JP5133028B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus such as a copying machine, a printer, and a facsimile using an electrophotographic system.

  2. Description of the Related Art Image forming apparatuses such as copiers, printers, and facsimiles that employ an electrophotographic system are provided with a fixing device for fixing a toner image transferred onto a recording medium. As this fixing device, a two-roller type fixing means having a heating roller and a pressure roller rotating in contact with each other is generally used. In this fixing device, when a sheet on which an unfixed toner image is transferred is conveyed to a fixing nip portion formed by contact between a heating roller and a pressure roller, the toner is melted by heat and pressure. The toner image is fixed as a permanent image on the surface of the paper. Here, as the heating roller and the pressure roller, those obtained by coating a metal roller core with fluorine rubber, silicon rubber or the like are generally used.

  The fixing device includes a fixing housing that covers the heating roller and the pressure roller, a paper transport guide that guides a paper transport path, a thermostat support member that supports the thermostat, and the like. The thermostat is for preventing the heating roller from overheating by cutting off the energization path of the heating element. As the fixing housing, the paper conveyance guide, and the thermostat support member, those made of a heat resistant resin such as PET (polyethylene terephthalate) are generally used.

  In recent years, in order to save energy, an induction heating type fixing device using an induction heating coil as a heating source having high energy efficiency has been proposed. Here, the member that supports the induction heating coil is generally made of a heat resistant resin such as PET.

  Recently, the prevention of air pollution derived from VOC (volatile organic compounds) has been screamed, and environmental considerations for VOCs discharged from image forming apparatuses such as copiers and printers used in offices, etc. Is becoming necessary. Regarding the amount of VOC released, there are many components derived from toner and components derived from the fixing device. Regarding the components derived from the fixing device, siloxane that is volatilized from the silicone rubber used in the pressure roller and BHT (2,6-di-) that is volatilized from the PET used in the resin member such as the fixing housing. tert-butyl-4-methylphenol). Many of these VOCs volatilize when the fixing device or toner is heated.

  Therefore, as a method for solving this problem, in Patent Document 1 and Patent Document 2, a member carrying an adsorbent is disposed in the vicinity of the fixing device to adsorb VOC generated at the time of fixing, and the inside and outside of the image forming apparatus. A technique for preventing the diffusion of odors and the generation of unpleasant odors is disclosed. Further, in Patent Document 3, the support member of the induction heating coil is configured by covering a sheet of a material that absorbs VOC on the outer surface of the base of the heat resistant resin, thereby reducing VOC emission generated from the heat resistant resin. Technology is disclosed.

JP-A-4-221968 JP 2005-338539 A JP 2004-271684 A

  However, even with these conventional techniques, the amount of VOC emission cannot be reduced to a satisfactory value, and it has been necessary to further reduce the amount of VOC emission from the viewpoint of environmental improvement.

  Therefore, a main object of the present invention is to provide a fixing device and an image forming apparatus that can reduce the amount of VOC released from a heat-resistant resin that becomes a high temperature.

The invention according to claim 1 is a fixing device having a fixing means for heating and fixing an unfixed image formed on the paper through the paper, the heat-resistant resin arranged so as to cover the fixing means The fixing device is characterized in that a carbon film having a gas barrier property is formed on the entire surface including the outer surface and the inner surface of the fixing housing. As the fixing unit, for example, a two-roller type including a heating roller and a pressure roller rotating in contact with each other is used.

In the first aspect of the present invention, the gas barrier property of the fixing housing is remarkably improved by forming the carbon film having the gas barrier property on the entire surface including the outer surface and the inner surface of the fixing housing made of a heat-resistant resin. When the temperature becomes high, the amount of VOC that volatilizes from the fixing housing made of heat-resistant resin is greatly reduced.

The invention according to claim 2 is an invention subordinate to the invention according to claim 1, wherein the heating means inserted in the fixing means, the thermostat for interrupting the energization of the heating means, and the heat resistant resin that supports the thermostat And a thermostat support member, and a carbon film having a gas barrier property is formed on the entire surface of the thermostat support member.

In the invention of claim 2, by forming a carbon film having a gas barrier property on the entire surface of the thermostat support member made of a heat resistant resin , the gas barrier property of the thermostat support member is remarkably improved, and the fixing device is heated to a high temperature. Sometimes, the amount of VOC released from the thermostat support member made of heat resistant resin is significantly reduced.

The invention according to claim 3 is an invention dependent on the invention according to claim 2, wherein the heating means comprises an induction heating coil and a coil support member made of a heat-resistant resin that supports the induction heating coil, and the coil support member A carbon film having gas barrier properties is formed on the entire surface of the fixing device.

In the invention of claim 3 , the gas barrier property of the coil support member is remarkably improved by forming a carbon film having a gas barrier property on the entire surface of the coil support member made of a heat-resistant resin that is heated to a high temperature by the induction heating coil. The amount of VOC released from the coil support member made of heat-resistant resin is greatly reduced.

The invention according to claim 4 is an invention dependent on the invention according to any one of claims 1 to 3, comprising a sheet conveyance guide member made of a heat resistant resin for guiding the sheet, and a sheet conveyance guide The fixing device is characterized in that a carbon film having gas barrier properties is formed on the entire surface of the member.

In the invention of claim 4, the entire surface of the sheet conveyance guide member made of a heat-resistant resin, by forming a carbon film having a gas barrier property, gas barrier properties of the sheet conveyance guide member is remarkably improved, made of a heat-resistant resin The amount of VOC that is volatilized from the paper transport guide member is greatly reduced, and the amount of wear on the surface of the paper transport guide member when the paper is transported is greatly reduced, so that the initial friction coefficient can be maintained for a long time.

The invention according to claim 5 is an invention dependent on the invention according to any one of claims 1 to 4 , wherein the carbon film is at least one of a hydrogenated amorphous carbon film, a DLC film, and a hard carbon film. One fixing device is provided.

In the invention of claim 5 , since the carbon film is a hydrogenated amorphous carbon film, a DLC film, or a hard carbon film, it can be formed by low-temperature plasma and can be formed on a material having a low heat resistance temperature such as a resin. .

The invention according to claim 6 is an image forming apparatus comprising the fixing device according to any one of claims 1 to 5 .

According to the sixth aspect of the present invention, an image forming apparatus including a fixing device capable of reducing the amount of VOC emitted from a fixing housing made of a heat resistant resin that reaches a high temperature can be obtained.

According to the present invention, the gas barrier property of the fixing housing or the like can be remarkably improved by forming the carbon film having the gas barrier property on the entire surface of the fixing housing or the like made of a heat resistant resin in the fixing device. When the temperature of the apparatus becomes high, the amount of VOC that volatilizes from a fixing housing made of a heat-resistant resin can be greatly reduced.

  The above-described object, other objects, features, and advantages of the present invention will become more apparent from the following description of the best mode for carrying out the invention with reference to the drawings.

(Image forming device)
FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus according to the present invention.

  The photosensitive drum 2 is driven at a predetermined speed in a clockwise direction indicated by an arrow in the drawing by a driving unit. Near the outer periphery of the photosensitive drum 2, a charger (not shown), a developing device 4, a transfer roller 6, and a cleaning member 7 are provided. The surface of the photosensitive drum 2 is charged by a charger. A laser scanning unit (not shown) is disposed on the downstream side of the charger in the rotation direction of the photosensitive drum 2. The laser light emitted from the laser scanning unit is irradiated onto the photosensitive drum 2 to form an electrostatic latent image.

  A developing device 4 is disposed on the downstream side of the laser scanning unit. The developing device 4 is for applying black toner to the photosensitive drum 2. A toner cartridge 8 is disposed for the developing device 4. A transfer roller 6 is disposed on the downstream side of the developing device 4. Further, a cleaning member 7 for removing the toner remaining on the photosensitive drum 2 is disposed on the downstream side of the transfer roller 6.

  On the other hand, in synchronization with the black toner image, the paper feed roller 14 pulls out paper as a recording medium from the paper feed cassette 12 and feeds it. The toner image formed on the photosensitive drum 2 is transferred to the sheet and is carried into the fixing device 16. The sheet onto which the toner image has been transferred is fixed by the fixing device 16 and is discharged out of the apparatus as a printed matter and stacked on a discharge tray.

(First Embodiment of Fixing Device)
FIG. 2 is a schematic configuration diagram showing a first embodiment of a fixing device according to the present invention. The fixing device 16 includes a pressure roller 20, a heating roller 22, fixing housings 24 a and 24 b that cover the pressure roller 20 and the heating roller 22, an induction heating coil 26, a coil support member 28 that supports the induction heating coil 26, and a thermostat 30. The thermostat 30 is configured to include a thermostat support member 32 that supports the thermostat 30, a paper transport guide member 36 that guides the paper transport path, and the like.

  The pressure roller 20 is formed by coating a metal (iron) roller cored bar having an outer diameter of 30 mm with an elastic layer of silicon rubber and a surface layer of fluororesin. The heating roller 22 is a cylindrical hollow roller formed of a conductive member such as stainless steel (SUS430) and having an outer diameter of 40 mm. The heating roller 22 is as thin as possible so that it can be quickly heated. A release layer coated with a fluororesin is provided. The rollers 20 and 22 are held rotatably around the central axis. The peeling claw 34 is in contact with the outer peripheral surface of the heating roller 22.

  The induction heating coil 26 is made of copper wire, and is wound around a coil support member 28 fixed to a beam member 29 attached to the main body of the image forming apparatus, as shown in FIG. Arranged in position. By supplying high-frequency power to the induction heating coil 26, an eddy current is generated in the heating roller 22 and the heating roller 22 is heated.

  The heated heating roller 22 is used to fix the toner image formed on the paper to the paper. That is, when the sheet on which the unfixed toner image is transferred is conveyed to the fixing nip formed by the contact between the heating roller 22 and the pressure roller 20, the toner is melted by heat and pressure, and the sheet is heated. A toner image is fixed on the surface as a permanent image.

  The thermostat 30 is supported in the vicinity of the heating roller 22 by a thermostat support member 32. The thermostat 30 is for preventing the heating roller 22 from being overheated by cutting off the energization of the induction heating coil 26. As shown in FIG. 4, the thermostat 30 is accommodated in a thermostat support member 32 by electrically connecting a pair of metal terminals 31 a and 31 b to a disk-shaped main body. The thermostat support member 32 is fixed to the inner wall surface of the fixing housing 24a.

  The paper transport guide member 36 is for guiding the paper after the toner image is fixed. The fixing housings 24a and 24b, the coil support member 28, the thermostat support member 32, and the paper transport guide member 36 are made of heat-resistant resin such as PET (polyethylene terephthalate).

Further, on the surfaces of the fixing housings 24a and 24b, the coil support member 28, the thermostat support member 32, and the paper transport guide member 36, a carbon film 38 (shown by a dotted line in FIG. 2) having a film thickness of 1.0 μm. Is formed. Examples of the carbon film 38 include a hydrogen amorphous carbon film, a DLC (diamond-like carbon) film, and a hard carbon film. In the present embodiment, a DLC film is used as the carbon film 38. These carbon films 38 have a thermal conductivity of 200 to 600 W / m · K, an electric resistance (volume resistivity) of 10 ⁶ to 10 ¹¹ Ω · cm, a Vickers hardness of 2000 to 5000 kg / mm ² , and a friction coefficient of 0. It has physical properties such as less than .2. In addition, it has a property that gas molecules are hardly transmitted, that is, a gas (VOC) barrier property. As a result, when the fixing device 16 reaches a high temperature, the amount of VOC released from the fixing housings 24a and 24b, the coil support member 28, the thermostat support member 32, and the paper transport guide member 36 can be greatly reduced.

  Further, since these carbon films 38 can be formed at room temperature using a low temperature plasma ion implantation method, they can be formed on a material having a low heat resistant temperature such as a resin, and an inexpensive fixing device 16 can be provided. it can.

  Further, since the carbon film 38 has a relatively small coefficient of friction, by forming the carbon film 38 on the surface of the paper transport guide member 38, the paper transport guide generated when the edge of the transport paper contacts the paper transport guide member 38. Scratches and wear on the surface of the member 38 can be greatly reduced, and the initial coefficient of friction can be maintained for a long time. Therefore, a desired toner image can be obtained without clogging the paper. Furthermore, since the surface of the paper transport guide member 38 is less likely to be uneven, there is no possibility that toner on the paper will enter and adhere to the surface of the paper transport guide member 38.

The VOC emission evaluation of the image forming apparatus equipped with the fixing device 16 having the above configuration was performed. That is, it is installed in a SUS chamber (volume 1 m ³ , inner surface electropolishing finish), the outside air environment is set to 23 ± 2 ° C., 50 ± 5% Rh, and the chamber is ventilated at 67 L / min. Set. After ventilation for about 1 hour, a printing operation was performed for 10 minutes, and the air in the chamber was continuously sampled at 100 mL / min with a TENAX (registered trademark) collection tube. Sampling was continuously performed for about 2 hours after printing was stopped. Then, the sampled TENAX (registered trademark) collection tube is desorbed with a heat desorption device, and the collected volatile organic compound (VOC) is measured by GC-MS. The amount of organic compound was estimated. As a result, the VOC discharge amount of the image forming apparatus equipped with the fixing device 16 was 5.6 mg / h.

  For comparison, an image forming apparatus equipped with a fixing device composed of the fixing housings 24a and 24b, the coil support member 28, the thermostat support member 32, and the paper transport guide member 36 in which the carbon film 38 is not formed is used. The measurement was performed under the same conditions as in the embodiment. As a result, the VOC discharge amount of the image forming apparatus equipped with the fixing device on which the carbon film 38 was not formed was 11.8 mg / h. Therefore, by forming the carbon film 38, the amount of VOC discharged outside the machine could be reduced to about ½.

(Second Embodiment of Fixing Device)
FIG. 5 is a schematic configuration diagram showing a second embodiment of the fixing device according to the present invention. The fixing device 16A includes a pressure roller 20, a heating roller 22, fixing housings 24a and 24b that cover the pressure roller 20 and the heating roller 22, a halogen heater 40, a thermostat 30, a thermostat support member 32 that supports the thermostat 30, and a sheet of paper. The sheet conveyance guide member 42 and the like for guiding the conveyance path are configured. The detailed description of the same parts and portions as those of the fixing device of the first embodiment will be omitted.

  The pressure roller 20 is formed by coating an elastic layer of silicon rubber and a surface layer of fluororesin on a metal (iron) core metal having an outer diameter of 25 mm. The heating roller 22 is a cylindrical hollow roller formed of a metal member such as aluminum and has an outer diameter of 30 mm. The heating roller 22 is as thin as possible so that it can be quickly heated. A release layer is provided. The rollers 20 and 22 are held rotatably around the central axis.

  The halogen heater 40 has a power consumption of 800 W and is disposed at a predetermined position inside the heating roller 22. By supplying electric power to the halogen heater 40, the heating roller 22 is heated.

  The paper conveyance guide member 42 is for guiding the paper on which the unfixed toner image is transferred to the surface. The fixing housings 24a and 24b, the thermostat support member 32, and the paper transport guide member 42 are made of heat-resistant resin such as PET (polyethylene terephthalate).

  Further, a carbon film 38 (shown by a dotted line in FIG. 5) having a film thickness of 1.0 μm is formed on the surfaces of the fixing housings 24 a and 24 b, the thermostat support member 32 and the paper transport guide member 42. Examples of the carbon film 38 include a hydrogen amorphous carbon film, a DLC (diamond-like carbon) film, and a hard carbon film. As a result, when the fixing device 16A becomes hot, the amount of VOC released from the fixing housings 24a and 24b, the thermostat support member 32, and the paper transport guide member 42 can be greatly reduced. Further, since these carbon films 38 can be formed at room temperature by using a low temperature plasma ion implantation method, they can be formed on a material having a low heat resistant temperature such as a resin, and an inexpensive fixing device 16A can be provided. it can.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is carried out within the range of the summary.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention. 1 is a schematic configuration diagram illustrating an example of a fixing device according to the present invention. It is a perspective view which shows the structure of a heating roller. It is a perspective view which shows typically a thermostat and a thermostat support member. FIG. 6 is a schematic configuration diagram illustrating another example of a fixing device according to the present invention.

Explanation of symbols

2 Photosensitive drum 4 Developer 6 Transfer roller 16, 16A Fixing device 20 Pressure roller 22 Heating roller 24a, 24b Fixing housing 26 Induction heating coil 28 Coil support member 30 Thermostat 32 Thermostat support member 36, 42 Paper transport guide member 40 Halogen Heater 38 Carbon film

Claims (6)

A fixing device having a fixing unit that heats and fixes an unfixed image formed on a sheet by passing the sheet,
A fixing device, wherein a carbon film having a gas barrier property is formed on an entire surface including an outer surface and an inner surface of a fixing housing made of a heat-resistant resin disposed so as to cover the fixing unit. Heating means inserted in the fixing means;
A thermostat for shutting off energization of the heating means;
A thermostat support member made of a heat-resistant resin that supports the thermostat,
The fixing device according to claim 1, wherein a carbon film having a gas barrier property is formed on the entire surface of the thermostat support member. The heating means includes an induction heating coil and a coil support member made of a heat resistant resin that supports the induction heating coil, and a carbon film having gas barrier properties is formed on the entire surface of the coil support member. The fixing device according to claim 2. A paper transport guide member made of a heat-resistant resin for guiding paper is provided, and a carbon film having gas barrier properties is formed on the entire surface of the paper transport guide member. Item 4. The fixing device according to Item 3. The fixing device according to claim 1 , wherein the carbon film is at least one of a hydrogenated amorphous carbon film, a DLC film, and a hard carbon film. An image forming apparatus comprising the fixing device according to claim 1 .