JP4691426B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, or a printer. For example, a driving force transmitting member capable of transmitting a driving rotational force around a roller axis to a cylindrical fixing roller includes an end of the fixing roller. The present invention relates to an image forming apparatus attached to a part.

Conventionally, as an image forming apparatus of this type, as shown in FIG. 1, a transfer paper P such as paper fed along a transport path is heated with the fixing roller 1 while being pressed with a pressure roller 2. When the fixing roller 1 is focused, as shown in FIG. 12, a cylindrical fixing roller 1 and an end portion of the fixing roller 1 are arranged. There was one provided with a driving force transmission member 21 arranged in an externally fitted state (see, for example, Patent Document 1). A notch 22 is formed at the end of the fixing roller 1 along the roller axis X direction. On the driving force transmitting member 21 side, the notch 22 protrudes inward from the fixing roller. The projection 23 is provided, and the rotational force of the driving force transmission member 21 is transmitted to the fixing roller 1 by the engagement of the projection 23 and the notch 22.
Further, as a second conventional example, as shown in FIG. 13, a hole 1a penetrating the peripheral surface portion of the fixing roller 1 is provided instead of the notch 22 of the fixing roller 1, and the hole 1a includes the hole 1a. A driving force transmission member 21 that is fitted on the fixing roller 1 is configured so that the protrusion 23 is fitted, and the rotational force of the driving force transmission member 21 is applied to the fixing roller 1 by the engagement between the protrusion 23 and the hole 1a. There was what was comprised so that it might transmit (for example, refer to patent documents 1).
Further, as a third conventional example, as shown in FIG. 14, the driving force transmission member 21 is disposed in an end fitting state at the end of the fixing roller 1, and the driving force transmission member 21 is caused by a frictional force therebetween. In some cases, the rotational force is transmitted to the fixing roller 1 (see, for example, Patent Document 2).

JP-A-2004-85652 (FIGS. 1 to 3 and FIG. 5) Japanese Unexamined Patent Publication No. 2004-126317 (FIGS. 1, 4, and 5)

According to this type of image forming apparatus described above, if the fixing roller can be heated to a predetermined temperature in a short time, the waiting time at the start of the apparatus can be shortened.
Therefore, in recent years, the fixing roller has been made thinner, and the temperature of the fixing roller can be quickly raised by the heat of the heater disposed inside the fixing roller. And even with such a thin fixing roller, there is no difference in rotationally driving it through the driving force transmission member, and it is necessary to give consideration to stress on the fixing roller whose strength has been reduced by thinning. It has become to.

  According to the image forming apparatus of the first conventional example described above, the rotational driving force from the driving force transmitting member acts on the notch periphery of the fixing roller from the protrusion. A cross-sectional defect occurs, and the strength of the peripheral edge of the notch is lowered, and there is a problem that the fixing roller is easily deformed or damaged with the rotational drive.

According to the image forming apparatus of the second conventional example described above, the rotational force is transmitted by the engagement between the protrusion and the hole, so that the end portion strength accompanying the rotation of the fixing roller is improved as compared with the first conventional example. However, since the driving force transmitting member is externally fitted to the fixing roller, if an excessive stress is applied, the circular shape of the cylinder is likely to be bent, and there is a risk that the function as the fixing roller may not be performed.
In other words, the fixing roller is only restrained on the outer peripheral surface by the driving force transmitting member, and there is no effective restraining means for deformation toward the inner peripheral surface side. There is a problem that a part of the wire is bent to the inner peripheral side and wrinkles are formed or it cannot be rotated normally.

  According to the image forming apparatus of the third conventional example described above, the inner peripheral side of the fixing roller is restrained by the driving force transmission member, so that the deformation of the fixing roller as in the second conventional example can be avoided, the fixing Since the connection between the roller and the driving force transmission member depends on the frictional resistance between them, if the fixing roller rises in temperature and thermal strain occurs in the direction of elongation, the frictional resistance of both of them decreases extremely, causing the slip state to rotate. There is a problem that force cannot be transmitted.

  Accordingly, an object of the present invention is to provide an image forming apparatus that solves the above-described problems and can receive a large rotational force even with a thin fixing roller and can stably form a formed image. It is in.

A first characteristic configuration of the present invention is an image forming apparatus in which a driving force transmitting member capable of transmitting a driving rotational force around a roller axis to a cylindrical fixing roller is attached to an end portion of the fixing roller. The driving force transmitting member is freely fitted in the fixing roller, receives a rotational driving force from a rotational driving system, and can rotate about the roller axis, and the transmission member main body. And a projecting portion provided in a state of projecting outward along the radial direction, the transmission member main body being fitted into the fixing roller, and the projecting portion surrounding the fixing roller. in a state of penetrating a hole formed in surface portion, Ri Oh attaching said driving force transmission member to the fixing roller, the transmission member main body, a plurality divided freely configured along the roller circumferential direction, the fixing roller The transmission part fitted inside Diameter preventing means for preventing the diameter of the body is in place is provided.

According to the first characteristic configuration of the present invention, the transmission member main body is fitted into the fixing roller, and the driving force transmission member is placed in a state in which the protrusion penetrates the hole formed in the peripheral surface portion of the fixing roller. Since it is attached to the fixing roller, even if a large rotational force acts between the driving force transmitting member and the fixing roller, the fixing roller can be prevented from being deformed or slipping, and stable. The rotation can be continued.
That is, the fixing roller has its inner peripheral portion restrained by the transmission member main body, so that it can be prevented that the fixing roller is bent and deformed to the inner peripheral side as it rotates, and the above-described bending deformation preventing state can be prevented. Rotational force can be transmitted to each other by a strong engagement force between the protrusion and the hole, and stable rotation can be realized without deformation of the fixing roller or slipping.
In addition, when the transmission member main body is attached to the fixing roller in a state of being fitted inside, it is possible to attach the transmission member more smoothly than the one constituted by a single part, which can be attached more smoothly. It is possible to improve the efficiency of operations such as assembly, disassembly and maintenance of the member and the fixing roller.
Further, in the operation of inserting the protrusion into the hole of the fixing roller, the single member driving force transmission member may be forcibly inserted into the end of the fixing roller. Therefore, if the driving force transmission member is divided and assembled in a state where it is fitted into the end portion of the fixing roller, the fixing roller can be attached without being damaged.
In addition, the state in which the inner peripheral surface of the fixing roller is held by the transmission member main body can be maintained by the diameter reducing means, and a more stable sheet feeding state can be realized.

A second characteristic configuration of the present invention is an image forming apparatus in which a driving force transmitting member capable of transmitting a driving rotational force around a roller axis to a cylindrical fixing roller is attached to an end portion of the fixing roller. The driving force transmitting member is freely fitted in the fixing roller, receives a rotational driving force from a rotational driving system, and can rotate about the roller axis, and the transmission member main body. And a projecting portion provided in a state of projecting outward along the radial direction, the transmission member main body being fitted into the fixing roller, and the projecting portion surrounding the fixing roller. The driving force transmission member is attached to the fixing roller so as to pass through the hole formed in the surface portion, and the transmission member main body is formed in a C-ring shape, and is compressed by bringing the end portions close to each other. The diameter and the end It is configured to expanded by separating the said diameter reduction preventing means for preventing the diameter of was fitted to the fixing roller the transfer member body is in place is provided.

According to the second characteristic configuration of the present invention, the driving force transmission member is placed in a state in which the transmission member main body is fitted in the fixing roller and the protrusion penetrates the hole formed in the peripheral surface portion of the fixing roller. Since it is attached to the fixing roller, even if a large rotational force acts between the driving force transmitting member and the fixing roller, the fixing roller can be prevented from being deformed or slipping, and stable. The rotation can be continued.
That is, the fixing roller has its inner peripheral portion restrained by the transmission member main body, so that it can be prevented that the fixing roller is bent and deformed to the inner peripheral side as it rotates, and the above-described bending deformation preventing state can be prevented. Rotational force can be transmitted to each other by a strong engagement force between the protrusion and the hole, and stable rotation can be realized without deformation of the fixing roller or slipping.
Also, when the transmission member body is attached to the fixing roller in an internally fitted state, it can be attached more smoothly when it is configured as a C-ring than when it is configured as a single part with a fixed shape. Thus, it is possible to improve the efficiency of operations such as assembly, disassembly and maintenance of the driving force transmission member and the fixing roller.
Furthermore, in the operation of inserting the protrusion into the hole of the fixing roller, the driving force transmission member of a single member having a fixed shape may be forcibly inserted into the end of the fixing roller. By being configured with a C-ring that can be reduced or increased in diameter, the driving force transmission member can be inserted into the end of the fixing roller with the diameter reduced, and the diameter can be increased so that the protrusion is inserted into the hole. In this case, the fixing roller can be easily attached without damaging it.
In addition, the state in which the inner peripheral surface of the fixing roller is held by the transmission member main body can be maintained by the diameter reducing means, and a more stable sheet feeding state can be realized.

According to a third characteristic configuration of the present invention, butt end portions facing each other in the circumferential direction of the transmission member main body are formed so as to overlap with each other in the roller axial direction .

According to the third characteristic configuration of the present invention, in addition to being able to achieve the above-described operational effects according to the first or second characteristic configuration of the present invention, as shown in FIG. 4, the outer periphery of the transmission member main body 6A. Even if a discontinuous portion such as a gap 10 is formed on the surface, for example, if the butted ends 6b overlap each other in the roller axis X direction, the fixing roller 1 can be The inner peripheral surface is constrained by the transmission member main body 6A at any part over the circumference, and a circular cross section can be maintained. That is, as in the comparative example shown in FIG. 5, when the restraint of the fixing roller 1 by the transmission member main body 6A becomes discontinuous in the circumferential direction, the fixing roller 1 cannot maintain an arc shape at the discontinuous portion, and rotates. However, according to the present invention, the image sheet can be fed out in a uniform state.

According to a fourth characteristic configuration of the present invention, an internal thread portion is formed on an inner peripheral surface of the transmission member body, and the diameter reduction preventing means includes an external thread portion that can be screwed into the internal thread portion of the transmission member body. It is in the place comprised with the provided ring-shaped member .

According to the fourth characteristic configuration of the present invention, in addition to being able to achieve the above-described operation effect according to any one of the first to third characteristic configurations of the present invention, the rotational driving force from the rotational driving system is It can be transmitted from the diameter reduction preventing means to the fixing roller via the transmission member main body.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the parts indicated by the same reference numerals as those in the conventional example indicate the same or corresponding parts.

FIG. 1 shows a fixing device portion of an image forming apparatus according to the present invention. Examples of this type of image forming apparatus G include a copying machine, a printer, a facsimile, and the like. After the image is formed, toner is supplied to the photosensitive drum to form a toner image, and then the toner image on the photosensitive drum is transferred to the transfer paper, and the transferred toner is melted by the fixing device and transferred to the transfer paper. It is configured to be fixed.
As shown in FIG. 1, the fixing device for that purpose includes a fixing roller 1 and a pressure roller 2 that forms a nip in contact with the fixing roller 1. The fixing roller 1 includes an electric heater as a heating unit. 3 is built-in.
The fixing roller 1 and the pressure roller 2 are respectively provided with claw bodies 4 and 5 for separating the transfer paper P after the toner is fixed from the rollers 1 and 2.

Although not shown in the drawing, both ends of the fixing roller 1 are rotatably held by the apparatus main body via a pair of bearings and around the roller axis X by receiving a rotational driving force from a rotational driving system. It is configured to be rotatable.
More specifically, as shown in FIGS. 2 and 3, a driving force transmitting member 6 capable of transmitting a driving rotational force around the roller axis X to the cylindrical fixing roller 1 is provided on the fixing roller 1. It is attached to the end.

  The fixing roller 1 is, for example, a thin metal body and is formed into a cylindrical shape, and a hole 1a into which the protrusion 6B of the driving force transmission member 6 can be fitted is spaced at the end in the circumferential direction. There are several. In the embodiment, the hole 1a is formed in a square hole shape.

The driving force transmission member 6 is fitted in the fixing roller 1 and receives a rotational driving force from a rotational driving system so as to be rotatable around the roller axis, and the transmission member main body 6A. The main body 6A is configured to include a protrusion 6B provided so as to protrude outward along the radial direction thereof. The transmission member body 6A is configured to be freely divided into a plurality of parts (in the embodiment, two parts) along the circumferential direction of the roller, and the protrusion 6B is provided for each of the divided bodies 6a.
The protrusion 6B is fitted into the hole 1a of the fixing roller 1 from the inside of the cylinder, thereby transmitting the rotational force of the driving force transmitting member 6 to the peripheral portion of the hole 1a and rotating the fixing roller 1. To be able to.
Further, an internal thread portion 7 is formed on the inner peripheral surface of the transmission member main body 6A, and is configured so that an external thread portion 9 of a ring-shaped diameter reduction preventing means 8 described later can be screwed together. In the transmission member main body 6A, the divided main bodies 6a are arranged in a ring shape, and the male screw portions 9 of the diameter reduction preventing means 8 are screwed into the female screw portions 7, so that each divided main body 6a and the fixing roller 1 are engaged. It is positioned by the diameter reduction preventing means 8 and is in a stable mounting state.
Further, the length of each divided body 6a is set such that a gap 10 is provided between the butted ends 6b of the fixing roller 1 in a state where it is fitted in a predetermined position of the fixing roller 1, as shown in FIG. Since the divided main bodies 6a are arranged in a state where the abutting end portions 6b are in contact with each other at the time of attachment to the fixing roller 1, the diameter becomes smaller than the original outer diameter, so that the smoothness can be smoothly achieved. It can be fitted inside, and it is possible to improve the efficiency of the mounting operation. Further, since an excessive force is not applied to the fixing roller 1, damage can be prevented.
Further, the shape of the butted ends 6b is formed such that the butted ends 6b overlap each other in the front and rear in the roller axis X direction. Specifically, it is formed as an inclined surface inclined with respect to the circumferential direction of the transmission member main body 6A.
As described above, if the two are formed so as to overlap in the front and rear directions in the roller axis X direction, the roller axis X is viewed in the direction of the roller axis X even though there is a gap 10 between the adjacent divided main bodies 6a. Then, the fixing roller 1 is supported by the divided main bodies 6a over the entire inner periphery thereof, and the outer peripheral surface of the fixing roller is easily maintained in a curved state.

As shown in FIGS. 2 and 3, the diameter reduction preventing means 8 is constituted by a ring-shaped member having a male screw portion 9 that can be screwed into the female screw portion 7 of the transmission member main body 6A. By screwing the diameter reducing means 8 over the divided main bodies 6a arranged in the circumferential direction in the inner space of the roller 1, the respective divided main bodies 6a are fixed in a state where they are not moved in the reduced diameter direction. It becomes possible.
Further, the diameter reduction preventing means 8 is provided with an operation projection 11 protruding in the roller axis X direction as an operation portion when screwed into the transmission member main body 6A.
Although not shown in the drawing, a drive member of the rotational drive system is attached to the diameter reduction prevention means 8, and the rotational driving force is transferred from the diameter reduction prevention means 8 via the transmission member body 6A to the fixing roller. 1 is transmitted.

  According to the image forming apparatus G of the present embodiment, even if the fixing roller is formed thin, an excessive rotational driving force is difficult to act, and stable rotation without deformation or slipping of the fixing roller is possible. Can be realized. In addition, it is possible to improve the efficiency of operations such as assembly, disassembly, and maintenance of the driving force transmission member and the fixing roller.

[Another embodiment]
Other embodiments will be described below.

<1> The transmission member main body 6A is not limited to the one configured by the plurality of divided main bodies 6a in the circumferential direction described in the previous embodiment. For example, as shown in FIG. These may be configured to be reduced in diameter by bringing the end portions close to each other and expanded in diameter by separating the end portions. In this case, since the number of parts is smaller than that divided into a plurality of parts, it is easy to manage the parts and the mounting operability is improved.
Further, the transmission member main body is not necessarily configured so as to be capable of reducing and expanding the diameter.
<2> The protrusion 6B is not limited to one integrally formed with a part of the transmission member main body 6A as described in the previous embodiment. For example, as shown in FIG. You may comprise with the screw member which can be attached to the main body 6A from the outer peripheral side.
<3> As described in the previous embodiment, the transmission member main body 6A is not limited to the one configured to receive the rotational force from the rotational drive system via the diameter reduction preventing means 8, for example, Further, it may be configured to receive the driving force directly from the rotational driving system.
<4> The butt end portions 6b of the transmission member main body 6A are not limited to being formed as inclined surfaces inclined with respect to the circumferential direction of the transmission member main body 6A as described in the previous embodiment. For example, as shown in FIG. 8, the transmission member body 6 </ b> A has a stepped shape with respect to the circumferential direction, or as shown in FIG. 9, it is formed in a “V” -shaped uneven shape. As shown in FIG. 10, it may be formed in a tenon set shape. In short, it may be formed so as to overlap with the front and rear in the roller axis X direction.

  In addition, as mentioned above, although the code | symbol was written in order to make contrast with drawing convenient, this invention is not limited to the structure of an accompanying drawing by this entry. In addition, it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.

Roller axis direction sectional view showing the fixing device portion Exploded perspective view showing mounting state of transmission member main body and fixing roller Roller side view sectional view showing the mounting state of the transmission member main body and the fixing roller Explanatory drawing which shows the attachment condition of a transmission member main body and a fixing roller Explanatory drawing which shows the attachment condition of the transmission member main body and fixing roller of a comparative example The disassembled perspective view which shows the attachment condition of the transmission member main body and fixing roller of another embodiment The disassembled perspective view which shows the attachment condition of the transmission member main body and fixing roller of another embodiment Roller side view sectional drawing which shows the transmission member main body of another embodiment Roller side view sectional drawing which shows the transmission member main body of another embodiment Roller side view sectional drawing which shows the transmission member main body of another embodiment Roller side view sectional view showing the mounting state of the driving force transmission member and the fixing roller of the conventional example Roller side view sectional view showing the mounting state of the driving force transmission member and the fixing roller of the conventional example Roller side view sectional view showing the mounting state of the driving force transmission member and the fixing roller of the conventional example

DESCRIPTION OF SYMBOLS 1 Fixing roller 1a Hole 6 Driving force transmission member 6A Transmission member main body 6b Butt end 6B Protrusion 8 Diameter reduction prevention means X Roller core

Claims (4)

An image forming apparatus in which a driving force transmitting member capable of transmitting a driving rotational force around a roller axis to a cylindrical fixing roller is attached to an end of the fixing roller,
The driving force transmitting member is freely fitted in the fixing roller, receives a rotational driving force from a rotational driving system, and can rotate about the roller axis, and has a diameter with respect to the transmitting member main body. And a projecting portion provided in a state of projecting outward along the direction, the transmission member main body is fitted into the fixing roller, and the projecting portion is formed on the peripheral surface portion of the fixing roller. in a state of penetrating the formed hole, Ri Oh attaching said driving force transmission member to the fixing roller,
The transmission member body is configured to be divided into a plurality of parts along the circumferential direction of the roller,
An image forming apparatus provided with a diameter reducing means for preventing a diameter reduction of the transmission member main body fitted into the fixing roller . An image forming apparatus in which a driving force transmitting member capable of transmitting a driving rotational force around a roller axis to a cylindrical fixing roller is attached to an end of the fixing roller,
The driving force transmitting member is freely fitted in the fixing roller, receives a rotational driving force from a rotational driving system, and can rotate about the roller axis, and has a diameter with respect to the transmitting member main body. And a projecting portion provided in a state of projecting outward along the direction, the transmission member main body is fitted into the fixing roller, and the projecting portion is formed on the peripheral surface portion of the fixing roller. The driving force transmitting member is attached to the fixing roller in a state of passing through the formed hole,
The transmission member body is formed in a C-ring shape, and is configured to reduce the diameter by bringing the end portions close to each other, and to increase the diameter by separating the end portions,
An image forming apparatus provided with a diameter reducing means for preventing a diameter reduction of the transmission member main body fitted into the fixing roller . 3. The image forming apparatus according to claim 1 , wherein abutting end portions facing each other in the circumferential direction of the transmission member main body are formed so as to overlap each other in the roller axial direction . Forming an internal thread portion on the inner peripheral surface of the transmission member body,
The diameter preventing means, an image forming apparatus according to any one of claims 1 to 3 into the female threaded portion are constituted by a ring-shaped member having a threaded freely male thread portion of the transmission member body .

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