JPH09258587A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device having high reliability at a low cost, and excellent functional peeling function. SOLUTION: On a heating material 14, a first large opening part 16 and a pair of second small opening parts 18 is bored. Both end sides of a fixing roller 20 formed in a thin circular tube shape, is inserted in the first opening part 16 while rotationally supported by the bearing material 14. From both end parts of the fixing roller 20, respective heaters 30 are inserted, and the fixing roller 20 is heated by heat generation of the heater 30. On a lower side of the fixing roller 20, a pressure roller 34 made of a silicone rubber is disposed. On both ends of a guide member 22, side plates 24 are arranged, a pair of projection parts 26 are planted on the side plate 24, the projection part 26 is inserted in the second opening part 18. The guide member 22, is provided with a supporting member 28 extending in the longitudinal direction for connecting between the side plates 24.

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 has a low cost, high reliability, and a high-performance peeling function.
It is applicable to a copying apparatus that fixes a toner image on copy paper.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a method of pressing a copy sheet against a photoconductor to transfer a toner image from the photoconductor onto the copy sheet has been used. Further, after the transfer of the toner image, the toner image is fixed on the copy sheet by a fixing roller and a pressure roller which constitute a fixing device in the image forming apparatus.

In this fixing device, when the unfixed toner on the copy sheet, which is a recording material, melts, the copy sheet is wrapped around the fixing roller by the adhesive force acting between the fixing roller and the copy sheet. In order to prevent this, a guide member is arranged near the fixing roller.

Further, although the guide member is arranged along the line extending parallel to the axial direction of the fixing roller while the tip portion thereof has a minute gap with the fixing roller, the guide member is composed of the fixing roller and the pressure roller. It was present on the pressure roller side with respect to the line extending in the normal direction of the straight line connecting the center of the fixing roller and the center of the pressure roller from the nip portion which is the contact portion.

[0005]

However, since the leading end portion of the guide member is arranged close to the fixing roller while having a minute gap in the fixing roller, the guide member must be installed accurately. The gap between the fixing roller and the tip of the guide member becomes narrow, and the guide member may come into contact with the fixing roller, damaging the fixing roller, or generating abnormal noise from the contact portion.

Further, parts such as brackets and springs for supporting the guide member are required, and the number of parts is increased, resulting in an increase in manufacturing cost.

Further, since both end portions of the leading edge of the copy sheet passing through the fixing roller are more difficult to separate from the fixing roller than the central portion of the leading edge of the copy sheet, both end portions of the leading edge of the copy sheet are guided by the guide member. It was caught or damaged and caused a paper jam.

The present invention has been made in view of the disadvantages of the prior art, and an object of the present invention is to provide a fixing device having a low cost, high reliability, and a high-performance peeling function. .

[0009]

According to a first aspect of the present invention, there is provided a fixing device which is heated by a heat source and driven and rotated to fix a toner image on a fixing material, and the fixing material is pressed against the fixing roller. Pressure roller, a bearing material having a first hole portion and a second hole portion and supporting the fixing roller in the first hole portion, and a convex portion having a convex portion in the second hole portion. And a guide member in which the portion is inserted and supported by the bearing material.

A fixing device according to a second aspect of the present invention is the fixing device according to the first aspect, wherein the position for forming the second hole on the bearing material is determined with reference to the first hole.

A fixing device according to a third aspect of the present invention is the fixing device according to the first aspect, wherein both end portions of the tip end portion of the guide member are located downstream of the central portion of the tip end portion of the guide member in the conveyance direction of the material to be fixed. It is characterized by that.

A fixing device according to a fourth aspect is the fixing device according to the first aspect, in which the material to be fixed is fixed at an angle of 30 ° to 45 ° with respect to the tangent line of the fixing roller in the portion facing the tip of the guide member. It is characterized in that an abutting surface of a guide member for guiding the material to be fixed is formed in a shape inclined to the passing side.

The operation of the fixing device according to the first aspect will be described below. A fixing roller heated by a heat source and driven to rotate heats a material to be fixed pressed against the fixing roller by a pressure roller to fix the toner image on the material to be fixed. At this time, the bearing material supports the fixing roller in the first hole portion, and also supports the guide member in which the convex portion is inserted in the second hole portion.

Therefore, since the guide member is also supported by the bearing material that supports the fixing roller, the guide member is positioned with respect to the fixing roller with high accuracy, and the guide member does not come into contact with the fixing roller. This will prevent scratches and noise from coming out of the contact area.

Further, since the bearing material supports not only the fixing roller but also the guide member, parts such as brackets and springs for supporting the guide member are not required, the number of parts is reduced and the manufacturing cost is reduced. Will be reduced.

Further, if the guide member is not arranged so as to extend toward the pressure roller side, the route of the material to be fixed after passing through the fixing roller is not restricted by the guide member.

As described above, the fixing device according to the first aspect has a low cost, high reliability, and a high-performance peeling function.

The operation of the fixing device according to the second aspect will be described below. This claim operates similarly to claim 1. However,
Since the present invention determines the position for forming the second hole on the bearing material with reference to the first hole, the first hole and the second hole are simply provided on the bearing material. Compared with the above, the guide member is more accurately supported by the bearing material, and damage to the fixing roller and generation of abnormal noise from the contact portion are more reliably prevented.

The operation of the fixing device according to the third aspect will be described below. This claim operates similarly to claim 1. However,
According to the present invention, since both end portions of the tip end portion of the guide member are located on the downstream side of the central portion of the tip end portion of the guide member in the conveyance direction of the material to be fixed, both end portions of the tip end of the material to be fixed having passed the fixing roller are The guide member ensures that the fixing roller is separated from the fixing roller, so that both end portions of the leading end are not damaged and a paper jam does not occur.

The operation of the fixing device according to the fourth aspect will be described below. This claim operates similarly to claim 1. However,
According to the present invention, a guide for guiding a material to be fixed into a shape inclined to a side through which the material to be fixed passes by an angle of 30 ° to 45 ° with respect to a tangent line of the fixing roller in a portion facing the tip of the guide member. Since the contact surface of the member is formed, the curled material is discharged from the fixing roller and is curled along the guide member, and the curl is corrected by contacting the contact surface of the guide member. Is reduced.

That is, according to the present invention, not only the fixing roller is not damaged but also the curl amount is reduced.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A fixing device according to a first embodiment of the present invention is shown in FIGS. 1 to 4, and the present embodiment will be described based on these drawings.

A visible image (toner image) is formed on the surface of a photosensitive drum (not shown), which is a photosensitive member, by the adhesion of toner serving as a developer, and a conveying roller (not shown) conveys a copy sheet P, which is a fixing material. The toner image is transferred onto the copy paper P. Then, the copy paper P is fed to the fixing device 10 of the present embodiment for heating the toner image and fixing it on the copy paper P.

The fixing device 10 is formed as shown in FIG. 1, and the main body case 12 constitutes the frame of the fixing device 10. As shown in FIGS. 1 and 2, a pair of plate-shaped bearing members 14 each having a square shape are arranged in the main body case 12 so as to face each other with a predetermined gap. .

Then, as shown in FIG. 3, this bearing material 1
A large first hole portion 16 is formed substantially at the center of the bearing 4, and a pair of second hole portions 18 that are each small are similarly formed in the bearing material 14. The positions of the pair of second hole portions 18 formed on the bearing material 14 are determined by the first hole portion 1
It is determined from dimensions such as the dimension X, the dimension Y, and the dimension Z as shown in FIG.

2 which is fitted in the first hole 16
Both ends of the fixing roller 20 having an outer diameter of 5 mm or less and formed in a thin circular tube shape are inserted into the first hole portion 16 and rotatably supported by the pair of bearing members 14.
In this rotatable state, the fixing roller 20 has the main body case 1
2 are arranged. Further, a transmission gear (not shown) is engaged with the fixing roller 20, and when the driving force is transmitted to the transmission gear from the outside, the fixing roller 20 is rotated with the rotation of the transmission gear. There is.

Further, heating elements 30 which are heat sources such as lamps are inserted from both ends of the fixing roller 20, and the fixing roller 20 is heated by the heating elements 30.
Is to be heated.

On the other hand, as shown in FIGS. 1 and 2, the fixing roller 20 has a cylindrical shape made of silicon rubber, which is a rubber material having a low hardness, so that the fixing roller 20 is wound around a supporting shaft 32 made of metal. The pressure roller 34 formed on the
It is arranged so as to extend parallel to the 0 axis direction.

Further, both ends of the support shaft member 32 are rotatably supported by U-shaped bearings 42 attached to the upper end portion of the coil spring 40. Therefore, the pressure roller 34 is elastically supported by the coil spring 40 via the bearing 42 and the support shaft member 32 while being pressed against the lower surface side of the fixing roller 20 by the coil spring 40. It can rotate integrally with the rotation.

On the other hand, side plates 24 are arranged at both ends of the guide member 22 shown in FIG. 4 for guiding the copy paper P, and a pair of pin-shaped convex portions projecting in the longitudinal direction of the guide member 22. 26 are planted in the pair of side plates 24, respectively. Then, these convex portions 26 are
The guide member 22 is supported by the bearing member 14 in a state where the guide member 22 is inserted between the pair of bearing members 14 and is inserted into the second hole 18 of the bearing member 14.

Further, the guide member 22 is the guide member 22.
Member 2 that extends along the longitudinal direction of the connection member and connects between the side plates 24
8, the guide member 22 is disposed between the pair of bearing members 14, and the tip end portion 28A formed at an acute angle of the support member 28 is disposed close to the fixing roller 20. become.

At this time, as shown in FIG. 1, the guide member 2
The second supporting member 28 includes a fixing roller 20 and a pressure roller 34.
From the nip portion N, which is the contact portion with the fixing roller 20, to the fixing roller 20 side than the straight line C extending in the normal direction of the straight line B connecting the center of the fixing roller 20 and the center of the pressure roller 34, The support member 2 of the guide member 22 is provided near the pressure roller 34 side.
8 is arranged without protruding.

Further, on the upstream side of the fixing roller 20 in the conveying direction of the copy sheet P, a pair of guide members 44 are provided.
A and 44B are arranged to face each other, and a pair of discharge rollers 46A and 46B for discharging the copy sheet P from the fixing device 10 are arranged in contact with each other on the downstream side in the transport direction of the copy sheet P. ing.

From the above, the pair of guide members 44A, 44B
When the copy sheet P on which the toner image is drawn is inserted between the fixing roller 20 and the pressure roller 34 of the fixing device 10 by being guided by the fixing roller 10, the coil spring 40 causes the fixing roller 2 to move.
0 and the pressure roller 34 are pressed against each other to sandwich the copy sheet P between the fixing roller 20 and the pressure roller 34, and as the rollers rotate, the copy sheet P is heated and the toner is transferred. Is fixed on the copy sheet P. After that, the sheet is guided by the guide member 22 and discharged by the pair of discharge rollers 46A and 46B.

Next, the operation of the present embodiment will be described. The fixing roller 20 which is heated by the heating element 30 and driven and rotated through the transmission gear heats the copy sheet P pressed against the fixing roller 20 side by the pressure roller 34 to form a toner image on the copy sheet P. Establish. At this time, bearing material 1
4 supports the fixing roller 20 whose both ends are respectively inserted into the first hole portion 16 with the first hole portion 16,
The guide member 22 into which the convex portion 26 is inserted is supported in the second hole portion 18.

Therefore, since the guide member 22 is also supported by the bearing material 14 that supports the fixing roller 20, the guide member 22 is positioned with respect to the fixing roller 20 with high accuracy. Therefore, the dimensional accuracy of the bearing member 14 and the guide member 22 determines the gap between the fixing roller 20 and the tip of the guide member 22, and the minute gap between them can be kept uniform, and the guide member 22 can be maintained. Does not come into contact with the fixing roller 20. As a result, the guide member 22
Does not damage the fixing roller 20 or generate abnormal noise from the contact portion.

Further, since the bearing member 14 supports not only the fixing roller 20 but also the guide member 22, parts such as brackets and springs for supporting the guide member 22 are not required, and the number of parts is reduced. Manufacturing cost is reduced.

Further, since the guide member 22 is not arranged so as to protrude toward the pressure roller 34 side, the fixing roller 2
The guide member 22 does not limit the path of the copy sheet P after passing 0.

From the above, the fixing device 1 according to the present embodiment
0 has a low cost, high reliability, and a high-performance peeling function.

On the other hand, since the position where the second hole 18 is formed on the bearing material 14 is determined with reference to the first hole 16, the first hole 16 and the second hole 18 are simply used as the bearing. Material 1
4, the guide member 22 has a bearing member 1
The fixing roller 2 is supported with higher precision with respect to the fixing roller 2
The damage of 0 and the generation of abnormal noise from the contact portion are more reliably prevented.

Next, a fixing device according to a second embodiment of the present invention is shown in FIGS. 5 and 6, and the present embodiment will be described based on these drawings. The same members as those in the first embodiment are designated by the same reference numerals, and duplicated description will be omitted.

The fixing device 10 of this embodiment has almost the same structure as that of the first embodiment, but FIGS.
As shown in, the end peeling portion 52 forming both end portions of the tip end portion 28A of the support member 28 constituting the guide member 22,
The support member 28 is positioned one step lower than the central portion of the front end portion 28A of the support member 28 on the downstream side of the copy sheet P in the transport direction indicated by the arrow A.

Therefore, this embodiment not only has the same effect as the first embodiment, but also copies both end portions of the tip portion 28A of the support member 28 from the central portion of the tip portion 28A of the support member 28. Since the sheet P is located on the downstream side in the conveying direction, the separation points of the copy paper P from the fixing roller 20 at both ends are slightly later than the central portion, and even at the both ends of the copy paper P having a weak stiffness, it is ensured. Be able to separate. Therefore, both end portions of the copy sheet P that have passed through the fixing roller 20 are reliably separated from the fixing roller 20, and neither end portion of the copy sheet P is damaged, resulting in no paper jam. Like

Next, a fixing device according to a third embodiment of the present invention is shown in FIGS. 7 and 8, and the present embodiment will be described based on these drawings. The same members as those in the first embodiment are designated by the same reference numerals, and duplicated description will be omitted.

The fixing device 10 of this embodiment has substantially the same structure as that of the first and second embodiments, but as shown in FIGS. The end peeling portion 54, which is both end portions of the front end portion 28A, is formed in a slope shape, and the end peeling portion is located downstream of the central portion of the front end portion 28A of the support member 28 in the transport direction of the copy sheet P indicated by the arrow A. The parts 54 are gradually displaced.

Therefore, this embodiment also has the same operation as that of the second embodiment.

Next, a fixing device according to a fourth embodiment of the present invention is shown in FIGS. 9 and 10, and the present embodiment will be described with reference to these drawings. The same members as those in the first embodiment are designated by the same reference numerals, and duplicated description will be omitted.

As shown in FIGS. 9 and 10, the fixing device 10 according to the present embodiment has a fixing roller 20 and a pressure roller 3.
4, the copy paper P is provided on the downstream side in the transport direction of the copy paper P.
A pair of guide members 62 and 64 are arranged with the transport path 66 of the pair of guide members 62 and 64 interposed therebetween.
46B is arranged.

The angle θ with respect to the straight line B connecting the center of the fixing roller 20 and the center of the pressure roller 34 is 45 °.
At a position inclined by an angle of ~ 55 °, the fixing roller 20
The front end portion 62A of the upper guide member 62 corresponding to is arranged.

Further, as shown in FIG. 10, the guide member 62
Of the fixing roller 20 in the portion facing the front end portion 62A of the
The contact surface 62B of the guide member 62 is formed in a shape in which the angle α with respect to the tangent line D of the guide member 62 is inclined by the angle of 30 ° to 45 ° toward the transport path 66 through which the copy sheet P passes.
The contact surface 62B contacts the copy sheet P and the copy sheet P
Will lead to. Further, the dimension E representing the length of the contact surface 62B has a value between 5 mm and 10 mm.

From the above, the contact surface 62B of the guide member 62 for guiding the copy paper P is formed in a shape inclined to the side where the copy paper P passes by an angle of 30 ° to 45 ° with respect to the tangent line D of the fixing roller 20. Since the formed copy sheet P is discharged from the fixing roller 20 and conveyed along the guide member 62, the copy sheet P comes into contact with the contact surface 62B of the guide member 62 to correct the curl, and the curl amount is reduced. Will be reduced.

Specifically, when the curl amount immediately after being ejected from the fixing roller 20 and the curl amount after 5 minutes from the ejection were measured, the values shown in Table 1 below were obtained.

Here, the current products in Table 1 are those of the prior art, and the countermeasure products are those of this embodiment. The unit of the numerical value in each column is mm, LL represents the left end of the copy sheet P, LR represents the right end of the copy sheet P, and TL represents the left end of the rear end of the copy sheet P. TR represents the right side of the trailing edge of the copy sheet P.

[0054]

[Table 1]

In the above embodiment, the bearing material 14 may be made of steel such as stainless steel.
The bearing material 14 may be made of resin. In addition, the guide member 2
The material of 2, 62, 64 may be a resin material, for example, but may be made of metal such as stainless steel or aluminum.

Further, although the second hole portion of the bearing material 14 is a pair in the above embodiment, it may be one, for example.
Also, a plurality of three or more may be used.

[0057]

As described above, according to the fixing device of the present invention, it is possible to obtain the effects of low cost, high reliability, and a high-performance peeling function.

[Brief description of drawings]

FIG. 1 is a sectional view of a fixing device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the inside of the fixing device according to the first embodiment of the present invention.

FIG. 3 is a front view of a bearing material applied to the fixing device according to the first embodiment of the invention.

FIG. 4 is a perspective view of a guide member applied to the fixing device according to the first embodiment of the present invention.

FIG. 5 is a perspective view of a fixing roller and a guide member applied to the fixing device according to the second embodiment of the present invention.

FIG. 6 is a plan view of a guide member applied to a fixing device according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a fixing roller and a guide member applied to a fixing device according to a third embodiment of the present invention.

FIG. 8 is a plan view of a guide member applied to a fixing device according to a third embodiment of the present invention.

FIG. 9 is a schematic sectional view of a fixing device according to a fourth embodiment of the present invention.

FIG. 10 is an enlarged view of a main part of a fixing device according to a fourth embodiment of the present invention.

[Explanation of symbols]

 10 Fixing Device 14 Bearing Material 20 Heating Roller 22 Guide Member 30 Heating Element (Heating Source) 34 Pressure Roller P Copy Paper (Fixed Material)

Claims (4)

[Claims] 1. A fixing roller that is heated by a heat source and is driven and rotated to fix a toner image on a material to be fixed; a pressure roller that presses the material to be fixed to the fixing roller; a first hole portion; It has a second hole and has a first fixing roller.
And a guide member having a convex portion and having the convex portion inserted into the second hole portion and supported by the bearing material. 2. A second bearing on the bearing material with reference to the first hole.
The fixing device according to claim 1, wherein a position for forming the hole portion of the fixing device is determined. 3. The fixing device according to claim 1, wherein both end portions of the tip end portion of the guide member are located on the downstream side of the central portion of the tip end portion of the guide member in the conveyance direction of the material to be fixed. 4. A guide member which guides a material to be fixed in a shape inclined by 30 ° to 45 ° with respect to a tangent line of the fixing roller in a portion facing the tip of the guide member. 2. The fixing device according to claim 1, wherein a contact surface of the fixing device is formed.