JP2001109298A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device capable of performing stable fixing operation. SOLUTION: This device has a pressure roller 120 press-contacting with a fixing roller 110 to be heated, and either the roller 110 or the roller 120 is driven and the other follows it. Then, recording material S where a toner image is formed is made to pass through the center part N1 of a press-contact part N so that the toner image is heated, melted and fixed on the material S. Cloth G having oil absorptivity is fixed at both ends of at least either of the rollers 110 and 120 in the peripheral direction thereof.

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 printer, a facsimile, a copying machine, etc., capable of forming a toner image on a recording material such as paper by using an electrophotographic technique. Relates to a fixing device using a heated fixing roller.

[0002]

2. Description of the Related Art In general, an image forming apparatus for forming a toner image on a recording material such as paper by using an electrophotographic technique includes a photoconductor which is driven to rotate, and an electrostatic latent image formed on the surface by exposing the photoconductor. Exposure means for forming an image, developing means for developing the electrostatic latent image into a toner image, transfer means for transferring the toner image to a recording material, and a recording material on which the toner image has been transferred by the transfer means And a fixing device for fixing the toner image on the recording material by heating while passing through the recording material.

A conventional general fixing device has a fixing roller to be heated and a pressing roller pressed against the fixing roller. The two rollers heat the recording material while pressing it while pressing the recording material. The toner image on the recording material is melted and fixed on the recording material. In such a fixing device, if there is a difference in peripheral speed between the two rollers, the toner image on the recording material passing through the pinching portion (pressing portion) is rubbed and the image is disturbed. It is not done to drive both, only one roller is driven,
The other roller is driven by this. Further, in order to prevent a phenomenon that the toner is transferred from the recording material to the surface of the roller (so-called offset phenomenon), a release oil such as silicone oil is applied as a release agent to at least one roller surface. A fixing device provided with a coating unit is also known.

[0004]

In the above-described conventional fixing device, when a relatively slippery recording material, for example, a synthetic resin sheet is supplied to a press-contact portion of two rollers of which only one is rotationally driven. , With the interposition of this slippery recording material,
Slip occurs between the driving roller and the recording material and / or between the recording material and the driven roller, thereby causing a peripheral speed difference between the driving roller and the driven roller, resulting in a stable There is a risk that the fixed fixing operation will not be performed. Further, in the fixing device in which the releasing oil is applied to the surface of the roller, the slip is promoted, and as a result, the fixing operation may become more unstable.
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems and to provide a fixing device capable of performing a stable fixing operation.

[0005]

According to one aspect of the present invention, there is provided a fixing device comprising: a fixing roller to be heated;
And a pressure roller pressed against the fixing roller. One of the two rollers is driven, the other is driven, and the recording material on which the toner image is formed is passed through the center of the pressure contact portion between the two rollers. A fixing device for heating and melting the toner image to fix the toner image on a recording material, wherein a cloth is fixed to both ends of at least one of the two rollers along a circumferential direction thereof. And

[0006]

According to the fixing device of the present invention, the recording material on which the toner image is formed passes through the center of the pressure contact portion between two rollers, one of which is driven and the other of which is driven, so that the recording material has the above-mentioned structure. The toner image is heated and melted and fixed on the recording material. Since the cloth is wound and fixed to both ends of at least one of the two rollers, a high grip portion for the other roller is formed by the cloth at both ends of the roller. It will be. Therefore, a relatively slippery recording material is supplied to the central portion of the pressure contact portion between the two rollers, and the interposition of the slippery recording material allows the recording material to be driven between the drive-side roller and the recording material. Even if a slip is likely to occur between the rollers on the drive side and the rollers on the drive side, the followability of the rollers on the driven side is improved by the action of the high grip portion, and both rollers rotate at substantially the same peripheral speed. Will be done. For this reason, the above-mentioned slip is prevented (at least hardly occurs), and as a result, a stable fixing operation is performed. Therefore, the toner image on the recording material is hardly rubbed, and the image is hardly disturbed. Further, since the high grip portion is formed of cloth, the surface of the high grip portion has fine irregularities due to the thread (woven or knitted thread) forming the cloth. The surface is almost uniformly spread on the surface. Therefore, the vibration and speed fluctuation generated by the drive transmission at both ends of the roller are extremely reduced,
As a result, smooth drive transmission is achieved.
In addition, since the unevenness is formed of a thread, the convex portion is rounded. Therefore, stress concentration in the roller pressed against the cloth is reduced, and the durability of the roller is improved. Furthermore, the high grip portion is superior in strength (particularly, strength against shearing force) as compared with a case where the high grip portion is made of, for example, a rubber member having irregularities. That is, when the high grip portion is made of, for example, a film or a rubber member, when a shear force is applied to the edge portion, first, a crack is formed in the edge portion, and then this propagates and expands rapidly. If the high grip part is made of cloth, it will tear, but if the fiber in the edge part cracks and breaks, this break will not propagate and one fiber break Therefore, the strength is also excellent. In addition, since the high grip portion can be configured by simply fixing a cloth to both ends of the roller along the circumferential direction, for example, the end of the roller itself is processed so as to be a high grip portion. The manufacturing of the roller is simpler than in the case where the roller is used.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 shows a first embodiment of a fixing device according to the present invention.
FIG. 2 is a schematic side view showing a main part of the embodiment, and FIG.

The fixing device 100 has a fixing roller 110 to be heated and a pressure roller 120 pressed against the fixing roller 110, and a recording material S on which a toner image T is formed is indicated by an arrow S1. Thus, the toner image T is heated and melted and fixed on the recording material S by passing through the central portion N1 of the pressure contact portion N between the fixing roller 110 and the pressure roller 120.

The fixing roller 110 includes a pipe-shaped core material 111 having excellent thermal conductivity, an elastic layer 112 provided on the surface of the core material 111, and a recording material formed on the surface of the elastic layer 112. A halogen lamp 113 serving as a heat source is disposed inside the core material 111. Fixing roller 110
Is a side plate (not shown) of the frame 101 of the fixing device 100
, And is rotatably driven in a direction indicated by an arrow in FIG. 1 by driving means provided in an image forming apparatus main body (not shown).

The pressure roller 120 has a hollow drum-shaped core material 121 having excellent heat conductivity, an elastic layer 122 provided on the surface of the core material 121, and a pressure roller 120 formed on the surface of the elastic layer 122. And a surface layer 122a having excellent releasability from the recording material and the toner. The pressure roller 120 is pressed against the fixing roller 110 by an appropriate urging means 123 and is driven to rotate. Reference numeral 124 denotes a shaft of the pressure roller 120.

Although not shown, a recording material S on which a toner image T is formed (transferred) by a transfer unit of an image forming apparatus is placed on a frame 101 at a pressure contact portion (nip portion) N between a fixing roller 110 and a pressure roller 120. A guide 102 is provided for guiding.

Reference numeral 130 denotes an oil application roller as oil application means, which applies a release oil to the surface of the fixing roller 110. Oil application roller 130
Is a shaft 131 and an oil holding layer 1 made of a thick porous material or a fibrous material fixed around the shaft 131.
32. The oil holding layer 132 is impregnated with a release oil, and the surface thereof is covered with an oil-permeable thin film sheet, such as a porous PTFE sheet 133, for achieving a uniform oil application amount. . The oil application roller 130 is pressed against the fixing roller 110 by an appropriate urging means 134 and is driven to rotate.
A release oil such as silicone oil is applied to the surface of the substrate. Note that the oil application roller 130 is a fixing roller 110
It is desirable that the length be shorter than that of the recording material S so that the oil is applied only to the area where the recording material S passes.

The feature of this embodiment is that at least one of the two rollers, ie, the fixing roller 110 and the pressing roller 120, is provided at both ends (only one end is shown in FIG. 2) along the circumferential direction. G is fixed. In this embodiment, the cloth G is provided at the end of the fixing roller 110 as shown in FIG. 2, but the cloth G may be provided on the pressing roller 120, or the fixing roller 110, the pressing roller 120 may be provided. Note that, instead of the fixing roller 110, the pressure roller 120 may be a driving roller.

FIG. 3A is an exploded perspective view of an end of the fixing roller 110, and FIG. 3B is a perspective view of the end. 4A is a partially omitted sectional view of the fixing roller 110 (a sectional view taken along line IVa-IVa in FIG. 3B), and FIGS. 4B and 4C are partially enlarged views of FIG.

As shown in FIG. 4, the cloth G has a weft 114a.
Woven or knitted with the warp 114b, and also includes a fine mesh. Further, as described later, a nonwoven fabric as shown in FIG. 5 is also included. Thread (weft and warp) 11
4 may be composed of a single wire (for example, a so-called monofilament) as shown in FIG. 4B, or an aggregate (for example, a so-called multifilament) of a plurality of fine wires 114c as shown in FIG. 4C. You may comprise. In any case, as a material of the thread 114, aramid, polyimide, glass fiber, PET (polyethylene terephthalate), or the like can be used. As shown in FIG. Even in this case, since the oil can be held in the gap C1 between the thread bodies 114, the cloth G has oil absorbency. However, as shown in FIG. If it is constituted by an aggregate, the oil will be absorbed inside the thread 114 itself. Therefore, in order to enhance the oil absorbency, it is desirable that the thread 114 be constituted by an aggregate of a plurality of fine wires. It is desirable that at least one of the weft thread 114a and the warp thread 114b be formed of an aggregate of a plurality of fine wires.
Further, since the gap C1 communicates with the roller in the roller circumferential direction (the direction perpendicular to the plane of FIG. 4), the cloth G has oil fluidity in the roller circumferential direction. As the cloth G, a nonwoven cloth (for example, Nomek nonwoven cloth) as shown in FIG. 5 can be used. The nonwoven fabric also has oil absorbency and oil fluidity in the roller circumferential direction. In FIGS. 4 and 5, reference numeral 115 denotes the cloth G
10 is an adhesive layer (for example, an adhesive) fixed to 10. In this embodiment, as shown in FIG. 3A, a state in which the cloth G formed in advance in a ring shape is slightly wider than the outer diameter of the fixing roller 110 by using its elasticity (expansion and contraction). Then, the cloth G is fixed to the end of the fixing roller 110 via an adhesive layer 115 (not shown in FIG. 3) as shown in FIG. It is fixed to the end of the roller 110.

According to the fixing device 100 of this embodiment, the following operational effects can be obtained. (A) The recording material S on which a toner image has been formed is formed by pressing a fixing roller 110, which is driven and driven by the other, and a pressing roller 120 pressed against the fixing roller 110 at a central portion of a pressing portion N. By passing through N1, the toner image is heated and melted and fixed on the recording material S.
Since a high grip member G in the form of a tape is wound and fixed to both ends of the fixing roller 110,
At both ends of the fixing roller 110, a high grip portion (G) for the pressing roller 120 is formed. Therefore, the relatively slippery recording material S is supplied to the central portion N1 of the pressure contact portion N between the fixing roller 110 and the pressure roller 120, and the driving side fixing roller 110 When the pressure roller 120 is a driving roller, the pressure roller 120 is applied between the pressure roller 120 and the recording material S and / or the recording material S and the driven pressure roller 120 on the driven side.
(If the pressure roller 120 is a driving roller and the fixing roller 110 is the same, the same applies to the following description.) Side pressure roller 1
20 is improved, and the fixing roller 110 and the pressure roller 120 rotate at substantially the same peripheral speed. For this reason, the above-mentioned slip is prevented (at least hardly occurs), and as a result, a stable fixing operation is performed. Therefore, the toner image on the recording material S is hardly rubbed, and the image is hardly disturbed. Further, since the high grip portion is formed of the cloth G, the surface G4 (see FIG. 4) of the high grip portion is formed into fine irregularities by the thread 114 forming the cloth. Is almost uniformly spread. Therefore, the vibration and the speed fluctuation generated by the drive transmission at both ends of the fixing roller 110 are extremely reduced, and as a result, the drive is smoothly transmitted. Further, since the irregularities are formed by the thread 114, the convex portions are rounded. Therefore, the pressure roller 120
Is reduced, and the durability of the pressure roller 120 is improved. Furthermore, the high grip portion is superior in strength (particularly, strength against shearing force) as compared with a case where the high grip portion is made of, for example, a rubber member having irregularities. That is, when the high grip portion G is made of, for example, a film or a rubber member, when a shearing force is applied to the edge, first, a crack is formed in the edge, and then the crack is rapidly propagated and expanded. If the high grip portion is made of cloth, the fiber (thread) 114 at the edge may crack and break,
Since this break does not propagate and is limited to one fiber break, the strength is also excellent. Moreover, the high grip portion is provided with the fixing roller 110.
(And / or the pressure roller 120; the same applies hereinafter) by simply adhering the cloth G along the circumferential direction at both ends thereof. The production of the fixing roller 110 is simplified as compared with the case where the fixing roller 110 is processed to be a part. (B) Since the oil applying means 130 for applying the release oil to the surface of the fixing roller 110 is provided, the offset phenomenon is less likely to occur. As described above, the fixing roller 1
If release oil is applied to the surface of the roller 10, the oil gradually enters the end portion N2 (see FIG. 2) of the pressure contact portion N between the fixing roller 110 and the pressure roller 120. However, according to the fixing device 100 of this embodiment,
A cloth G is provided on both ends of the fixing roller 110 along the circumferential direction thereof.
Is fixed, and the cloth G has an oil absorbing property, so that the oil that has entered the end portion N2 of the press-contact portion is absorbed by the cloth G. Therefore, the amount of oil existing on the surfaces of both ends of the fixing roller 110, that is, the surface G4 of the cloth G forming the high grip portion is small, and as a result, the grip force at both ends N2 of the press contact portion is secured, and the slip is prevented. Is performed (at least hardly occurs), and a stable fixing operation is performed. That is, the fixing device 1 of this embodiment
According to 00, it is possible to obtain a stable fixing operation even though the releasing oil is applied to the surface of the fixing roller 110. (C) Since the cloth G has oil fluidity in the circumferential direction of the roller, even if the cloth G is saturated with oil, the oil absorbed in the cloth G remains in the pressing portion. N2
In the case of, the pressing force causes the roller to be removed to a portion other than the pressing portion N2 in the circumferential direction of the roller.
Therefore, even if the cloth G becomes saturated with oil, the amount of oil existing on the surface G4 of the cloth G forming the high grip portion at both ends of the fixing roller 110 becomes small in the press contact portion, and as a result, As a result, the gripping force at both ends N2 of the press contact portion is ensured, the above-mentioned slip is prevented (at least hardly to occur), and a stable fixing operation is performed.

<Second Embodiment> FIGS. 6 and 7 show a main part of a second embodiment of a fixing device according to the present invention. FIG. 6A is a partial perspective view of a fixing roller 110. FIG. 7B is a front view of the cloth G, and FIG. 7A is VIIa-VI in FIG.
It is Ia sectional drawing. This embodiment is different from the first embodiment in that a tape-shaped cloth G as shown in FIG. 6B is attached to the end of the fixing roller 110 as shown in FIG. It is wrapped along the circumferential direction with an adhesive 115 (see FIG. 4) and fixed with the adhesive 115, and the other points remain the same. In this embodiment, FIG.
(A) and FIG. 7 (a), the tape-shaped cloth G
Is wound and fixed so that the winding start end G1 and the end G2 do not overlap. Therefore, a small gap L is formed between the winding start end G1 and the winding end G2. Shorter than the length in the direction). FIG.
As shown in (b), the winding start end G1 and the end G2.
May be wound so as to overlap with each other, but in this case, the winding start end G1 and the end G
2 becomes thicker, so that the overlapping portion G3
The speed of the driven pressure roller 120 may fluctuate between the time when the pressure roller 120 is in pressure contact with the pressure roller 120 and the other time.
20, the stress concentrates on the pressure roller 120 at a portion facing the overlapping portion G3, and the pressure roller 1
This is not desirable because the durability of the No. 20 may decrease. According to this embodiment, the following operation and effect can be obtained in addition to the operation and effect obtained by the first embodiment. In other words, since the high grip portions at both ends of the fixing roller 110 can be formed simply by winding the tape-shaped cloth G around the both ends of the fixing roller 110 and fixing the same, manufacturing of the fixing roller (and thus manufacturing of the fixing device) is possible. Becomes even easier.

<Third Embodiment> FIGS. 8A and 8B show a main part of a fixing device according to a third embodiment of the present invention. FIG. 8A is a partial front view of a fixing roller 110, and FIG. Is a development view of the tape-shaped cloth G. In FIG. 8, the same or corresponding portions as those in the second embodiment are denoted by the same reference numerals. This embodiment differs from the second embodiment in that the winding start end G1 and the end G2 of the tape-shaped cloth G are inclined to face each other. No change. That is, the winding start end G1 and the end G2 of the tape-shaped cloth G in this embodiment.
Is not parallel to the axial direction of the fixing roller 110. According to this embodiment, the following operation and effect can be obtained in addition to the operation and effect obtained by the second embodiment. That is, if the winding start end G1 and the end G2 of the tape-shaped cloth G are not inclined, the gap L formed between the start end G1 and the end G2 is a pressure roller. The speed of the driven pressure roller 120 may fluctuate between the time when the pressure roller 120 is in contact with the pressure roller 120 and the other time. For example, if the gap L in the second embodiment is longer than the circumferential length of the pressure contact portion N between the fixing roller 110 and the pressure roller 120, the above-described speed fluctuation may occur. It grows. On the other hand, according to the third embodiment, the winding start end G1 and the end G2 of the tape-shaped cloth G are wound.
Are inclined in opposition to each other, so that the driven pressure roller 120 is less likely to fluctuate in speed.

<Fourth Embodiment> FIGS. 9A and 9B show a main part of a fourth embodiment of a fixing device according to the present invention. FIG. 9A is a partial plan view of the fixing roller 110, and FIG. It is bb sectional drawing in figure (a). In FIG.
The same reference numerals are given to the same or corresponding parts as in the embodiment. The feature of this embodiment is that cloth G is
The point is that it is fixed to both ends of the roller through an adhesive layer (for example, a silicone rubber layer) 116 having oil permeability and having oil absorbency. The non-woven fabric shown in FIG. 5 may be fixed to both ends of the roller via the adhesive layer 116. According to this embodiment, the oil that has entered the end portion N2 of the press contact portion N is absorbed by the adhesive layer 116 via the cloth G. Therefore, the amount of oil existing on the surface G4 of the both ends of the fixing roller is further reduced, and as a result, the grip force at both ends of the press contact portion is sufficiently ensured, and the slip is prevented (at least significantly less likely to occur). Thus, a more stable fixing operation is performed.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be appropriately modified within the scope of the present invention.

[0021]

According to the fixing device of the first aspect, a stable fixing operation can be performed. In addition to smooth drive transmission, the durability of the rollers has been improved,
Excellent in strength and easy to manufacture.

[0022]

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a main part of a first embodiment of a fixing device according to the present invention.

FIG. 2 is a schematic front view partially omitted.

FIG. 3A is an exploded perspective view of an end of a fixing roller 110,
(B) is a perspective view of the end.

4A is a partially omitted sectional view of a fixing roller 110 (a sectional view taken along line IVa-IVa in FIG. 3B), and FIG.
(C) is a partial enlarged view of FIG.

5A is a partially omitted cross-sectional view of the fixing roller 110 (a cross-sectional view taken along a line IVa-IVa in FIG. 3B), and FIG.
3 is a partially enlarged view of FIG.

FIG. 6 is a diagram showing a main part of a second embodiment of a fixing device according to the present invention, wherein (a) is a partial perspective view of a fixing roller 110,
(B) is a front view of the cloth G.

7A and 7B are diagrams showing a main part of the embodiment, wherein FIG. 7A is a cross-sectional view taken along the line VIIa-VIIa in FIG. 6, and FIG. 7B is a cross-sectional view in a state where a winding start end G1 and a terminal end G2 overlap.

FIG. 8 is a diagram showing a main part of a third embodiment of a fixing device according to the present invention, wherein (a) is a partial front view of a fixing roller 110,
(B) is a development view of the tape-shaped cloth G.

FIG. 9 is a diagram showing a main part of a fourth embodiment of a fixing device according to the present invention, wherein (a) is a partial plan view of a fixing roller 110;
(B) is a bb sectional view in (a) of FIG.

[Explanation of symbols]

 S Recording material 100 Fixing device 110 Fixing roller G Cloth 120 Pressure roller N Pressure contact portion N1 Central portion of pressure contact portion N2 End of pressure contact portion

Continued on front page F term (reference) 2H033 AA31 BA43 BB01 BB30 BB37 3J103 AA02 AA14 AA15 AA21 AA41 AA52 AA53 BA03 BA41 EA07 FA12 FA23 GA02 GA57 GA58 GA60 GA66 GA68 HA03 HA04 HA05 HA12 HA15 HA19 HA42 HA46

Claims (1)

[Claims] A recording material having a fixing roller to be heated and a pressing roller pressed against the fixing roller, wherein one of the two rollers is driven and the other is driven to form a toner image Through the center of the pressure contact part of both rollers,
A fixing device for heating and melting the toner image and fixing the toner image on a recording material, wherein a cloth is fixed to both ends of at least one of the two rollers along a circumferential direction thereof. Fixer.