JP4396545B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus having a heat fixing device used for an electrophotographic system such as a copying machine, a printer, and a fax machine, and more particularly to an image forming apparatus having a heat fixing device using a fixing belt.

  A belt heating type fixing device used as a toner image fixing device in an image forming apparatus such as a copying machine or a printer will be described as an example.

  FIG. 4 is a schematic configuration diagram of one form of a belt heating type fixing device.

  In FIG. 4, reference numeral 40 is an endless fixing belt made of nickel or heat-treated polyimide, and 41 is a fixing roller, which receives power from a drive source (not shown) and rotates in the direction of the fixing belt 1 as indicated by an arrow. Reference numeral 43 denotes a fixed sliding member 43 of aluminum heating means whose outer surface is coated with a fluorine resin. The fixing belt 40 is stretched between the fixing roller 41 and the fixed sliding member 43, and the inner side of the fixing belt 40 and the fixed sliding member 43 slide to rotate the fixing belt 40. Reference numeral 42 denotes a pressure roller, which has a mechanism capable of pressing and releasing the pressure from the fixing roller 41 via the fixing belt 40. Further, the pressure roller 42 can also apply a residual heat by a halogen heater 46.

  When the fixing belt 40 has slid on the fixed sliding member 43 for a long time by such a mechanism, foreign matter such as abrasion powder such as fluorine resin of the fixed sliding member 43 is generated along with the sliding, There is a problem that the toner adheres to the inside of the fixing belt 40 and the fixing roller 41 and the fixing belt 40 slip to cause a belt conveyance failure or create a non-uniform heat distribution state on the belt to cause a fixing failure.

In order to avoid such a problem, there is a method in which a blade 402 is provided on the inner side of the fixing belt, abutted against the inner surface of the belt, abrasion powder is scraped off, and a receiving tray 403 for storing this is disposed. In addition, a method has been proposed in which foreign matter such as abrasion powder is removed from the surface of the driving roller corresponding to the fixing roller 41 with a brush or a cleaning roller (see, for example, Patent Document 1).
JP-A-10-73125

  However, as described above, the method of separately providing the blades has drawbacks that lead to cost increase factors such as attachment accuracy and an increase in the number of parts when attaching the blades. Since only the surface of the belt is cleaned, it is conceivable that the foreign matter remaining on the belt may cause temperature irregularities and inconvenience of belt conveyance failure.

  The present invention has been devised in order to avoid the above disadvantages and disadvantages, and has a fixing belt inner surface cleaning means having advantages such as simplification of installation of improvement means, improvement of installation accuracy, and cost reduction. An object of the present invention is to provide an image forming apparatus provided with the above.

  The above object is achieved by the following configuration.

A transfer material in which a fixing belt is stretched between a fixed sliding member as a heating means and a fixing roller, and an unfixed toner image is carried at a nip formed by the fixing roller and a pressure roller via the fixing belt. In the image forming apparatus having a fixing device that fixes and fixes the toner image on the transfer material by sandwiching and transporting the fixing belt, the upstream end of the fixed sliding member on the upstream side of the fixing belt is stretched. An image forming apparatus comprising: a cleaning member that cleans the fixing belt and the fixed sliding member as one member by forming an edge shape that abuts on the inside .

  Fixing the cleaning member to the heating means or the fixed sliding member leads to simplification of installation, improvement of installation accuracy, cost reduction, and the like.

  First, the entire image forming apparatus of the present embodiment will be described.

  In the description of the embodiment of the present invention, the technical scope of the present invention is not limited by the terms used in this specification.

  FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus.

  In FIG. 1, the configuration will be described. 10 is a photoconductor, 11 is a scorotron charger as charging means, 12 is a writing device as image writing means, 13 is a developing device as developing means, and 14 is a photoconductor 10. A cleaning device for cleaning the surface, 15 a cleaning blade, 16 a developing sleeve, and 20 an intermediate transfer belt. The image forming unit 1 includes a photoconductor 10, a scorotron charger 11, a developing unit 13, a cleaning device 14, and the like. Since the mechanical configuration of the image forming unit 1 for each color is the same, in FIG. Reference numerals are assigned to configurations of only the (yellow) series, and reference symbols are omitted for the constituent elements of M (magenta), C (cyan), and K (black).

  The arrangement of the image forming means 1 for each color is in the order of Y, M, C, K with respect to the running direction of the intermediate transfer belt 20, and each photoconductor 10 contacts the stretched surface of the intermediate transfer belt 20. The contact point rotates in the same direction as the traveling direction of the intermediate transfer belt 20 and at the same linear speed.

  The intermediate transfer belt 20 is stretched around a driving roller 21, an earth roller 22, a tension roller 23, a static elimination roller 27, and a driven roller 24. The belt unit 3 includes these rollers, the intermediate transfer belt 20, a transfer device 25, a cleaning device 28, and the like. Configure.

  The intermediate transfer belt 20 is driven by rotation of the driving roller 21 by a driving motor (not shown).

  The photosensitive member 10 is formed by forming a photosensitive layer such as a conductive layer, an a-Si layer, or an organic photosensitive member (OPC) on the outer periphery of a cylindrical metal base formed of, for example, an aluminum material, and the conductive layer is grounded. In the state, it rotates counterclockwise as indicated by the arrow in FIG.

  An electrical signal corresponding to the image data from the reading device 80 is converted into an optical signal by the image forming laser, and is projected onto the photoconductor 10 by the writing device 12.

  The developing unit 13 is a developing sleeve formed of a cylindrical nonmagnetic stainless steel or aluminum material that keeps a predetermined interval with respect to the circumferential surface of the photoconductor 10 and rotates in the same direction as the rotation direction of the photoconductor 10. 16.

The intermediate transfer belt 20 is an endless belt having a volume resistivity of 10 ⁶ to 10 ¹² Ω · cm. It is a semiconductive seamless belt having a thickness of 0.04 to 0.10 mm in which a conductive material is dispersed.

  A transfer unit 25 has a function of transferring a toner image formed on the photoreceptor 10 onto the intermediate transfer belt 20 by applying a direct current having a polarity opposite to that of the toner. As the transfer unit 25, a transfer roller can be used in addition to the corona discharger.

  Reference numeral 26 denotes a transfer roller which can be brought into contact with and released from the earth roller 22 and retransfers the toner image formed on the intermediate transfer belt 20 onto a transfer material P which is paper.

  A cleaning device 28 is provided to face the driven roller 24 with the intermediate transfer belt 20 interposed therebetween. After the toner image is transferred to the transfer material P, the intermediate transfer belt 20 has the charge of the residual toner weakened by the neutralizing roller 27 to which an AC voltage superimposed with a DC voltage having the same or opposite polarity as that of the toner is applied. The toner remaining on the peripheral surface is cleaned.

  7 is a transport path, 70 is a paper feed roller, 71 is a timing roller, 72 is a paper cassette, and 73 is a transport roller.

  81 is a paper discharge roller, and 85 is an operation panel. B1 is a control unit for an image forming process, transfer material conveyance, fixing temperature, and the like.

  Next, the fixing device according to the present invention will be described.

A fixing device 4 fixes the toner image on the transfer material, and includes a fixing roller 41, a pressure roller 42, a fixing belt 40, and a fixed sliding member 43 serving as a heating unit. The fixing roller 41 and the pressure roller 42 are pressed against each other to form a nip portion T, and a transfer material P carrying an unfixed toner image is passed through the nip portion T, thereby heating and pressing. As a result, the toner image is melted onto the transfer material P. The transfer material P on which the toner image is fixed is separated from the fixing belt 40 at the end of the nip portion T, proceeds along the fixing guide 44, and is discharged from the fixing discharge roller 45. Since the toner used here contains wax, it is excellent in releasability from the belt during the fixing process, and therefore it is not necessary to apply oil or the like.

  In the fixing roller 41, a silicone sponge layer 411 is attached to an aluminum cored bar 410, and PTFE (polytetrafluoroethylene), which is a heat-resistant film 412, is attached as a surface layer thereon.

  The pressure roller 42 is provided with a heat-resistant layer 422 of foamed silicone rubber as an elastic body on a cylindrical cored bar 423 made of aluminum, and a preheating heater 46 is provided in the hollow.

  FIG. 2 shows an enlarged view of the fixed sliding member and the cleaning member in FIG. 1 according to the present invention.

In FIG. 2 (a), reference numeral 43 denotes a fixed sliding member made of a heat plate, and the structure thereof is as shown in FIG. 2 ( c ), which is a SUS foil carrying a heating electric resistor (in this embodiment, 20 μm). ) Is coated with an insulating layer PI (20 μm), an aluminum plate (0.8 mm) thereon, and a fluorine resin (20 μm). The belt running upstream S portion of the fixed sliding member 43 has a knife edge shape coated with metal or resin, and is in contact with the inside of the fixing belt 40.

  As described above, when the fixing belt 40 slides on the fixed sliding member 43 for a long time, foreign matters such as fluorine resin abrasion powder are generated and adhere to the inside of the fixing belt 40, and the fixing roller 41, the fixing belt 40, and the like. This causes problems such as slippage of the belt and poor belt conveyance, or a non-uniform heat distribution state on the belt, resulting in poor fixing.

A first aspect of the present invention is integrated S portion of the stationary sliding member and the cleaning member 431 abrasion powder inside of the fluororesin of the fixing belt 40 to remove, stable fixing processing features capable and to Turkey the and to have foreign matters abrasion powder of the removed fluorine-based resin is retained in the receiving tray 43 2.

Further, as shown in FIG. 2B , a metal or resin cleaning blade 433 as a cleaning member is attached to and integrated with the fixed sliding member 43 on the belt traveling upstream side S portion of the fixed sliding member 43 to fix the fixing. You may make it contact | abut on the inner side of the belt 40, remove the abrasion powder of a fluorine-type resin, etc., and store the removed foreign material in the tray 43B.

  FIG. 3 is a schematic configuration diagram of another type of belt heating type fixing device.

  In FIG. 3, reference numeral 4A denotes a fixing device as fixing means, which includes a fixing pad 41A as a fixed sliding member, a pressure roller 42, a fixing belt 40, and a heating roller 43A as a heating member, and a transfer material. P is pressed between the fixing pad 41A and the pressure roller 42 via the fixing belt 40 to form a nip portion T, and the transfer material P carrying an unfixed toner image is passed through the nip portion T. Thus, the toner image is melted on the transfer material P by heating and pressing. The transfer material P on which the toner image is fixed is separated from the fixing belt 40 at the end of the nip portion T, proceeds along the fixing guide 44 (see FIG. 1), and is discharged from the fixing discharge roller 45.

  In the fixing pad 41A, a foamable silicone sponge layer 412 is attached to an aluminum core bar 411, and a fluororesin 413, which is a heat-resistant film, is further adhered as a surface layer. There is an advantage that a wide width of the nip portion T can be secured by using the fixing pad 41A.

  In the pressure roller 42, a heat resistant layer 422 of foamed silicone rubber, which is an elastic body, is lined on a cylindrical cored bar 423 made of aluminum, and a preheating halogen heater 46 is provided in the hollow. In the heating roller 43A, a halogen heater 47 is disposed in the hollow of a pipe member 431 made of aluminum, and rotates clockwise by receiving power from a driving unit (not shown) and rotates the fixing belt 40 in the direction of the arrow. To do.

  As in the case of the fixed sliding member described in FIG. 2, when the fixing belt 40 slides on the surface of the fixing pad 41A for a long time, foreign matter such as abrasion powder of fluorine-based resin is generated and adheres to the inside of the fixing belt 40, thereby fixing The roller 41 and the fixing belt 40 slip to cause a belt conveyance failure, or a problem is caused in which a non-uniform heat distribution state is created on the belt and a fixing failure is caused.

  The second invention is provided with a cleaning blade 433 that is a metal or resin cleaning member that is fixed to the fixing pad 41A that is a fixed sliding member and is in contact with the inside of the fixing belt 40. By removing foreign matters such as powder, a non-uniform heat distribution state of the fixing belt 40 and fixing failure of belt conveyance failure can be avoided, and stable fixing processing can be performed.

  As described above, according to the first and second inventions, the cleaning member is integrated with the fixed sliding member as the heating means or the fixing pad as the fixing means, thereby simplifying the mounting, improving the mounting accuracy, and reducing the cost. Can do.

1 is a schematic diagram illustrating an example of an image forming apparatus. 3 shows a fixed sliding member and a cleaning member according to the present invention. It is a schematic block diagram of the other form of the fixing apparatus of a belt heating system. 1 is a schematic configuration diagram of one type of a belt heating type fixing device;

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photoconductor 20 Intermediate transfer belt 4 Fixing device 40 Fixing belt 41 Fixing roller 41A Pressure pad 42 Pressure roller 43 Fixed sliding member 433 Cleaning blade 43A Heating roller 46, 47 Halogen heater

Claims (1)

A transfer material in which a fixing belt is stretched between a fixed sliding member as a heating means and a fixing roller, and an unfixed toner image is carried at a nip formed by the fixing roller and a pressure roller via the fixing belt. In the image forming apparatus having a fixing device that fixes and fixes the toner image on the transfer material by sandwiching and transporting the fixing belt, the upstream end of the fixed sliding member on the upstream side of the fixing belt is stretched. An image forming apparatus comprising: a cleaning member that cleans the fixing belt and the fixed sliding member as one member by forming an edge shape that abuts on the inside .

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