JP2008139776A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prolong the service life of a fixing device using a fixing sleeve by preventing the occurrence of crack, etc. in the end portion of the sleeve. <P>SOLUTION: The fixing device using the fixing sleeve is configured to provide a fixing flange so that the fixing sleeve is supported from its circumferential surface and end portion and is provided with a drive transmission means for preventing the stop of the rotation of the fixing flange. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes a heating device that heats a material to be heated by passing the material to be heated through a pressure nip portion between the heating member and the pressure member, and the heating device as an image heat fixing device. The present invention relates to an image forming apparatus.

  Specifically, a heating apparatus having a film-like rotator, a guide member that guides the rotator, and a heating unit that heats a transfer material conveyed in the nip as the rotator rotates with respect to the guide member, The present invention also relates to an image forming apparatus provided with the heating device as a heat fixing device for images.

  A fixing device using a metal film is known, and a fixing device in which an elastic layer is provided on the surface of the metal film has been proposed.

  In the fixing device using this metal thin film (hereinafter referred to as a fixing sleeve), there is a problem that cracks are generated at the end of the fixing sleeve due to repeated use in a rotating state, leading to breakage. In the fixing sleeve manufacturing process, a fixing sleeve end burr and a minute crack are generated, and a crack starting from the burr and the crack is generated.

In order to prevent such cracks at the fixing end, Japanese Patent Laid-Open No. 2002-231419 has a structure in which a fixing flange that supports the fixing sleeve end is supported from the outer peripheral surface and the end of the fixing sleeve, and the fixing sleeve comes into contact with the fixing sleeve. The fixing flange rotates with the fixing sleeve.
Japanese Patent Laid-Open No. 2002-231419

  However, in the above conventional example, since the rotational driving force is not positively applied to the fixing flange, when the sliding resistance of the portion supporting the fixing flange is large, the fixing flange does not rotate due to the frictional force with the fixing sleeve. The fixing flange and the end surface of the fixing sleeve sometimes rubbed.

  When the pressure balance between the right and left sides of the pressure roller is not uniform, the fixing sleeve tries to move in one direction, and the end of the fixing sleeve presses the fixing flange. As a result, the fixing flange is brought into pressure contact with the support portion, and the pressure contact portion has a large sliding resistance. When this sliding resistance is larger than the sliding resistance between the fixing sleeve and the fixing flange, the fixing flange does not rotate and the end portion of the fixing sleeve rubs against the fixing flange. At this time, there was a case in which the end of the fixing sleeve was subjected to frictional force due to rubbing resistance, and the end of the metal film was subjected to stress and cracked.

  In the present invention, a fixing flange driving auxiliary member for assisting the rotation of the fixing flange is provided.

  The fixing flange driving auxiliary member has a portion that contacts the fixing flange, and the contacting portion is configured to be driven in a direction in which the fixing flange rotates together with the fixing sleeve at least during rotation of the fixing sleeve.

  As described above, according to the present invention, when the fixing sleeve is moved to one side and the fixing flange is pressed outward due to non-uniform left-right pressure balance of the pressure roller, the surface of the fixing flange opposite to the fixing sleeve. Contacts the fixing flange driving auxiliary member, and the driving force of the fixing flange driving auxiliary member is transmitted to the fixing flange, so that the fixing flange rotates without stopping. Since the fixing flange rotates reliably, sliding friction between the fixing sleeve end and the fixing flange can be reduced.

  Therefore, cracks at the end of the fixing sleeve can be prevented, and the life of the fixing device can be further extended.

(Example 1)
FIG. 1 is a diagram that best represents the characteristics of the present invention, and is a diagram schematically showing a cross section of a fixing sleeve and a pressure roller. Reference numeral 1 denotes a fixing sleeve in which a silicone rubber layer is bonded to the surface of a SUS belt portion formed by drawing a SUS base tube into a seamless belt shape having a thickness of about 50 μm. Reference numeral 2 denotes a fixing flange that regulates the end portion of the fixing sleeve. Reference numeral 3 denotes a flange support member which is supported by the frame 10 of the fixing device and rotatably supports the fixing flange 2.

  4 is a pressure roller, 5 is a pressure roller bearing that rotatably supports the pressure roller 4 so that the pressure roller 4 is pressed against the fixing sleeve 1 by a pressure spring 11, and 6 is a shaft end of the pressure roller 4 The pressure roller gear is attached to the pressure roller 4 so as to rotate integrally therewith. Reference numeral 7 denotes a pressure roller driving gear for transmitting a rotational driving force from a driving source (not shown) to the pressure roller gear 6. When the drive source is driven, the rotational driving force is transmitted to the pressure roller gear 6 via the pressure roller drive gear 7, and the pressure roller 4 rotates. At this time, since the pressure roller 4 is in pressure contact with the fixing sleeve 1, the fixing sleeve 1 rotates in accordance with the rotation of the pressure roller 4.

  Reference numeral 8 denotes a fixing flange driving auxiliary member, which is fixed to the shaft of the pressure roller 4 by being stopped by a parallel pin 9 so as to rotate integrally with the pressure roller 4. The fixing flange drive assisting member 8 moves outward when the fixing flange 2 contacts the fixing flange drive assisting member 8 when a biasing force is generated on the fixing sleeve 1 and the fixing flange 2 is pressed toward the fixing frame. The position of the pressure roller 4 in the axial direction is determined so as to be restricted.

By providing the fixing flange driving assisting member 8 as described above, for example, in the drawing shown in FIG. 1, when a shifting force in the left direction is generated in the fixing sleeve 1, the end surface of the fixing sleeve 1 is first fixed to the fixing flange 2a. The fixing flange 2a is pressed to the left. As a result, the outer surface of the fixing flange 2a comes into contact with the fixing flange driving auxiliary member 8a. Since the fixing flange drive assisting member 8a rotates integrally with the pressure roller 4, a rotational driving force is supplementarily applied to the fixing flange 2a by the frictional force of the contact surface by the contact. Therefore, even when the fixing flange 2 is pressed outward, the fixing flange 2 rotates without stopping, so that the frictional resistance between the fixing sleeve 1 and the fixing flange 2 does not increase. As a result, even if a biasing force is generated in the fixing sleeve 1, the stress at the end of the sleeve can be reduced, and cracks and breakage at the end can be made difficult to occur. The driving force transmission to is not limited to the means according to the present invention. For example, the same effect can be obtained by providing means such as providing a gear to the fixing flange and actively driving.

Schematic sectional view around the fixing sleeve and the pressure roller according to the first embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing sleeve 2 Fixing flange 3 Flange support member 4 Pressure roller 5 Pressure roller bearing 6 Pressure roller gear 7 Pressure roller drive gear 8 Fixing flange drive auxiliary member 9 Parallel pin 10 Fixing frame 11 Pressure spring

Claims (3)

A film-like rotating body (hereinafter, referred to as a fixing sleeve), a guide member that guides the fixing sleeve, a pressure roller that forms a pressure nip with respect to the guide member via the fixing sleeve, and the fixing sleeve In a heating and pressure fixing device having a heating means for heating and heating a transfer material conveyed in the nip as the pressure roller rotates,
A fixing flange that is rotatable and restricts at least the axial position of the fixing sleeve;
A fixing device for an image forming apparatus, characterized in that, in addition to the fixing sleeve, a means capable of applying a rotational driving force to the fixing flange is provided. The fixing device according to claim 1,
Can contact the fixing flange,
At least when the fixing sleeve is rotating,
When a fixing flange comes into contact, a rotational force is applied to the fixing flange in the same direction as the rotation direction of the fixing sleeve.
A fixing device for an image forming apparatus, comprising a fixing flange driving auxiliary member.   3. The fixing device according to claim 2, wherein the fixing flange driving auxiliary member is provided on the pressure roller shaft so as to rotate integrally with the pressure roller.

Images