JP2005134795A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of maintaining the function to separate recording media from roller surfaces surely for a long period, reducing the wear of the rollers and separating members and prolonging the life of both members. <P>SOLUTION: The fixing device is equipped with fixing and separating members 4 of which the front ends come into sliding contact with the surfaces of the fixing rollers to separate the transfer paper wrapped around the surface of the fixing rollers 1 from the surfaces of the fixing rollers 1. The fixing and separating members 4 are equipped with elastic members 4a for directly applying separating force to the transfer paper wrapped around the surfaces of the fixing roller 1 and holding members 4b packed with mold releasing agents for improving the mold releasability of the transfer paper and ensure that the mold releasing agents are melted out of the holding members 4b by the effect of the heat from the fixing rollers 1 and are applied to the fixing rollers 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as a copying machine, and more particularly to a fixing device capable of reducing the wear of a separating member for separating a rotating member for fixing and a recording medium and extending the life of both members. About.

An image forming apparatus such as a copying machine includes a fixing device that fixes an image on a recording medium (transfer paper). The fixing device includes a fixing roller having a heater lamp and the like therein, a pressure roller in pressure contact with the fixing roller, a separation member (separation claw) for separating the transfer paper, and the like. For the separation claw, the life of the roller is shortened due to wear due to sliding contact with the surface of the fixing roller and the pressure roller, and the roller wear is further promoted by the toner adhering to the tip of the separation claw. Another problem is that the user accidentally damages the roller surface by the tip of the separation claw when the transfer paper is jammed.
In contrast, the occurrence of noise and slight vibration between the toner fixed on the tip of the separation claw and the fixing roller is suppressed, and furthermore, the wear of the fixing roller and the separation claw is reduced. An extended technique has also been proposed (see, for example, Patent Document 1). In this fixing device, a separation claw for separating the transfer paper is in equal contact with at least one of the fixing rotating body pair, and an oil application mechanism is provided on the separation claw.
JP-A-10-010911

However, in the fixing device disclosed in Japanese Patent Laid-Open No. 10-010911, the oil application mechanism provided on the separation claw reduces the wear on the fixing roller. However, the separation claw is an inelastic body, and thus the fixing roller is damaged. There is a problem. Also, because the groove is provided in the separation claw and oil is applied, for example, the oil is supplied from the separation claw to the fixing roller even when it is not used for image formation or during machine storage, and the surface of the fixing roller There is a disadvantage that it is soiled with oil more than necessary.
Therefore, the present invention has been made in consideration of the above-described circumstances, maintains the function of reliably separating the recording medium from the roller surface over a long period of time, and reduces wear between the roller and the separation member, It is an object of the present invention to provide a fixing device capable of extending the life of both members.

In order to solve the above-mentioned problem, the invention described in claim 1 is configured to pass a recording medium carrying an unfixed image or a fixed image between a fixing rotator and a pressure rotator pressed against each other. A fixing heating body that is lit by receiving power supply from a power supply source is a fixing device that heats the recording medium through the fixing rotator, and the tip portion is in sliding contact with the surface of the fixing rotator. A fixing separation member that separates the recording medium wound around the surface of the fixing rotator from the surface of the fixing rotator, and the fixing separation member directly gives a separating force to the recording medium wound around the surface of the fixing rotator; And a holding member filled with a release agent that improves the releasability of the recording medium, and the release agent is eluted from the holding member by the action of heat from the fixing rotator, and the fixing rotator. Painted on The most important feature of the fixing device was set to be.
According to a second aspect of the invention, a main feature of the fixing device is that the elastic member is a polyimide film or a polyimide tube.
According to a third aspect of the invention, a main feature of the fixing device is that the release agent is a wax such as paraffin or polyolefin.
According to a fourth aspect of the present invention, a fixing device including a release agent application device for uniformly applying the release agent to at least the surface of the fixing rotator is a main feature.

According to the fifth aspect of the present invention, power is supplied from a power supply source while passing an unfixed image or a recording medium carrying a fixed image between a fixing rotator and a pressure rotator pressed against each other. In response, the fixing heating body that is turned on performs a heat treatment on the recording medium through the fixing rotator, and the pressure heating body that is lit by receiving power supply from the power supply source A fixing device that heat-treats the recording medium via a fixing separation member that separates the recording medium wound around the surface of the fixing rotator from the surface of the fixing rotator by sliding a tip portion of the recording medium on the surface of the fixing rotator. And a pressure separating member that separates the recording medium wound around the surface of the pressure rotator by sliding the tip portion thereof on the surface of the pressure rotator, and the fixing separation member comprises: Above An elastic member that directly applies a separation force to the recording medium wound around the surface of the landing rotating body, and a holding member that is filled with a release agent that improves the releasability of the recording medium. The release agent is eluted from the holding member by the action of heat and applied to the fixing rotator, and the pressure separation member directly gives a separation force to the recording medium wound around the surface of the pressure rotator. An elastic member and a holding member filled with a release agent for improving the release property of the recording medium, and the release agent is eluted from the holding member by the action of heat from the pressure rotating body, and The main feature is a fixing device that is applied to a pressure rotating body.
According to a sixth aspect of the present invention, the elastic member is mainly a fixing device that is a polyimide film or a polyimide tube.
According to a seventh aspect of the invention, a main feature of the fixing device is that the release agent is a wax such as paraffin or polyolefin.
According to an eighth aspect of the invention, a fixing device including a release agent coating device for uniformly applying the release agent to at least the surface of the fixing rotator is a main feature.
According to a ninth aspect of the invention, there is provided the fixing device according to any one of the first to eighth aspects.

According to the present invention, the fixing separating member for separating the recording medium and the release agent (wax such as paraffin, polyolefin, etc.) filled in the holding member of the pressure separating member is used only when the apparatus is in operation. Since it elutes by heat from the body and is supplied to each roller surface, it is possible to maintain the function of reliably separating the recording medium from the roller surface over a long period of time. Further, since the release agent is supplied only during operation, the release agent is not supplied more than necessary on the surfaces of the fixing rotator and the pressure rotator, and the release agent is not contaminated.
Further, since heat in the fixing process is used, the separation function maintaining effect can be obtained with a simple configuration. In addition, since an elastic polyimide film or polyimide tube is used for the elastic member, the wear of the fixing rotator and the fixing separation member and the wear of the pressure rotator and the pressure separation member can be reduced with an inexpensive and simple configuration. It is possible to extend the life of both members. Further, since the release agent on the roller surface is smoothed by the release agent coating device, it is possible to stably obtain the release effect and to suppress the occurrence of uneven wear due to partial release agent shortage. it can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic sectional view of a fixing device 100 according to an embodiment of the present invention. The fixing device 100 is a device that fixes an image on a transfer sheet by pressurizing and heating a recording medium (hereinafter referred to as a transfer sheet) on which a toner image is formed in an image forming unit (not shown) positioned in the right direction. As shown in the figure, the fixing device 100 includes a transfer paper guide member 7, a fixing roller (fixing rotating body) 1 including a heater (fixing heating body) 1a, and a pressure roller (including a heating heater) 6a. A pressure rotator 6, a fixing cleaning roller 2, a release agent coating device 3, a fixing separation member 4, a pressure separation member 5, and discharge rollers 8 and 9.
As shown in FIG. 1, the transfer paper carrying an unfixed image conveyed to the fixing device 100 is heated by the heat from the heaters 1a and 6a and the pressure of the portion where the fixing roller 1 and the pressure roller 6 are pressed against each other. The image on the transfer paper is fixed. At this time, the transfer paper may be wound around the fixing roller 1, but the transfer paper can be separated from the fixing roller 1 by the fixing separation member 4. Further, when the transfer paper is attached to the pressure roller 6, it can be separated by the pressure separation member 5. The transfer paper separated from the fixing roller 1 or the pressure roller 6 is discharged by discharge rollers 8 and 9. On the other hand, the fixing cleaning roller 2 collects the offset toner.
The fixing separation member 4 includes an elastic member 4a that directly applies a separating force to the wound transfer paper and a bracket (holding member) 4b filled with a release agent that improves the release property of the transfer paper. Composed. The bracket 4b is fixed to a fixing portion of a fixing device (not shown).
FIG. 2 is a three-side view of the elastic member 4a. FIG. 2A shows a member in which one end of an integrally structured cylindrical polyimide tube (t = 0.03 to 0.5) is cut obliquely with a rotary cutter and the tip is formed into a nail shape. The claw-shaped tip portion is disposed so as to be in sliding contact with the roller, and when the transfer paper is wound around the roller, the transfer paper enters between the transfer paper and the roller to peel off the transfer paper.
FIG. 2 (B) shows an example in which the polyimide film is cut with a big die and the tip is made into a nail shape. A sheet-like film is formed into a cylindrical shape so that both ends overlap. As described above, since the polyimide tube or polyimide film having elasticity is used, the wear of the fixing roller can be reduced. Further, when the user removes the transfer paper remaining in the apparatus by jamming or the like, the elastic member 4a itself is elastically deformed even if an unreasonable force is applied to the claw portion of the elastic member 4a. There is an advantage of not scratching.

FIG. 3 is a cross-sectional view of the bracket 4b. The bracket 4b is a hollow structure member formed of a heat-resistant resin (for example, PET) and can be filled with a release agent (wax such as paraffin or polyolefin). The bracket 4b has an air hole 4c and a drip hole 4d. The air hole 4c has a cylindrical shape protruding in the hole direction, and the elastic member 4a is installed at a predetermined position of the bracket 4b by fitting the hole 4e formed in the elastic member 4a. It has become.
A holding spring material 4f is arranged on the bracket 4b on which the elastic member 4a is installed, and the elastic member 4a is fixed to the bracket 4b (see FIG. 4). The fixing separation member 4 configured as described above is fixedly attached to the side plate of the main body of the fixing device 100 with a stiff material. Three to eight fixing separation members 4 are attached to the stay material. In this example, the pressure separation member 5 has the same configuration as that of the fixing separation member 4, and the arrangement relationship with respect to the rollers is the same, and therefore detailed description thereof is omitted.

In the fixing device 100 configured as described above, the heat of the heater 1a is transmitted from the fixing roller 1 to the bracket 4b via the elastic member 4a during operation of the device. As a result, the release agent filled in the bracket 4b melts and flows from the drip hole 4d to the claw-shaped tip portion of the elastic member 4a, and is supplied from there to the surface of the fixing roller 1.
The supplied release agent is leveled by the release agent coating device 3 so as to have a uniform distribution on the surface of the fixing roller 1. For this reason, the release agent coating device 3 is installed on the side where the transfer paper is carried in and in the vicinity of the portion where the transfer paper is wound so that the release agent on the surface of the roller is smoothed and then hits the transfer paper. This facilitates release even when the transfer paper is wound around the roller. Note that the release material is supplied to the pressure roller 6 in the same manner as the fixing roller 1.
Therefore, in the fixing device 100, the fixing separation member 4 for separating the transfer paper, and the release agent (wax such as paraffin or polyolefin) filled in the bracket 4b of the pressure separation member 5 is used only when the device is in operation. Since it is eluted by the heat from the pressure roller 6 and supplied to the roller surface, the function of reliably separating the transfer paper from the roller surface over a long period of time can be maintained. Further, since the release agent is supplied only during operation, the release agent is not supplied to the surfaces of the fixing roller 1 and the pressure roller 6 more than necessary and is not soiled.

In addition, since the heat in the fixing process is used, the effect can be obtained with a simple configuration without adding a heating means. Further, since an elastic polyimide film or polyimide tube is used for the elastic member 4a, the fixing roller 1 and the fixing separation member 4 are worn and the pressure roller 6 and the pressure separation member 5 are worn with an inexpensive and simple configuration. Can be reduced, and the lifetime of both members can be extended. Further, since the release agent on the roller surface is smoothed by the release agent coating device, it is possible to stably obtain the release effect and to suppress the occurrence of uneven wear due to partial release agent shortage. it can.
In this example, the case where the release agent coating device 3 is provided only for the fixing roller 1 has been described. However, the present invention is not limited to this, and the release agent coating device is provided for the pressure roller 6. May be installed.
The fixing device shown in each of the above embodiments can be applied to an electrophotographic image forming apparatus such as a copying machine, a printer, or a facsimile machine.

1 is a schematic cross-sectional view of a fixing device 100 according to an embodiment of the present invention. It is a three-view figure of the elastic member 4a. It is sectional drawing of the bracket 4b (holding member). It is sectional drawing of the state which attached the elastic member 4a to the bracket 4b.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fixing roller (fixing rotary body), 1a Heater (fixing heating body), 2 Fixing cleaning roller, 3 Release agent coating device, 4 Fixing separation member, 4a Elastic member, 4b Bracket (holding member), 4c Air hole, 4d Dropping hole, 4e hole, 5 pressure separation member, 6 pressure roller (pressure rotating body), 6a heater (pressure heating body), 7 transfer paper guide member, 8, 9 discharge roller, 100 fixing device

Claims (9)

The fixing heating body that is lit by receiving the power supply from the power supply source while passing the unfixed image or the recording medium carrying the fixed image between the fixing rotator and the pressure rotator that are in pressure contact with each other. A fixing device that heats a recording medium via a rotating body,
A fixing separation member that separates the recording medium wound around the surface of the fixing rotator from the surface of the fixing rotator by sliding the tip portion on the surface of the fixing rotator;
The fixing separation member includes an elastic member that directly gives a separation force to a recording medium wound around the surface of the fixing rotator, and a holding member filled with a release agent that improves the releasability of the recording medium, The fixing device according to claim 1, wherein the releasing agent is eluted from the holding member by the action of heat from the fixing rotator and applied to the fixing rotator.   The fixing device according to claim 1, wherein the elastic member is a polyimide film or a polyimide tube.   The fixing device according to claim 1, wherein the release agent is a wax such as paraffin or polyolefin.   4. The fixing device according to claim 1, further comprising a release agent coating device for uniformly applying the release agent to at least the surface of the fixing rotator. The fixing heating body that is lit by receiving the power supply from the power supply source while passing the unfixed image or the recording medium carrying the fixed image between the fixing rotator and the pressure rotator that are in pressure contact with each other. A fixing device that heats a recording medium via a rotating body, and a pressure heating body that is lit by receiving power supply from the power supply source heats the recording medium via the pressure rotating body Because
A fixing separation member that separates a recording medium wound around the surface of the fixing rotator from the surface of the fixing rotator by the sliding contact of the front end with the surface of the fixing rotator; A pressure separating member for separating the recording medium wound around the surface of the pressure rotator from the surface of the pressure rotator,
The fixing separation member includes an elastic member that directly gives a separation force to a recording medium wound around the surface of the fixing rotator, and a holding member filled with a release agent that improves the releasability of the recording medium, The release agent is eluted from the holding member by the action of heat from the fixing rotator and applied to the fixing rotator,
The pressure separation member includes an elastic member that directly applies a separation force to the recording medium wound around the surface of the pressure rotator, and a holding member filled with a release agent that improves the releasability of the recording medium. And a fixing device, wherein the release agent is eluted from the holding member by the action of heat from the pressure rotator and applied to the pressure rotator.   The fixing device according to claim 5, wherein the elastic member is a polyimide film or a polyimide tube.   6. The fixing device according to claim 5, wherein the releasing agent is a wax such as paraffin or polyolefin.   8. The fixing device according to claim 5, further comprising a release agent coating device for uniformly applying the release agent to at least the surface of the fixing rotator.   An image forming apparatus comprising the fixing device according to claim 1.

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