JP2020134717A - Heating device, fixing device, and image forming apparatus - Google Patents

Abstract

To improve the heat efficiency and energy-saving property of a heating device and to reduce size, weight, and cost.SOLUTION: The heating device includes an endless rotation member (fixing belt 310), a heating source (halogen heater 361) which emits radiation heat, a nip forming member 380 which is heated by the radiation heat, and an opposite member (pressure roller 320) which holds the rotation member 310 between the opposite member and the nip forming member 380, to form a nip part SN through which a sheet being heated passes. A reflection surface 362 which reflects the radiation heat except the radiation heat directly directed to the nip forming member from the heating source toward the nip forming member is disposed on the surface of the heating source.SELECTED DRAWING: Figure 3

Description

The present invention relates to a heating device, a fixing device and an image forming device using a heating source such as a halogen heater.

Various types of fixing devices used in electrophotographic image forming devices are known. One of them is a model in which a thin-walled fixing belt having a low heat capacity is heated by a halogen heater (see, for example, Patent Document 1). In this type of fixing device, a nip forming member is arranged inside and a pressure roller is arranged outside with an endless fixing belt sandwiched between them.

The halogen heater in the fixing belt heats the nip forming member, and the nip forming member heats the fixing belt. The nip forming member is supported by a metal stay having a channel-shaped cross section. A reflective member is provided inside the stay in order to prevent overheating of the stay and increase thermal efficiency.

In the fixing device of Patent Document 1, since the radiant heat from the halogen heater spreads in all directions by 360 °, a reflective member is indispensable for protecting peripheral members such as stays that are originally not desired to be heated from radiant heat and improving thermal efficiency. However, if the reflective member is provided, the weight and size of the fixing device are increased, and the cost is increased because the process of assembling the reflective member is also required. Furthermore, since there is a certain distance from the halogen heater to the reflective member, there are problems in terms of thermal efficiency and energy saving.

The present invention has been made in view of such a situation, and an object of the present invention is to improve the thermal efficiency and energy saving of the fixing device, and to reduce the weight and size of the fixing device and reduce the cost.

In order to solve the above problems, the heating device of the present invention comprises an endless rotating member, a heating source arranged inside the rotating member to generate radiant heat, and a heating source arranged on the inner peripheral side of the rotating member. A nip portion through which the heated sheet passes is formed by sandwiching the rotating member between the nip forming member heated by the radiant heat generated and the rotating member arranged opposite to the outer peripheral side of the rotating member. A heating device including an opposing member, and a reflective surface that reflects radiant heat other than radiant heat directly directed from the heating source to the nip forming member in the direction of the nip forming member is arranged on the surface of the heating source. It is characterized by being installed.

According to the present invention, since a reflective surface for reflecting radiant heat other than the radiant heat directly directed from the heating source to the nip forming member in the direction of the nip forming member is arranged on the surface of the heating source, the reflecting member is surrounded by the heating source. It is not necessary to provide a heating device, the weight and size of the heating device can be reduced, and the cost can be reduced. Further, since the radiant region of radiant heat can be limited to the nip forming member, the thermal efficiency and energy saving can be improved.

It is a principle figure of the image forming apparatus which concerns on embodiment of this invention. It is sectional drawing of the fixing apparatus which concerns on 1st Embodiment used for an image forming apparatus. It is a perspective view of the fixing device of FIG. It is sectional drawing of the fixing apparatus which concerns on 2nd Embodiment which limited the radiation region by the reflection surface. It is sectional drawing of the fixing apparatus which concerns on 3rd Embodiment which limited the radiation region by the reflection surface. It is sectional drawing of the fixing apparatus which concerns on 4th Embodiment which limited the radiation region by the reflection surface. It is sectional drawing of the fixing apparatus which concerns on 5th Embodiment which limited the radiation region by the reflection surface. It is a figure which shows (a) the intensity distribution of the radiant heat of a halogen heater, and (b) is a figure which shows the opening angle.

Hereinafter, the fixing device and the image forming device (laser printer) according to the embodiment of the present invention will be described with reference to the drawings. The laser printer is an example of an image forming apparatus, and it goes without saying that the image forming apparatus is not limited to the laser printer.

That is, the image forming apparatus can be configured as any one of a copying machine, a facsimile, a printer, a printing machine, and an inkjet recording apparatus, or a compound machine in which at least two or more of these are combined.

The same or corresponding parts in each drawing are designated by the same reference numerals, and the duplicated description thereof will be appropriately simplified or omitted. Further, the dimensions, materials, shapes, relative arrangements thereof, etc. in the description of each component are examples, and the scope of the present invention is not intended to be limited thereto unless otherwise specified.

In the following embodiments, the "recording medium" is described as "paper", but the "recording medium" is not limited to paper (paper). The "recording medium" includes not only paper but also transparencies, fabrics, metal sheets, plastic films, and prepreg sheets in which carbon fibers are pre-impregnated with resin.

A medium to which a developing agent or ink can be attached, a recording paper, and a recording sheet are all included in the "recording medium". In addition to plain paper, "paper" also includes thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like.

Further, "image formation" used in the following description means not only giving an image having meaning such as characters and figures to the medium, but also giving an image having no meaning such as a pattern to the medium. Also means.

(Laser printer configuration)
FIG. 1 is a principle diagram of a laser printer as an embodiment of an image forming apparatus 100 provided with the fixing apparatus 300 of the present invention. The image forming apparatus 100 includes an image carrier 2 (for example, a photoconductor drum) and a drum cleaning apparatus 3.

Further, a charging device 4 as a charging means for uniformly charging the surface of the image carrier, a developing device 5 as a developing means for performing visible image processing of an electrostatic latent image formed on the image carrier, and an image supporting It has a transfer means TM disposed below the body 2, a static eliminator, and the like.

The exposure device 7 is arranged above the image carrier 2. The exposure device 7 performs write scanning according to the image information, that is, reflects the laser beam Lb from the laser diode by the mirror 7a based on the image data and irradiates the image carrier 2.

The paper feeding device 50 has a tray on which the paper P is loaded and is installed below the image forming device 100. The paper feeding device 50 can accommodate a large number of sheets P as a recording medium in a bundle, and is unitized together with a paper feeding roller 60 as a means for conveying the paper P.

A resist roller pair 250 as a separation and transporting means is arranged on the downstream side of the paper feed roller 60. The paper P fed from the paper feeding device 50 is temporarily stopped by the resist roller pair 250. By this temporary stop, a slack is formed on the tip side of the paper P, and the skew of the paper P is corrected.

The paper P, which is abutted against the resist roller pair 250 and has a slack formed at the tip, is sent to the transfer nip N of the transfer means TM at the timing when the toner image on the image carrier 2 is suitably transferred. Then, on the paper P that has been sent out, the toner image on the image carrier 2 is electrostatically transferred to a desired transfer position by the bias applied at the transfer nip N.

The fixing device 300 is arranged on the downstream side of the transfer nip N. The fixing device 300 includes a fixing belt 310 as a rotating member including a halogen heater 361 as a heating source for generating radiant heat, which will be described later, and an opposing member that rotates while abutting the fixing belt 310 at a predetermined pressure. A pressure roller 320 is provided.

(Laser printer operation)
Next, the basic operation of the laser printer according to this embodiment will be described. The paper feed roller 60 rotates in response to the paper feed signal from the control unit of the image forming apparatus 100. The rotation of the paper feed roller 60 separates the topmost paper of the bundled paper P loaded on the paper feed device 50 and feeds it to the paper feed path.

When the tip of the fed paper P reaches the nip of the resist roller pair 250, it forms a slack and stands by in that state. Then, the optimum timing (synchronization) for transferring the toner image on the image carrier 2 to the paper P is set, and the tip skew of the paper P is corrected.

The charging device 4 uniformly charges the surface of the image carrier 2 to a high potential. Then, the exposure device 7 reflects the laser beam Lb based on the image data by the mirror 7a and irradiates the surface of the image carrier 2.

On the surface of the image carrier 2 irradiated with the laser beam Lb, the potential of the irradiated portion is lowered to form an electrostatic latent image. The developing apparatus 5 has a developing agent carrier that supports a developer containing toner, and an electrostatic latent image is formed on the unused black toner supplied from the toner bottle via the developing agent carrier 5a. The image carrier 2 is transferred to the surface portion of the image carrier 2.

The image carrier 2 to which the toner has been transferred forms (develops) a toner image on its surface. Then, the toner image formed on the image carrier 2 is transferred to the paper P by the transfer means TM.

The drum cleaning device 3 uses a cleaning blade 3a to remove residual toner adhering to the surface of the image carrier 2 after the transfer process. The removed residual toner is collected in the waste toner housing.

The paper P as a sheet to be heated to which the toner image is transferred is conveyed to the fixing device 300. The paper P conveyed to the fixing device 300 is sandwiched between the fixing belt 310 and the pressurizing roller 320, and the unfixed toner image is fixed to the paper P by heating and pressurizing. The paper P on which the toner image is fixed is sent out from the fixing device 300.

(Fixing device)
Next, the fixing device 300 according to the embodiment of the present invention will be further described. As shown in FIGS. 2 and 3, the fixing device 300 according to the first embodiment is composed of a thin-walled fixing belt 310 having a low heat capacity and a pressure roller 320.

The fixing belt 310 is set to have a thickness of 1 mm or less and a diameter of 20 to 40 mm as a whole from the viewpoint of reducing the heat capacity. In order to further reduce the heat capacity, the thickness of the entire fixing belt 21 is preferably 0.2 mm or less, more preferably 0.16 mm or less, and the diameter is 30 mm or less.

The fixing belt 310 can be composed of a substrate on the inner peripheral side (thickness 20 to 50 μm), a release layer on the outer peripheral side (thickness 10 to 50 μm), and an intermediate elastic layer (thickness 100 to 300 μm). The inner peripheral side substrate can be formed of a metal material such as nickel or SUS or a resin material such as polyimide in order to reduce the heat capacity. The inner peripheral surface of the fixing belt 310 may be coated with polyimide, PTFE or the like as a sliding layer.

The release layer on the outer peripheral side is for enhancing durability and ensuring releasability, and is a fluororesin such as PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) or PTFE (polytetrafluoroethylene). Can be formed with.

The elastic layer in the middle is for absorbing minute irregularities on the surface of the belt, and can be formed of a rubber material such as silicone rubber, foamable silicone rubber, or fluororubber. When the thickness of the elastic layer is set to about 100 μm, when the unfixed toner is crushed and fixed, the elastic deformation of the elastic layer absorbs minute irregularities on the belt surface, and the occurrence of uneven gloss can be avoided.

The pressure roller 320 has, for example, an outer diameter of 25 mm, and has a solid iron core metal 321 and an elastic layer 322 formed on the surface of the core metal 321 and a release layer 323 formed on the outside of the elastic layer 322. It is composed of and.

The elastic layer 322 can be formed of silicone rubber, solid rubber, sponge rubber, or the like, and the thickness of the elastic layer 322 is, for example, 3.5 mm. When sponge rubber is used for the elastic layer 322, the heat insulating property is enhanced, so that the heat of the fixing belt 310 is less likely to be taken away.

It is desirable that the surface of the elastic layer 322 is formed with a release layer 323 made of a fluororesin layer having a thickness of, for example, about 40 μm, in order to improve the release property. The pressurizing roller 320 is in pressure contact with the fixing belt 310 by urging means.

Although the pressure roller 320 is shown as a solid roller in FIGS. 2 and 3, the pressure roller 320 may be a hollow roller. In that case, a heat source such as a halogen heater may be arranged inside the pressurizing roller 320.

(Internal structure of fixing belt)
Inside the fixing belt 310, a stay 330 as a support member and a nip forming member 380 are arranged in the axial direction. The stay 330 is made of a metal channel material having a U-shaped cross section, and both ends in the longitudinal direction are supported by both side plates of the fixing device 300.

As the material of the stay 330, a highly rigid iron-based material such as SUS or SECC is suitable. By using such an iron-based material, the pressing force of the pressurizing roller 320 acting on the nip forming member 380 is surely received by the stay 330, and the nip portion SN is stably formed.

The nip forming member 380 transfers heat in the axial direction (width direction) to make the temperature of the fixing belt 310 uniform in the width direction. As the nip forming member 380, a thin plate-shaped member such as copper (398 W / mk), aluminum (236 W / mk), or silver having high thermal conductivity is used in order to facilitate heat transfer in the width direction. Further, in consideration of cost, processed surface, etc., it is desirable to use a thin plate of copper.

The nip-forming surface of the nip-forming member 380 may be anodized or coated with a fluororesin-based material in order to improve wear resistance and slidability. Further, for the purpose of ensuring slidability over time, a lubricant such as fluorine grease may be applied and maintained.

The nip forming member 380 of FIGS. 2 and 3 shows the nip forming surface in a flat shape, but the nip forming surface may have a concave shape or another shape. For example, when the concave nip forming surface is used, the discharge direction of the paper tip is closer to the pressure roller 320, the separability is improved, and the occurrence of jam is suppressed.

Further, a separating member for separating the paper P from the fixing belt 310 may be provided on the downstream side of the fixing device 300 in the paper transport direction. Further, a releaseable pressurizing means for pressurizing the pressurizing roller 320 to the fixing belt 310 may be provided.

As shown in FIG. 2 and FIG. 3 in detail, the stay 330 has an upstream side wall 330a, a ceiling wall 330b, and a downstream side wall 330c, and the ceiling wall 330b causes the upper ends of the upstream side wall 330a and the downstream side wall 330c to be formed. It is connected. Then, both ends of the nip forming member 380 in the lateral direction are fixed and supported at the downward opening end of the stay 330, that is, the lower ends of the upstream side wall 330a and the downstream side wall 330c.

Therefore, a space is formed inside the stay 330 in which the top, bottom, left, and right sides are closed. By supporting the nip forming member 380 at two locations, the upstream side wall 330a of the stay 330 and the lower end of the downstream side wall 330c, the heat capacity of the nip forming member 380 is not increased, and the heat transfer efficiency can be improved. It can be reduced.

A halogen heater 361 as a heating source is arranged in the axial direction in a closed space inside the stay 330. Both ends of the halogen heater 361 are supported by both side plates of the fixing device 300. The radiant heat generated from the halogen heater 361 heats the nip forming member 380, and the nip forming member 380 heats the fixing belt 310.

The output control of the halogen heater 361 is performed, for example, by detecting the temperature of the belt surface with a temperature sensor provided on the outer periphery of the fixing belt 310 on the upstream side in the belt rotation direction. By controlling the output of the heater in this way, the temperature of the fixing belt 310 (fixing temperature) is set to a desired temperature.

(Reflective surface of halogen heater)
A reflection surface 362 is formed on the upper half of the surface of the halogen heater 361 as shown in FIG. The reflecting surface 362 is provided on the surface of the valve 361a of the halogen heater 361. The valve 361a is composed of a cylindrical quartz tube that covers the filament 361b of the halogen heater 361.

In the present embodiment, since the reflecting surface 362 is integrated with the halogen heater 361, it is not necessary to assemble the reflecting member as a separate member as in the conventional case, and the size and cost of the device can be reduced. Further, since the heat capacity of the fixing device 300 can be reduced by downsizing, the temperature rise time of the nip portion SN can be shortened.

The reflective surface 362 is formed by fixing a heat-resistant reflective material to the upper half of the surface of the valve 361a. As a method for fixing the reflective material, various methods such as vapor deposition, adhesion, and coating can be adopted. As the reflective material, various heat-resistant reflective materials such as ceramics and metals (gold, silver, copper, aluminum) can be used individually or in combination (mixed). For example, a molybdenum alloy foil or an aluminum foil can be fixed to the upper half of the surface of the valve 361a.

By using the halogen heater 361 with the reflecting surface 362, the radiant intensity on the downward opening side in FIGS. 2 and 3 opposite to the reflecting surface 362 can be increased, and the heat amount distribution in the circumferential direction is limited. It becomes possible to do.

Conventionally, a reflective member has been arranged as a separate member around the halogen heater 361, but when the device is miniaturized, the reflective member must be arranged close to the halogen heater 361. Then, there is a problem that the reflective member is discolored due to high heat and the reflectance is lowered.

In the present embodiment, since the heat-resistant reflective surface is formed on the valve 361a of the halogen heater 361 itself, the reflective surface does not discolor even with high heat, and it is not necessary to arrange a reflective member, so that energy saving is reduced. It is possible to miniaturize the device without inviting.

Further, since the radiant region of the radiant heat of the halogen heater 361 can be limited to the nip forming member 380 by the reflecting surface 362, the temperature rise of the surrounding members such as the stay 330 can be suppressed.

The forming range of the reflecting surface 362 is 180 ° on the surface of the halogen heater 361. That is, a reflection surface 362 is formed on the outer peripheral surface of the valve 361a in the upper half from the horizontal line passing through the center of the filament 361b of the halogen heater 361. As a result, the fan-shaped radiation region R1 from the halogen heater 361 toward the nip forming member 380 can be narrowed down inside the downward 180 ° opening angle of the halogen heater 361. The above-mentioned forming range of the reflecting surface 362 (upper half 180 °) corresponds to the distance (height) from the nip forming member 380 to the halogen heater 361, the short width of the nip forming member 380, the width of the nip portion SN, and the like. May be changed.

The radiation region R1 is within the width of the nip forming member 380 in the lateral direction, and its upstream end R1a and downstream end R1b are located inside the upstream side wall 330a and the downstream side wall 330c of the stay 330. The positions of the upstream end R1a and the downstream end R1b of the radiation region R1 can be realized by optimizing the distance between the halogen heater 361 and the nip forming member 380.

The fixing device 300 is configured as described above. In FIG. 2, when the paper P carrying the toner image is passed from the direction of the arrow toward the nip portion SN, the nip portion between the fixing belt 310 and the pressurizing roller 320 is passed. The paper P is heated by the SN and the toner image is fixed on the paper P.

At this time, the fixing belt 310 is heated by the radiant heat from the halogen heater 361 via the nip forming member 380. At this time, since the reflection surface 362 is formed on the valve 361a of the halogen heater 361 itself, all the radiant heat of the halogen heater 361 can be concentrated on the nip forming member 380, and the nip forming member 380 can be efficiently heated. it can.

(Second Embodiment of Fixing Device)
FIG. 4 shows the fixing device 300 according to the second embodiment, in which a fan-shaped radiation region R2 from the halogen heater 361 to the nip forming member 380 is formed. The end portion R2a of the radiation region R2 on the upstream side (nip portion SN inlet side) in the paper transport direction is a corner portion (intersection point) where the inner surface of the upstream side wall 330a of the stay 330 and the upper surface of the nip forming member 380 intersect.

Further, the end portion R2b of the radiation region R2 on the downstream side in the paper transport direction (nip portion SN outlet side) is a corner portion (intersection point) where the inner side surface of the downstream side wall 330c of the stay 330 and the upper surface of the nip forming member 380 intersect. .. By setting the radiation region R2 in this way, it is possible to prevent unnecessary heating of the stay 330 and to efficiently heat the stay 330 with the maximum area of the upper surface of the nip forming member 380 as the radiation target region.

(Third Embodiment of fixing device)
FIG. 5 shows the fixing device 300 according to the third embodiment, in which a fan-shaped radiation region R3 from the halogen heater 361 to the nip forming member 380 is formed. The end portion R3a of the radiation region R3 on the upstream side in the paper transport direction (nip portion SN inlet side) coincides with the inlet end of the nip portion SN, and is on the downstream side of the radiation region R2 in the paper transport direction (nip portion SN exit side). The end portion R3b coincides with the outlet end of the nip portion SN.

That is, the width of the radiant region R3 is the same as the width of the nip portion SN, and the radiant heat is not applied to the stay 330. By setting the radiation region R3 as shown in FIG. 5, it is possible to prevent unnecessary heating of the stay 330 and efficiently heat the nip portion SN.

The portion of the fixing device 300 that is most desired to be heated is the nip portion SN, and it is more desirable that all the radiant heat limited by the radiant region R3 of the halogen heater 361 with a reflective surface is applied to the nip portion SN. Even with such a configuration, since the nip forming member 380 is made of a material having good thermal conductivity such as a metal plate, the fixability is not affected.

With the configuration shown in FIG. 5, the nip portion SN can be heated more efficiently, so that the energy saving of the fixing device 300 can be further improved. Also in this case, the above-mentioned radiation region R3 can be realized by optimizing the distance between the halogen heater 361 with a reflective surface and the nip forming member 380.

(Fourth Embodiment of fixing device)
FIG. 6 shows the fixing device 300 according to the fourth embodiment. In this embodiment, the fan-shaped radiation region R4 from the halogen heater 361 to the nip forming member 380 is formed more predominantly in terms of fixing property.

The end portion R4a of the radiation region R4 on the upstream side in the paper transport direction (nip portion SN inlet side) is a corner portion where the inner side surface of the upstream side wall surface 330a of the stay 330 and the upper surface of the nip forming member 380 intersect, as in FIG. (Intersection). Further, the end portion R4b of the radiation region R2 on the downstream side in the paper transport direction (nip portion SN outlet side) coincides with the outlet end of the nip portion SN, as in FIG. That is, the direction of the opening of the halogen heater 361 is slightly tilted toward the SN inlet side of the nip portion in FIG.

Since there is a time lag in heat conduction from the nip forming member 380 to the fixing belt 310, the upstream side of the nip needs to be warmed more positively (earlier) than the downstream side. Therefore, in FIG. 6, the end portion R4a on the inlet side of the nip portion SN is set as the inner surface of the upstream side wall surface 330a of the upstream limit.

On the other hand, the end portion R4b on the nip portion SN outlet side was aligned with the position of the nip portion SN outlet end. This is because even if the end portion R4b is located downstream of this, not only does it not contribute to the heating of the nip portion SN, but also the heating range is unnecessarily expanded and the thermal efficiency is lowered.

In the radiation region R4 of FIG. 6, the distance between the halogen heater 361 and the nip forming member 380 is optimized, and the direction (angle) of the opening of the halogen heater 361 is optimized to rotate the opening to the upstream side of the nip SN. It can be realized by making it. By setting the radiation region R4 in this way, it is possible to prevent unnecessary heating of the stay 330 and efficiently heat the nip portion.

The orientation (angle) of the opening of the halogen heater 361 can be changed in the longitudinal direction of the halogen heater 361. For example, the opening may be tilted toward the nip SN inlet side at both ends of the halogen heater 361 in the longitudinal direction as shown in FIG. 6, and the opening may be directed directly downward as shown in FIG. 4 or 5 at the central portion in the longitudinal direction. .. As a result, it is possible to suppress / alleviate the temperature dripping at the end of the fixing belt 310.

(Fifth Embodiment of fixing device)
FIG. 7 shows the fixing device 300 according to the fifth embodiment, and the stay 330 is omitted in this embodiment. Bending rigidity of the nip forming member 380 in the longitudinal direction is ensured by bending portions 381 and 382 bent at right angles to the side opposite to the nip portion SN at both ends of the nip forming member 380 in the lateral direction.

Then, both ends of the nip forming member 380 in the longitudinal direction are supported by flange portions arranged on both sides of the device. By omitting the stay 330, the device can be further reduced in size and weight.

In FIG. 7, the fan-shaped radiation region R5 from the halogen heater 361 to the nip forming member 380 includes the entire upper surface (width X) of the nip forming member 380 inside the bent portions 381 and 382. Therefore, the nip portion SN can be heated efficiently.

(Intensity distribution of radiant heat)
FIG. 8 shows an example of the relationship between the reflecting surface 362 of the halogen heater 361 with a reflecting surface, the opening angle, and the radiant intensity distribution. FIG. 8B is a cross-sectional view of the halogen heater 361 with a reflective surface, in which the reflective surface 362 is provided on the upper side (90 ° to 270 °) in the circumferential direction and the lower side (270 ° to 0 ° to 90 °) in the circumferential direction. °) is the opening.

The radiant intensity distribution of the halogen heater 361 is in the range of the lower side (300 ° to 0 ° to 60 °) in the circumferential direction as shown in FIG. 8A, and is narrower than the opening angle of FIG. 8B. It is in the range. It is desirable to determine the positional relationship between the halogen heater 361 with a reflective surface and the nip forming member 380 by utilizing the fact that the radiation region (the range having the intensity distribution) is narrower than the opening angle. For example, the width X having a high intensity of radiant heat in FIG. 8 can be matched with the entire upper surface (width X) of the nip forming member 380 in FIG.

As described above, in the embodiment of the present invention, the radiation region of the halogen heater 361 can be freely limited by the reflecting surface 362, so that it is not necessary to provide a reflecting member around the halogen heater 361 as in the conventional case. , The fixing device 300 can be made smaller and less costly.

By equipping the image forming apparatus 100 with such a fixing device 300, it is possible to provide a small image forming apparatus having excellent energy saving. Further, by forming the reflective surface 362, the thermal efficiency is improved, and the warm-up time can be shortened and energy can be saved.

Although the present invention has been specifically described above based on the embodiments, the present invention is not limited to the above-described embodiments and can be variously modified within the scope of the technical idea described in the claims. Needless to say. For example, in the above embodiment, one halogen heater 361 is used, but it goes without saying that two or three or more halogen heaters may be used.

These plurality of halogen heaters form a plurality of heating regions corresponding to the paper size in the longitudinal direction of the heating source orthogonal to the paper transport direction. This prevents an excessive temperature rise in both ends of the heating source in the width direction when fixing paper narrower than the heating source, suppresses thermal damage in both ends, and avoids unnecessary heating. It is possible to increase the heating efficiency.

Further, the heating device of the present invention can be applied not only to the fixing device of the layer forming device but also to the heating device (drying device) for drying ink of an inkjet printer.

2: Image carrier 3: Drum cleaning device 3a: Cleaning blade 4: Charging device 5: Developing device 5a: Developer carrier 7: Exposed device 7a: Mirror 21: Fixing belt 50: Paper feeding device 60: Paper feed roller 100: Image forming device 180: Upper half of the surface 250: Resist roller pair 300: Fixing device 310: Fixing belt (rotating member)
320: Pressurized roller (opposing member) 321: Core metal 322: Elastic layer 323: Demolding layer 330: Stay 330a: Upstream side wall 330b: Ceiling wall 330c: Downstream side wall 361: Halogen heater (heating source) 361a: Valve 361b: Filament 362: Reflective surface 380: Nip forming member 381, 382: Bent part Lb: Laser beam N: Transfer nip P: Bundled paper P: Paper (heated sheet)
R1 to R5: Radiation region SN: Nip part TM: Transfer means

Japanese Patent No. 6164014

Claims (7)

Endless rotating member and
A heating source that is placed inside the rotating member and emits radiant heat,
A nip forming member arranged on the inner peripheral side of the rotating member and heated by radiant heat generated from the heating source, and a nip forming member.
A heating device provided with an opposing member that is arranged to face the outer peripheral side of the rotating member and forms a nip portion through which the sheet to be heated passes by sandwiching the rotating member with the nip forming member. hand,
A heating device characterized in that a reflecting surface that reflects radiant heat other than radiant heat directly directed from the heating source to the nip forming member in the direction of the nip forming member is arranged on the surface of the heating source. The heating device according to claim 1, wherein the radiant region of the radiant heat with respect to the nip forming member is equal to or less than the short width of the nip forming member in the passing direction of the sheet to be heated. Both ends of the short width of the nip forming member are supported by the support member disposed inside the rotating member, and the radiant region of the radiant heat with respect to the nip forming member is supported by the support member. The heating device according to claim 1, wherein it is an inner region of both ends of a short width of the nip forming member. The radiant region of the radiant heat with respect to the nip forming member is from the upstream end of the short width of the nip forming member supported by the support member to the downstream end of the nip in the passing direction of the heated sheet. The heating device according to claim 3, wherein the heating device is up to a unit. The heating device according to claim 1, wherein the radiant region of the radiant heat with respect to the nip forming member is within the width of the nip portion. A fixing device including the heating device according to any one of claims 1 to 5, wherein the heated sheet carrying a toner image passes through the nip portion. An image forming apparatus comprising the fixing apparatus according to claim 6.

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