JPH01101574A - Fixing device for image forming device - Google Patents

Abstract

PURPOSE:To effectively prevent the periphery of a rotor from being damaged by a paper peeling edge by optionally reciprocating a weight for exciting and abutting the paper peeling edge on the periphery of a rotor along a guide groove. CONSTITUTION:The weight 11 for exciting and abutting the paper peeling edge (e) on the periphery of the rotor is optionally reciprocated along the guide groove 34. When an excessive load is applied to the tip side of a paper peeling claw 33 by paper stuck to the peripheries of the rotors 24, 27, the claw 33 is separated from the peripheries of the rotors and freely oscillated, so that the peripheries of the rotors 24, 27 can be prevented from being engaged with the edge (e). When the claw 33 is slightly rocked, the value of the weight W applied to the claw 33 is extremely reduced, so that the rock of the claw 33 is reduced. Thus, the generation of paper jam or accordion jam between the claw 33 and the peripheries of the rotors 24, 27 can be prevented and the peripheries of the rotors can be prevented from being damaged by the paper peeling edge.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a fixing device installed in an image forming apparatus such as an electrostatic photocopier or a facsimile machine, and more specifically, the present invention relates to a fixing device installed in an image forming apparatus such as an electrostatographic copying machine or a facsimile machine. This invention relates to improvements in techniques for peeling off adhered paper.

[Conventional technology]

As a fixing device of the above-mentioned image forming apparatus, for example, JP-A-59
As seen in Japanese Patent Application No. 204072 and also shown in FIG. The fixed paper that has adhered to the fixing rotary body 41 is transferred to the rotary body 41 for fixing.
The contact point Q of the paper peeling edge h of the paper peeling claw 43 for peeling the paper from the circumferential surface of the rotary body S
, and is provided so as to be swingable around the axis P on the side of the rotating body rather than the tangent R+ passing through , and the paper peeling edge h is provided so as to be biased into contact with the circumferential surface Sl of the rotating body by a spring 44. .

According to the fixing device configured as described above, when the paper after fixing adheres to the circumferential surface S1 of the fixing rotary body 41 on the upper side, the paper is scooped up by the paper peeling claw 43 and the paper is removed from the circumference of the rotary body. Since the sheet is peeled off from the surface S, it is possible to effectively prevent the so-called wrapping jam of the paper between the surfaces of the rotating body.

Alternatively, the paper may enter between the paper peeling claw 43 and the circumferential surface S of the rotating body, or the leading edge of the paper attached to the circumferential surface Sl of the rotating body may strongly press against the paper peeling edge h of the paper peeling claw 43. If an excessive load is applied to the tip side of the paper stripping claw 43, the paper stripping claw 4
3 is able to swing freely around the axis P on the side of the rotating body rather than the tangent line R1 passing through the contact point Q1, so that the paper peeling edge h of the paper peeling claw 43 moves away from the circumferential surface S1 of the rotating body due to the action of the above-mentioned load. As shown in FIG. 10, the spring 44 against the paper peeling claw 43
When the biasing point Q exceeds the Punto point line V, the paper peeling claw 43 rotates and the rotating body circumferential surface S
, the paper peeling edge h is prevented from digging into the circumferential surface S1 of the rotating body.

[Problem that the invention seeks to solve]

However, since the configuration is such that the biasing force of the spring 44 increases sequentially until the biasing point Q2 of the spring 44 crosses the dead point line V, smooth rocking of the paper peeling claw 43 is expected. If the paper is strongly jammed between the paper peeling claw 43 and the circumferential surface S1 of the rotating body, or the above-mentioned upper and lower There is a drawback that the paper that is forcibly ejected by the fixing rotary bodies 41 and 42 jams in an accordion shape near the tip of the paper peeling claw.

Moreover, if the biasing point Q2 of the spring 44 exceeds the dead point line (2), the paper peeling claw 4
No. 3 completely misses the paper peeling function, making it impossible to complete the paper peeling process afterward. Therefore, a mechanism for detecting such a state is provided, and the paper is removed based on information from the mechanism. It is necessary to perform an operation to return the peeling claw 43 to its initial state, resulting in a disadvantage that it takes time to resume operation and leads to an increase in cost.

The present invention has been made in view of the above circumstances, and
It is an object of the present invention to provide a fixing device which is an extremely simple improvement and which eliminates the above-mentioned drawbacks at once.

[Means for solving problems]

To achieve the above object, the fixing device of the image forming apparatus according to the present invention includes a paper peeling claw for peeling the paper attached to the circumferential surface of the fixing rotary body from the circumferential surface of the rotary body. The edge is provided so as to be swingable around an axis on the side of the rotor with respect to a tangent passing through a point of contact with the circumferential surface of the rotor, and the guide end near the horizontal line passing through the rocking axis and on the downstream side in the paper ejection direction is A guide groove located slightly below the guide end near the swing axis is formed in the paper peeling claw, and a weight is provided in the guide groove to bias the paper peeling edge into contact with the circumferential surface of the rotating body. It is unique in that it can be moved back and forth along the line.

[Effect]

According to the above characteristic structure, when an excessive load is applied to the tip end of the paper m1iil claw, the paper peeling claw can swing freely around the axis on the side of the rotating body rather than the tangent passing through the contact point. As in the conventional art, the paper peeling edge of the paper @ separation claw swings freely to escape from the circumferential surface of the rotating body due to the action of the above-mentioned load.

A weight is used to force the paper peeling edge of the paper peeling claw into contact with the rotating body, and the weight is positioned near the horizontal line, so that the paper peeling claw can move around the rotating body. When swinging away from the surface, the biasing force of the weight applied to the paper peeling claw hardly changes, or if the weight is positioned above the horizontal line, the biasing force decreases. and
Moreover, when the paper peeling claw moves slightly in the direction of separation,
Since the weight moves toward the swing axis along the guide groove, the biasing force of the weight applied to the paper peeling claw is extremely reduced.

As a result, excessive load may be applied to the tip side of the paper peeling pawl due to the paper being strongly pressed against the tip side of the paper peeling pawl or the paper getting stuck between the paper peeling pawl and the circumferential surface of the rotating body. In this case, although a predetermined urging force is exerted to force the paper peeling edge into contact with the circumferential surface of the rotating body at the initial stage of the swing, the paper peeling claw is then easily oscillated away from the circumferential surface of the rotating body. This prevents the paper from being strained, and therefore prevents the paper from jamming like an accordion or jamming. There is no possibility of a strong jam between the Ij release claw and the circumferential surface of the rotating body, and
As the paper moves downstream in the paper ejection direction as the paper peeling claw swings, the occurrence of a jam itself is suppressed.

Then, the paper passes through the paper peeling claw, etc.
When the load on the paper stripping claw is removed, the paper stripping claw returns to the initial paper stripping position and swings.
Since the weight is located near the swing axis in the range near the end of the swing, the biasing force of the weight applied to the paper peeling claw is small until near the end of the swing. And, by the subsequent return swing of the paper peeling claw, the weight moves to the guide end on the downstream side in the paper ejection direction, so that a predetermined biasing force is applied to the paper peeling edge of the paper peeling claw. Since the application of this biasing force is delayed by the return swing of the paper peeling claw to the initial paper peeling posture, the paper peeling edge of the paper peeling claw comes into soft contact with the circumferential surface of the rotating body, and then A predetermined biasing force is applied to the paper peeling edge, thereby effectively preventing the peripheral surface of the rotating body from being damaged by the paper peeling edge of the paper peeling claw.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 2 shows an electrostatographic copying machine as an example of an image forming apparatus, in which a photoreceptor 3 is placed horizontally on an apparatus main body 2 having a document presser 1 on the top. At the same time, a charging device 4, a developing device 5, a transfer device 6, a paper separating device 7, and a cleaning device 8 are arranged around the photoconductor 3 in that order in the rotational direction of the photoconductor 3, and An exposure device 9 with a movable optical system is provided in the upper space of the main body 2, and a manual feed section 10 or a cassette case 1 is provided.
A paper feed conveyance device 12 that conveys the paper a from 1, a paper discharge conveyance device 14 that conveys the separated paper to the fixing device 13, and paper discharge rollers 16 and 17 that discharge the fixed paper to the tray 15. It consists of a pair of

The fixing device 13 and the paper ejection rollers 16 and 17 are unitized and can be inserted into and removed from the apparatus main body 2, and are configured as follows.

That is, as shown in FIG. 1, an upper fixing case 21 is pivotally connected to a lower fixing case 19 mounted on a unit receiver 18 on the apparatus main body side via a support shaft 20 of a lower paper ejection roller 17. At the same time, a rotary body 24 for heat fixing on the upper side (for example, a roller body 22 made of metal such as aluminum coated with fluorine thread resin on the circumferential surface and a heater 23 built in) 24 and a rotary body 24 on the upper side The paper discharge roller 16 is pivotally mounted to the upper fixing case 21, and the lower pressure fixing rotating body (for example, a thick elastic cylinder 25 made of silicone rubber or the like is replaced with a roller body made of metal such as aluminum). A pair of upper and lower paper ejection guides 28 are provided between the pair of fixing rotating bodies 24 and 27 and the paper ejection rollers 16 and 17. .2
9, and a paper peeling device 30 for peeling off the paper from the circumferential surface S of the rotary body when the fixed paper adheres to the circumferential surface S of the rotary body 24 on the upper side. It is provided in the lower fixing case 19.

Next, the specific structure of the paper peeling device 30 will be explained. As shown in FIG. Openings 31 are formed at predetermined intervals in the direction (the axial direction of the rotating body 24, 27), and the openings 3
Brackets 32 are erected on both sides of the rotary body 1, and the edge e on the lower end of the swing comes into contact with the circumferential surface S of the fixing rotary body 24, thereby peeling off the paper attached to the circumferential surface S of the rotary body. The pawl 33 is pivotally attached to the bracket 32, and the swing axis P of the paper peeling pawl 33 is set from a tangent R passing through the contact point Q of the paper peeling edge e of the paper peeling pawl 33 with the circumferential surface S of the rotating body. is also set to be located on the rotating body 24 side, and a long hole is provided in the paper peeling claw portion near the horizontal line T passing through the swing axis P and immediately downstream of the swing axis P in the paper ejection direction. A guide groove 34 of the structure is formed.

More specifically, the guide groove 34 has a long hole configuration.
An extension line U of the axis of the long hole 4 passes through the swing axis P, and the guide end C on the downstream side in the paper ejection direction is located slightly lower than the guide end d near the swing axis P. In the embodiment, the angle between the horizontal line T and the extension line U is set to about 5 degrees.

A weight W is provided that can freely move back and forth along the guide groove 34 having the above structure, so that the paper stripping edge e of the paper stripping claw 33 is forced into contact with the circumferential surface S of the rotating body.

The lower edge f of the paper peeling claw 33 is slightly curved upward, and a stopper g is provided on the upper side of the curved edge f and near the paper peeling edge e, with which the leading edge of the paper comes into contact. has been formed.

Further, when the paper IMiII claw 33 swings greatly in the direction away from the circumferential surface S of the rotating body and the paper peeling edge e of the paper peeling claw 33 is pulled out from the upper paper ejection guide 28, A stopper 35 is provided in the main body 2 of the apparatus to prevent the paper peeling claw 33 from swinging as described above.

According to the above configuration, the weight W is moved by its own weight to the guide end C of the guide groove 34 on the downstream side in the paper ejection direction.
By being located at , a large urging force by the weight W is applied to the paper peeling edge e of the paper peeling claw 33, so that when the fixed paper adheres to the circumferential surface S of the rotating body, the The paper is peeled off from the rotating body circumferential surface S so as to be picked up by the paper peeling edge e, and the paper is moved along the lower curved edge f of the paper peeling claw 33 to the upper and lower paper discharge guides 28. The paper is ejected during the .29 period.

Then, if the leading edge of the paper after fixing strongly presses against the paper peeling edge e of the paper peeling claw 33, the paper peeling claw 33 moves around the swing axis P by receiving the load of the pressing. Then, the paper is swung in a direction away from the circumferential surface S of the rotating body, and the paper is ejected toward the pair of paper ejection rollers 16 and 17 together with the paper peeling claw 33.

On the other hand, as shown in FIG. 4, if a part of the paper a after fixing in the width direction enters between the paper peeling claw 33 and the circumferential surface S of the rotating body, the remaining part of the paper a As the portion of the paper a is peeled off from the circumferential surface S of the rotating body by the other paper peeling claw 33, the part of the paper a is pulled in the paper ejection direction, and this pulling load is applied to the paper peeling claw 33. It takes. Alternatively, when the leading edge of some of the sheets comes into contact with the stopper g, the pressing load due to the contact and the above-mentioned tensile load are applied to the sheet peeling claw 33.

As shown in FIGS. 5 and 6, the paper stripping claw 33 moves as shown in FIG. It is swung around a swiveling axis P.

As the paper stripping claw 33 swings, the paper stripping claw 3
The urging force of the weight W applied to the weight W changes as follows.

That is, until the paper peeling claw 33 swings 5 degrees, the weight W remains positioned at the guide end C of the guide groove 34 on the downstream side in the paper ejection direction, so that the biasing force hardly changes. do not have.

When the swing angle of the paper peeling claw 33 exceeds 5 degrees, the weight W begins to move toward the guide end d near the swing axis P along the guide groove 34, and the biasing force increases due to acceleration. decreases to

Therefore, after the swing angle of the paper separation claw 33 exceeds 5 degrees, the paper # separation claw 33 easily swings under a light load, so that the paper a is accordion-like in the vicinity of the paper separation edge e. If there is a jam, the paper peeling claw 33 and the rotating body circumferential surface S
This prevents the material from entering strongly between the two.

On the other hand, the paper a changes its position so as to follow the lower paper ejection guide 29, or the trailing edge of the paper a passes through the paper peeling edge e of the swinging paper release claw 33. When the load on the paper peeling claw 33 is removed, the paper peeling claw 33 returns and swings to return to its initial position, but the weight W is attached to the guide end on the downstream side in the paper ejection direction. Until it shifts to the C side, there is almost no variation in the biasing force due to the weight W.

Then, at the initial stage of the remaining 5-degree swing of the paper #J release claw 33, the weight W begins to move toward the guide end C side on the downstream side in the paper ejection direction, so that the biasing force by the way W is accelerated. At the same time, the biasing force becomes maximum (initial state B) when the weight W is located at the guide end C on the downstream side in the paper ejection direction, and until this biasing force reaches the maximum. Paper peeling edge e of the paper peeling claw 33
comes into contact with the circumferential surface S of the rotating body.

After the paper peeling edge part e softly contacts the rotating body circumferential surface S, a biasing force by the weight W is applied to the paper peeling edge e, so that the rotating body circumferential surface S
This effectively prevents the paper from being damaged by the paper peeling edge e.

Another embodiment of the paper peeling claw 33 is shown in FIGS. 7 and 8.

The one shown in FIG. 7 has the guide groove 34 formed directly below the swing axis P, and the one shown in FIG. 8 has the guide groove 34 formed just above the swing axis P. The guide groove 34 of the paper peeling claw 33 shown in FIG. 1 is moved in parallel.

In the embodiment, the rotary body 24 for heat fixing is exemplified as the rotary body to which the paper peeling claw 33 is attached, but the rotary body 27 for pressure fixing may also be attached, or the rotary body 27 for pressure fixing may be attached. The rotating bodies 24 and 27 may also be attached.

Further, in the embodiment, an electrophotographic copying machine is shown as an image forming apparatus, but other devices such as a facsimile machine and a printer can be used as the image forming apparatus.

〔Effect of the invention〕

As explained above, according to the present invention, when an excessive load is applied to the tip side of the paper peeling claw due to the paper adhered to the circumferential surface of the rotating body, the paper peeling claw can escape from the circumferential surface of the rotating body and swing freely. By moving the paper separation edge, it is possible to prevent the paper peeling edge from digging into the circumferential surface of the rotating body, as in the past.

Then, when the paper stripping claw swings, the weight applied to the paper stripping claw becomes extremely small, so the swinging of the paper stripping claw becomes lighter, and thus the paper stripping claw and the rotating body Paper jams and accordion jams between the paper and the surrounding surface are prevented.

Furthermore, when the above-mentioned load is removed, the paper peeling edge of the paper peeling claw is urged to come into contact with the circumferential surface of the rotary body in a soft and automatic manner, and the paper peeling edge of the paper peeling claw is able to press against the circumferential surface of the rotary body. In addition to being able to prevent scratches on the surface, there is no longer any need to return the paper peeling claw to its initial position as in the past, and as a whole, all of the conventional drawbacks have been overcome through simple improvements.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fixing device, FIG. 2 is a schematic longitudinal sectional side view of an electrostatographic copying machine as an example of an image forming device, FIG. 3 is a side view of a paper peeling device, and FIGS. 4 to 6 are FIGS. 7 and 8 are explanatory diagrams showing the swinging state of the paper peeling claw over time, and FIGS. 7 and 8 are side views of the paper peeling claw of different embodiments, respectively. 9 and 10 are explanatory diagrams of conventional examples. 24, 27...Rotating body (thermal fixing roller, pressure roller), 33...Paper peeling claw, 34...Guide groove, a
... Paper, C ... Guide end on the downstream side in the paper ejection direction, d
...Guide end near the swing axis, e...paper peeling edge, P...swing axis, Q...contact point, R...tangential line, S...rotating body circumferential surface, T...horizontal line, U...extension line, W...weight. Applicant: Sanda Kogyo Co., Ltd. Representative: Patent Attorney: Hideo Fujimoto Figure 1: 33...Paper! 4N claw 34...Guide groove e...Paper peeling edge Fig. 4 Fig. 5 Fig. 9 Fig. 10

Claims (2)

[Claims] (1) Set the paper peeling claw for peeling off the paper attached to the circumferential surface of the fixing rotary body from the circumferential surface of the rotary body, so that the paper peeling claw is set so that the paper peeling claw is connected to the tangent line passing through the contact point of the paper peeling edge with the circumferential surface of the rotary body. It is installed so that it can swing freely around the axis of the rotating body, and
forming a guide groove in the paper peeling claw, the guide end of which is located near a horizontal line passing through the swing axis and on the downstream side in the paper ejection direction is located slightly below the guide end near the swing axis; A fixing device for an image forming apparatus, characterized in that a weight that biases the paper peeling edge into contact with the circumferential surface of the rotating body is provided so as to be movable back and forth along the guide groove. (2) The guide groove is an elongated hole, and the extension line of the long axis of the elongated hole is configured to pass near the swing axis of the paper peeling claw. A fixing device of the image forming apparatus described above.