JPH08305199A - Fixing device - Google Patents

Abstract

PURPOSE: To provide a fixing device capable of preventing the deformation of a heater by bundle wire stress caused by the wire processing and the fall-off of a power supplying member out of the heater. CONSTITUTION: The fixing device provided with the heater 1 generating heat by energizing, and the power supplying member 2 for supplying the power to the heater 1 being attachable/detachable to/from the power supplying part 20 of the heater 1, in which unfixed toner is fixed onto a recording material by the heat from the heater 1 transmitted through a fixing film 9 transported while slid on a surface of the heater 1, is provided with a positioning opening (positioning part) 19-a for the power supplying member 2 on the fixing device frame body 19. Since the bundle wire stress of the power supplying wire 18 is absorbed by the positioning opening 19-a of the fixing device frame body 19, the deformation of the heater 1 by the bundle wire stress and the fall-off of the power supplying member 2 from the heater 1 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device which heats and fixes an image formed on a recording material using a heat-meltable toner in an image forming apparatus.

[0002]

2. Description of the Related Art A fixing device adopting a film heating method is a heat roller fixing method or other well-known belt fixing method,
Compared with heat fixing type devices that adopt flash fixing method, open fixing method, etc., firstly, since a linear heating element with low heat capacity can be used, power saving and shortening of wait time (quick start property) ), And secondly, the fixing point and the separation point can be set separately, so that there is an advantage that offset is prevented.

A fixing device adopting such a film heating system belongs to, for example, the fixing device described in Japanese Patent Laid-Open No. 63-313182, and includes a thin heat-resistant fixing film and a movement of the fixing film. It is configured to include a driving unit, a heating body, and a pressure member which is disposed on one side of the fixing film so as to face the heating body with the fixing film inside.

Thus, the pressing body makes the developed image bearing surface of the recording material to be image-fixed adhere to the heating body via the fixing film, and the fixing film is at least in the conveying direction of the recording material at the time of fixing the image. The recording material is moved in the forward direction at the same speed, and the recording material is passed through a fixing nip portion formed by pressure contact between a heating body and a pressing member with the fixing film sandwiched therebetween, so that the visible image bearing surface of the recording material is moved. The toner is softened and melted by applying heat energy to the visible image through a fixing film to heat the toner, and then the fixing film and the recording material are separated from each other, or the fixing film and the recording material are cooled and solidified after the toner is solidified. Separate.

A fixing device adopting such a film heating system has an energization heat generating layer having a longitudinal direction in a direction intersecting the moving and passing direction of the recording material, and between the energizing electrodes at both longitudinal ends of the energization heating layer. When a voltage is applied, each part of the effective heating area of the energization heat generating layer generates heat with a predetermined heat generation amount per unit length.

The effective full-length area of the energizing heat generating layer has a length corresponding to the width (maximum width, maximum size width) of the maximum size recording material that can be supplied and used in an image forming apparatus incorporating a fixing device. There is. A method of directly soldering the cord or a method using a connector using a plate-shaped spring is adopted for coupling with the electrode supply cord or the terminal portion for applying a voltage to the conducting electrodes at both longitudinal ends of the electricity generating layer. It had been.

[0007]

However, in the above-mentioned conventional example, as shown in FIG. 9, there is a problem in the method of coupling the power supply section 20 of the heating element 1 and the power supply wire 18 to each other.

That is, when the power supply section 20 and the power supply member (connector) 2 are directly joined, the H-direction bundle stress generated during the bundle processing of the electric wires 18 is directly transmitted to the heating element 1. The heating element 1 is deformed and moved from the normal position shown by the chain double-dashed line in FIG. 9 to the position shown by the solid line, and the transportability of the fixing film (endless film) 9, particularly the heating element 1
The crown shape of the heating element 1 or the tension applied to the fixing film 9 which has an influence on the deviation of the fixing film 9 in the longitudinal direction of the fixing film 9 deviates from the design value, and the deviation force of the fixing film 9 increases, so that the fixing film 9 Buckling deformation occurs near the end on one side. When the deviation control of the fixing film 9 is performed by regulating the ribs provided at the end portions of the fixing film 9, the fixing nip shape changes due to the damage of the rib or the change of the crown shape of the heating element 1, There is a problem in that the recording material transportability such as paper wrinkles and paper trailing edge is adversely affected.

Further, the stress of the power supply wire 18 may act in the direction of arrow K in FIG. 9 depending on the wiring process. In this case, the terminal member 2 comes out of the heating element 1 in the direction K. As a result, problems such as leakage of the heating element 1 and power failure occur.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent deformation of a heating element and disconnection of a power supply member from a heating element due to bundle stress caused by wire treatment. To provide a fixing device capable of performing.

[0011]

In order to achieve the above object, the invention according to claim 1 is to attach a power source to the heat generating body and a power generating portion of the heat generating body which can be detachably attached to the heat generating body. And a power supply member for fixing the unfixed toner to the recording material by the heat from the heating element that is transmitted through the fixing film that is conveyed while sliding on the surface of the heating element. A positioning part for the power supply member is provided on the device frame.

According to a second aspect of the invention, the invention according to the first aspect is characterized in that engaging means for fixing the power supply member and the fixing device frame to each other is provided.

Further, the invention of claim 3 is characterized in that, in the invention of claim 2, the positioning portion of the fixing device frame also serves as the engaging means.

[0014]

According to the first aspect of the invention, since the bundle stress of the power supply wires is absorbed by the positioning portion of the fixing device frame, the heating element is deformed and the power supply member is removed from the heating element. It is prevented.

According to the second aspect of the present invention, the fixing of the power supply member to the fixing device frame becomes more reliable.

Further, according to the third aspect of the invention, the positioning portion of the fixing device frame also serves as the engaging means, so that the structure can be simplified.

[0017]

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

<First Embodiment> FIG. 1 is a cross-sectional view (a cross-sectional view in the direction of arrow A in FIG. 2) of a joining portion between a heating element and a power supply member of a fixing device according to a first embodiment of the present invention. 2 is a side sectional view of the identification attachment device.

In the fixing device shown in FIG. 2, reference numeral 1 is a linear heating element (thermal head) having a low heat capacity, which is fixedly supported by a stay 4 having high rigidity via a heat insulating member 3, and a stay 4 is provided. Is fixedly arranged between the device frames (not shown) on the front side and the back side. Further, 5 is a film driving roller which is also rotatably disposed between the front and rear device frames, and 6 is a rotatable shaft of both ends between front and rear movable bearings 7 and 8. It is a film tension roller supported by. The tension roller 6 is constantly urged in one direction (the direction of arrow F in FIG. 2) by the tension springs 10 and 11 locked to the movable bearings 7 and 8, respectively.

The heating element 1, the film driving roller 5 and the tension roller 6 are arranged substantially parallel to each other.
An endless film (hereinafter referred to as a fixing film) 9 as an endless belt member is wound around these, and a predetermined tension is applied to the fixing film 9 by a tension roller 6. The fixing film 9 is formed by coating a release layer such as PTFE on the outer peripheral surface of a base film having a thickness of 20 μm and made of a heat-resistant resin such as polyimide, polyetherimide or PES.

Reference numeral 12 is a pressure roller which is pressed against the heating element 1 with a predetermined pressing force through the fixing film 9, and is rotatably supported between the front and rear device frames. There is. A pressure contact nip portion (fixing nip portion) N is formed between the heating body 1 and the pressure roller 12 with the fixing film 9 interposed therebetween.

The drive roller 5 is rotationally driven in the direction of the arrow (clockwise direction) in the figure by the drive system M to rotatably convey the fixing film 9 in the direction of the arrow B in the figure. The inner surface is closely contacted with and slides while being rotated. In order to reliably convey the fixing film 9, the drive roller 5 is constructed by forming a coating layer of silicone rubber or the like on the surface of a cored bar of iron or the like.

The pressure roller 12 has a rubber elastic layer having a good releasability such as silicone rubber, and is driven to rotate as the fixing film 9 is rotated and conveyed.

Then, the fixing film 9 is rotatively conveyed by the rotation of the driving roller 5 and is conveyed from the image forming mechanism section (not shown) in a state where the heating element 1 is heated to a predetermined temperature by energization. Recording material P carrying an unfixed toner image t
Is introduced along the inlet guide 13 between the fixing film 9 and the pressure roller 12 in the pressure contact nip portion N.

The recording material P introduced into the pressure contact nip portion N is
The heat of the heating element 1 is received through the fixing film 9 to be heated by being tightly conveyed to the outer surface of the fixing film 9 in the rotating and conveying state and being nipped and conveyed together with the fixing film 9 in the pressure contact nip portion N, and the recording is performed. The unfixed toner image t on the material P is heated and fixed. Then, the recording material P passing through the pressure contact nip portion N
Is subjected to curvature separation from the outer surface of the fixing film 9, passes through the separation guide 14, and is discharged and conveyed by the discharge roller 15.

By the way, the fixing film 9 is a winding member in a rotating state if there is no restriction,
A phenomenon occurs in which the film 9 naturally shifts toward the one end side (front side) or the other end side (back side) of the film 9 in the width direction along the lengths of the drive roller 5 and the tension roller 6 more or less naturally.

Therefore, in this embodiment, a rib 16 is provided on the outer periphery of the front end of the fixing film 9 in the width direction, and the side surface of the rib 16 is regulated by a regulation member 17 with a predetermined force to control the deviation of the fixing film 9. It is carried out.

Further, as shown in FIG. 1, both ends of the heating element 1 constitute a power feeding section 20 for supplying electric power, and the power feeding section 20 is connected to the fixing device frame 19 to the outside of the apparatus. It projects and is joined to the power supply member 2. Reference numeral 18 is an electric wire for supplying electric power to the heating element 1 via the power supply member 2.

By the way, in FIG. 1, reference numeral 2-a is a contact spring provided in the power supply member 2, which is in direct contact with the power feeding portion 20 and receives the electric power from the electric wire 18 as the heating element 1.
Supply to. Further, 2-b is a positioning boss provided on the power supply member 2, and the positioning boss 2-b is fitted into a positioning hole 19-a formed in the fixing device frame 19 to fix the power supply member 2. It is positioned.

Therefore, the power supply member 2 is moved by the positioning boss 2-b with respect to the fixing device frame 19 as indicated by the arrow C in FIG.
It is fixed so that it does not have directional freedom.

By adopting the above-mentioned structure, the stress in the direction C of the electric wire 18 generated during the processing of the electric wire 18 at the time of assembling the fixing device is not directly transmitted to the heating element 1, and the heat generated by the stress of the electric wire 18 is generated. The deformation of the body 1 can be easily prevented, and the deviation of the fixing film 9 and the recording material transporting property are both stabilized.

As shown in FIG. 3, the positioning boss 2-
The tip portion of b is a trapezoidal patch portion 2-c having elasticity, and the patch portion 2-c is the heating element 1 of the power supply member 2.
You may make it serve also as a retaining means.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5
FIG. 4 is a cross-sectional view of a joint between a heating element and a power supply member.

As shown in FIG. 4, the shape of the end of the power supply member 2 on the side of the frame 19 is a stepped shape having an upper step 2-b and a lower step 2-c, and a bent portion raised from the frame 19 is provided. 19-a
By bringing the lower surface of the upper step 2-b into contact with the upper surface of
The movement of the power supply member 2 in the direction of the arrow E in the figure is restricted. Further, in this case, by abutting the side surface of the lower step portion 2-c and the side surface of the frame body 19 facing it at the portion D, the regulation of the rotation of the power supply member 2 in the direction of the arrow I in the figure becomes more reliable.

By adopting the above-mentioned structure, compared with the first embodiment, the strength for withstanding the regulation of the power supply member 2 is increased, and its detachability is also improved, so that the parts of the fixing unit are replaced. Workability is improved.

Further, as shown in FIG. 5, in addition to the above structure, an elastic portion 2-d integrally formed with the upper step portion 2-b on the upper step portion 2-b of the power supply member 2. Since the tip of the elastic portion 2-d is provided as a claw-shaped portion 2-c and the claw-shaped portion 2-c is abutted against the side surface of the frame body 19, the power supply member 2 can be regulated with respect to the heating element 1. As a countermeasure against the power supply member 2 coming off, and by applying a force in the F direction to the elastic portion 2-d due to the elasticity of the elastic portion 2-d, the power supply member 2 is pulled out (the direction of arrow J). It is also possible to easily remove the regulation.

When the power supply member 2 is locked to the frame body 19, the upper slope of the claw portion 2-e is slid on the G surface of the frame body 19 to elastically deform the elastic portion 2-d. Then, the power supply member 2 can be bonded to the frame body 19.

By adding the above configuration,
Not only the deformation of the heating element 1 due to the stress of the electric wire 18 can be prevented, but also the disconnection of the power supply unit 2 from the heating element 1 due to the stress of the electric wire 18 can be reliably prevented.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7
FIG. 8 is a perspective view of a joint between a heating element and a power supply member, and FIG. 8 is a perspective view of the power supply member.

In FIG. 6, reference numeral 21 denotes a recessed notch formed in the fixing device frame 19, and the end faces 19-b and 19-c of the notch 21 are formed on both side surfaces of the power supply member 2. Grooves 2-f corresponding to the rib shape are formed. Also, 1
9-a is the bottom surface of the notch portion 21, and this bottom surface 19-a
Serves as a positioning surface in the H direction when the power supply member 2 is dropped in the cutout portion 21 in the direction of the arrow H in the figure. or,
The longitudinal direction of the heating element (the direction perpendicular to the H direction) is also regulated by the groove 2
This is done by engaging -f with the notch 21.

In the above structure, the power supply member 2
Considering the detachability of the power supply member 2, it is desirable that the inserting direction and the dropping direction (H direction) of the power supply member 2 into the heating element are the same.

By adopting the above-mentioned structure, the same effect as that of the above-mentioned embodiment can be obtained in preventing the deformation of the heating element due to the stress of the electric wire 18, and the shapes of the notch portion 21 and the power supply member 2 are changed. Since the simplification can be achieved, it is possible to obtain the effect that the positioning accuracy can be easily obtained.

By the way, as shown in FIG. 7, a flange portion 2a is formed on the power supply member 2 as a countermeasure against the power supply member 2 coming off the notch 21 in the dropping direction, and the flange portion 2a is screwed and inserted. The power supply member 2 may be fastened to the fixing device frame 19 with the screw 22.

Further, as shown in FIG. 8, not only the groove portions 2-f are provided on both side surfaces of the power supply member 2, but also the frame body positioning surface 19 for restricting the movement of the power supply member 2 in the dropping direction. -A groove (2) is also formed on the bottom surface that a
-G is provided, and the surface 2-h that abuts the side surface of the frame body 19 is shown in FIG.
In addition, as shown by the diagonal line, the restriction in the longitudinal direction of the heating element may be further strengthened by making it substantially U-shaped. In this regard, when the attachment / detachment direction of the power supply member 2 to / from the heating element is not the H direction in FIG.

[0045]

As is apparent from the above description, claim 1
According to the invention described above, since the bundle stress of the power supply wire is absorbed by the positioning portion of the fixing device frame, there is an effect that deformation of the heating element and disconnection of the power supply member from the heating element can be prevented. can get.

According to the second aspect of the invention, it is possible to more reliably fix the power supply member to the fixing device frame.

Further, according to the third aspect of the invention, since the positioning portion of the fixing device frame also serves as the engaging means, there is an effect that the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional view (cross-sectional view in the direction of arrow A in FIG. 2) of a joint between a heating element and a power supply member of a fixing device according to a first exemplary embodiment of the present invention.

FIG. 2 is a side sectional view of the fixing device according to the first exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view of a positioning portion of a power supply member of the fixing device according to the first exemplary embodiment of the present invention.

FIG. 4 is a cross-sectional view of a joint between a heating element and a power supply member of a fixing device according to a second exemplary embodiment of the present invention.

FIG. 5 is a cross-sectional view of a joint between a heating element and a power supply member of a fixing device according to a second exemplary embodiment of the present invention.

FIG. 6 is a perspective view of a joint portion between a heating element and a power supply member according to a third embodiment of the present invention.

FIG. 7 is a perspective view of a joint portion between a heating element and a power supply member according to a third embodiment of the present invention.

FIG. 8 is a perspective view of a power supply member according to a third embodiment of the present invention.

FIG. 9 is a sectional view of a joint between a heating element and a power supply member in a conventional fixing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating element 2 Power supply member 9 Fixing film 18 Power supply wire 19 Fixing device frame 19-a Positioning hole (positioning part) 20 Power supply part 21 Notch part (positioning part) 22 Screw P recording material

Claims (3)

[Claims] 1. A heating element that generates heat when energized and a power supply member that is attachable to and detachable from a power feeding portion of the heating element to supply power to the heating element, and slides on the surface of the heating element. In a fixing device for fixing unfixed toner to a recording material by heat from a heating element transmitted through a conveyed fixing film, a positioning portion for the power supply member is provided on a fixing device frame. Fixing device. 2. The fixing device according to claim 1, further comprising engaging means for fixing the power supply member and the fixing device frame to each other. 3. The fixing device according to claim 2, wherein the positioning portion of the fixing device frame also serves as the engaging means.