JP3245249B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device in which the outer peripheral surfaces of a pair of rollers are pressed against each other.

[0002]

2. Description of the Related Art In a conventional fixing device, one roller is provided in a fixed position, and the other roller is provided so as to be movable toward and away from one roller, and a pair of rollers are biased by a spring. Generally, the outer peripheral surfaces are pressed against each other. The biasing force of the spring for pressing the outer peripheral surfaces of the pair of rollers against each other is set to, for example, about 25 kg.

In order to attach a spring at the time of assembling the fixing device or to release the pressed state between the outer peripheral surfaces of the rollers for maintenance or the like, one end of the spring is gripped and extended with a tool such as pliers. By this, one end of the spring is locked to the locking portion, or one end of the spring is removed from the locking portion. In these cases, the biasing force of the spring in the set state in which the pair of rollers is pressed against each other is used. The spring has to be pulled with great force, which requires great effort.

Therefore, one end of the spring is locked to a lever member which is rotatable around a support shaft, and by operating this lever member, the operation of setting the spring in the biased state and the biasing force of the spring are reduced. A fixing device has been invented in which the operation of releasing is reduced by using the principle of leverage, for example, those disclosed in JP-A-62-164077 and JP-A-62-164078. There is.

[0005]

However, Japanese Patent Application Laid-Open No. Sho 62-62
In the fixing device disclosed in Japanese Patent No. 164077,
The structure is such that the operating lever, to which one end of the spring is locked, is gripped and rotated by hand, so that there is a disadvantage that operability is poor. Also, in order to secure a large leverage and reduce the operating force, the operating lever must be enlarged, and if the operating lever is enlarged, it is difficult to reduce the size of a copier or the like equipped with the fixing device. become.

On the other hand, the fixing device disclosed in Japanese Patent Application Laid-Open No. Sho 62-164078 has a structure in which the conveying means having one end of a spring is held and rotated by hand, so that operability is improved. There is a disadvantage that it is bad. In addition, in order to secure a large leverage and reduce the operating force, the conveying means must be enlarged, and if the conveying means is enlarged, it is difficult to reduce the size of a copying machine or the like equipped with the fixing device. become. Further, since the transporting means has a paper discharging mechanism, the strength of the parts must be increased, and it is difficult to reduce the weight of a copying machine or the like having the fixing device. In addition, when a paper jam is to be performed in the paper discharge unit, the pressed state of the pair of rollers is released. Depending on the paper jam, the paper having an unfixed portion may be pulled out, and the toner may scatter and the fixing device may be scattered. There is a disadvantage that the paper discharge mechanism and the like are soiled. In addition, since the pair of rollers is released from the pressure-contact state each time the jam processing is performed, when a long time is required for the jam processing, one of the rollers having no heat source is cooled to a fixing temperature or lower. There is a drawback that a state such as a fixing failure or a fixing standby after the jam processing occurs.

[0007]

According to the first aspect of the present invention,
In a fixing device in which the outer peripheral surfaces of a first roller and a second roller having a rotation center parallel to each other are pressed against each other by the urging force of a spring, the first roller is provided at a fixed position, and the second roller is connected to the first roller. A spring locking member provided so as to be movable toward and away from the roller, one end of the spring being locked, and being rotatable around a support shaft; and the biasing force of the spring is applied to the first roller. The pressure contact position acting to press the roller against the second roller and the biasing force of the spring have a small tension.
The spring locking member is rotatably provided to a pressing release position where the pressing state between the first roller and the second roller is released after being set to a state where the first roller and the second roller are released, and the spring locking member is rotated. An insertion hole into which a rod-shaped rotating operation tool is detachably inserted is formed in the spring locking member.

According to a second aspect of the present invention, in the first aspect of the present invention, a fall prevention stopper for preventing the spring locking member from falling to a side substantially orthogonal to a rotation surface rotating around the support shaft. Was provided on the spring locking member.

According to a third aspect of the present invention, in the first aspect of the present invention, an insertion depth stopper for regulating the insertion depth of the rotary operation tool into the insertion hole is provided in the insertion hole.

According to a fourth aspect of the present invention, in the first aspect of the present invention, a rotation restricting stopper for positioning the spring locking member rotated to the pressure contact position is provided.

[0011]

According to the first aspect of the present invention, the rotary operating member is inserted into the locking hole of the spring locking member, and the spring operating member is rotated by rotating the rotary operating member, so that the spring locking member is also integrated with the support shaft as a fulcrum. To rotate. Then, by rotating the spring locking member to the pressure release position, the urging force of the spring is released, and the pressure contact state between the first roller and the second roller is released. Further, by rotating the spring locking member to the pressing position, the outer peripheral surfaces of the first roller and the second roller are pressed against each other by the urging force of the spring.

According to the second aspect of the present invention, the spring locking member is prevented from falling down to the side substantially orthogonal to the rotation surface that rotates around the support shaft by the fall prevention stopper, and the rotation around the support shaft is prevented. Movement is performed smoothly.

According to the third aspect of the invention, the insertion depth of the rotary operation tool into the insertion hole is regulated by the insertion depth stopper,
The rotation operation tool inserted into the insertion hole is prevented from protruding to the opposite side of the insertion hole, and the rotation operation of the spring locking member by the rotation operation of the rotation operation tool is performed smoothly.

According to the fourth aspect of the present invention, since the spring locking member rotated to the pressure contact position is positioned by the rotation restricting stopper, the pressure contact state between the first roller and the second roller is always kept constant. As a result, a stable fixing process is performed.

[0015]

An embodiment of the present invention will be described with reference to the drawings. First, the drawing shows a fixing device in a copying machine, in which a peripheral portion is formed by an elastic member such as a sponge.
A fixing roller 1 serving as a roller and a pressure roller 2 serving as a second roller having an outer peripheral portion made of metal are rotatably arranged with rotation centers parallel to each other. The fixing roller is fixedly mounted by being held on a side plate (not shown) by a bearing, and the pressure roller 2 is arranged along an arc-shaped long hole (not shown) formed in the side plate. The fixing roller 1 is held so as to be movable in the direction of coming and going with respect to the fixing roller 1.

Next, a lever 4 is provided, one end of which is supported by a support shaft 3. The upper surface of the lever 4 has an outer peripheral surface of a bearing 2b fitted to the rotary shaft 2a of the pressure roller 2. Is in contact with At the other end of the lever 4, a locking portion 5 for locking a spring described later is formed.

Next, at a position close to the fixing roller 1 and the pressure roller 2, a support shaft 6 having an axis parallel to the rotation center of the fixing roller 1 and the pressure roller 2 and the support shaft 3. As a result, a spring locking member 7 is pivotally supported, and the spring locking member 7 is provided rotatably around the support shaft 6. The spring locking member 7 is provided with a locking projection 8. Between the locking projection 8 and the locking portion 5, the pressure roller 2 is attached upward through the lever 4. A spring 9 that presses the outer peripheral surface of the pressure roller 2 against the outer peripheral surface of the fixing roller 1 by being urged is stretched.

Here, the spring locking member 7 is rotatably provided around the support shaft 6, and FIG. 1 shows that the urging force of the spring 9 is applied to the fixing roller 1 and the pressure roller 2. 2 shows a state in which the spring locking member 7 is rotated to a pressure contact position where pressure is applied. In this state, the urging force of the spring 9 acts to rotate the spring locking member 7 around the support shaft 6 in a counterclockwise direction. A rotation restricting stopper 10 is formed on a side plate 11 provided in proximity to the spring locking member 7 when the locking projection 8 comes into contact with the rotation locking member 8 when it is rotated to the pressure contact position.

On the other hand, FIG. 2 shows that the urging force of the spring 9 is released and the fixing roller 1 and the pressing roller 2 are released.
1 shows a state in which the spring locking member 7 is rotated to a pressure releasing position where the pressure contact state with which the spring locking member 7 is released is released. This rotation operation supports the spring locking member 7 from the state shown in FIG. This is done by rotating clockwise around axis 6. In this state, a part of the outer peripheral surface of the spring locking member 7 comes into contact with a stopper (not shown), so that the rotation of the spring locking member 7 in the clockwise direction is restricted. Since the springs 9 have a small tension and their dimensions are set, the springs 9 are prevented from coming off the locking projections 8 and the locking portions 5.

Next, the spring locking member 7 includes
An insertion hole 13 for detachably inserting a tool 12 such as a driver, which is a rod-shaped rotation operating tool for rotating the spring locking member 7, is formed. In addition, an insertion depth stopper 14 for regulating the insertion depth of the tool 12 is formed in a deep portion of the insertion hole 13.

Further, in the spring locking member 7, since the spring 9 is locked at a position displaced from a rotation surface on which the spring locking member 7 rotates about the support shaft 6, the spring 9 is locked. The spring locking member 7 is provided with a fall prevention stopper 15 for preventing the spring locking member 7 from falling to the side substantially orthogonal to the rotation surface due to the urging force of the spring 9. A side plate 16 with which the tip of the fall prevention stopper 15 abuts is provided at a position close to the spring locking member 7.

FIG. 1 shows a state in which the spring locking member 7 is rotated to the pressure contact position in such a configuration, and the urging force of the spring 9 raises the pressing roller 2 via the lever 4. The fixing roller 1
And the outer peripheral surface of the pressure roller 2 are pressed against each other.
On the other hand, when releasing the pressure contact state between the fixing roller 1 and the pressure roller 2 for maintenance or the like, the tool 12 is inserted into the insertion hole 13 as shown by an arrow A, and the inserted tool 12 is locked by a spring. It is rotated clockwise (in the direction of arrow B) about the support shaft 6 together with the member 7. When it is rotated to the pressure release position shown in FIG. 2, the urging force of the spring 9 is released, and the pressure contact between the fixing roller 1 and the pressure roller 2 is released. After the maintenance or the like is completed, the tool 12 is inserted into the insertion hole 13 again, and the inserted tool 12 is rotated counterclockwise around the support shaft 6 together with the spring locking member 7 so that the spring locking member is rotated. 7 is returned to the pressure contact position shown in FIG. 1, and the fixing roller 1 and the pressure roller 2 are pressed against each other by the urging force of the spring 9.

Here, when the spring locking member 7 is rotated between the pressure contact position and the pressure release position, a force directed in the rotation direction is applied to the tool 12 inserted into the insertion hole 13. Since the distance from the support shaft 6 to the point of application of the force on the tool 12 is increased, the lever can be rotated with a very small force by the principle of leverage. Further, it is not necessary to increase the size of the spring locking member 7 itself in order to secure a large leverage, and the provision of the spring locking member 7 prevents the copying machine equipped with the fixing device from being enlarged. You. Further, the spring locking member 7 is
When the spring is rotated to the pressure contact position shown in FIG. 7, the urging force of the spring 9 acts to rotate the spring locking member 7 in the counterclockwise direction. Further rotation in the counterclockwise direction is restricted by contacting the stopper 10, so that even after the rotation operation of the spring locking member 7 is repeated, the fixing roller 1 and the pressure roller 2 are rotated. Is constantly maintained constant, and a stable fixing process is performed.

Next, when the tool 12 is inserted into the insertion hole 13, the insertion depth of the tool 12 into the insertion hole 13 is regulated by the insertion depth stopper 14. The tool 12 inserted into the insertion hole 13 is prevented from protruding to the opposite side of the insertion hole 13. Therefore, the spring locking member 7
Is prevented from being damaged by the tool 12 protruding to the opposite side of the insertion hole 13, and the insertion depth of the tool 12 is deviated during the rotation operation. Since this does not occur, the turning operation of the spring locking member 7 by turning the tool 12 can be performed smoothly.

Further, when the spring locking member 7 is rotated, the tip of the fall prevention stopper 15 is
, The spring locking member 7 is prevented from falling to the side substantially orthogonal to the rotation surface due to the urging force of the spring 9. Therefore, the rotation operation of the spring locking member 7 can be performed more smoothly.

[0026]

According to the first aspect of the present invention, as described above, one end of a spring for engaging the outer peripheral surfaces of the first roller and the second roller having the rotation centers parallel to each other is engaged. A member is provided, and the spring locking member is rotatable between a pressing position where the urging force of the spring acts to press the first roller and the second roller against each other and a pressing release position where the pressing state is released. The insertion hole into which the rod-shaped rotation operating tool for rotating and operating the spring locking member is detachably inserted is formed in the spring locking member, so that the rotation operating tool is inserted into the locking hole. By rotating the spring locking member together with the rotating operation tool, the spring locking member can be easily rotated with a small force by applying the leverage principle, and
Since it is not necessary to increase the size of the spring locking member in order to secure a large leverage, the present invention has an effect that a copying machine or the like provided with the fixing device can be downsized.

According to a second aspect of the present invention, as described above, in the first aspect of the present invention, the spring locking member is prevented from falling to the side substantially orthogonal to the rotation surface that rotates around the support shaft. Since the fall prevention stopper is provided on the spring locking member, the operation of rotating the spring locking member between the pressure contact position and the pressure release position can be smoothly performed.

According to a third aspect of the present invention, as described above, in the first aspect of the present invention, the insertion depth stopper for restricting the insertion depth of the rotary operation tool into the insertion hole is provided in the insertion hole. Provided, it is possible to reliably prevent the rotating operation tool inserted into the insertion hole from protruding to the opposite side of the insertion hole and damaging surrounding components. It is possible to prevent the depth of insertion of the moving operation tool into the insertion hole from being shifted, thereby providing an effect that the rotation operation of the spring locking member can be smoothly performed.

According to the fourth aspect of the present invention, as described above, since the rotation restricting stopper for positioning the spring locking member rotated to the pressure contact position is provided in the invention according to the first aspect, the rotation restricting stopper is rotated to the pressure contact position. The position of the spring locking member to be moved can always be kept constant by the rotation restricting stopper, so that the pressure contact state between the first roller and the second roller can always be kept constant and stable fixing processing can be performed. And the like.

[Brief description of the drawings]

FIG. 1 is a front view showing a state in which a spring locking member according to an embodiment of the present invention is rotated to a pressure contact position.

FIG. 2 is a front view showing a state in which a spring locking member is rotated to a pressure release position.

FIG. 3 is a side view showing an attached state of a spring locking member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st roller 2 2nd roller 6 Support shaft 7 Spring locking member 9 Spring 10 Rotation restriction stopper 12 Rotation operation tool 13 Insertion hole 14 Insertion depth stopper 15 Fall prevention stopper

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-164077 (JP, A) JP-A-61-190365 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/20 G03G 15/20

Claims (4)

(57) [Claims] 1. A fixing device in which the outer peripheral surfaces of a first roller and a second roller having rotation centers parallel to each other are pressed against each other by the urging force of a spring, wherein the first roller is provided at a fixed position and the second roller is fixed. A roller is provided so as to be movable in a direction in which the roller comes into contact with and separates from the first roller, and a spring locking member that locks one end of the spring and is rotatable around a support shaft is provided. A pressing position at which the first roller and the second roller act to press against each other, and a biasing force of the spring is a minute force.
The spring locking member is rotatably provided to a pressure releasing position where the pressing state between the first roller and the second roller is released in a state where the first roller and the second roller are released, and the spring locking member is rotated. A fixing device, wherein an insertion hole into which a rod-shaped rotating operation tool to be operated is detachably inserted is formed in the spring locking member. 2. A spring locking member is provided with a stopper for preventing the spring locking member from falling down to a side substantially orthogonal to a rotation surface that rotates around a support shaft. The fixing device according to claim 1. 3. The fixing device according to claim 1, wherein an insertion depth stopper that regulates an insertion depth of the rotary operation tool into the insertion hole is provided in the insertion hole. 4. The fixing device according to claim 1, further comprising a rotation restricting stopper for positioning the spring locking member rotated to the pressure contact position.