JP2006113179A - Fixing device heater, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce consumption of power during a rise and an operation by efficiently transmitting generated heat to a fixing member and reducing heat that is not used for heating a fixing belt. <P>SOLUTION: The heating body 130 of the fixing device of an image forming apparatus includes a housing 134 of an approximately D-shaped section, which is formed from an aluminum curved section 131 with which a heating belt is in planar contact and a flat section 132 connecting both ends of the curved section 131. The housing 134 incorporates a halogen lamp 135 and is fixed so as not to rotate. The surface of the curved section 131 has been subjected to a surface treatment that enhances the slide of the heating belt. The flat section 132 includes a heat insulation material 132a made of a phenol resin and an aluminum reflecting plate 132b. The surface of the reflecting plate 132b has been subjected to a glossy nickel-chrome treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heating body of a fixing device, a fixing device, and an image forming apparatus, and more particularly to a fixing device in an image forming apparatus such as a printer or a copying machine that can reduce power consumption.

  2. Description of the Related Art Image forming apparatuses such as printers and copiers are provided with a fixing device that fixes a toner image (unfixed image). In this fixing device, a sheet is held and conveyed by a fixing roller or a fixing belt and a pressure roller pressed against the fixing roller, and heat and pressure are applied to fix the toner image on the sheet.

  Among such fixing devices, there is one as shown in FIG. 6 that uses a fixing belt. The fixing device 400 includes a heating roller 410 that is a heating body and a fixing roller 420 that are spaced apart from each other, and a fixing belt 430 that is stretched between the rollers 410 and 420. In this example, a halogen lamp 411 is disposed as a heating element inside the heating roller 410 to heat the fixing belt 430. In such a fixing device 400, from the viewpoint of power saving and shortening of the rise time, the heating roller is being made of a material having a small heat capacity such as a thin metal tube.

  In the fixing device 400, the fixing belt 430 is heated by heating the heating roller 410 with the halogen lamp 411. During heating, the temperature of the heating roller 410 is monitored by the thermistor 412 and the amount of heat generated by the halogen lamp 411 is controlled by a control device (not shown).

As such a fixing device, Patent Document 1 includes a fixing device having a fixing roller, a heating roller, a pressure roller, and a fixing belt stretched between the fixing roller and the heating roller. A small size heat source having a light distribution distribution corresponding to a small size paper to be heated and a large size heat source having a light distribution distribution corresponding to a large size paper, while the fixing roller is raised to a predetermined temperature capable of fixing, and a large size A large-size heat source is used when fixing paper, a small-size heat source and a large-size heat source are used when fixing small-size paper. ing.
JP 2001-318557 A

  Here, in the fixing device described above, the portion where the fixing belt 430 is wound around and contacts the heating roller 410 is about half of the entire circumference of the heating roller 410. It is considered that the portion contributing to heating is about half of the entire circumference of the heating roller. The heating roller 410 is always rotated to heat the entire circumference of the heating roller 410.

  In the fixing device described above, the heat generated from the halogen lamp 411 is dissipated from a portion of the periphery of 410 that is not in contact with the fixing belt 430, and the generated heat is efficiently transmitted to the fixing belt 430. Absent. For this reason, there is a problem that the rise time becomes longer and more heat is dissipated without being transmitted to the fixing belt 430, and a large amount of power is consumed for heating.

  The present invention relates to a fixing device capable of efficiently transmitting heat generated from a heating body to a fixing belt and reducing heat not used for heating the fixing belt, thereby reducing power consumption during start-up and operation. It is an object of the present invention to provide a heating member, a fixing device, and an image forming apparatus.

  According to the first aspect of the present invention, there is provided a heating body of a fixing device in which a heating belt of a fixing device for fixing an unfixed image on a transfer body is stretched over and heating the heating belt in contact with the heating belt. The heating belt is composed of a curved portion that comes into surface contact and a flat portion that connects both ends of the curved portion, and a housing having a substantially D-shaped cross section including a heating element is fixed so as not to rotate. And a heating element of the fixing device.

  According to a second aspect of the present invention, in the heating element of the fixing device according to the first aspect, the curved portion is made of a metal containing aluminum.

  According to a third aspect of the present invention, in the heating body of the fixing device according to the first or second aspect, surface processing for reducing frictional resistance is performed on a surface of the curved portion.

  According to a fourth aspect of the present invention, in the heating body of the fixing device according to any one of the first to third aspects, the flat portion of the housing includes a heat insulating material.

  According to a fifth aspect of the present invention, in the heating body of the fixing device according to any one of the first to third aspects, the flat portion of the housing is constituted by a heat insulator.

  The invention according to claim 6 is the heating body of the fixing device according to claim 4 or 5, wherein the heat insulating material is made of a synthetic resin containing a phenol resin.

  According to a seventh aspect of the present invention, in the heating body of the fixing device according to any one of the first to third aspects, a reflecting plate for reflecting heat rays is provided on a side surface in the flat portion of the housing.

  According to an eighth aspect of the present invention, in the heating body of the fixing device according to the seventh aspect, the reflecting plate includes a metal portion containing aluminum or copper.

  According to a ninth aspect of the present invention, in the heating body of the fixing device according to the seventh or eighth aspect, the surface of the reflecting plate is subjected to a surface treatment excellent in heat ray reflectivity.

  According to a tenth aspect of the present invention, in the heating element of the fixing device according to any one of the first to ninth aspects, the heating element is a halogen lamp.

  An eleventh aspect of the present invention is a fixing device comprising the heating element according to any one of the first to tenth aspects.

  A twelfth aspect of the invention is an image forming apparatus comprising the fixing device of the eleventh aspect.

  According to the present invention, the rise time of the fixing device can be shortened, and the thermal efficiency during operation of the fixing device is improved, so that the amount of energy consumed by the heating element, the fixing device, and the image forming apparatus can be reduced.

  Embodiments as the best mode for carrying out the present invention will be described below with reference to the drawings.

  Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view conceptually showing an image forming apparatus such as an electrophotographic copying machine or printer according to the present invention. The image forming apparatus according to the present embodiment mainly includes a reading unit 11 that reads a document, an image forming unit 12 that forms an image, an automatic document feeder (ADF) 13, and a document that stacks documents sent from the ADF 13. A paper discharge tray 14, a paper supply unit 19 including paper supply cassettes 15 to 18, and a paper discharge unit (discharge tray 20) for stacking recording paper are configured.

  Then, when the document D is set on the document table 21 of the ADF 13 and an operation on an operation unit (not shown), for example, a press operation of a print key is performed, the uppermost document D is sent out in the direction of the arrow B1 by the rotation of the pickup roller 22. Then, by the rotation of the document conveying belt 23, the paper is fed onto the contact glass 24 fixed to the image reading unit 11, and stops there. The image of the document D placed on the contact glass 24 is read by a reading device 25 located between the image forming unit 12 and the contact glass 24. The reading device 25 includes a light source 26 that illuminates the document D on the contact glass 24, an optical system 27 that forms an image of the document, a photoelectric conversion element 28 that includes a CCD that forms an image of the document, and the like. After the image reading is completed, the document D is transported in the direction of arrow B2 by the rotation of the transport belt 23 and discharged onto the paper discharge tray 14. In this way, the document D is fed one by one onto the contact glass 24 and the document image is read by the image reading unit 11.

  On the other hand, inside the image forming unit 12, a photoconductor 30 as an image carrier is disposed. The photosensitive member 30 is driven to rotate clockwise in the drawing, and the surface is charged to a predetermined potential by the charging device 31. Further, the writing unit 32 emits a laser beam L that is light-modulated in accordance with image information read by the reading device 25, and the surface of the charged photoreceptor 30 is exposed with the laser beam L, whereby the photoreceptor is exposed. An electrostatic latent image is formed on the surface 30. When the electrostatic latent image passes through the developing device 33, the electrostatic latent image is transferred to the recording medium P fed between the photosensitive member 30 and the transfer device 34 by the opposing transfer device 34. The surface of the photoconductor 30 after the toner image is transferred is cleaned by a cleaning device 35.

  A plurality of paper feed cassettes 15 to 18 arranged below the image forming unit 12 contain recording media P such as paper, and the recording media P is fed from any of the paper feed cassettes 15 to 18 in the direction of arrow B3. The toner image formed on the surface of the photoreceptor 30 as described above is transferred onto the surface of the recording medium P. Next, the recording medium P is passed through the fixing device 100 in the image forming unit 12 as indicated by an arrow B4, and the toner image transferred to the surface of the recording medium P by the action of heat and pressure is fixed. The recording medium P that has passed through 36 is conveyed by the discharge roller pair 37, discharged to the discharge tray 20 as indicated by an arrow B5, and stacked. In this example, the fixing device 100 includes a heating body 110 (120, 130), a fixing roller 140, a fixing belt 150, and a pressure roller 160. In this example, the heating element 110 has a substantially D-shaped cross section, and is fixedly disposed so as not to rotate at a predetermined position.

  Hereinafter, the heating elements 110, 120, and 130 according to the first to third embodiments of the fixing device 100 according to the embodiment will be described in comparison with the conventional example illustrated in FIG. 6 as a comparative example.

  First, a comparative example will be described with reference to FIG. In the fixing device 400 shown in FIG. 6, the fixing belt 430 is stretched between the fixing roller 420 and the heating roller 410 as described above. A ball bearing (not shown) is attached to the journal portion of the heating roller so that the heating roller 410 rotates. Further, the outer diameter of the fixing roller is 29, the material is made of silicone rubber, and the core metal is 14 mm. A pressure roller 160 having an outer diameter of 40 was used. The fixing belt has a diameter of 57 and a thickness of 0.24 mm. The surface is a silicone rubber layer having a thickness of 0.15 mm. A fixing belt 430 made of polyimide having a thickness of 0.09 mm was used under the silicone rubber layer. A heating roller 410 having an outer diameter of φ23.4, aluminum and a thickness of 1 mm was used. The heating roller 410 has a hollow shape, and a halogen lamp 411 (700 W) is attached to the heating roller 410. A thermistor 412 is attached to the surface of the heating roller, thereby controlling the temperature.

  The fixing device described above was mounted on a printer, and the rise time of the printer was actually measured. As a result, the rise time of the fixing device is as indicated by the curve of the graph shown in FIG. The rising start temperature is 20 ° C., and the rising end temperature is up to 170 ° C., which is the allowable printing temperature of the printer. In the comparative example, it took 72 seconds to raise the temperature to 170 ° C.

  Next, the case where the heating element according to the first embodiment is used will be described. In this example, as shown in FIG. 2, the heating body 110 is composed of a curved portion 111 where the heating belt comes into surface contact and a flat portion 112 connecting both ends of the curved portion 111, and a halogen which is a heating element inside. A housing 114 having a substantially D-shaped cross section including the lamp 115 is provided.

  In this example, the journal part of the heating body 110 is fixed with a mold part (not shown) so that the heating body 110 does not rotate. In addition, aluminum was used as the material of the heating body 110. Then, the surface of the heating roller is coated so that the fixing belt smoothly slides on the surface of the heating roller. Other components are the same as those in the comparative example.

  As shown by the curve of Example 1 in FIG. 5, in Comparative Example 1, it took 60 seconds for the temperature to rise to 170.degree. That is, the rise time is earlier than that of the comparative example. This is because the heating roller was heated earlier because the heat capacity was reduced by using the heating roller as in this example. Moreover, it is because the dispersion | distribution of the heat reduced by not rotating the heating body 110 like the heating roller 410 of a comparative example.

  Next, the case where the heating body 120 according to the second embodiment is used will be described. In this example, as shown in FIG. 3, the heating body 120 includes a curved portion 121 where the heating belt is in surface contact and a flat portion 122 connecting both ends of the curved portion 121, and a halogen which is a heating element inside. A housing 124 having a substantially D-shaped cross section including a lamp 125 is provided.

  In this example, the plane part 122 is comprised with the heat insulating material. The heat insulating material had a rectangular shape, and the height was 21.2 mm, the width was 1 mm, and the axial direction was the same as that of the heating body 120. In this example, phenol resin was used as the heat insulating material. Among plastics, phenolic resins are characterized by having the most thermally and chemically stable properties and excellent heat insulating properties.

  As shown by the curve of Example 1 in FIG. 5, in this example, it took 43 seconds to increase the temperature to 170 ° C., which is the allowable printing temperature. This is even faster than the first embodiment. This is because heat is not transmitted to the flat surface portion 112 by using the heat insulating material, and heat generated from the halogen lamp 125 is transmitted only to the curved portion 121 around which the fixing belt of the heating body 120 is wound. is there.

Furthermore, the case where the heating body 130 which concerns on a 3rd Example is used is demonstrated. In this example, as shown in FIG. 4, the heating body 120 includes a curved portion 131 in which the heating belt is in surface contact and a flat portion 132 that connects both ends of the curved portion 131. A housing 134 having a substantially D-shaped cross section including a lamp 135 is provided.
In this example, the flat portion 132 includes a heat insulating material 132a and a reflecting plate 132b that reflects heat rays from the halogen lamp 135. The shape of the heat insulating material 132a is the same as that of the second embodiment. In this example, the reflecting plate 132b is made of copper, and the surface of the halogen lamp 135 is made of bright nickel-chrome having excellent heat reflectivity. The reflecting plate 132b is rectangular and has the same height as the heating body 130 in terms of height 21.2 mm, width 1 mm, and axial direction.

  As shown by the curve of Example 3 in FIG. 5, in this example, it took 36 seconds to increase the temperature to 170 ° C., which is the allowable print temperature. This is even faster than the second embodiment. This is because the reflection plate 132b is provided in addition to the heat insulating material, so that the heat rays of the halogen lamp 135 can be effectively blocked from being reflected by the reflection plate 132b and transmitted to the flat portion 132 side.

  In the above embodiment, the curved portion of the heating body is made of aluminum. However, other materials may be used. Furthermore, although the case where the whole plane part was comprised with a heat insulating material was shown in the said example, it can be set as the structure provided with a heat insulating material in a part of plane part. In the above example, the reflecting plate is made of copper, but other metals such as aluminum may be used. Besides, the entire reflector is made of metal, other materials that reflect heat rays are used, and the reflector is subjected to a bright nickel-chrome treatment, but the surface treatment is not performed or other surface treatment is applied. You may do it.

1 is a diagram illustrating an example of a fixing device and an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a configuration of a heating element of the fixing device according to the first embodiment. It is sectional drawing which shows the structure of the heat generating body of the fixing device which concerns on a 2nd Example. FIG. 10 is a cross-sectional view illustrating a configuration of a heating element of a fixing device according to a third embodiment. It is a graph which compares the heat_generation | fever state of the heat generating body which concerns on a comparative example and the 1st thru | or 3rd Example. It is a figure which shows the conventional fixing device.

Explanation of symbols

11 Reading unit 12 Image forming unit 13 Automatic document feeder (ADF)
14 Paper discharge trays 15 to 18 Paper feed cassette 19 Paper feed unit 20 Paper discharge tray 21 Document base 22 Pickup roller 23 Transport belt 24 Contact glass 25 Reading device 26 Light source 27 Optical system 28 Photoelectric conversion element 30 Photoconductor 31 Charging device 32 Writing Unit 33 Developing device 34 Transfer device 35 Cleaning device 37 Discharge roller pair 100 Fixing device 110 Heating body 111 Bending portion 112 Flat portion 114 Housing 115 Halogen lamp 120 Heating body 121 Bending portion 122 Flat portion 124 Housing 125 Halogen lamp 130 Heating body 131 Bending Part 132 flat part 132a heat insulating material 132b reflector 134 housing 135 halogen lamp 140 fixing roller 150 fixing belt 160 pressure roller

Claims (12)

In the heating body of the fixing device for heating the heating belt in contact with the heating belt, the heating belt of the fixing device for fixing the unfixed image on the transfer body is stretched over,
The heating body includes a curved portion where the heating belt is in surface contact and a flat portion connecting both ends of the curved portion, and is configured such that a substantially D-shaped housing having a heating element therein is fixed so as not to rotate. A heating element of a fixing device. The heating element of the fixing device according to claim 1, wherein the curved portion is made of a metal including aluminum. The heating body of the fixing device according to claim 1, wherein the surface of the curved portion is subjected to surface processing for reducing frictional resistance. The heating body of the fixing device according to claim 1, wherein the flat portion of the housing includes a heat insulating material. The heating body of the fixing device according to claim 1, wherein the flat portion of the housing is formed of a heat insulator. 6. The heating body of a fixing device according to claim 4, wherein the heat insulating material is made of a synthetic resin including a phenol resin. The heating body of a fixing device according to any one of claims 1 to 3, further comprising a reflecting plate that reflects heat rays on a side surface in a flat portion of the housing. The heating body of the fixing device according to claim 7, wherein the reflection plate includes a metal portion containing aluminum or copper. 9. The heating body of a fixing device according to claim 7, wherein the surface of the reflecting plate is subjected to a surface treatment excellent in heat ray reflectivity. The heating body of the fixing device according to claim 1, wherein the heating element is a halogen lamp. A fixing device comprising the heating element according to claim 1. An image forming apparatus comprising the fixing device according to claim 11.