JP7067110B2 - Fixing device and image forming device - Google Patents

Description

The present invention relates to a fixing device for fixing a toner image on paper and an image forming device provided with the fixing device.

In the image forming apparatus, the toner image formed on the surface of the image carrier is transferred to the paper and then heated and pressurized by the fixing apparatus to be fixed on the paper.

As a fixing method of the fixing device, there is a sliding fixing method in which the fixing belt is driven by a press roller to rotate. The fixing belt is pressed against the press roller by the pressing pad. If the fixing belt stops during the fixing operation (during heating), abnormal heat generation will occur. Therefore, as a safety measure, the sliding fixing type fixing device is equipped with a rotation detection mechanism that detects the presence or absence of rotation of the fixing belt. Be done. The rotation detection mechanism covers the end of the fixing belt and detects the rotation of the cap that rotates integrally with the fixing belt. An elastic member having a high coefficient of friction is interposed between the fixing belt and the cap so that the rotation of the fixing belt is surely transmitted to the cap.

On the other hand, a lubricant having a relatively low viscosity is interposed between the fixing belt and the pressing pad in order to reduce the sliding load between the fixing belt and the pressing pad. If this lubricant flows out from the inner peripheral surface of the fixing belt and adheres to the elastic member, the elastic member may slip and the rotation from the fixing belt to the cap may not be smoothly transmitted. Therefore, it is necessary to control the flow of the leaked lubricant.

Therefore, in the fixing device described in Patent Document 1, a gap is provided between the cap and the elastic member to prevent the lubricant from wrapping around.

WO2015 / 162977

However, in the fixing device described in Patent Document 1, there is a limit to the amount of the lubricant that can be held, and there is a possibility that the lubricant may wrap around to the elastic member side depending on the fluctuation of the oil absorbing action.

Therefore, in consideration of the above circumstances, it is an object of the present invention to provide a fixing device capable of suppressing rotation transmission failure from the fixing belt to the cap due to leakage of the lubricant, and an image forming device provided with the fixing device.

In order to achieve the above object, the fixing device of the present invention comprises a rotatable endless fixing belt, a pressure member forming a pressure region between the fixing belt, and the fixing in the pressure region. A pressing member that comes into contact with the inner peripheral surface of the belt via a lubricant and presses the fixing belt against the pressurizing member, and the fixing belt is attached to the end of the fixing belt via an elastic member. The cap member includes a cap member that rotates integrally, and the cap member has a contact portion with which the end face of the fixing belt abuts, and the contact portion has the contact portion from the contact position with the end face of the fixing belt. It is characterized in that a flow path of the lubricant is formed in a direction away from the elastic member.

In the fixing device of the present invention, a plurality of the flow paths are formed along the radial direction of the cap member, and the contact portion is formed with respect to the elastic member rather than the contact position with the end face of the fixing belt. It may be characterized in that a holding groove communicating with the plurality of said flow paths is formed on the side separated from each other.

The fixing device of the present invention may be characterized in that the flow path is linear.

In the fixing device of the present invention, the flow path may be characterized by having a curved shape.

The image forming apparatus of the present invention is characterized by including an image forming portion for forming a toner image on paper and the fixing apparatus described above for fixing the toner image formed by the image forming portion on paper. And.

According to the present invention, the lubricant leaking from the end of the fixing belt flows into the flow path and does not flow out to the elastic member side, so that the lubricant adheres to the elastic member and slips against the fixing belt. Such a situation does not occur. Therefore, the rotation of the fixing belt can be reliably transmitted to the cap member via the elastic member.

It is a schematic diagram which shows the outline of the color printer which concerns on one Embodiment of this invention. It is sectional drawing which shows the fixing apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the end part of the fixing device which concerns on one Embodiment of this invention. It is a perspective view which shows the end part of the fixing device which concerns on one Embodiment of this invention. It is a front view which shows the end wall part of the cap member in the fixing device which concerns on one Embodiment of this invention. It is a front view which shows the 1st modification of the end wall part of the cap member in the fixing device which concerns on one Embodiment of this invention. It is a front view which shows the 2nd modification of the end wall part of the cap member in the fixing device which concerns on one Embodiment of this invention.

Hereinafter, the image forming apparatus and the fixing apparatus according to the embodiment of the present invention will be described with reference to the accompanying drawings.

First, with reference to FIG. 1, the entire configuration of the color printer 1 as an image forming apparatus will be described. FIG. 1 is a front view schematically showing the internal configuration of a color printer. In the following description, the front side of the paper surface of FIG. 1 is referred to as the front side (front side) of the color printer 1. L and R shown in each figure indicate the left side and the right side of the color printer 1, respectively.

The main body of the color printer 1 includes a paper feed cassette 3 in which the paper S is housed, a paper feed device 5 that feeds the paper S from the paper feed cassette 3, and an image forming unit 7 that forms a full-color toner image on the paper S. A fixing device 9 for fixing the toner image to the paper S, a paper ejection device 11 for ejecting the paper S, and a paper ejection tray 13 on which the ejected paper S is loaded are provided. Further, the apparatus main body is formed with a transport path 15 in which the paper S is conveyed from the paper feed device 5 to the paper discharge device 11 through the image forming unit 7 and the fixing device 9.

Next, the fixing device 9 will be described with reference to FIGS. 2 to 4. FIG. 2 is a cross-sectional view showing a fixing device, FIG. 3 is a cross-sectional view showing an end portion of the fixing device, and FIG. 4 is a perspective view showing the end portion of the fixing device.

As shown in FIG. 2, the fixing device 9 is used as a pressure member that forms a pressure region N between the endless fixing belt 21, the IH heater 23 that heats the fixing belt 21, and the fixing belt 21. The press roller 25, a pressing pad 27 as a pressing member for pressing the fixing belt 21 against the press roller 25 in the pressurizing region N, and the fixing belt 21 are attached to the end of the fixing belt 21 via an elastic member 29. A cap member 31 (see FIGS. 3 and 4) that rotates integrally with the cap member 31 and a rotation detection mechanism 33 (see FIG. 4) that detects the rotation of the cap member 31 are provided.

The fixing belt 21 is an endless belt having a predetermined inner diameter and a width longer than the width of the paper S. The fixing belt 21 is made of a flexible material and has a base material layer, an elastic layer provided on the outer peripheral surface of the base material layer, and a release layer provided on the outer peripheral surface of the elastic layer. There is. The base material layer is formed of a polyimide resin to which a magnetic metal such as Ni or a metal such as Cu, Ag, or Al is added. The elastic layer is made of silicon rubber or the like. The release layer is formed of a PFA tube or the like.

As shown in FIGS. 2 and 3, the holding member 41 penetrates the hollow portion of the fixing belt 21. The holding member 41 is a square cylindrical member having a length shorter than the width of the fixing belt 21. As shown in FIG. 3, stays 43 are fitted to both ends of the holding member 41. A flange portion 45 and an annular groove 47 are formed in the stay 43 along the circumferential direction, respectively. The annular groove 47 is formed outside the flange portion 45 in the axial direction of the fixing belt 21. The end portion of the holding member 41 is in contact with the flange portion 45. Both stays 43 are supported by a housing (not shown) of the fixing device 9.

As shown in FIG. 2, the belt guide 51 is supported on one surface of the holding member 41, and the pressing pad 27 is supported on the other surface. The belt guide 51 has an arcuate cross-sectional shape along the inner peripheral surface of the fixing belt 21, and is made of a springy material. The belt guide 51 applies tension to the fixing belt 21 to stabilize the rotation trajectory of the fixing belt 21. The pressing pad 27 is a flat, substantially rectangular parallelepiped member that is long in the width direction of the fixing belt 21, and is made of a resin such as a liquid crystal polymer. The outer peripheral surface of the pressing pad 27 is covered with a sliding sheet 53. The sliding sheet 53 is in contact with the inner peripheral surface of the fixing belt 21 via a lubricant. The lubricant is a relatively low viscosity lubricant such as fluorine grease or silicone oil. When the fixing belt 21 rotates, the sliding sheet 53 slides with respect to the fixing belt 21.

The IH heater 23 has a coil portion, a coil bobbin that holds the coil portion, and an arch core. The IH heater 23 is arranged so as to face the belt guide 51 with the fixing belt 21 interposed therebetween. A magnetic field is generated by applying a high-frequency AC voltage to the coil portion, and an eddy current is generated in the base material layer of the fixing belt 21 by the action of this magnetic field, the base material layer generates heat, and the fixing belt 21 is heated. ..

The press roller 25 has a core metal, an elastic layer provided on the outer peripheral surface of the core metal, and a release layer provided on the outer peripheral surface of the elastic layer. The elastic layer is made of silicon rubber or the like. The release layer is formed of a PFA tube or the like.

The press roller 25 is pressed against the pressing pad 27 with the fixing belt 21 interposed therebetween. As a result, a pressure region N is formed between the press roller 25 and the fixing belt 21. The press roller 25 is driven by a drive source (not shown) and rotates in the clockwise direction of FIG. When the press roller 25 rotates, the fixing belt 21 follows the press roller 25 and rotates in a counterclockwise direction opposite to the rotation direction of the press roller 25. As a result, the conveyed paper S passes through the pressurized region N.

The cap member 31 will be described with reference to FIGS. 3, 4 and 5. FIG. 5 is a front view showing the end wall of the cap member.

The cap member 31 is a bottomed cylindrical resin molded product that covers the end portion of the fixing belt 21, and as shown in FIG. 3, has a circular end wall 61 and a cylindrical shape along the outer circumference of the end wall 61. It has an outer peripheral wall 63 and. The end wall 61 has a contact portion 61a with which the end surface of the fixing belt 21 abuts. The outer peripheral surface of the end portion of the fixing belt 21 faces the outer peripheral wall 63 with a predetermined gap. A through hole 65 is opened in the center of the end wall 61. The stay 43 fitted to the holding member 41 projects through the through hole 65. The cap member 31 is rotatably supported between the flange portion 45 of each stay 43 and the C ring 67 mounted in the annular groove 47.

As shown in FIG. 5, a plurality of flow paths 71 and a holding groove 73 are formed in a concave shape in the contact portion 61a of the end wall 61. Each flow path 71 is formed linearly along the radial direction of the cap member 31 from the contact position between the end surface of the fixing belt 21 and the contact portion 61a toward the center of the end wall 61. The plurality of flow paths 71 are arranged at equal intervals with respect to the center of the end wall 61. The holding groove 73 is formed in an annular shape centered on the center of the end wall 61. The inner end of each flow path 71 in the radial direction communicates with the holding groove 73. As an example, the number of flow paths 71 is 18, and the depth of each flow path 71 is 0.3 mm to 0.5 mm, and the width is 0.5 mm to 1.0 mm. The depth of the holding groove 73 is 0.3 mm to 0.5 mm, and the width of the holding groove 73 is 0.5 mm to 1.0 mm.

With reference to FIG. 3 again, a gear 77 is formed on the outer surface of the end wall 61 along the periphery of the through hole 65.

An elastic member 29 is interposed in the gap between the outer peripheral surface of the end portion of the fixing belt 21 and the outer peripheral wall 63 of the cap member 31. That is, the elastic member 29 is arranged radially outside the flow path 71. In other words, the flow path 71 extends in a direction away from the elastic member 29 from the contact position between the end surface of the fixing belt 21 and the contact portion 61a. The elastic member 29 is a cylindrical member and is made of a material having a high coefficient of friction such as silicon rubber. As described above, when the fixing belt 21 rotates, the rotation of the fixing belt 21 is transmitted to the cap member 31 via the elastic member 29.

As shown in FIG. 4, the rotation detection mechanism 33 includes an idle gear 81, an actuator 83 that rotates by rotation of the idle gear 81, and an optical sensor 85 that detects the actuator 83. The idle gear 81 is rotatably supported by the housing so as to mesh with the gear 77 of the cap member 31. The actuator 83 has a gear portion 87 that meshes with the idle gear 81, and three detection pieces 89 that project radially from the gear portion 87. The three detection pieces 89 are arranged at equal intervals around the gear portion 87. As the gear portion 87 rotates, the detection piece 89 rotates along a predetermined rotation trajectory. The optical sensor 85 has a light emitting unit and a light receiving unit, and forms an optical path from the light emitting unit to the light receiving unit. The optical sensor 85 is supported so that the detection piece 89 of the actuator 83 passes between the light emitting unit and the light receiving unit.

The fixing operation of the fixing device 9 having the above configuration will be described. First, the press roller 25 is driven by a drive source to rotate, and the fixing belt 21 rotates driven in the clockwise direction of FIG. 2, which is opposite to the rotation direction of the press roller 25. At the same time, the IH heater 23 is driven to heat the fixing belt 21. The fixing belt 21 is heated to a predetermined controlled temperature (for example, 160 ° C.). After the fixing belt 21 is heated in this way, the paper S on which the toner image is transferred is conveyed to the pressure region N. When the paper S passes through the pressure region N, it is heated by the fixing belt 21 and pressed by the press roller 25 and the fixing belt 21, so that the toner image is fixed to the paper S. The paper S on which the toner image is fixed is conveyed from the pressurized region N along the conveying path 15.

Further, when the fixing belt 21 rotates, the cap member 31 rotates via the elastic member 29. Then, the actuator 83 rotates via the idle gear 81 that meshes with the gear 77 of the cap member 31, and the detection piece 89 passes between the light emitting portion and the light receiving portion of the optical sensor 85 to block or restore the optical path. As a result, the optical sensor 85 detects the rotation of the actuator 83, and it is determined that the fixing belt 21 is rotating normally.

In the fixing operation, since the lubricant is applied to the outer peripheral surface of the pressing pad 27 (sliding sheet 53), the sliding load on the pressing pad 27 of the fixing belt 21 is reduced, and the fixing belt 21 smoothly moves. Rotate. On the other hand, when the fixing belt 21 rotates, the end surface of the fixing belt 21 comes into contact with the contact portion 61a of the end wall 61 of the cap member 31. At this time, the lubricant adhering to the inner peripheral surface of the fixing belt 21 from the pressing pad 27 may leak from the end surface of the fixing belt 21 to the abutting portion 61a of the end wall 61. The leaked lubricant is guided to each flow path 71 of the contact portion 61a by the capillary phenomenon, further moves in each flow path 71 toward the holding groove 73, and is stored in the holding groove 73. When the fixing belt 21 rotates, the lubricant flowing through each flow path 71 is subjected to a centrifugal force in the radial direction, but the moving force of the lubricant due to the capillary phenomenon is larger than the moving force due to the centrifugal force. Therefore, the lubricant moves in the flow path 71 toward the holding groove 73.

As described above, according to the fixing device 9 of the present invention, the lubricant leaking from the end of the fixing belt 21 is guided to each flow path 71 by the capillary phenomenon, and the holding groove 73 is guided along each flow path 71. It moves toward and is stored in the holding groove 73. That is, since the lubricant does not flow out to the side of the elastic member 29, the situation in which the lubricant adheres to the elastic member 29 and slips against the fixing belt 21 does not occur. Therefore, since the rotation of the fixing belt 21 can be reliably transmitted to the cap member 31 via the elastic member 29, the rotation of the fixing belt 21 can be accurately detected by the rotation detecting mechanism 33. Since the rotation failure of the fixing belt 21 due to the leakage of the lubricant can be prevented in this way, the selection range of the viscosity and the amount of the lubricant can be expanded, and the fixing torque (sliding load of the fixing belt 21) can be further reduced. Become.

Although it is not always necessary to provide the holding groove 73, it is preferable to provide the holding groove 73 because the holding amount of the leaked lubricant increases by providing the holding groove 73.

Further, since the leaked lubricant is guided to each flow path 71 by the capillary phenomenon and further moves toward the holding groove 73, the leaked lubricant is automatically guided to the holding groove 73 and stored. Can be done. Further, since the flow path 71 is linear, the effect that the lubricant can easily move can be obtained.

Further, the cap member 31 is a resin molded product, and both the flow path 71 and the holding groove 73 are formed at the contact portion 61a of the end wall 61 of the cap member 31, so that the configuration of the mold can be simplified. It is possible and has excellent mass productivity. In particular, since the flow path 71 is linear, the mold can be configured more easily.

Next, a modification of the flow path 71 will be described with reference to FIGS. 6 and 7. 6 and 7 are front views showing a first modification and a second modification of the flow path.

In the first modification shown in FIG. 6, the flow path 71 is curved in an arc shape from the outside in the radial direction to the inside. In the second modification shown in FIG. 7, the flow path 71 is curved in an S shape from the outside in the radial direction to the inside.

By bending the flow path 71 in this way, the length of the flow path 71 can be increased, and the amount of the lubricant held in the flow path 71 can be increased.

Further, since the above-described description of the embodiment of the present invention describes a preferred embodiment of the fixing device and the image forming device according to the present invention, there may be various technically preferable limitations. However, the technical scope of the present invention is not limited to these aspects unless otherwise specified to limit the present invention. That is, the components in the above-described embodiment of the present invention can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the embodiment of the present invention described above does not limit the content of the invention described in the claims.

1 Printer (image forming device)
7 Image forming part 9 Fixing device 21 Fixing belt 25 Press roller (pressurizing member)
27 Pressing pad (pressing member)
29 Elastic member 31 Cap member 61a Abutment 71 Flow path 73 Holding groove

Claims (5)

With a rotatable endless fixing belt and
A pressure member forming a pressure region between the fixing belt and the fixing belt,
In the pressurizing region, a pressing member that contacts the inner peripheral surface of the fixing belt via a lubricant and presses the fixing belt against the pressurizing member.
A cap member, which is attached to the end of the fixing belt via an elastic member and rotates integrally with the fixing belt, is provided.
The cap member has a contact portion with which the end face of the fixing belt abuts.
A flow path of the lubricant is formed in the contact portion in a direction away from the elastic member from the contact position with the end surface of the fixing belt.
A plurality of the flow paths are formed along the radial direction of the cap member.
The contact portion is characterized in that a holding groove communicating with a plurality of the flow paths is formed on a side separated from the elastic member from the contact position with the end surface of the fixing belt. Fixing device. The fixing device according to claim 1 , wherein the flow path is linear. The fixing device according to claim 1 , wherein the flow path is curved. With a rotatable endless fixing belt and
A pressure member forming a pressure region between the fixing belt and the fixing belt,
In the pressure region, a pressing member that contacts the inner peripheral surface of the fixing belt via a lubricant and presses the fixing belt against the pressure member.
A cap member, which is attached to the end of the fixing belt via an elastic member and rotates integrally with the fixing belt, is provided.
The cap member has a contact portion with which the end face of the fixing belt abuts.
A flow path of the lubricant is formed in the contact portion in a direction away from the elastic member from the contact position with the end surface of the fixing belt.
The fixing device characterized in that the flow path has a curved shape. An image forming part that forms a toner image on paper,
An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 4, wherein the toner image formed by the image forming portion is fixed on paper.

Images