Patent Application
20210382424
This application is based upon and claims the benefit of priority from the corresponding Japanese Patent Application No. 2020-100086 filed on Jun. 9, 2020, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a fixing device and an image forming apparatus.
There is known an image heating device that processes the lubricant with a configuration where a projection portion is provided on either of the upstream side and the downstream side of a heater guide in the rotation direction of a fixing film.
A fixing device according to an aspect of the present disclosure includes a fixing belt, a pressure applying member, and a heater holding member. The fixing belt is configured to fix toner to a sheet. The pressure applying member forms a nip portion together with an outer peripheral surface of the fixing belt and causes the fixing belt to peripherally rotate while applying pressure to the fixing belt at the nip portion. The heater holding member holds a heater that applies heat to the fixing belt. The heater holding member includes a side portion and a plurality of inclined ribs. The side portion extends from the nip portion along an inner peripheral surface of the fixing belt and guides the fixing belt. The plurality of inclined ribs are disposed on the side portion to face the inner peripheral surface and are formed such that an interval between the inclined ribs is gradually narrowed as the inclined ribs proceed in a direction in which the fixing belt peripherally rotates.
An image forming apparatus according to another aspect of the present disclosure includes the fixing device described above and an image forming portion. The image forming portion is configured to form an image on the sheet.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description with reference where appropriate to the accompanying drawings. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
The following describes Embodiment 1 of the present disclosure with reference to the accompanying drawings. It is noted that in the drawings, same or similar portions are assigned the same reference signs, and the explanation is not repeated. In addition, in Embodiment 1, X-axis, Y-axis, and Z-axis that are perpendicular to each other are shown in the drawings. The Z-axis is parallel to a vertical plane, and the X-axis and the Y-axis are parallel to a horizontal plane.
The following describes an image forming apparatus 100 according to Embodiment 1 of the present disclosure with reference to
As shown in
The reading portion 3 reads an image of a document sheet D. The reading portion 3 generates image data from the read image. The document sheet conveyance portion 4 conveys the document sheet D to the reading portion 3. The sheet feed portion 5 stores a plurality of sheets S, and feeds a sheet S to the conveyance portion 6. The sheet S is made from, for example, paper or synthetic resin. The sheet S is an example of a recording medium. The conveyance portion 6 includes a plurality of pairs of conveyance rollers, and conveys the sheet S to the discharge portion 7 via the image forming portion 2.
The image forming portion 2 forms a toner image T (
The fixing device 1 applies heat and pressure to the toner image T to fix the toner image T to the sheet S. The conveyance portion 6 conveys the sheet S with the toner image T fixed thereto to the discharge portion 7. The discharge portion 7 discharges the sheet S to outside the housing of the image forming apparatus 100.
Next, the following describes a detailed configuration of the fixing device 1 according to Embodiment 1 with reference to
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
As shown in
In the following, a detailed description is given with reference to
The fixing belt 10 fixes the toner image T to the sheet S. That is, the fixing belt 10 is heated by the heater 30 described below and biased by the pressure applying member 20 such that the toner image T is fixed to the sheet S while the sheet S passes through the nip portion N between the fixing belt 10 and the pressure applying member 20.
The fixing belt 10 is endless. The fixing belt 10 is approximately cylindrical in shape. The fixing belt 10 is flexible. The fixing belt 10 is configured to peripherally rotate around a first rotation axis line L1. The fixing belt 10 extends along the first rotation axis line L1.
The fixing belt 10 includes an end portion 11, an end portion 12, an outer peripheral surface 13, and an inner peripheral surface 14. The end portions 11 and 12 are opposite ends of the fixing belt 10 in the direction along the first rotation axis line L1. In the following description, the direction along the first rotation axis line L1 may be denoted as “rotation axis direction”, “rotation axis direction of the fixing belt 10”, or “width direction of the fixing belt 10”. In addition, a middle (center) 10c of the fixing belt 10 in the rotation axis direction may be denoted as “middle 10c of the belt”. In addition, the middle 10c may be denoted as “center 10c”. Furthermore, an imaginary line that passes through the middle 10c of the belt may be denoted as a middle line CL. The middle line CL may be denoted as “center line CL”.
The fixing belt 10 further includes a plurality of layers. The fixing belt 10 includes, for example, a polyimide layer and a release layer. The release layer is formed on the outer peripheral surface of the polyimide layer. The release layer is, for example, a heat-resistant film made of fluororesin.
The pressure applying member 20 is freely rotatable around a second rotation axis line L2 as its axial center. When the pressure applying member 20 rotates, the fixing belt 10 rotates following the pressure applying member 20. With these configurations, when the sheet S passes through the nip portion N, the toner image T is fixed to the sheet S. It is noted that the sheet S is conveyed in a direction A (the positive side of the Z-axis). The pressure applying member 20 extends along the second rotation axis line L2. It is noted that the second rotation axis line L2 and the first rotation axis line L1 are approximately parallel to each other.
The pressure applying member 20 includes a columnar metal core 21, a cylindrical elastic layer 22, and a release layer 23. The elastic layer 22 is formed on the metal core 21. The release layer 23 is formed to cover the surface of the elastic layer 22. The metal core 21 is freely rotatable around the second rotation axis line L2 as its axial center. The metal core 21 is formed from, for example, stainless or aluminum. The elastic layer 22 is elastic, and is formed from, for example, silicone rubber. The release layer 23 is formed from, for example, fluororesin.
The heater holding member 40 holds the heater 30. As shown in
As shown in
The heater holding portion 32 includes a reinforcement member 33 and the heater 30. Specifically, the inner peripheral surface 14 of the fixing belt 10 faces the heater 30.
The reinforcement member 33 is configured to reinforce the heater holding member 40. The reinforcement member 33 is, for example, an elongated metal stay member. The reinforcement member 33 is, when viewed from the positive side of the Y-axis, approximately in the shape of inverted letter U. The reinforcement member 33 extends along the first rotation axis line L1.
The heater 30 heats the fixing belt 10. The heater 30 extends along the first rotation axis line L1. The heater 30 is, for example, a surface heater or an elongated thin-plate heater. The heater 30 is, for example, a ceramic heater, and includes a ceramic substrate and a heating resistor. The heater 30 is, for example, 1 mm thick. The heater 30 receives a pressure from the pressure applying member 20 via the fixing belt 10.
The heater holding portion 32 of the heater holding member 40 holds the heater 30. The heater holding portion 32 faces the fixing belt 10 across the heater 30. The heater holding member 40 is disposed inside the fixing belt 10 to face the pressure applying member 20 (on the opposite side from the outer peripheral surface 13 facing the pressure applying member 20). The heater holding member 40 is made from, for example, heat-resistant resin. The heater holding member 40 extends along the first rotation axis line L1. One of opposite ends of the heater holding member 40 in the direction along the first rotation axis line L1 is configured to fit to a connector provided in the main body of the image forming apparatus 100.
Meanwhile, there is known an image heating device that processes the lubricant with a configuration where a projection portion is provided on either of the upstream side and the downstream side of a heater guide in the rotation direction of a fixing film.
However, the above-mentioned image heating device has a problem that the lubricant accumulates on, for example, side walls of the projection portions and is deposited.
On the other hand, the fixing device 1 of Embodiment 1 is configured to prevent deposition of the lubricant between the ribs and promote circulation of the lubricant, as described in the following.
As shown in
The side portion 44 guides the fixing belt 10 (
As shown in
The downstream side portion 46 extends from the nip portion N of the heater holding member 40 along the inner peripheral surface 14 of the fixing belt 10 toward the downstream in the direction R1 in which the fixing belt 10 peripherally rotates.
The upstream side portion 48 extends from the nip portion N of the heater holding member 40 along the inner peripheral surface 14 of the fixing belt 10 toward the upstream in the direction R1 in which the fixing belt 10 peripherally rotates.
As shown in
The plurality of inclined ribs 52 and 54 of the heater holding member 40 are disposed on the downstream side portion 46.
The heater holding member 40 includes the storage portion 58 formed between the inclined rib 52 and the inclined rib 54 to store the lubricant M.
Specifically, the inclined rib 52 and the inclined rib 54 are disposed at least on the downstream side portion 46 of the heater holding member 40 to face the inner peripheral surface 14 of the fixing belt 10. The inclined rib 52 and the inclined rib 54 adjacent to each other are formed such that the interval between them is gradually narrowed as they proceed in a direction R1 in which the fixing belt 10 peripherally rotates.
It is preferable that a plurality of inclined ribs 52 and a plurality of inclined ribs 54 are provided. However, the present disclosure is not limited to the configuration where the plurality of inclined ribs 52 and the plurality of inclined ribs 54 are provided. In addition, the inclined rib 52 and the inclined rib 54 adjacent to each other may not join.
The heater holding member 40 includes the storage portion 58 formed between the inclined rib 52 and the inclined rib 54 to store the lubricant M.
Next, the behavior of lubricant M in the heater holding member 40 is described with reference to
As the fixing belt 10 further peripherally rotates, the lubricant M is stored and accumulated in the storage portion 58 between the inclined rib 52 and the inclined rib 54. Furthermore, due to the configuration where the interval between the inclined rib 52 and the inclined rib 54 adjacent to each other is gradually narrowed, as shown in
Even in a case where the inclined rib 52 and the inclined rib 54 adjacent to each other are formed not to join, the joint portion 56 may be a region where the inclined rib 52 and the inclined rib 54 adjacent to each other are most close to each other.
As shown in
According to the present embodiment, the lubricant M stored in the joint portion 56 is not deposited between the inclined rib 52 and the inclined rib 54, but is re-supplied to the inner peripheral surface 14 of the fixing belt 10. As a result, it is possible to suitably circulate the lubricant M between the fixing belt 10 and the heater holding member 40 and prevent coagulation of the lubricant M.
According to the present embodiment, the storage portion 58 formed between the inclined rib 52 and the inclined rib 54 is configured to store the lubricant M applied to the inner peripheral surface 14 of the fixing belt 10.
According to the present embodiment, it is possible to re-supply the lubricant M from the joint portion 56 where the inclined rib 52 and the inclined rib 54 adjacent to each other come closest to each other, to the inner peripheral surface 14 of the fixing belt 10. As a result, it is possible to suitably circulate the lubricant M between the fixing belt 10 and the heater holding member 40 and prevent coagulation of the lubricant M.
Next, as shown in
The joint rib 50 is formed such that the inclined rib 52 and the inclined rib 54 approach each other as they proceed in the direction R1 in which the fixing belt 10 peripherally rotates, and join at the joint portion 56.
The joint rib 50 includes the storage portion 58 to store the lubricant M in a space between the inclined rib 52 and the inclined rib 54.
The joint rib 50 includes the joint portion 56 at which the inclined rib 52 and the inclined rib 54 join. At the joint portion 56, the lubricant M stored in the storage portion 58 accumulates. The joint portion 56 supplies the lubricant M to the fixing belt 10.
Next, the behavior of lubricant M in the heater holding member 40 is described with reference to
As the fixing belt 10 further peripherally rotates, the lubricant M is stored and accumulates in the storage portion 58 between the inclined rib 52 and the inclined rib 54. Due to the configuration where the interval between the inclined rib 52 and the inclined rib 54 adjacent to each other is gradually narrowed, as shown in
As shown in
Furthermore, as shown in
According to the present embodiment, the lubricant M stored in the storage portion 58 of the joint rib 50 is not deposited between the inclined rib 52 and the inclined rib 54, but is re-supplied from the joint portion 56 to the inner peripheral surface 14 of the fixing belt 10. As a result, it is possible to suitably circulate the lubricant M between the fixing belt 10 and the heater holding member 40 and prevent coagulation of the lubricant M.
According to the present embodiment, with the configuration where the joint portion 56 is inclined toward the downstream in the direction R1 in which the fixing belt 10 peripherally rotates, the lubricant M is further suitably re-supplied from the joint portion 56 to the inner peripheral surface 14 of the fixing belt 10. As a result, it is possible to prevent coagulation of the lubricant M.
Furthermore, according to the present embodiment, the plurality of inclined ribs 52 and 54 are disposed on the downstream side portion 46. With this configuration, it is possible to suitably reduce the friction between the fixing belt 10 that passes through the nip portion N and the heater holding member 40, and suitably circulate the lubricant M between the fixing belt 10 and the heater holding member 40.
Next, the side portion 44 includes the upstream side portion 48 extending from the nip portion N toward the upstream in the direction R1 in which the fixing belt 10 peripherally rotates, and the joint rib 50 and the inclined rib 52 and the inclined rib 54 constituting the joint rib 50 are disposed on the upstream side portion 48.
As shown in
The joint rib 50 may be disposed on the upstream side portion 48. The joint rib 50 may be disposed only on the upstream side portion 48, not disposed on the downstream side portion 46. The joint rib 50 may be disposed on both the downstream side portion 46 and the upstream side portion 48.
After passing through the downstream side portion 46, the fixing belt 10 peripherally rotates without restraint relatively for a long time. As a result, the lubricant M applied to the inner peripheral surface 14 of the fixing belt 10 may flow to the end portion 11 or the end portion 12 shown in
The joint rib 50 disposed on the upstream side portion 48 collects the lubricant M applied to the inner peripheral surface 14 of the fixing belt 10, and re-supplies the lubricant M to the inner peripheral surface 14 of the fixing belt 10.
According to the present embodiment, with the configuration where the joint rib 50 is disposed on the upstream side portion 48, it is possible to restrict the oxidation of the lubricant M, and restrict the lubricant M from flowing out from the end portion 11 or the end portion 12. Furthermore, with the configuration where the joint rib 50 is disposed on the upstream side portion 48, it is possible to apply the lubricant M to the inner peripheral surface 14 of the fixing belt 10 in a stable manner.
Furthermore, according to the present embodiment, with the configuration where the joint rib 50 is disposed on both the downstream side portion 46 and the upstream side portion 48, it is possible to further suitably circulate the lubricant M between the fixing belt 10 and the heater holding member 40.
Embodiments of the present disclosure have been described above with reference to the accompanying drawings. However, the present disclosure is not limited to the above-described embodiments, but may be implemented in various manners without departing from the scope of the present disclosure. In the drawings, the components are shown schematically for easy understanding, and the components are drawn as different from the actual ones in thickness, length, number, and so on for the sake of drawing. In addition, the material, shape, measurement and the like of each component are not limited to those described in the embodiments, but may be varied without departing from the effect of the present disclosure.
The present disclosure is applicable to the fields of the fixing device and the image forming apparatus.
It is to be understood that the embodiments herein are illustrative and not restrictive, since the scope of the disclosure is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-100086 | Jun 2020 | JP | national |
