double-sided printing, the rotation of the third roller pair 53 is stopped and rotated in the opposite direction while the paper T printed on one side is held by the third roller pair 53. Thus, when the third roller pair 53 is rotated in the reverse direction, the paper T held by the third roller pair 53 moves in the reverse direction (from the paper discharge unit 50 to the first branching unit Q1) along the third conveyance path L3. Transported in the direction of heading).

  As described above, when the paper T is transported in the reverse direction on the third transport path L3, it is introduced into the second roller pair 54b (not the first roller pair 54a). The paper T then joins the second transport path L2 via the return transport path Lb and the second joining portion P2. Here, the paper T is turned upside down from the one-side printing.

  Further, after the skew correction and timing adjustment are performed by the registration roller pair 80, the paper T is introduced between the photosensitive drum 2 and the transfer roller 8 through the first conveyance path L1. Since the non-printing surface of the paper T passes through the return conveyance path Lb, the non-printing surface faces the photosensitive drum 2, so that the toner image is transferred to the non-printing surface, and as a result, duplex printing is performed.

Next, the operation of the fixing device 9 which is a characteristic part of the printer 1 of the first embodiment will be described with reference to FIGS.
In the printer 1 of the first embodiment, when the power of the printer 1 is turned on, the charging unit 10, the laser scanner unit 4, the developing device 16, the transfer roller 8, the printer control unit (not shown), the fixing device from the power source unit. 9 and the heater 910 are supplied with electric power, and the charging unit 10, the laser scanner unit 4, the developing device 16, the transfer roller 8, the fixing device 9 and the heater 910 are controlled by a control signal from the printer control unit. The Then, the charging process, the exposure process, the development process, the transfer process, and the fixing process are sequentially performed.

  Specifically, in the printer 1 of the present embodiment, the paper T sent out from the registration roller pair 80 is conveyed to the transfer nip N between the photosensitive drum 2 and the transfer roller 8 through the first conveyance path L1. Is done. When the paper T is conveyed toward the photosensitive drum 2 as described above, first, the charging unit 10 charges the entire surface of the photosensitive drum 2 in the charging process, and the laser scanner unit 4 performs laser irradiation in the exposure process. Laser light is irradiated from a light source (not shown) toward the photosensitive drum 2 to form an electrostatic latent image on the surface of the photosensitive drum 2 irradiated with the laser light.

  Next, the developing device 16 supplies the toner charged in the developing process to the photosensitive drum 2 by the developing roller 17, thereby attaching the toner to the electrostatic latent image formed on the surface of the photosensitive drum 2, Develop the toner image. Subsequently, the transfer roller 8 transfers the toner image attached to the surface of the photoconductive drum 2 onto the paper T that passes between the photoconductive drum 2 and the transfer roller 8 in the transfer process.

  Then, the paper T onto which the toner image has been transferred in the transfer process is transported toward the fixing device 9 through the second transport path L2, and is transported between the heating roller 9a and the pressure roller 9b in the fixing device 9. The

  Further, by turning on a control signal output from the printer control unit to the heater 910, power supply from the power source unit to the heater 910 is started, and the heater 910 is heated. At the same time, by turning on a control signal output from the printer control unit to the pressure roller driving unit (not shown), power supply from the power source unit to the pressure roller driving unit is started, and the pressure roller 9b While being driven to rotate, the heating roller 9a is driven to rotate as the pressure roller 9b is driven to rotate. As a result, the fixing device 9 causes the heating roller 9a heated by the radiant heat from the heater 910 to the toner TN adhering to the paper T passing between the heating roller 9a and the pressure roller 9b in the fixing process. Heat is applied to the toner TN, and the toner TN is dissolved by the heat, and the pressure is applied to the paper T by the pressure roller 9b, whereby the toner image is fixed on the paper T.

  During the fixing operation as described above by the fixing device 9, the heating roller 9a is heated from the inside of the heating roller 9a by light (radiant heat) radiated from the heater 910 disposed inside the heating roller 9a. The heated heat is transmitted to the fixing nip N9.

  Here, in the first embodiment, the end of the first width region 901a that becomes the maximum sheet passing region on the outer peripheral surface of the heating roller 9a when the paper T having the maximum width (A4 size lateral direction) is conveyed to the fixing nip N9. A heat shielding member 920 having a light reflecting surface 922 is disposed in the vicinity of the position corresponding to the portion 901e. Therefore, the radiant heat from the heater 910 is shielded. Thereby, the heat radiation outside the vicinity of the position corresponding to the end 901e of the first width region 901a is suppressed. That is, the temperature rise at the end 902 in the first rotation axis I direction of the heating roller 9a located outside the sheet passing area is suppressed.

  In particular, the light reflecting surface 922 of the heat shielding member 920 is formed as a concave curved surface portion on the inner side in the first rotation axis I direction of the heating roller 9a. Therefore, a part of the light from the heater 910 is reflected so as to go to the vicinity of the position corresponding to the first width region end 901e on the inner peripheral surface of the heating roller 9a, as shown by the dotted arrow in FIG. . Thereby, the light from the heater 910 is condensed on the first width region 901a of the heating roller 9a. In addition, it is possible to suppress a drop in temperature at the center of the first width region 901a of the heating roller 9a that consumes the most heat energy during fixing. Moreover, the temperature of the vicinity of the position corresponding to the 1st width area | region edge part 901e in the internal peripheral surface of the heating roller 9a can be raised efficiently. As a result, the temperature distribution in the entire first width region 901a of the heating roller 9a can be made uniform efficiently.

Next, the fixing device 9 of the first embodiment will be described in more detail with reference to FIG. 6 using examples and comparative examples. However, the present invention is not limited to the following examples.
In the fixing device 9 according to the first embodiment, the first thermistor 970 and the second thermistor 980 are used to heat the case with the heat shielding member 920 and the case without the heat shielding member (hereinafter referred to as “comparative example”). The temperature of the outer peripheral surface of the roller 9a was compared. Specifically, using the first thermistor 970 and the second thermistor 980, the temperatures of the center portion of the first width region 901a and the first width region end 901e of the heating roller 9a were detected. Based on each detected temperature, the temperature distribution in the first rotation axis I direction on the outer peripheral surface of the heating roller 9a was measured. As a result, temperature distribution characteristics as shown in FIG. 6 were obtained.

  As shown in FIG. 6, in the fixing device 9 of the first embodiment having the heat shielding member 920, the temperature of the end portion 902 of the heating roller 9a in the first rotation axis I direction is lower than that in the comparative example. Thereby, it can confirm that the heat radiation to the outer side rather than the edge part 901e of the 1st width area | region 901a of the heating roller 9a is suppressed. In the fixing device 9 of the first embodiment, the temperature inside the first width region end 901e of the heating roller 9a is higher and gentler than that in the comparative example. Thereby, it has confirmed that the temperature of the 1st width area | region 901a of the heating roller 9a was equalized efficiently.

According to the fixing device 9 of the first embodiment, the following effects are exhibited.
In the fixing device 9 of the first embodiment, the position corresponding to the end portion 901e of the first width region 901a that is the maximum sheet passing region on the outer peripheral surface of the heating roller 9a when the maximum width sheet T is conveyed to the fixing nip N9. A heat shielding member 920 is disposed in the vicinity of.
Therefore, it is suppressed that the radiant heat from the heater 910 moves outside the first width region end 901e. Thereby, the heat loss by the radiation | emission of the radiant heat from the heater 910 can be suppressed. The vicinity of the position corresponding to the first width region end 901e on the inner peripheral surface of the heating roller 9a can be efficiently heated to raise the temperature. As a result, it is possible to reduce the heat energy required for heating the heating roller 9a to a predetermined temperature required for fixing and raising the temperature. Further, power consumption in the fixing device 9 can be suppressed.

In the first embodiment, the outer edge 921 of the heat shielding member 920 is disposed in the vicinity of the position corresponding to the first width region end 901e on the inner peripheral surface of the heating roller 9a.
Therefore, it is possible to minimize heat loss due to heat radiation in which the radiant heat from the heater 910 moves outward from the gap formed between the inner peripheral surface of the heating roller 9a and the outer edge 921 of the heat shielding member 920. It is. In addition, the efficiency of raising the temperature in the vicinity of the first width region end 901e can be maximized.

  Further, in the first embodiment, the heat shielding member 920 causes the amount of heat energy corresponding to the heat energy that is suppressed from radiating outward from the first width region end 901e to the center of the first width region 901a. Can be used for heating on the part side. Therefore, it is possible to increase the speed of the temperature increase of the entire first width region 901a. Thereby, the warm-up time at the start of fixing can be shortened.

In the first embodiment, the heat shielding member 920 has a concave curved surface portion on the inner side in the first rotation axis I direction (second direction D2) of the heating roller 9a, and light is reflected on the concave curved surface portion. A surface 922 is formed.
Therefore, the light from the heater 910 is totally reflected on the inner peripheral surface of the heating roller 9a. Further, a part of the reflected light reflected by the light reflecting surface 922 is reflected so as to go to the vicinity of the position corresponding to the first width region end 901e on the inner peripheral surface of the heating roller 9a.
Thereby, the light from the heater 910 is condensed at a position corresponding to the first width region 901a of the heating roller 9a. Therefore, it is possible to suppress a drop in temperature at the center of the first width region 901a of the heating roller 9a that consumes the most heat energy during fixing. Moreover, the temperature of the vicinity of the position corresponding to the 1st width area | region edge part 901e in the internal peripheral surface of the heating roller 9a can be raised efficiently. As a result, the temperature distribution in the entire first width region 901a of the heating roller 9a can be made uniform efficiently.

Second Embodiment
Next, the fixing device 9A of the second embodiment will be described. FIG. 7 is a longitudinal side view of the fixing device 9 according to the second embodiment when viewed from the first rotation axis I direction. FIG. 8 is a longitudinal front view of the fixing device 9 according to the second embodiment viewed from the sheet conveyance direction.
The second embodiment will be described mainly with respect to differences from the first embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and detailed description thereof will be omitted. In the second embodiment, the description of the first embodiment is appropriately applied to points that are not particularly described. Also in the second embodiment, the same effects as in the first embodiment are achieved.

  As shown in FIGS. 7 and 8, the fixing device 9 of the second embodiment includes a heating rotary belt 9a as a first rotating body, a pressure roller 9b as a second rotating body, a pressure receiving member 940, and a support. A member 960, two heaters 910 and 910, a heat shielding member 920, and thermistors 970 and 980 as non-contact type temperature detection sensors are provided.

  As shown in FIG. 7, the heating rotary belt 9a is a rotary belt that is annular and has flexibility and heat resistance. The heating rotary belt 9a is configured to be rotatable around a first rotation axis I extending in a second direction D2 perpendicular to the transport direction D1 of the paper T. For example, the heating rotary belt 9a is provided with an elastic layer of silicone rubber having a thickness of about 200 to 500 μm on the outer peripheral surface of a metal belt such as SUS (stainless steel) or Ni steel having a thickness of about 30 to 50 μm. A mold release comprising a heat-resistant film made of a fluororesin such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) or PTFE (polytetrafluoroethylene) having a thickness of about 30 μm on the outer peripheral surface of the elastic layer Constructed by providing layers.

  As shown in FIGS. 7 and 8, the two heaters 910 and 910 are arranged on the downstream side (left side in FIG. 8) and the upstream side (right side in FIG. 8) of the support member 960 inside the heating rotating belt 9a. ) Installed in each. These two heaters 910 apply heat to the paper T that is nipped and conveyed between the heating rotary belt 9a and the pressure roller 9b via the heating rotary belt 9a. As a result, the paper T on which the toner image is transferred is conveyed to the fixing nip N9 and passed therethrough, whereby the toner TN on the paper T is melted and fixed on the paper T.

As shown in FIG. 7, the pressure receiving member 940 is formed to extend long in the first rotation axis I direction (second direction D2) of the heating rotary belt 9a inside the heating rotary belt 9a. The pressure receiving member 940 is fixed to both ends of the casing (not shown) in the longitudinal direction at both ends in the longitudinal direction.
The pressure receiving member 940 is a member that forms a fixing nip N9 with the pressure roller 9b via the heating rotary belt 9a. The pressure receiving member 940 needs to have a certain strength or higher in order to receive the pressure received by the heating rotary belt 9a from the pressure roller 9b. Further, since the pressure receiving member 940 is in contact with the inner peripheral surface of the heating rotating belt 9a, it is necessary to have excellent heat capacity, heat resistance, wear resistance, and the like. In order to satisfy these necessary conditions, the pressure receiving member 940 is made of, for example, SUS (stainless steel). In addition, if the said conditions are provided, the pressure receiving member 940 can also be comprised from resin.

  A specific configuration of the pressure receiving member 940 will be described. As shown in FIG. 7, the pressure receiving member 940 includes a sliding contact flat plate portion 941 that slidably contacts the inner peripheral surface of the heating rotary belt 9a, and two side plate portions that extend perpendicularly to the sliding contact flat plate portion 941. 942, 942 and two inclined plate portions 943, 943 that connect the two side plate portions 942, 942 and the sliding contact flat plate portion 941. The pressure receiving member 940 has a C-shape that is open toward the radial center of the heating rotary belt 9a in the cross section of the heating rotary belt 9a in the first rotation axis I direction (second direction) D2. The pressure receiving member 940 is made of, for example, SUS (stainless steel) having a thickness of about 0.2 mm. Since the pressure receiving member 940 has the two inclined plate portions 943 and 943 on both sides of the sliding contact flat plate portion 941, sliding of the heating rotating belt 9a with respect to the pressure receiving member 940 becomes smooth.

  As shown in FIG. 7, the support member 960 is disposed inside the heating rotary belt 9a in order to receive and support the pressure received by the pressure receiving member 940 from the pressure roller 9b, that is, to reinforce the pressure receiving member 940. Is done. The support member 960 has a substantially T shape in a cross section in the first rotation axis I direction (second direction) D2 of the heating rotary belt 9a. Specifically, the support member 960 has a lower end plate portion 960 </ b> A that is abutted against the sliding contact flat plate portion 941 of the pressure receiving member 940 and a rising end that extends toward the radial center of the heating rotating belt 9 a with the heat insulating member 962 interposed therebetween. And a plate portion 960B. The rising plate portion 960B has a height at which the free end is close to the inner peripheral surface of the heating rotary belt 9a.

As shown in FIG. 7, the support member 960 is fixed at both ends in the longitudinal direction of the lower end plate portion to both ends in the longitudinal direction of the casing (not shown).
Due to the presence of the support member 960 as described above, the pressure (fixing pressure) in the fixing nip N9 is stabilized, and it is possible to apply a strong pressure to the paper T passing through the fixing nip N9, thereby preventing fixing failure.

  The support member 960 is made of SUS (stainless steel) having a thickness of about 3 mm. The heat insulating member 962 is made of a heat-resistant silicon sponge having a thickness of about 2 mm, a silicon fiber processed cloth, glass wool, or the like, and suppresses heat transfer from the pressure receiving member 940. Further, the entire surface of the lower end plate portion 960 </ b> A of the support member 960 and both surfaces of the rising plate portion 960 </ b> B are covered with the reflection member 963. The reflection member 963 is made of aluminum or a gold film having a thickness of about 0.5 mm, and reflects the radiant heat so that the radiant heat of the heater 910 is not converted into light heat.

The heat shielding member 920 will be described.
As shown in FIG. 8, the heat shielding member 920 is located at a position corresponding to the first width region end portion 901e in the vicinity of both ends in the first rotation axis I direction of the heating rotation belt 9a inside the heating rotation belt 9a. It is arranged in the vicinity and on top of the two heaters 910. The heat shielding member 920 is fixed to and supported by the rising plate portion 960B of the support member 960, and protrudes on both sides of the rising plate portion 960B.

As shown in FIG. 7, the heat shielding member 920 is formed in a rectangular plate shape when viewed from the first rotation axis I direction (second direction D2) of the heating rotating belt 9a.
As shown in FIG. 8, the heat shielding member 920 is formed to be curved in a convex arc shape on the outer side in the first rotation axis I direction when viewed from above. The heat shielding member 920 is disposed so that the corner portions of the outer edge 921 at both ends in the longitudinal direction face the vicinity of the position corresponding to the first width region end portion 901e on the inner peripheral surface of the heating rotating belt 9a. The heat shielding member 920 has a light reflection surface 922 formed of a concave (curved surface) curved surface inside the first rotation axis I direction (second direction D2) of the heating roller 9a. Specifically, the curved surface portion of the heat shielding member 920 extends inward in the first rotation axis I direction from the center in the radial direction of the heating rotary belt 9a toward the inner peripheral surface of the heating rotary belt 9a. Is formed.
Thereby, the heat shielding member 920 shields radiant heat from the two heaters 910 toward the end portion 902 of the heating rotating belt 9a in the first rotating shaft I direction. Thereby, the heat shielding member 920 suppresses an increase in the temperature of the end portion 902 in the first rotation axis I direction of the heating rotating belt 9a located outside the sheet passing area.

As described above, in the fixing device 9 according to the second embodiment, the heating rotating belt 9a that is an annular and flexible rotating belt is used as the first rotating body.
Therefore, it is possible to reduce the heat capacity of the heating rotating belt 9a as compared with the case where a heating roller is used. Thereby, the heat radiation by the radiant heat from the heater 910 moving outside the first width region end 901e with the presence of the heat shielding member 920 is suppressed, thereby suppressing the heat loss. Further, the temperature raising efficiency in the vicinity of the first width region end 901e can be further increased, and the time required for warming up the fixing device 9 can be further shortened.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to 1st Embodiment and 2nd Embodiment which were mentioned above, It can implement with a various form.
For example, in the embodiment, the pressure roller 9b (second rotating body) is driven to rotate, and the heating roller or the heating rotating belt 9a (first rotating body) is driven to rotate. The first rotating body may be driven to rotate, and the second rotating body may be driven to rotate.

  In the first embodiment, the heat shielding member 920 is formed in a circular ring shape when viewed from the first rotation axis I direction (second direction D2) of the heating rotating belt 9a, but is not limited thereto. . For example, the heat shielding member 920 may be formed in a rectangular plate shape when viewed from the direction of the first rotation axis I (second direction D2) of the heating rotating belt 9a.

Further, in the second embodiment, the heat shielding member 920 is formed in a rectangular plate shape when viewed from the first rotation axis I direction (second direction D2) of the heating rotating belt 9a. It is not limited. For example, the heat shielding member 920 surrounds the two heaters 910 and avoids the positions of the support member 960 and the pressure receiving member 940 when viewed from the first rotation axis I direction (second direction D2) of the heating rotating belt 9a. In addition, it may be formed in a substantially circular shape.
The fixing device of the present invention may be unitized and configured to be detachable from the apparatus main body of the image forming apparatus, or may be configured integrally with the apparatus main body of the image forming apparatus.

The type of the image forming apparatus of the present invention is not particularly limited, and may be a copier, a printer, a facsimile, or a complex machine thereof.
The sheet-shaped transfer material is not limited to paper, and may be a film sheet, for example.

  DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus), 2 ... Photosensitive drum (image carrier), 16 ... Developing device, 9 ... Fixing device, 9a ... Heating roller or heating rotating belt (first rotating body), 9b: Pressure roller (second rotating body), 901a: First width region, 901e ... End of first width region, 902 ... End, 910 ... Heater, 920 ... Heat shielding member, 922 ... ... light reflecting surface, 940 ... pressure receiving member, 960 ... support member, I ... first rotating shaft, N9 ... fixing nip, T ... paper (transfer material), TN ... toner

Claims (8)

A hollow first rotating body rotatable around a first rotation axis;
A heater that is disposed inside the first rotating body and that heats the first rotating body from the inside;
A fixing nip that is disposed opposite to the first rotating body and through which the sheet-like transfer material is conveyed is formed by the first rotating body and is centered on a second rotating shaft that is parallel to the first rotating shaft. A rotatable second rotating body;
A first width region formed on the first rotating body and through which a transfer material having a maximum width passes in a transport width direction orthogonal to the transport direction;
A heat shielding member disposed inside the first rotating body, and disposed in the vicinity of a position corresponding to an end of the first width region, which is an end of the first width region in the first rotation axis direction. And a heat shielding member that shields radiant heat from the heater toward the end of the first rotating body. 2. The fixing device according to claim 1, wherein an outer edge of the heat shielding member is disposed in the vicinity of a position corresponding to an end of the first width region on an inner peripheral surface of the first rotating body. The fixing device according to claim 1, wherein the heat shielding member has a light reflecting surface formed on an inner side in the first rotation axis direction. The fixing device according to claim 3, wherein the heat shielding member has a concave curved surface portion on an inner side in the first rotation axis direction. The heat shielding member reflects light from the heater, and at least part of the light from the heater is in the vicinity of a position corresponding to the end of the first width region on the inner peripheral surface of the first rotating body. The fixing device according to claim 3, wherein the fixing device reflects toward the head. The fixing device according to claim 1, wherein the first rotating body is a cylindrical rotating roller. The fixing device according to claim 1, wherein the first rotating body is an annular and flexible rotating belt. One or more image carriers on which electrostatic latent images are formed; and
A developer for developing a toner image on the electrostatic latent image formed on the one or more image carriers;
A transfer unit that directly or indirectly transfers the toner image formed on the image carrier to a sheet-like transfer material;
An image forming apparatus comprising: the fixing device according to claim 1.

Images