JP2009037133A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device and image forming apparatus allowing cost reduction by integrating components constituting the electric circuit and simplifying the processing processes while securing safety. <P>SOLUTION: This fixing device makes a toner image pass in the orientation where it comes into contact with the surface of a fixing belt 25, and applies heat and pressure to the toner of the toner image during passing to fix the toner image to a record medium. Electric supply to heaters 30 and 31 is performed by a thin electrode plate 40 crept in a cover 33 made of resin under the fixing device while a predetermined amount or more is spaced from a metal member in a device main body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine having at least two functions thereof, and a fixing device installed therein.

  In a fixing device of an image forming apparatus of the above type, a radiant heating method in which heating is performed by a halogen heater disposed inside a roller is often used. Power supply to the halogen heater at this time is often performed to a metal electrode through a litz wire coated with insulation by bringing a lead wire close to a connecting component called a drawer connector which is an inlet terminal of the device. Also in the fixing device described in No. 1, an energizing wire which is an electric cable is used for scooping up to the electrode of the heating means.

Japanese Patent No. 3698487

  At this time, one end of the pin in the drawer connector is connected to a litz wire (hereinafter referred to as a harness) with a cover that can be bent freely. The harness is wound around the unit and connected to the terminal block of the halogen heater. Will be supplied. In addition, a terminal part is provided to fasten the end of the harness not connected to the drawer connector with a heater terminal and a screw.

  In the case of this configuration, a plurality of components are required from the end of the power supply receiving section from the main body to the halogen heater, and it is necessary to run the harness while ensuring safety at the manufacturing stage, so that the manufacturing cost is reduced. There was a problem of being bulky.

  In view of the above-described conventional problems, the present invention provides a fixing device and an image forming apparatus capable of reducing costs by consolidating components constituting the electric circuit and simplifying a processing process while ensuring safety. The purpose is to provide.

  In order to achieve the above object, the present invention includes a fixing member heated by a heating unit, and a pressure member that forms a nip portion in pressure contact with the fixing member, and is a toner to be fixed in the nip portion. A recording medium carrying an image is passed in a direction in which the toner image is in contact with the surface of the fixing member, and heat and pressure are applied to the toner of the toner image during the passage to fix the toner image on the recording medium. In the fixing device, power is supplied to the heating means by a thin plate-like electrode plate that is wound around in a resin fixing device cover at a predetermined distance or more with respect to a metal member in the device main body. A fixing device is proposed.

The present invention is effective when the electrode plate is wound between the terminal exposed to the outside of the fixing device cover and the terminal block of the heating unit.
Furthermore, the present invention is effective when the thickness of the electrode plate is 0.5 mm or less.

  Furthermore, the present invention is effective when a holding member made of resin for determining the position of the electrode plate to be rolled is provided integrally with the fixing device cover.

  In order to achieve the above object, the present invention fixes the toner of the toner image transferred onto the recording medium by applying heat and pressure using the fixing device according to any one of claims 1 to 4. An image forming apparatus characterized by the above is proposed.

  According to the present invention, a sufficient space distance is secured for the metal member in the apparatus, and the power supply to the heating means in the fixing device is performed by the thin plate-like electrode plate, thereby eliminating the insulation coating. Cost can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional view of an image forming apparatus having an image forming device 2 and a fixing device 20 arranged in the image forming apparatus main body 1. The image forming apparatus 2 shown in FIG. 1 has first to fourth image carriers 3Y, 3C, 3M, and 3K configured as drum-shaped photosensitive members, and a yellow toner image is formed on each of the image carriers. Then, a cyan toner image, a magenta toner image, and a black toner image are formed. An intermediate transfer belt 4 is disposed opposite to the first to fourth image carriers 3Y to 3K, and this intermediate transfer belt 4 is wound around support rollers 5, 6, 7, and 8 and is driven to rotate in the direction of the arrow. Is done.

  The first image carrier 3Y is driven to rotate clockwise in FIG. 1. At this time, the image carrier 3Y is charged to a predetermined polarity by the charging roller 9, and then emitted from the laser writing unit 10 to the charged surface. A light-modulated laser beam is irradiated. As a result, an electrostatic latent image is formed on the image carrier 3Y, and the electrostatic latent image is visualized as a yellow toner image by the developing device 11.

  A primary transfer roller 12 is disposed on the side opposite to the image carrier 3Y with the intermediate transfer belt 4 interposed therebetween, and a transfer voltage is applied to the primary transfer roller 12 so that the toner image on the image carrier 3Y is changed to an arrow. Primary transfer is performed on the intermediate transfer belt 4 traveling in the direction. The residual transfer toner adhering to the image carrier 3Y after the toner image transfer is removed by the cleaning device 13. In exactly the same manner, a cyan toner image, a magenta toner image, and a black toner image are formed on the second to fourth image carriers 3C, 3M, and 3K shown in FIG. 1, respectively, and these toner images are converted into yellow toner images. The toner images are transferred onto the intermediate transfer belt 4 and transferred to the primary transfer, and a toner image is formed on the intermediate transfer belt 4.

  On the other hand, as shown in FIG. 1, a paper feed cassette 14 containing a recording medium P made of, for example, transfer paper and a paper feed device having a paper feed roller 15 are arranged in the lower part of the image forming apparatus main body 11. As the paper feed roller 15 rotates, the uppermost recording medium P is sent out in the direction of the arrow. The fed recording medium P is fed by a registration roller pair 16 between the portion of the intermediate transfer belt 4 wound around the support roller 5 and the secondary transfer roller 17 placed on the support roller 5 at a predetermined timing. Sent. At this time, a predetermined transfer voltage is applied to the secondary transfer roller 17, whereby the superimposed toner image on the intermediate transfer belt 4 is secondarily transferred to the recording medium P.

  The recording medium P onto which the toner image has been secondarily transferred is further conveyed upward and passes through the fixing device 20, and at this time, the toner image on the recording medium is fixed by the action of heat and pressure. The recording medium P that has passed through the fixing device 20 is discharged to the paper discharge unit 18 at the top of the image forming apparatus main body 1. Further, the transfer residual toner adhering to the intermediate transfer belt 4 after the toner image transfer is removed by the cleaning device 19.

  FIG. 2 is an enlarged front view of the fixing device 20 shown in FIG. 1 and 2 includes a pressure roller 21, a fixing roller 22, a tension roller 23, and a heating roller 24. The fixing roller 22, the tension roller 23, and the heating roller 24 include Is wrapped around an endless fixing belt 25. As described above, the fixing belt 25 of the fixing device of this example is wound around the three support rollers 22, 23, and 24. The number of the support rollers can be appropriately selected. In short, the fixing belt 25 may be wound around the fixing roller 22 and at least one other supporting roller.

  Heaters 30 and 31 as heating means are provided inside the heating roller 24 and the pressure roller 21, respectively, and the pressure roller 21 and the fixing belt 25 are heated by the heaters 30 and 31. At this time, contact type thermistors 26 and 27 are provided as temperature detecting means around the heating roller 24 and the pressure roller 21, respectively, and the pressure roller 21 and the fixing belt 25 are connected to the toner image based on the detected temperature of the thermistor. At a temperature suitable for fixing. Note that a thermopile may be used as the temperature detection means instead of the thermistor.

  The pressure roller 21 is rotationally driven in the direction shown in FIG. 2, whereby the fixing belt 25 is driven in the direction of the arrow, and accordingly, the fixing roller 22 and the heating roller 24 are counterclockwise in FIG. Followed rotation. At this time, as described above, the recording medium P carrying the toner image secondarily transferred from the intermediate transfer belt 4 shown in FIG. 1 is fed into the nip between the pressure roller 21 and the fixing belt 25, and the toner image Comes into contact with the surface of the fixing belt 25. As a result, heat and pressure are applied to the toner image carried on the recording medium P, the toner of the toner image is melted, and the toner image is fixed on the recording medium P. Reference numeral 28 denotes a separation plate for preventing the recording medium P from being wound around the fixing belt 25, and 29 denotes an exit guide for the recording medium P.

  The heaters 30 and 31 are halogen heaters, and power supply to the halogen heaters is performed by electrically connecting the drawer connector 32 provided on the unit casing of the fixing device 20 to the heater. Conventionally, the interior of the fixing device 20 is wound around with a harness having a covering for insulation from the drawer connector 32 to the terminals of the heaters 30 and 31. With such a configuration, a plurality of components are required from the end of the power supply receiving unit from the main body to the halogen heater, and the manufacturing cost increases because the harness is wound around while maintaining safety in the manufacturing stage. I explained earlier.

  Therefore, in this embodiment, power is supplied from the drawer connector 32 to the heaters 30 and 31 by using a thin electrode plate 40 that does not have an insulating coating on the surface as shown in FIG. Yes. The electrode plate 40 is not subjected to any processing other than a round hole for fastening.

  Since the electrode plate 40 does not have an insulating coating, the electrode plate 40 is kept at a spatial distance of 4 mm or more from the metal member in the fixing device which is a metal fixing structure for holding the key parts as shown in FIG. Thus, the insulating property is secured, and the resin is wound around in the resin lower cover 33 of the fixing device 20. By winding the electrode plate 40 along the wall-shaped support 34 in the lower cover 33, it is not necessary to wind the harness around the structure of the unit, so that the assembly can be performed easily. As shown in FIGS. 4B and 4C, if the support body 34 is provided with a restriction wall for restricting the upper part, the electrode plate 40 after scooping moves upward for some reason. Is prevented. In addition, unlike the litz wire that just brings the lead wires close together, the electrode plate 40 is a thin plate, so there is no need to combine separate parts for fastening at the end, and fastening with the heater terminal using screws, etc. only by drilling a round hole Since it can be performed together with the heater terminal, the cost can be reduced by reducing the number of parts.

Next, an example of the scooping method in the lower cover 33 will be described with reference to FIG.
In FIG. 5, the lower cover 33 is provided with a pin or loop / hook-shaped electrode plate holding portion 35 by integral molding with the lower cover 33 instead of the support body 34 along the path for winding the electrode plate 40. . An electrode plate having a thickness of 0.5 mm or less is wound around the holding portion 35. If the electrode plate 40 has a thickness of 0.5 mm or less, the electrode plate 40 itself has sufficient flexibility, so that it can be wound along the path without bending.

  Thus, by using the electrode plate 40 described above, the electrode plate 40 can be reliably and easily wound along the scooping path by the pin-shaped holding portion 35. Moreover, since this electrode plate 40 has not been subjected to any processing other than round hole drilling, there is almost no portion to be discarded even if the machine is recovered and disassembled. Therefore, parts can be manufactured from one roll with very high efficiency.

  As shown in FIG. 6, the electrode plate 40 projects and exposes one end of the electrode plate to the outside of the fixing unit, and receives power therefrom. At this time, when power is transferred from the pin 32A of the drawer connector 32 to the heaters 30, 31 as in the conventional case shown in FIG. 6A, even if the electrode plate 40A is used, it is once converted into the harness 50. From there, it is connected to the pins in the drawer connector 32. In contrast, in the present embodiment, as shown in FIG. 6B, the harness 50 and the pin 32A of the drawer connector can be reduced by directly turning on the electrode plate 40 used for scooping inside the unit. Can do.

  Therefore, in this embodiment, cost reduction can be expected by reducing the number of parts and simplifying the configuration, and it is possible to provide a fixing device that is inexpensive and excellent in maintainability with such a configuration.

Next, wiring from the electrode plate 40 to the heater 30 will be described.
As shown in FIG. 7, a terminal block 36 is fixed to the end of the electrode plate 40 on the heaters 30 and 31 side by screws or the like, and a round hole formed in the electrode plate 40 at this time is used. The terminal block 36 is connected via a cable 37 when directly connected to the heater 30 and when the terminal block 36 and the heater 30 are separated from each other.

  As shown in FIG. 2, when the heaters 30 and 31 are provided in the heating roller 24 and the pressure roller 21 in the fixing device 20, two sets of scooping of the electrode plate 40 are prepared.

1 is a schematic cross-sectional view of an image forming apparatus including a fixing device according to the present invention. FIG. 2 is an enlarged configuration diagram illustrating the fixing device illustrated in FIG. 1. It is a perspective view of an electrode plate. It is a figure which shows the positional relationship of the electrode plate to be turned and the metal member of a fixing device. FIG. 6 is a perspective view showing an electrode plate that is wound around in the cover of the fixing device. FIG. 6 is an explanatory diagram illustrating a wiring state from a power receiving unit to a heater terminal of the fixing device. It is a perspective view which shows the example of wiring from a heater terminal block to a heater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Fixing device 21 Pressure roller 22 Fixing roller 24 Heating roller 25 Fixing belt 30, 31 Heater (heating means)
33 Lower cover 40 Electrode plate

Claims (5)

A recording medium having a fixing member heated by a heating means and a pressure member that presses against the fixing member to form a nip portion, and carries a toner image to be fixed to the nip portion, is recorded on the recording medium. In a fixing device that passes in a direction in contact with the surface of the fixing member and applies heat and pressure to the toner of the toner image when passing through the fixing member to fix the toner image on a recording medium.
The fixing is characterized in that power supply to the heating means is performed by a thin plate-like electrode plate that is wound around in a resin fixing device cover at a predetermined distance or more with respect to a metal member in the apparatus main body. apparatus.   2. The fixing device according to claim 1, wherein the electrode plate is wound between a terminal exposed to the outside of the fixing device cover and a terminal block of the heating unit.   The fixing device according to claim 1, wherein the electrode plate has a thickness of 0.5 mm or less.   3. The fixing device according to claim 1, wherein a resin holding member for determining a scooping position of the electrode plate is provided integrally with the fixing device cover on the fixing device cover. Fixing device.   An image forming apparatus, wherein heat and pressure are applied to toner of a toner image transferred onto a recording medium using the fixing device according to claim 1.

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