Blower device and image forming apparatus

Abstract

To prevent the positional deviation between channel forming members that relatively approach and separate from each other.SOLUTION: A blower device comprises: an airflow generating member that generates an airflow sent to a heating device; and a plurality of channel forming members 33, 34 that guide the airflow from the airflow generating member to the heating device. The plurality of channel forming members 33, 34 relatively approach and separate from each other. The channel forming members 33, 34 relatively approaching and separating from each other have positioning parts 33c, 34c that are in direct or indirect contact with each other to perform positioning of the channel forming members.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a blower device and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art As an example of a heating device installed in an image forming apparatus such as a copier or a printer, a fixing device is known that heats paper while sandwiching the paper between a pair of rotating bodies such as an endless belt or rollers, thereby fixing an image on the paper.

[0003] In a fixing device, since the heat of the non-paper passing area where the paper does not pass tends not to be taken away by the paper, when multiple sheets of paper are passed continuously, the heat of the rotor in the non-paper passing area gradually accumulates, and the temperature rise becomes significant. To address this problem, for example, in the image forming device described in the following Patent Document 1 (Patent Publication No. 5401441), a fan is used to blow air to the non-paper passing area of ​​the rotor to suppress the temperature rise in the non-paper passing area. Summary of the Invention [Problem to be solved by the invention]

[0004] In addition, in the image forming apparatus described in the above Patent Document 1, a duct is provided as a flow path forming member to guide the airflow generated by the fan to the fixing device. By guiding the airflow through the duct, the airflow can be efficiently blown to a desired location on the fixing device.

[0005] However, since the duct described in Patent Document 1 is divided into a portion provided on the image forming apparatus main body side and a portion provided on the cover member of the image forming apparatus, when the cover member is opened and closed, there is a risk that the relative positions of the duct on the cover member side and the duct on the image forming apparatus main body side may shift accordingly. If the relative positions of the ducts shift, it becomes difficult to efficiently guide the airflow from the duct on the upstream side in the air blowing direction (the duct on the cover member side) to the duct on the downstream side (the duct on the image forming apparatus main body side). Patent Document 1 does not consider such a problem at all. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an air blower including an airflow generating member that generates an airflow to be blown to a heating device, and a plurality of flow path forming members that guide the airflow from the airflow generating member to the heating device, the plurality of flow path forming members being configured to be relatively close to and spaced apart from one another, and the relatively close and spaced apart flow path forming members having positioning portions that directly or indirectly contact each other to position the flow path forming members relative to one another. Among the flow path forming members that are relatively close to and far from each other, the flow path forming member that is disposed on the upstream side in the air blowing direction has a side wall opposite to the side wall on which the positioning portion is provided, the side wall having an inclined portion that faces inward toward the downstream side in the air blowing direction. It is characterized by: Effect of the Invention

[0007] According to the present invention, it is possible to suppress misalignment between flow passage forming members that move relatively close to and away from each other. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic configuration diagram of a fixing device according to the present embodiment. [Diagram 3] FIG. 2 is a diagram showing a fixing device and a blower device mounted on the image forming apparatus. [Figure 4] FIG. 2 is an external perspective view of a duct included in the blower device according to the embodiment. [Diagram 5] FIG. [Figure 6]13 is a diagram showing an example in which the front side walls of the upstream duct and the downstream duct are configured to overlap each other. FIG. [Figure 7] 11 is a diagram showing the positional relationship between a duct and a maximum paper passing area. FIG. [Figure 8] FIG. 4 is an external perspective view of the upstream duct as viewed from the protrusion side. [Figure 9] 13A and 13B are diagrams showing modified examples of the protrusions. [Figure 10] FIG. 13 is a diagram showing an example in which a plurality of protrusions are provided. [Figure 11] 13A and 13B are diagrams illustrating another modified example of the positioning portion. [Figure 12] 13 is a diagram showing an example in which an elastic member is attached to a positioning portion of the upstream duct. FIG. [Figure 13] 13 is a diagram showing an example in which the upstream duct and the downstream duct are positioned on the front side; FIG. [Figure 14] FIG. 4 is a diagram showing the positional relationship between a duct and a heater. [Figure 15] FIG. 13 is a diagram showing an example in which a duct is disposed on the fixing belt side. [Figure 16] FIG. 13 is a diagram showing an example in which ducts are arranged on both the fixing belt side and the pressure roller side. [Figure 17] 11A and 11B are diagrams illustrating examples of other fixing devices to which the present invention can be applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described below with reference to the accompanying drawings. In each drawing for explaining the present invention, components such as members and components having the same function or shape are given the same reference numerals as far as they can be distinguished, and the description thereof will be omitted after the first description.

[0010] FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. In this specification, the term "image forming apparatus" includes a printer, a copier, a facsimile, a printing machine, or a multifunction machine that combines two or more of these. In addition, the term "image formation" used in the following description means not only forming an image having meaning such as a character or a figure, but also forming an image having no meaning such as a pattern. First, the overall configuration and operation of the image forming apparatus according to this embodiment will be described with reference to FIG. 1.

[0011] As shown in FIG. 1, the image forming apparatus 100 according to this embodiment includes an image forming unit 200 that forms an image on a sheet-like recording medium such as paper, a fixing unit 300 that fixes the image on the recording medium, a recording medium supply unit 400 that supplies the recording medium to the image forming unit 200, and a recording medium discharge unit 500 that discharges the recording medium outside the apparatus.

[0012] The image forming section 200 is provided with four process units 1Y, 1M, 1C, and 1Bk as image creating units, an exposure device 6 that forms an electrostatic latent image on the photosensitive member 2 provided in each of the process units 1Y, 1M, 1C, and 1Bk, and a transfer device 8 that transfers the image onto a recording medium.

[0013] Each process unit 1Y, 1M, 1C, and 1Bk has basically the same configuration, except that it contains toner (developer) of a different color, yellow, magenta, cyan, or black, which corresponds to the color separation components of a color image. Specifically, each process unit 1Y, 1M, 1C, and 1Bk includes a photoconductor 2 as an image carrier that carries an image on its surface, a charging member 3 that charges the surface of the photoconductor 2, a developing device 4 that supplies toner as a developer to the surface of the photoconductor 2 to form a toner image, and a cleaning member 5 that cleans the surface of the photoconductor 2.

[0014] The transfer device 8 includes an intermediate transfer belt 11, a primary transfer roller 12, and a secondary transfer roller 13. The intermediate transfer belt 11 is an endless belt member, and is stretched by a plurality of support rollers. Four primary transfer rollers 12 are provided inside the intermediate transfer belt 11. Each primary transfer roller 12 contacts each photoconductor 2 via the intermediate transfer belt 11, thereby forming a primary transfer nip between the intermediate transfer belt 11 and each photoconductor 2. The secondary transfer roller 13 contacts the outer peripheral surface of the intermediate transfer belt 11, forming a secondary transfer nip.

[0015] Fixing section 300 is provided with fixing device 20. Fixing device 20 includes fixing belt 21 as a fixing member, pressure roller 22 as a pressure member, etc. Fixing belt 21 and pressure roller 22 are in pressure contact with each other, and a nip portion (fixing nip) is formed between fixing belt 21 and pressure roller 22.

[0016] The recording medium supply unit 400 is provided with a paper feed cassette 14 that stores paper P as a recording medium, and a paper feed roller 15 that feeds paper P from the paper feed cassette 14. In the following description, the "recording medium" will be described as "paper", but the "recording medium" is not limited to paper (paper). The "recording medium" includes not only paper (paper) but also overhead projector sheets or fabrics, metal sheets, plastic films, or prepreg sheets in which carbon fibers are pre-impregnated with resin. In addition to plain paper, "paper" also includes cardboard, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like.

[0017] The recording medium ejection section 500 is provided with a pair of ejection rollers 17 for ejecting the paper P outside the image forming apparatus, and an ejection tray 18 on which the paper P ejected by the ejection rollers 17 is placed.

[0018] Next, the printing operation of the image forming apparatus 100 according to this embodiment will be described with reference to FIG.

[0019] When a printing operation is started in the image forming apparatus 100, the photoconductors 2 of the process units 1Y, 1M, 1C, and 1Bk and the intermediate transfer belt 11 of the transfer device 8 start to rotate. Also, the paper feed roller 15 starts to rotate, and the paper P is fed out from the paper feed cassette 14. The fed paper P comes into contact with a pair of timing rollers 16 and stops, and the transport of the paper P is temporarily stopped until an image to be transferred onto the paper P is formed.

[0020] In each process unit 1Y, 1M, 1C, 1Bk, first, the surface of the photoconductor 2 is charged to a uniform high potential by the charging member 3. Next, the exposure device 6 exposes the surface (charged surface) of each photoconductor 2 based on the image information of the document read by the document reading device or the print image information instructed to be printed from the terminal. As a result, the potential of the exposed portion is reduced and an electrostatic latent image is formed on the surface of each photoconductor 2. Then, the developing device 4 supplies toner to this electrostatic latent image, and a toner image is formed on each photoconductor 2. When the toner image formed on each photoconductor 2 reaches the primary transfer nip (the position of the primary transfer roller 12) as each photoconductor 2 rotates, it is transferred to the rotating intermediate transfer belt 11 so as to be overlapped in sequence. In this way, a full-color toner image is formed on the intermediate transfer belt 11. In the image forming apparatus 100, a single color image can be formed by using any one of the process units 1Y, 1M, 1C, and 1Bk, or a two-color or three-color image can be formed by using any two or three of the process units. After the toner image is transferred from the photoconductor 2 to the intermediate transfer belt 11, the cleaning member 5 removes residual toner and the like from each photoconductor 2.

[0021] The toner image transferred onto the intermediate transfer belt 11 is transported to the secondary transfer nip (the position of the secondary transfer roller 13) as the intermediate transfer belt 11 rotates, and is transferred onto the paper P that has been transported thereto by the timing roller 16. The paper P is then transported to the fixing device 20, and the toner image on the paper P is heated and pressurized by the fixing belt 21 and the pressure roller 22, thereby fixing the toner image to the paper P. The paper P is then transported to the recording medium discharge section 500, and is discharged onto the paper discharge tray 18 by the paper discharge roller 17. This completes the series of printing operations.

[0022] Next, the configuration of the fixing device 20 according to the present embodiment will be described with reference to FIG.

[0023] As shown in FIG. 2, the fixing device 20 includes, in addition to the fixing belt 21 and the pressure roller 22, a heater 23 as a heat source, a heater holder 24 as a heat source holding member, and a stay 25 as a support member.

[0024] The fixing belt 21 is a rotating body (first rotating body) that functions as a fixing member that fixes unfixed toner T (toner image) to paper P. The fixing belt 21 is held in a so-called free belt manner (at least in a state where no tension is applied when not rotating) by a pair of belt holding members inserted inside both ends of the fixing belt 21. For example, the fixing belt 21 is made of an endless belt having a cylindrical substrate mainly composed of polyimide (PI) having an outer diameter of 25 mm and a thickness of 40 to 120 μm. The material of the substrate is not limited to polyimide, but may be a heat-resistant resin such as PEEK, or a metal material such as nickel or SUS. When a metal material is used as the material of the substrate, a sliding layer made of polyimide, PTFE, or the like may be provided on the inner peripheral surface of the substrate.

[0025] In order to enhance durability and ensure releasability, a release layer made of a fluorine-based resin such as PFA or PTFE and having a thickness of 5 to 50 μm is formed on the outermost surface of the fixing belt 21. In addition, an elastic layer made of rubber or the like and having a thickness of 50 to 500 μm may be provided between the base material and the release layer.

[0026] The pressure roller 22 is a rotating body (second rotating body) disposed opposite the fixing belt 21. The pressure roller 22 is also a pressing member that presses the fixing belt 21 to form the nip portion N. Specifically, the pressure roller 22 is made of a roller having a metal core such as iron, an elastic layer provided on the outer peripheral surface of the core, and a release layer provided on the outer peripheral surface of the elastic layer. The elastic layer is made of silicone rubber having a thickness of, for example, 3.5 mm, and the release layer is made of a fluororesin layer having a thickness of, for example, about 40 μm.

[0027] The pressure roller 22 is pressed toward the fixing belt 21 by a biasing member such as a spring, and is in pressure contact with the outer circumferential surface of the fixing belt 21. As a result, a nip portion N is formed between the fixing belt 21 and the pressure roller 22 (at the contact point).

[0028] A heater 23, a heater holder 24, and a stay 25 are disposed inside the fixing belt 21.

[0029] The heater 23 is a plate-shaped heater that extends longitudinally across the longitudinal direction of the fixing belt 21 (the paper width direction intersecting the paper conveying direction) and is disposed so as to contact the inner peripheral surface of the fixing belt 21. Therefore, when the heater 23 generates heat, the fixing belt 21 is heated from the inside. In addition, the output of the heater 23 is controlled based on the temperature of the heater 23 detected by a temperature sensor such as a thermistor, so that the temperature of the fixing belt 21 is maintained at a predetermined temperature. In this state, as shown in FIG. 2, when the paper P carrying the unfixed toner T enters between the fixing belt 21 and the pressure roller 22 (the nip portion N), the unfixed toner T is pressurized and heated by the fixing belt 21 and the pressure roller 22, and the toner image is fixed on the paper P.

[0030] The heater 23 according to this embodiment includes a plate-shaped substrate 231, a resistance heating element 232 provided on the surface of the substrate 231 on the side of the nip portion N, and an insulating layer 233 covering the resistance heating element 232. The substrate 231 is made of a material having excellent heat resistance and insulation properties, such as ceramics such as alumina or aluminum nitride, glass, mica, or polyimide. The substrate 231 may also be made of a metal material (conductive material) such as stainless steel (SUS), iron, or aluminum on which an insulating layer is formed. In particular, when the substrate 231 is made of a highly thermally conductive material such as aluminum, copper, silver, graphite, or graphene, the uniform heat distribution of the heater 23 is improved, and image quality can be improved. The resistance heating element 232 is formed by, for example, applying a paste made of a mixture of silver palladium (AgPd) and glass powder to the surface of the substrate 231 by screen printing or the like, and then firing the substrate 231. Also, resistance materials such as silver alloy (AgPt) or ruthenium oxide (RuO2) can be used as the material of the resistance heating element 232. The insulating layer 233 is made of a material having excellent heat resistance and insulating properties, such as ceramics such as alumina or aluminum nitride, glass, mica, or polyimide. As a heat source for heating the fixing belt 21, other heat sources such as a halogen heater or a carbon heater may be used in addition to the plate-shaped heater of this embodiment. Furthermore, the heat source may be provided on the pressure roller 22 side as well as on the fixing belt 21.

[0031] The heater holder 24 is a member that holds the heater 23. The heater holder 24 is preferably made of a heat-resistant material because it is likely to become hot due to the heat of the heater 23. In particular, when the heater holder 24 is made of a heat-resistant resin with low thermal conductivity such as LCP or PEEK, the heat resistance of the heater holder 24 is ensured while heat transfer from the heater 23 to the heater holder 24 is suppressed, so that the fixing belt 21 can be heated efficiently.

[0032] The stay 25 is a member that supports the heater holder 24. The stay 25 supports the surface of the heater holder 24 opposite to the surface on the nip portion N side, thereby preventing the heater holder 24 from being deflected by the pressure of the pressure roller 22. As a result, the nip portion N of a uniform width is formed between the fixing belt 21 and the pressure roller 22. In order to ensure the rigidity of the stay 25, it is preferable that the stay 25 is made of an iron-based metal material such as SUS or SECC.

[0033] 3, in the image forming apparatus 100 according to the present embodiment, in order to suppress an excessive rise in temperature of the fixing device 20, an air blowing device (cooling device) 30 is provided that blows air to the fixing device 20. The air blowing device 30 has a fan 31 as an airflow generating member that generates an airflow, and a duct 32 as a flow path forming member that guides the airflow generated by the fan 31 to the fixing device 20.

[0034] In this embodiment, the fixing device 20 is provided in the image forming apparatus main body 101. In contrast, the fan 31 is provided in a cover member 102 that can be opened and closed relative to the image forming apparatus main body 101. Therefore, as indicated by the two-dot chain line in Fig. 3, when the cover member 102 is opened, the fan 31 moves together with the cover member 102. Similarly, when the cover member 102 is closed, the fan 31 moves together with the cover member 102.

[0035] In this manner, in this embodiment, since the fan 31 moves in conjunction with the opening and closing operation of the cover member 102, the duct 32 that guides the airflow from the fan 31 to the fixing device 20 is divided into an upstream duct 33 provided on the cover member 102 side and a downstream duct 34 provided on the image forming apparatus main body 101 side. In other words, of the duct 32, the upstream duct 33 is configured to move together with the cover member 102 and the fan 31 provided thereon when the cover member 102 is opened or closed.

[0036] In the case of such a configuration, if the upstream duct 33 is misaligned with respect to the downstream duct 34 when the cover member 102 is closed, airflow is likely to leak between the upstream duct 33 and the downstream duct 34, and there is a risk that efficient air blowing will not be possible. Therefore, in order to blow air efficiently, the accuracy of the relative positions of the ducts 33, 34 when the cover member 102 is closed is important. Therefore, in this embodiment, the misalignment of the ducts 33, 34 is suppressed and the accuracy of the relative positions is improved as follows.

[0037] The positioning structure for the ducts 33, 34 according to this embodiment will be described below.

[0038] FIG. 4 is an external perspective view of the upstream duct 33 and the downstream duct 34 according to this embodiment, and FIG. 5 is a cross-sectional perspective view of each of the ducts 33 and 34. As shown in FIG.

[0039] 4 and 5, both the upstream duct 33 and the downstream duct 34 are tubular members having a rectangular (rectangular or square) cross-sectional shape, and have openings 33a, 33b, 34a, and 34b formed at the upstream end and downstream end in the air blowing direction, respectively. The upstream opening 33a of the upstream duct 33 is disposed so as to face the fan 31, and the downstream opening 34b of the downstream duct 34 is disposed so as to face the outer circumferential surface of the pressure roller 22 of the fixing device 20 (see FIG. 3).

[0040] 4 and 5 show a state in which the downstream opening 33b of the upstream duct 33 faces the upstream opening 34a of the downstream duct 34, and the ducts 33, 34 communicate with each other. That is, FIGS. 4 and 5 show a state in which the cover member 102 is closed and air can be sent from the fan 31 to the fixing device 20. In addition, in FIGS. 4 and 5, the direction of arrow A indicates the direction in which the upstream duct 33 moves away from the downstream duct 34 in conjunction with the opening operation of the cover member 102. Conversely, the direction of arrow B indicates the direction in which the upstream duct 33 approaches the downstream duct 34 in conjunction with the closing operation of the cover member 102.

[0041] Specifically, the upstream duct 33 and the downstream duct 34 are positioned by contact between a protrusion 33c as a positioning portion (first positioning portion) provided on the upstream duct 33 and a receiving portion 34c as a positioning portion (second positioning portion) provided on the downstream duct 34. The protrusion 33c is provided on the outer surface of a back side wall 331 facing forward (arrow B direction) in the approach direction of the upstream duct 33, among the four side walls constituting the upstream duct 33. Therefore, when the upstream duct 33 approaches the downstream duct 34 in conjunction with the closing operation of the cover member 102, the protrusion 33c comes into contact with a receiving portion 34c (inner surface) provided on a back side wall 341 of the downstream duct 34 facing the protrusion 33c. This restricts the movement of the upstream duct 33 in the approach direction, and the upstream duct 33 is positioned relative to the downstream duct 34.

[0042] In this manner, in this embodiment, when the cover member is closed, the positioning portions (protrusion 33c and receiving portion 34c) of the upstream duct 33 and the downstream duct 34 come into contact with each other, thereby positioning the ducts 33, 34. This improves the positioning accuracy of the ducts 33, 34, suppressing air leakage between the ducts and allowing efficient blowing of air to the pressure roller 22. This provides a good cooling effect.

[0043] In this embodiment, in order to more effectively suppress airflow leakage between the ducts, an inclined portion 33d is provided on the edge of the downstream opening 33b of the upstream duct 33. The inclined portion 33d is provided on the downstream end of the front (opposite) side wall 332 facing the rear side wall 331 on which the protrusion 33c is provided, and is inclined so as to face inward toward the downstream. As a result, when the airflow is guided from the upstream duct 33 to the downstream duct 34, the airflow is guided inward by the inclined portion 33d, making it less likely to leak out to the outside.

[0044] In particular, in this embodiment, when the upstream duct 33 is positioned close to the downstream duct 34, the front side wall 342 of the downstream duct 34 needs to be positioned at a position removed from the movement trajectory of the upstream duct 33 so that the upstream duct 33 does not interfere with the front side wall 342 of the downstream duct 34 (the side wall 342 opposite to the side wall 341 on which the receiving portion 34c is provided). For this reason, a gap is likely to occur between the front side wall 342 of the downstream duct 34 and the front side wall 332 of the upstream duct 33 positioned close thereto. Therefore, in this embodiment, in order to suppress airflow leakage from a location where such a gap is likely to occur, an inclined portion 33d is provided at the downstream end of the front side wall 332 of the upstream duct 33, and the inclined portion 33d guides the airflow inward.

[0045] 6, the side wall 332 on the front side of the upstream duct 33 may overlap the side wall 342 on the front side of the downstream duct 34. That is, the downstream end of the side wall 332 on the front side of the upstream duct 33 may be located downstream of the upstream end of the side wall 342 on the front side of the downstream duct 34. In particular, when the side walls 332, 342 contact each other at the overlapping portion, air leakage between the ducts is effectively suppressed. Even if the side walls 332, 342 are not in contact with each other, as long as the side walls 332, 342 are arranged close to each other so as to overlap, air leakage between the ducts can be suppressed compared to the case where the side walls 332, 342 do not overlap each other.

[0046] 7, in this embodiment, the upstream duct 33 and the downstream duct 34 are disposed on both ends of the pressure roller 22 in the longitudinal direction (rotation axis direction) X. In each downstream duct 34, the air outlet (downstream opening 34b) that blows air to the pressure roller 22 is disposed on the widthwise outer side (non-paper passing area) of the maximum paper passing area (maximum recording medium passing area) W through which the maximum width of the paper P passes through the fixing device 20. Note that the "widthwise outer side" of the maximum paper passing area here means the outer space of the space that exists in a direction perpendicular to the widthwise direction (arrow X direction in FIG. 7) of the maximum paper passing area. The "width direction" of the paper passing area means the direction that intersects or is perpendicular to the direction in which the paper is transported, and is the same direction as the longitudinal direction of the fixing belt 21 or the rotation axis direction of the pressure roller 22.

[0047] In this manner, in the present embodiment, the air outlets (downstream openings 34b) of each downstream duct 34 are disposed on the outside in the width direction of the maximum paper passing area W. Therefore, even if the temperature in the non-paper passing area rises when multiple maximum-width sheets P are continuously passed through, the air flow can be blown to the non-paper passing area of ​​the pressure roller 22. This suppresses the temperature rise in the non-paper passing area. On the other hand, if the air outlets (downstream openings 34b) of each downstream duct 34 are disposed on both ends on the inside in the width direction of the maximum paper passing area W, the both ends of the maximum-width sheet P are not sufficiently heated, and toner is not fixed well, which may cause image defects such as so-called edge offset. For this reason, in the present embodiment, the air outlets (downstream openings 34b) of each downstream duct 34 are disposed on the outside in the width direction of the maximum paper passing area W.

[0048] 7, when there are a plurality of combinations of the upstream duct 33 and the downstream duct 34, it is preferable that the positioning of the ducts 33, 34 in each pair is performed independently for each pair. That is, in the case of this embodiment, it is preferable that the positioning of the ducts 33, 34 in one pair is not affected by the positioning of the ducts 33, 34 in the other pair. This allows the positioning of each pair to be performed reliably, and air leakage between the ducts can be effectively suppressed.

[0049] FIG. 8 is an external perspective view of the upstream duct 33 as viewed from the protrusion 33c side.

[0050] As shown in Fig. 8, in this embodiment, the protrusion 33c provided on the upstream duct 33 has a planar contact surface 330. Therefore, the protrusion 33c comes into surface contact with the planar receiving portion 34c of the downstream duct 34 (see Figs. 4 and 5). In this way, the protrusion 33c comes into surface contact with the receiving portion 34c rather than in point contact, thereby improving positioning accuracy.

[0051] The shape of the projection 33c is not limited to that shown in FIG. 8, and may be a hemispherical shape as shown in FIG. 9. In this case, the projection 33c is in point contact with the receiving portion 34c. Furthermore, as shown in the example of FIG. 10, a plurality of hemispherical projections 33c may be provided. Also, as shown in the example of FIG. 11, the positioning portions of the upstream duct 33 and the downstream duct 34 may be configured by a tapered projection 33e and a tapered recess 34e that can be engaged with each other. In this case, the engagement between the projection 33e and the recess 34e not only positions the upstream duct 33 relative to the downstream duct 34 in the approach direction B, but also positions the upstream duct 33 in the direction intersecting the approach direction B, so that the relative positional accuracy of the ducts is improved and air leakage between the ducts can be more reliably suppressed. Also, the projection or projection as the positioning portion and the receiving portion or recess may be provided on either the upstream duct 33 or the downstream duct 34.

[0052] In the above embodiment, the positioning portions (the protrusions 33c and the receiving portions 34c) of the upstream duct 33 and the downstream duct 34 are in direct contact with each other (see Figs. 4 and 5), but the positioning portions may be indirectly in contact with each other via other members. For example, as shown in Fig. 12, an elastic member 35 such as sponge or rubber may be attached to the positioning portion of the upstream duct 33, and the positioning portions of the upstream duct 33 and the downstream duct 34 may be indirectly in contact with each other via the elastic member 35. In this case, the adhesion of the elastic member 35 to the positioning portion of the downstream duct 34 makes it difficult for gaps to occur between the positioning portions, and it becomes possible to more effectively suppress airflow leakage between the ducts. In addition, as shown in Fig. 12, the elastic member 35 may be attached to a surface of the upstream duct 33 that does not have the protrusions 33c, or may be attached on the protrusions 33c. In addition, the elastic member 35 may be attached to the downstream duct 34 instead of the upstream duct 33.

[0053] In the above embodiment, the positioning portions (protrusion 33c and receiving portion 34c) are provided on the rear side walls 331, 341 of the upstream duct 33 and the downstream duct 34 (see Figs. 4 and 5), but the locations where the positioning portions are provided are not limited to the rear side walls 331, 341. For example, as in the example shown in Fig. 13, the positioning portions (protrusion 33c and receiving portion 34c) may be provided on the front side walls 332, 342 of the upstream duct 33 and the downstream duct 34.

[0054] Furthermore, in order to improve the positional accuracy of the air outlet (downstream opening 34b) relative to the pressure roller 22, the downstream duct 34 is preferably attached to a frame 29 (see FIG. 3) of the fixing device 20 that holds the pressure roller 22. By attaching the downstream duct 34 to the fixing device 20, the stacking error of parts between the pressure roller 22 and the downstream duct 34 is reduced compared to when the downstream duct 34 is attached to the image forming apparatus main body 101, and therefore the positional accuracy of the downstream duct 34 relative to the pressure roller 22 is improved.

[0055] FIG. 14 is a diagram showing the positional relationship between the heater 23 and the duct 32 provided in the fixing device.

[0056] 14 has a plurality of resistance heating elements 232 arranged along the longitudinal direction of a base material 231 (longitudinal direction X of the fixing belt 21 or pressure roller 22). Each resistance heating element 232 is electrically connected in parallel to two electrode portions 234 provided on one longitudinal end side of the base material 231 via power supply lines 235. The surface of each resistance heating element 232 and the surface of each power supply line 235 are covered with an insulating layer 233. When a voltage is applied to each electrode portion 234 and a potential difference is generated between each electrode portion 234, a current flows through each resistance heating element 232 and heats up.

[0057] In the example shown in FIG. 14, when a sheet P of maximum width W is passed through, the temperature on both outer sides in the width direction of the maximum paper passing area W is likely to rise, so similarly to the example shown in FIG. 7, it is preferable that the air outlet (downstream opening 34b) of the downstream duct 34 is disposed on both outer sides in the width direction of the maximum paper passing area W. Specifically, in the example shown in FIG. 14, the air outlet (downstream opening 34b) of the downstream duct 34 is disposed at a position indirectly facing (through a fixing belt and a pressure roller, etc.) each of the resistance heating elements 232 disposed at both ends in the longitudinal direction of the base material 231. In addition, the air outlet (downstream opening 34b) of the downstream duct 34 may be disposed only on the side of one of the resistance heating elements 232 disposed at both ends.

[0058] 7 and 14 show an example of an image forming apparatus using a so-called center-based transport system in which sheets of various width sizes are transported based on the center of each sheet in the width direction, but the blower device according to the present invention is not limited to being applied to an image forming apparatus using the center-based transport system. The blower device according to the present invention can also be applied to an image forming apparatus using a so-called end-based transport system in which sheets of various width sizes are transported based on one end of each sheet in the width direction.

[0059] The blower device according to the present invention is not limited to blowing air to pressure roller 22, but may blow air to fixing belt 21 as in the example shown in Fig. 15. Also, as in the example shown in Fig. 16, ducts 32 may be disposed on both sides of fixing belt 21 and pressure roller 22, and air may be blown to both fixing belt 21 and pressure roller 22 through each duct 32.

[0060] In the above embodiment, the upstream duct 33 is configured to be movable together with the cover member 102, and the downstream duct 34 is fixed to the image forming apparatus main body 101, but conversely, the upstream duct 33 may be fixed to the image forming apparatus main body 101, and the downstream duct 34 may be movable together with the cover member 102. Even in such a case, as in the above embodiment, the upstream duct 33 and the downstream duct 34 have positioning parts that contact each other, so that the ducts can be positioned to each other and air leakage between the ducts can be suppressed. In addition, the movement trajectory of one duct approaching and moving away from the other duct is not limited to the arc trajectory (see Figs. 4 and 5) as in the above embodiment, but may be a linear trajectory.

[0061] The configuration of the fixing device is not limited to that of the above embodiment. For example, the fixing device may be configured to include a fixing roller 26 as a fixing rotator, a pressure roller 27 as a pressure rotator, and a halogen heater 28 as a heat source, as shown in FIG.

[0062] The blower device according to the present invention is not limited to blowing air to a fixing device. For example, the blower device according to the present invention can be applied to a drying device (heating device) that heats paper in order to dry liquid such as ink discharged onto the paper in an inkjet image forming apparatus. [Explanation of symbols]

[0063] 20 Fixing device (heating device) 21 Fixing belt (fixing member) 22 Pressure roller (pressure member) 30 Blower 31 Fan (airflow generating component) 32 Duct (flow path forming member) 33 Upstream duct 33a Upstream opening 33b Downstream opening 33c Protrusion (positioning part) 33d slope part 34 Downstream duct 34a Upstream opening 34b Downstream opening (air outlet) 34c Receiving part (positioning part) 35 Elastic member 232 Resistance heating element N Nip P Paper (recording medium) W Maximum paper passing area [Prior art documents] [Patent documents]

[0064] [Patent Document 1] Patent No. 5401441

Claims

1. an airflow generating member that generates an airflow to be blown to the heating device; A blower device including a plurality of flow path forming members that guide airflow from the airflow generating member to the heating device, The flow path forming members are configured to be relatively close to and spaced apart from each other, the flow path forming members which are relatively close to and spaced apart from each other have positioning portions which directly or indirectly contact each other to position the flow path forming members relative to each other, A blower device characterized in that, among the flow path forming members that are relatively close to and farther apart, the flow path forming member that is arranged upstream in the air blowing direction has an opposite side wall that faces the side wall on which the positioning portion is provided, the opposite side wall having an inclined portion that faces inward toward the downstream in the air blowing direction.

2. An airflow generating member that generates an airflow to be blown to a heating device; A blower device including a plurality of flow path forming members that guide airflow from the airflow generating member to the heating device, The flow path forming members are configured to be relatively close to and spaced apart from each other, the flow path forming members which are relatively close to and spaced apart from each other have positioning portions which directly or indirectly contact each other to position the flow path forming members relative to each other, A blower device characterized in that, among the flow path forming members that are relatively close to and farther apart, in the flow path forming member that is arranged upstream in the air blowing direction, the side wall opposite the side wall on which the positioning portion is provided is arranged so as to overlap with the side wall of the flow path forming member that is arranged downstream in the air blowing direction.

3. There are a plurality of pairs of flow path forming members that are relatively close to and spaced apart from each other, The blower device according to claim 1 or 2, wherein the positioning of the flow passage forming members relative to each other is performed independently for each group.

4. A blower device described in any one of claims 1 to 3, wherein the positioning portions are in surface contact with each other.

5. A blower device described in any one of claims 1 to 4, wherein the positioning portions indirectly contact each other via an elastic member.

6. A blower device described in any one of claims 1 to 5, wherein the air outlet of the flow path forming member that blows airflow into the heating device is positioned widthwise outside the maximum recording medium passing area through which the widest recording medium passes through the heating device.

7. A blower device described in any one of claims 1 to 6, wherein the flow path forming member arranged downstream in the air blowing direction among the flow path forming members that are relatively close to and spaced apart is attached to the heating device.

8. A heating device, An image forming apparatus comprising the air blower according to claim 1 for blowing air to the heating device.

9. The heating device comprises: a rotatable endless fixing belt; a rotatable pressure member that contacts an outer peripheral surface of the fixing belt to form a nip portion; 9. The image forming apparatus according to claim 8, further comprising a fixing device including a heat source in contact with an inner circumferential surface of the fixing belt.

10. The heating source has a plurality of resistive heating elements arranged in a longitudinal direction of the fixing belt, 10. The image forming apparatus according to claim 9, wherein the air outlet of the flow path forming member that blows out an air flow to the heating device is arranged indirectly facing at least one of the resistance heating elements arranged at both ends in the longitudinal direction.

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