JPH08254919A - Fixing device - Google Patents

Abstract

PURPOSE: To make separation smooth by integrally providing a butting part abutted on the periphery of a fixing roller with a part different from the recording paper separating part of a separating pawl and forming a constant gap between the top end of the separating pawl and the periphery of the fixing roller. CONSTITUTION: The separating pawl 9 is rotatably supported by a supporting shaft 5 and energized in a direction where the pawl 9 is abutted on the periphery of the fixing roller 1 by a spring 6 using the supporting shaft 5 as a supporting point. Moreover, the separating pawl 9 is constituted of a resin or metallic member. The plural pawls 9 are arranged in the longitudinal direction of the periphery of the roller 1. The butting part 10 is integrally formed with the part different from the recording paper separating part of the pawl 9 and abutted on the periphery of the roller 1 by the energization of the spring 6, to form the gap A between the top end part. 9a of the pawl 9 as the recording paper separating part and the roller 1. The gap A is of a very small gap in a degree that contact with toner remaining on the periphery of the roller 1 is not obtained and kept to such a degree that the leading edge of the recording paper can not enter into the gap.

Description

Detailed Description of the Invention

[0001]

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, a digital multi-functional peripheral, a laser printer, a facsimile and the like.

[0002]

2. Description of the Related Art FIG. 5 is a schematic view of a main part of a fixing device. The fixing roller 1 is supported by a pair of side plates (not shown), a thermistor 3 and a separating claw 4 are provided on the outer peripheral surface thereof, and a heater 1a composed of a heatable halogen lamp is incorporated therein. . A pressure roller 2 is provided so as to be in pressure contact with the fixing roller 1. Both ends of the pressure roller are supported by side plates (not shown) so that they can rotate together with the fixing roller 1. The thermistor 3 is for detecting the fixable temperature of the fixing roller 1. The separation claw 4 is used to separate the recording paper that is in close contact with the fixing roller 1, is supported by a support shaft 5, and is biased by a spring 6 in a direction to come into contact with the fixing roller 1. The support shaft 5 is supported by a side plate (not shown). The fixing cover 7 covers the upper side of the fixing roller 1 and locks one end of the spring 6. The arrow B indicates the rotation direction of the fixing roller 1.

In such a structure, the unfixed toner image transferred onto the recording paper P by the transfer device 8 is conveyed between the fixing roller 1 and the pressure roller 2 and heated and pressed to melt. It is fixed.

[0004]

By the way, in the above-mentioned fixing device, since the separation claw 4 abuts the peripheral surface of the fixing roller 1 to separate the recording paper which is in close contact with the fixing roller 1,
At the time of fixing, the toner remaining on the fixing roller 1 side is
It gradually adhered to the tip of the separation claw and became a solid substance that hooked the tip of the recording paper, and then expanded, causing transport problems and paper jams. Therefore, as disclosed in Japanese Patent Laid-Open No. 4-147178, it has been proposed to provide a separating claw that is not in contact with the peripheral surface of the fixing roller. However, since the separation claw is locked by another member to form non-contact, the gap between the fixing roller peripheral surface and the separation claw is not constant between the individual separation claws, and large and small variations occur, Where there is a large gap,
There are problems that the leading edge of the recording paper may get in and the recording paper may not be separated, or a paper jam may occur.

The present invention provides a fixing device which can stably maintain a gap between a fixing roller and a separation claw and prevent toner from adhering to the separation claw to improve the separation of recording paper. With the goal.

[0006]

In order to achieve the above object, the fixing device of the invention according to claim 1 has an abutting portion which comes into contact with the peripheral surface of the fixing roller at a portion of the separating claw different from the recording paper separating portion. Is provided integrally with the separating claw, and a gap is formed between the recording paper separating portion of the separating claw and the peripheral surface of the fixing roller.

A fixing device according to a second aspect of the invention is characterized in that the abutting portion is integrally molded with the separating claw.

Further, the fixing device of the invention according to claim 3 is characterized in that the abutting portion is attached as a member different from the separating claw.

Further, the fixing device of the invention according to claim 4 is characterized in that the abutting portion is a roller-shaped member which is rotated along the peripheral surface of the fixing roller.

According to the fifth aspect of the present invention, in the fixing device, a portion of the separating claw different from the recording paper separating portion is brought into contact with the peripheral surface of the fixing roller and a cleaning member for cleaning the residual toner on the fixing roller is projected. It is characterized in that the contact portion is provided and a gap is formed between the recording paper separating portion of the separating claw and the peripheral surface of the fixing roller.

[0011]

According to the structure of the first aspect, the abutting portion which comes into contact with the peripheral surface of the fixing roller is integrally provided at a portion of the separation claw different from the recording paper separation portion, and the tip of the separation claw which is the recording paper separation portion. Since a certain gap is formed between the fixing roller and the peripheral surface thereof, it is possible to prevent the toner remaining on the fixing roller from adhering to the tip of the separation claw. Therefore, the recording paper and the fixing roller can be smoothly separated, and the recording paper can be prevented from being caught or jammed. Further, since the abutting portion is in contact with the peripheral surface of the fixing roller, it is possible to prevent the gap between the separation claw and the fixing roller from being varied or enlarged, and to always stabilize the gap to be constant. Therefore, it is possible to prevent the recording paper from entering the gap and prevent the paper jam caused thereby.

According to the second aspect of the present invention, since the separation claw and the abutment portion are integrally formed, the mutual positional relationship between the separation claw and the abutment portion can be obtained with high accuracy, and the separation is performed. The gap between the claw and the fixing roller can be accurately set to a desired gap and can be held.

According to the third aspect of the present invention, the separating claw and the abutting portion are formed of different members, so that the abutting member can be selected from materials having good durability and slidability.
As a result, the gap between the separation claw and the fixing roller can be stably maintained with a constant width. If the abutting member is a low friction member, damage to the peripheral surface of the fixing roller can be reduced and durability can be improved.

According to the fourth aspect of the present invention, the abutting portion is formed of a roller-shaped member, so that the durability and slidability of the abutting portion are improved and the peripheral surface of the fixing roller is roughened. Now, it is possible to prevent deterioration of the releasability of the toner, which is caused by abrasion of the release layer, and deterioration of the fixing quality.

According to a fifth aspect of the present invention, the abutting portion provided at a portion different from the recording paper separating portion of the separating pawl is used as a cleaning member, so that the tip of the separating pawl, which is the recording paper separating portion, and the fixing roller. A gap between them can be formed, and the residual toner adhering to the peripheral surface of the fixing roller can be eliminated, so that the deterioration of the fixing quality due to the residual toner can be prevented.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of a fixing device according to the first embodiment of the present invention. In FIG. 1A, a separation claw a9 is rotatably supported by a support shaft 5, and a spring 6 having the support shaft 5 as a fulcrum causes the separation claw a9 to come into contact with the peripheral surface of the fixing roller 1. Being energized. The separating claws a9 are made of a resin or metal member, and a plurality of separating claws a9 are arranged in the longitudinal direction of the peripheral surface of the fixing roller 1. The abutting portion 10 is formed at a portion different from the recording paper separating portion of the separation claw a9, contacts the peripheral surface of the fixing roller 1 by the bias of the spring 6, and separates the recording paper separating portion a9. A gap A is formed between the front end portion 9 a of the sheet and the fixing roller 1. This gap A is shown in FIG.
An enlarged view is shown in (b). With this structure, the variation in the gap A can be extremely reduced, and the gap A is so small that the toner remaining on the peripheral surface of the fixing roller 1 does not come into contact with the recording. It is held so that the leading edge of the paper cannot penetrate. Therefore, the recording paper P on which the toner image is transferred from the transfer device 8 is conveyed between the fixing roller 1 and the pressure roller 2 and is heated and fixed,
The recording paper P that has been brought into close contact with the fixing roller 1 is reliably separated by the tip 9a of the separation claw a9.

Further, as in the second embodiment of the present invention, if the separating claw a9 and the abutting portion 10 are integrally molded by resin molding or the like,
The positional relationship between the separation claw a9 and the abutting portion 10 can be obtained with high accuracy.

FIG. 2 is a block diagram showing the main parts of a fixing device according to the third embodiment of the present invention. The separation claw b11 is
It is composed of a resin or metal member, and the abutting portion 12 of another member is provided at a portion different from a portion of the recording paper separating portion. The abutting portion 12 of this separate member comes into contact with the peripheral surface of the fixing roller 1 by the urging force of the spring 6 with the support shaft 5 as a fulcrum, thereby fixing the tip end portion 11a of the separation claw b11, which is a recording paper separation portion, to the fixing portion 1. Gap A between roller 1
Is being formed. Since the separating claw b11 is provided with the abutting portion 12 as a separate member in this way, a member having a different slidability and durability different from that of the separating claw b11 can be used. Accordingly, the release layer on the peripheral surface of the fixing roller 1 can be protected for a long period of time. Further, since the surface of the release layer does not become rough, the releasability does not deteriorate, and the toner attached to the fixing roller 1 can be reduced. Further, when the abutting portion is provided as a low friction member, durability and slidability are further improved, and surface roughness can be prevented even on the release layer on the peripheral surface of the fixing roller 1.

FIG. 3 is a block diagram showing the main parts of a fixing device according to the fourth embodiment of the present invention. The separation claw c13 is
The abutting portion 14 having a rotatable roller 14a is provided at a portion different from the recording paper separating portion, which is made of a resin or metal member. This roller 1
4a is rotatably supported by a roller shaft 14b supported by the separation claw c13. The roller 14a comes into contact with the peripheral surface of the fixing roller 1 by the urging force of the spring 6 with the support shaft 5 as a fulcrum, so that the separation claw c which is a recording paper separation portion is formed.
A gap A is formed between the tip portion 13 a of 13 and the fixing roller 1. By providing the roller-shaped abutting portion 14 in this manner, sliding contact between the abutting portion 14 and the peripheral surface of the fixing roller 1 is eliminated, and wear due to this is prevented. Further, even when the fixing roller 1 is used for a long period of time, the release layer formed on the peripheral surface of the fixing roller 1 can be held without being damaged, and the surface of the release layer is prevented from becoming rough. It is possible to reduce the amount of toner that adheres to the surface. The roller 14 described above
Although the member a is made of resin, it is not limited to this and may be made of rubber or metal. Further, the shape may be a roller shape.

FIG. 4 is a schematic view of the main parts of a fixing device according to the fifth embodiment of the present invention. The separation claw d15 made of a resin or metal member is supported by an elastic support member 17 and is biased in a direction to come into contact with the peripheral surface of the fixing roller 1. An abutting portion 16 of the cleaning member is provided at a portion of the separating claw d15 different from the recording paper separating portion. The abutting portion 16 comes into contact with the peripheral surface of the fixing roller 1 by the urging force of the support member 17 that supports the separation claw d15, and the tip portion 15a of the separation claw d15, which is a recording paper separation portion, and the fixing roller. A gap A between the first and second portions is formed. By thus providing the abutting portion 16 of the cleaning member, the toner adhering to the peripheral surface of the fixing roller 1 is removed and the separation claw d1 is removed.
The double action is performed so that the residual toner on the fixing roller 1 does not adhere to the tip portion 15a of the No. 5 roller. From this,
Since the surface of the release layer on the peripheral surface of the fixing roller 1 is not damaged or roughened, the amount of toner attached to the peripheral surface of the fixing roller 1 can be reduced. Although the above-mentioned cleaning member uses the silicon oil impregnated felt material, it is not limited to this and may be a resin or rubber-based material, which may or may not be oil-impregnated. The fixing roller 1 is made of a material such as aluminum, iron, stainless steel, glass and ceramics. In the case of the present invention, the halogen lamp heater 2 is incorporated in the fixing roller 1, but the heating of the fixing roller 1 is not limited to this, and may be a heating element layer. The pressure roller 2 is a cored bar covered with an elastic layer, and the elastic layer is coated with silicon rubber, ethylene propylene diene morimer, chloroprene rubber, chlorosulfonated polyethylene rubber, cross-linked polyethylene or the like. But it's okay.

[0022]

According to the first aspect of the present invention, since a constant gap can be formed between the tip of the separating claw and the peripheral surface of the fixing roller, the tip of the separating claw remains on the fixing roller. It is possible to prevent the adhered toner from adhering to the recording paper and prevent the recording paper from being jammed. In addition, it is possible to prevent the gap between the separation claw and the fixing roller from expanding and expanding, and to keep the gap constant and stable at all times.
It is possible to prevent the occurrence of paper jam or the like.

According to the second aspect of the present invention, the separation claw and the abutment portion are integrally formed, so that the accuracy of the positional relationship between the separation claw and the abutment portion is improved, and the separation claw and the fixing portion are fixed. The gap between the rollers can be stably obtained and held.

According to the third aspect of the present invention, by forming the separating claw and the abutting portion by different members, the durability and slidability of the abutting member can be improved and the durability of the fixing device can be improved. improves. Further, since the abutting portion can be easily replaced, the maintainability is improved.

According to the fourth aspect of the present invention, the abutting portion is formed of a roller-shaped member, so that the durability and slidability of the abutting portion are improved, and the peripheral surface of the fixing roller is separated. The durability of the mold layer is also improved, and the fixing performance and the fixing quality can be prevented from being deteriorated.

According to the invention of claim 5, in addition to the effect of claim 1, by using the abutting member as a cleaning member, the toner adhering to the peripheral surface of the fixing roller can be removed, and the fixing performance and the fixing performance can be improved. It is possible to prevent quality deterioration. Further, since the abutting portion also serves as a cleaning member, a member dedicated to cleaning can be eliminated, and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a fixing device according to a first exemplary embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of a fixing device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a main part of a fixing device according to a third exemplary embodiment of the present invention.

FIG. 4 is a configuration diagram of a main part of a fixing device according to a fourth exemplary embodiment of the present invention.

FIG. 5 is a configuration diagram of main parts of a conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixing roller 1a ... Heater 2 ... Pressure roller 3 ... Thermistor 4 ... Separating claw 5 ... Spindle 6 ... Spring 7 ... Fixing cover 8 ... Transfer device 9 ... Separating claw a 9a, 11a, 13a, 15a ... Tip part 10, 12, 14, 16 ... Abutting portion 11 ... Separation claw b 13 ... Separation claw c 15 ... Separation claw d 17 ... Support member

Claims (5)

[Claims] 1. A fixing roller which is heated and rotated, a pressure roller which is brought into pressure contact with the fixing roller, a separation claw for separating the recording paper and the fixing roller arranged on the peripheral surface of the fixing roller, and the separation claw. And a spring means for urging the fixing roller to the peripheral surface of the fixing roller, and nipping and conveying the recording paper between the pressure roller and the fixing roller to fix an unfixed toner image on the recording paper. An abutting portion that comes into contact with the fixing roller peripheral surface is provided integrally with the separating claw at a portion different from the recording paper separating portion of the separating claw, and the recording paper separating portion of the separating claw and the fixing roller peripheral surface are provided. A fixing device characterized in that a gap is formed between the fixing device and the fixing device. 2. The fixing device according to claim 1, wherein the abutting portion is integrally molded with the separation claw. 3. The fixing device according to claim 1, wherein the abutting portion is attached as a member different from the separating claw. 4. The fixing device according to claim 1, wherein the abutting portion is a roller-shaped member that rotates along the peripheral surface of the fixing roller. 5. A fixing roller that rotates by heating, a pressure roller that presses against the fixing roller, a separation claw that separates the recording paper and the fixing roller arranged on the peripheral surface of the fixing roller, and the separation claw. Is provided on the peripheral surface of the fixing roller and a supporting member of a supporting elastic body is provided, and the recording paper is sandwiched and conveyed between the pressure roller and the fixing roller to fix an unfixed toner image on the recording paper. In the fixing device, an abutting portion of a cleaning member that abuts the peripheral surface of the fixing roller and that cleans residual toner on the fixing roller is provided at a portion of the separating claw different from the recording paper separating portion. A fixing device, wherein a gap is formed between the recording paper separating portion of the separating claw and the peripheral surface of the fixing roller.