JP2008165002A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a fixing belt from being electrified when removing a foreign matter adhering to the fixing belt, and to remove the foreign matter adhering to the fixing belt with simple constitution. <P>SOLUTION: A fixing part 4 for fixing a toner image includes a heating roller 41, a fixing roller 42, the fixing belt 43, a pressure roller 44, a cleaning brush 45 and a reservoir 46. The fixing roller 42 is arranged near the heating roller 41. The fixing belt 43 is a circular belt which is laid over the heating roller 41 and the fixing roller 42, and whose temperature rises by the heat of the heating roller 41. The pressure roller 44 holds a part of the fixing belt 43 together with the fixing roller 42, is arranged to be opposed to the fixing roller 42, and applies pressure to the toner image. The cleaning brush 45 removes the foreign matter adhering to the fixing belt 43 and eliminates charge with which the fixing belt 43 is charged. The reservoir 46 is arranged under the cleaning brush 45. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixing device and an image forming apparatus, and more particularly, to a fixing device that is disposed in an image forming apparatus and fixes a toner image onto a sheet, and an image forming apparatus using the fixing device.

  An electrophotographic image forming apparatus includes an image forming unit that forms a toner image based on image information, a fixing unit that fixes an image formed by the image forming unit on paper, and a sheet that is attached to the image forming unit and the fixing unit. A sheet conveying unit for conveying and a sheet discharging unit for discharging the sheet on which the image is fixed are provided.

  In the image forming unit, a toner image based on the image information is formed on the sheet by the image forming unit, and the sheet on which the image is formed by the sheet conveying unit is conveyed to the fixing unit. The toner image is fixed on the paper by the fixing unit, and the paper on which the toner image is fixed is discharged from the paper discharge unit.

  Here, the fixing unit is arranged to face the fixing roller, a heating roller having a heat source, a fixing roller arranged to face the heating roller, a fixing belt stretched between the heating roller and the fixing roller, and the fixing roller. And a pressure roller. In the fixing unit, the heating roller is heated by a heat source, and heat is transmitted from the heating roller to the fixing belt. The fixing belt is circulated with the rotation of the pressure roller, and when the pressure roller and the fixing roller are positioned opposite to each other with the fixing belt interposed therebetween, the toner is generated by the heat of the fixing belt and the pressure of the pressure roller. The image is fixed on the paper.

  In such a fixing unit, when foreign matter enters the inner peripheral side of the fixing belt, for example, when resin or the like adhering to the surface of the heating roller is peeled off when the image forming apparatus is assembled, scraped pieces such as the fixing roller may enter. is there. As described above, when a foreign substance enters the inner peripheral side of the fixing belt, the fixing belt may be deformed.

In order to solve such a problem, there is a fixing unit provided with a cleaning device for cleaning foreign matter adhering to the fixing belt (see Patent Document 1).
JP 2006-30746 A

  The fixing unit described in Patent Document 1 includes a cleaning blade that comes into contact with the fixing belt, a container that stores foreign matter scraped by the cleaning blade, and a discharge mechanism that discharges foreign matter in the container. Here, since the cleaning blade and the fixing belt are in sliding contact, the fixing belt may be charged. In this case, the foreign matter attached to the fixing belt is difficult to peel off from the fixing belt. In addition, a large space is required to arrange the cleaning device, which increases the cost.

  An object of the present invention is to prevent the fixing belt from being charged when cleaning the foreign matter adhering to the fixing belt. Another object is to remove foreign matter adhering to the fixing belt with a simple configuration.

  A fixing device according to a first aspect is a fixing device that is disposed in an image forming apparatus and fixes a toner image onto a sheet, and includes a heating roller, a fixing roller, a fixing belt, a pressure roller, and a cleaning member. And a storage member. The heating roller includes a heat source and is heated by the heat source. The fixing roller is disposed in the vicinity of the heating roller. The fixing belt is an annular belt that is stretched between the heating roller and the fixing roller, and the temperature is increased by the heat of the heating roller. The pressure roller sandwiches a part of the fixing belt together with the fixing roller, and is arranged to face the fixing roller, and applies pressure to the toner image. The cleaning member removes the foreign matter adhering to the fixing belt and removes electric charges from the fixing belt. The storage member is disposed below the cleaning member.

  In this fixing device, the heating roller is heated by the heat source, and the heat of the heating roller is transmitted to the fixing belt. When the pressure roller rotates, the fixing belt is circulated as the pressure roller rotates. When the sheet on which the toner image is transferred is conveyed to a portion where the pressure roller and the fixing belt are in contact with each other, the toner image is fixed on the sheet by the heat of the fixing belt and the pressure of the pressure roller. At this time, the foreign matter attached to the fixing belt is scraped off by the cleaning member. Thereafter, the foreign matter is stored in a storage member disposed below the cleaning member.

  Here, since the charge on the fixing belt is removed by the cleaning member, it is possible to prevent foreign matters from being electrically attached to the fixing belt, and cleaning becomes easy. Further, since the cleaning can be performed by the cleaning member and the storage container, the foreign matter attached to the fixing belt can be removed with a simple configuration.

  A fixing device according to a second aspect of the present invention is the fixing device according to the first aspect, further comprising a temperature detection device that contacts the heating roller and detects the temperature of the heating roller.

  Here, the surface of the heating roller may be scraped due to contact between the temperature detection device and the heating roller, and foreign matter may be generated. The invention of this claim is particularly effective in such a case.

  A fixing device according to a third aspect is the fixing device according to the first or second aspect, wherein the cleaning member extends beyond the width of the sheet in the width direction of the fixing belt.

  Here, foreign matters at least where the paper and the fixing belt are in contact can be cleaned, and deterioration in image quality due to deformation of the fixing belt due to foreign matters can be prevented.

  A fixing device according to a fourth aspect is the fixing device according to any one of the first to third aspects, wherein the storage member extends from the cleaning member in the width direction of the fixing belt.

  Here, the foreign matter cleaned by the cleaning member can be stored.

  A fixing device according to a fifth aspect is the fixing device according to any one of the first to fourth aspects, wherein the cleaning member is swingable in the width direction of the fixing belt.

  Here, it becomes easier to remove foreign matter adhering to the fixing belt.

  A fixing device according to a sixth aspect is the fixing device according to any one of the first to fifth aspects, wherein the cleaning member includes a rotatable rotating shaft and a brush-like member provided around the rotating shaft. Have.

  Here, it becomes easier to remove foreign matter adhering to the fixing belt.

  An image forming apparatus according to claim 7 is an electrostatic latent image carrier that can carry an electrostatic latent image on its surface, a developing device that supplies developer to the electrostatic latent image carrier, and And a fixing device according to any one of the above.

  In this image forming apparatus, an electrostatic latent image is formed on the electrostatic latent image carrier, and toner is supplied from the developing device onto the electrostatic latent image carrier. The toner image formed in this manner is transferred to a sheet and fixed on the sheet by a fixing unit.

  In the present invention, it is possible to prevent the fixing belt from being charged when cleaning the foreign matter adhering to the fixing belt. In addition, foreign matters adhering to the fixing belt can be removed with a simple configuration.

1. Configuration FIG. 1 shows a color printer 1 as an image forming apparatus according to an embodiment of the present invention. FIG. 1 is a schematic diagram for illustrating the arrangement of each component, and details of each part are omitted.

  The color printer 1 is connected to a computer (not shown) or the like, and is a device that can print a color image on paper based on image information sent from an external computer or the like. The color printer 1 includes an image forming unit 2, a paper transport unit 3, a fixing unit 4, a paper storage unit 5, a discharge unit 6, and a toner supply device 7. The fixing unit 4 will be described in detail later.

  The image forming unit 2 includes a photosensitive drum 21, a rotary developing device 22, a charging device 23, a laser unit 24, and a cleaning device 25.

  The photosensitive drum 21 is a member on which an electrostatic latent image is formed, and is disposed at the approximate center of the color printer 1. The photosensitive drum 21 is a drum-shaped member, and a rotation shaft is provided in a direction orthogonal to the paper surface of FIG. An intermediate transfer belt 211 for transferring a toner image on the photosensitive drum 21 to a sheet is disposed below the photosensitive drum 21 in the vicinity of the photosensitive drum 21.

  The rotary developing device 22 is a member disposed adjacent to the photosensitive drum 21 and is a cylindrical device as a whole. The rotary developing device 22 includes four developing devices 221 (developing devices) and a frame 222 that supports the four developing devices 221. The developing device 221 includes a container body 223 and a developing roller 224 as shown in FIG. The container body 223 has a shape in which a cylinder is divided into four in the circumferential direction, and has an opening extending in the longitudinal direction. Further, a toner supply port 223a through which a toner supply pipe 72 described later can pass is formed on the surface of the container body 223, and the toner supply port 223a has a seal member with a slit. The four container main bodies 223 store yellow, cyan, magenta, and black toners, respectively. Here, FIG. 2 shows one of the developing devices 221. The developing roller 224 extends in the rotation axis direction of the rotary developing device 22 and is disposed in the opening of the container main body 223. The developing roller 224 is a member for supplying toner to the surface of the photosensitive drum 21. At both ends of the developing roller 224, distance regulating rollers 225 for maintaining a distance between the photosensitive drum 21 and the developing roller 224 are disposed. The distance regulating roller 225 is a disk-shaped member having a radius larger than that of the developing roller 224, and the distance between the photosensitive drum 21 and the developing roller 224 is fixed by contacting the surface of the photosensitive drum 21. It keeps in.

  The charging device 23 is a device for charging the surface of the photosensitive drum 21, and is disposed on the upper side of the photosensitive drum 21.

  The laser unit 24 is a member arranged on the upper side of the rotary developing device 22 and is a device capable of irradiating a laser beam to form an electrostatic latent image based on image data on the photosensitive drum 21. is there.

  The cleaning device 25 is a device for removing deposits such as residual toner remaining on the photosensitive drum 21. In the color printer 1, the cleaning is performed on the entire axial direction of the photosensitive drum 21 above the photosensitive drum 21. A blade 251 is provided.

  The paper transport unit 3 has a transport path that continues from the paper storage unit 5 through the image forming unit 2 and the fixing unit 4 to the discharge unit 6.

  The paper storage unit 5 is a part disposed at the lower part of the color printer 1 and has a paper feed cassette 51.

  The discharge unit 6 is disposed on the upper surface of the color printer 1 and discharges a sheet on which an image is formed.

  The toner replenishing device 7 is a device for replenishing toner when the toner in the developing device 221 decreases, and includes a toner storage container 71 and a toner supply pipe 72.

2. Fixing part The fixing part 4 is a part for fixing an image on a sheet. As shown in FIGS. 3 and 4, the heating roller 41, the fixing roller 42, the fixing belt 43, the pressure roller 44, and the cleaning are performed. A brush 45 and a storage container 46 are provided. The fixing unit 4 is disposed below the color printer 1. 3 is a schematic sectional view of the fixing unit 4, and FIG. 4 is a diagram showing the cleaning brush 45, the storage container 46, and the like.

  The heating roller 41 is a member for heating the fixing belt 43, and the first heat source 411 is disposed inside. The first heat source 411 heats the fixing belt 43 with an electric power of 1000 w. The heating roller 41 is disposed above the fixing roller 42 and is in contact with the fixing belt 43. A temperature detection device 47 is disposed below the heating roller 41 so as to contact the surface of the heating roller 41.

  The fixing roller 42 is a roller member that is disposed below the heating roller 41 and contacts the fixing belt 43. The fixing roller 42 includes a shaft member and a water foam sponge arranged on the surface of the shaft member.

  The fixing belt 43 is an annular belt member formed of nickel and silicon rubber, and is stretched between the heating roller 41 and the fixing roller 42.

  The pressure roller 44 is a roller member disposed so as to face the fixing roller 42, and the second heat source 441 is disposed therein. The second heat source 441 heats the pressure roller 44 with an electric power of 600 w. The pressure roller 44 is a member in which silicon rubber is disposed around the shaft member, and is in contact with the fixing belt 43. Further, the pressure roller 44 is connected to a driving source (not shown), and the fixing belt 43 is circulated by the driving force of the pressure roller 44.

  The cleaning brush 45 is in contact with the fixing belt 43 from the inner peripheral side, and is a portion between the heating roller 41 and the fixing roller 42 and moving from the fixing roller 42 side to the heating roller 41 side of the fixing belt 43. That is, it is arranged on the left side of FIG. Further, the cleaning brush 45 is disposed in parallel to the rotation axis of the heating roller 41. Further, the cleaning brush 45 is a member extending in the width direction of the fixing belt 43 beyond the width through which the paper passes, and is grounded. For this reason, the charge on the fixing belt 43 is removed through the cleaning brush 45. The cleaning brush 45 is formed of a conductive material, and includes a rotation shaft 451 and a brush-like member 452 provided around the rotation shaft 451.

  The storage container 46 is a container for storing foreign substances cleaned by the cleaning brush 45, and is disposed below the cleaning brush 45. The storage container 46 is a member that extends from the cleaning brush 45 in the width direction of the fixing belt 43, and is disposed in parallel with the cleaning brush 45. Furthermore, the storage container 46 is formed so as to be recessed in a direction orthogonal to the extending direction.

3. Operation An image forming operation of the color printer 1 will be described.

  When image information connected to the outside is sent from a computer or the like, the surface of the photosensitive drum 21 is charged, and the laser unit 24 irradiates the photosensitive drum 21 with laser light based on the image information. When the electrostatic latent image is formed on the surface of the photosensitive drum 21 in this manner, toner is supplied from the rotary developing device 22 to the electrostatic latent image. In this way, a toner image is formed on the surface of the photosensitive drum 21. The toner image formed on the surface of the photosensitive drum 21 is transferred onto a sheet via the intermediate transfer belt 211. The sheet on which the toner image has been transferred is conveyed to the fixing unit 4 and fixed on the sheet by the fixing unit 4. The sheet on which the toner image is fixed is discharged from the discharge unit 6.

  Next, the cleaning operation of the fixing belt 43 will be described.

  When the pressure roller 44 rotates, the fixing belt 43 is circulated as the pressure roller 44 rotates. At this time, the cleaning brush 45 is rotating, the inner peripheral surface of the fixing belt 43 and the cleaning brush 45 are in sliding contact with each other, and foreign matter adhering to the inner peripheral surface of the fixing belt 43 is cleaned. At this time, the cleaning brush 45 is grounded, and the charge on the fixing belt 43 is removed via the cleaning brush 45. For this reason, it is difficult for foreign matter to adhere to the fixing belt 43 by an electric force. The foreign matter cleaned by the cleaning brush 45 is stored in the storage container 46.

  Here, since the cleaning brush 45 is grounded, the charge on the fixing belt 43 can be removed, and foreign matters adhering to the surface of the fixing belt 43 due to static electricity can be easily removed. Further, since the cleaning brush 45 rotates with the rotation of the rotation shaft 451, it is easy to remove foreign matters adhering to the fixing belt 43. Further, since the cleaning brush 45 extends beyond the width of the sheet in the width direction of the fixing belt 43, at least a part of the contact between the sheet and the fixing belt 43 can be cleaned, and the fixing belt 43 is deformed by the foreign object. Therefore, it is possible to prevent the image quality from being lowered. Since the storage container 46 is disposed below the cleaning brush 45, foreign substances are easily stored.

3. Other Embodiments In the above-described embodiment, the brush-like member 452 rotates by rotating the rotating shaft 451. However, the present invention is not limited to this, and the cleaning brush 45 swings in the width direction of the fixing belt 43. You may make it move. In this case, it becomes easier to scrape foreign matter than when the cleaning brush 45 is fixed.

1 is an overall schematic diagram of a color printer. The perspective view which shows a developing device. The figure which shows a fixing device. The figure which shows a cleaning brush, a storage container, etc.

Explanation of symbols

1 Color printer (image forming device)
4 Fixing part (fixing device)
21 Photosensitive drum (electrostatic latent image carrier)
41 Heating roller 42 Fixing roller 43 Fixing belt 44 Pressure roller 46 Storage container (storage member)
47 Temperature detector 221 Developer (Developer)
441 First heat source (heat source)
451 Rotating shaft 452 Brush-like member

Claims (7)

A fixing device that is disposed in an image forming apparatus and fixes a toner image on a sheet,
A heating roller comprising a heat source and heated by the heat source;
A fixing roller disposed in the vicinity of the heating roller;
An annular fixing belt that is stretched over the heating roller and the fixing roller, and whose temperature is increased by the heat of the heating roller;
A pressure roller that sandwiches a part of the fixing belt together with the fixing roller and is arranged to face the fixing roller and applies pressure to the toner image;
A cleaning member that removes the foreign matter adhering to the fixing belt and removes electric charges from the fixing belt;
A storage member disposed below the cleaning member;
A fixing device provided with   The fixing device according to claim 1, further comprising a temperature detection device that contacts the heating roller and detects a temperature of the heating roller.   The fixing device according to claim 1, wherein the cleaning member extends beyond a width of the sheet in a width direction of the fixing belt.   The fixing device according to claim 1, wherein the storage member extends from the cleaning member in a width direction of the fixing belt.   The fixing device according to claim 1, wherein the cleaning member is swingable in a width direction of the fixing belt.   The fixing device according to claim 1, wherein the cleaning member includes a rotatable rotation shaft and a brush-like member provided around the rotation shaft. An electrostatic latent image carrier capable of carrying an electrostatic latent image on its surface;
A developing device for supplying a developer to the electrostatic latent image carrier;
A fixing device according to any one of claims 1 to 6;
An image forming apparatus.

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