Image forming apparatus

Abstract

To provide an image-forming device capable of inhibiting temperature deviation between a measurement temperature measured by fixing temperature measurement means and an actual fixing temperature.SOLUTION: In an image-forming device having a partition 8 for partitioning a space, a fixing device 5 for fixation by heating and pressurization is provided in a first space S1 in one side of the partition 8, an opening 80 is provided in the partition 8, fixing temperature measurement means 9 for measuring a fixing temperature of the fixing device 5 without any contact while facing the opening 80 of the partition 8 is provided in a second space S2 in the other side of the partition 8, and shielding means for shielding circulation of air between the first space S1 and the second space S2 via the opening 80 is provided.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an image forming apparatus such as a copying machine, a multifunction peripheral, a printer, and a facsimile machine.

Background Art

[0002] Conventionally, as a means for measuring the fixing temperature of a fixing device for fixing a toner image on a sheet, a non-contact fixing temperature measuring means may be used. Such a fixing temperature measuring means is provided outside the housing of the fixing device so as to be separated from the fixing member, for example, in view of its heat resistance temperature, and measures the temperature of the fixing member facing an opening provided in the housing of the fixing device (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the structure around the conventional fixing temperature measuring means, if air flows through the opening of the housing of the fixing device, the air hits the fixing temperature measuring means facing the opening, and there is a risk that the temperature measured by the fixing temperature measuring means deviates from the actual fixing temperature due to this air.

[0005] The present invention has been made to solve the above conventional problems, and an object thereof is to provide an image forming apparatus capable of suppressing a temperature deviation between a measured temperature measured by a fixing temperature measuring means and an actual fixing temperature.

Means for Solving the Problems

[0006] To achieve the above object, the image forming apparatus described in the present application is an image forming apparatus including a partition wall that partitions a space. A fixing device that fixes by heating and pressing is provided in a first space on one side of the partition wall. An opening is provided in the partition wall. In a second space on the other side of the partition wall, there is provided fixing temperature measuring means for non-contact measurement of the fixing temperature of the fixing device facing the opening of the partition wall, and An air flow path that communicates with the outside of the image forming apparatus and through which air flows along the partition wall, offset from the partition wall, inside the air flow path a mounting plate to which the fixing temperature measuring means is attached, and and from the outer peripheral edge of the opening of the partition wall to the mounting plate, vertically installed a blocking rib are provided. The blocking rib is fixed to the partition wall by a fastening member, and air flowing along the partition wall blocks to prevent air from hitting the fixing temperature measuring means, is blocked, and a fixing portion for fixing to the partition wall is continuously provided at the edge portion of the blocking rib and is characterized by this.

[0010] Further, in the image forming apparatus, a part of the partition wall including the opening may be configured to be detachable from the image forming apparatus main body together with the fixing temperature measuring means, the mounting plate, and the blocking rib.

[0011] Further, in the image forming apparatus, a positioning pin for positioning the mounting plate projects from the blocking rib toward the mounting plate side. A positioning hole through which the positioning pin is inserted is formed in the mounting plate. The positioning hole may be blocked by the positioning pin in a state where the mounting plate is positioned by the blocking rib.

[0012] Further, in the image forming apparatus, a positioning pin for positioning the mounting plate projects from the blocking rib toward the mounting plate side. A positioning hole through which the positioning pin is inserted is formed in the mounting plate. The positioning hole may be located outside the inner peripheral edge of the blocking rib in a state where the mounting plate is positioned by the blocking rib.

[0013] Further, in the image forming apparatus, the fixing temperature measuring means may be composed of a thermopile element, and the mounting plate may be composed of a substrate on which the fixing temperature measuring means is mounted.

[0015] Further, in the image forming apparatus, in the air flow path, an opening is provided on the downstream side in the air flow direction of the air flowing in the air flow path, and the mounting plate hood covering the

[0016] Further, in the image forming apparatus, in the second space on the other side of the partition wall, an air flow path communicating with the outside of the image forming apparatus is provided. The fixing temperature measuring means is composed of a thermopile element. The mounting plate extends downstream in the air flow direction of the air flowing in the air flow path from the blocking rib, and is composed of a substrate on which the fixing temperature measuring means is mounted on the mounting surface. On the mounting surface of the substrate constituting the mounting plate on the downstream side in the flow direction from the blocking rib, connecting means connectable to an external device are mounted. In the air flow path, an opening is provided on the downstream side in the air flow direction of the air flowing in the air flow path, and a hood covering the fixing temperature measuring means and the mounting plate may be provided.

[0017] Further, in the image forming apparatus, the partition wall may be provided with an air induction port for inducing air in a direction away from the fixing temperature measuring means facing the opening.

Advantages of the Invention

[0018] According to the present invention, it is possible to suppress the temperature deviation between the measured temperature measured by the fixing temperature measuring means and the actual fixing temperature.

Brief Description of the Drawings

[0019]

Figure 1

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Figure 11

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Figure 17

Mode for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals are given to the same components among the following-described embodiments, and redundant descriptions of these components are omitted.

[0021] (Embodiment 1) - Overall Configuration of Image Forming Apparatus - First, the overall configuration of the image forming apparatus A in Embodiment 1 will be described.

[0022] FIG. 1 is a schematic cross-sectional view showing the configuration of the image forming apparatus A in Embodiment 1. In the figure, reference sign X indicates the width direction (depth direction), the -X direction (minus X direction) is the front direction, and the +X direction (plus X direction) is the rear direction. Reference sign Y indicates the left-right direction Y orthogonal to the width direction X, the -Y direction (minus Y direction) is the left direction, and the +Y direction (plus Y direction) is the right direction. Reference sign Z indicates the up-down direction, the -Z direction (minus Z direction) is the downward direction, and the +Z direction (plus Z direction) is the upward direction. These settings are the same in the following embodiments.

[0023] The image forming apparatus A is an electrophotographic image forming apparatus and is a color multifunction printer of an intermediate transfer type capable of printing full-color images. The image forming apparatus A includes an image reading unit 1, an image forming unit 2, an intermediate transfer member 3, a secondary transfer unit 4, a fixing device 5, a sheet storage unit 6, a sheet roller group 7, and a sheet discharge unit 70 (see FIG. 1). The remaining part of the image forming apparatus A other than these configurations is referred to as the "image forming apparatus main body". The image forming apparatus A is provided with a sheet conveyance path S through which a sheet is conveyed. In the present embodiment, for printing by the image forming apparatus A, toners of each color of yellow (Y), magenta (M), cyan (C), and black (K) are used.

[0024] The image reading unit 1 reads an image from a document and is provided at the upper part of the image forming apparatus A. The image reading unit 1 includes a document reading device 10, a document placement table 11, and an automatic document processing device 12 (see FIG. 1).

[0025] The original document reading device 10 irradiates light on the original document and reads an image from the original document based on the reflected light thereof. The original document reading device 10 incorporates, for example, a light source that irradiates light on the original document, a lens and an image sensor, a mirror that guides the reflected light of the original document to the lens, and the like. The reflected light of the original document incident on the image sensor through the lens is photoelectrically converted by the image sensor, thereby generating image data.

[0026] The original document placing table 11 is a part where the original document is placed by the user and is provided above the original document reading device 10 (see FIG. 1). The original document placing table 11 is formed of transparent glass. The automatic original document processing device 12 automatically and continuously conveys the original document inserted by the user to the original document reading device 10 and is provided above the original document placing table 11 (see FIG. 1). The image of the original document is read by the original document reading device 10 in a state where it is placed on the original document placing table 11 or in a state where it is conveyed to the original document reading device 10 by the automatic original document processing device 12.

[0027] The image forming unit 2 forms a toner image based on the image data and includes an exposure device 20, a developing device 21, an image carrier 22, a charger 23, and a cleaning unit 24 (see FIG. 2). Note that the image data may be generated by the image reading unit 1 or may be supplied from an external device.

[0028] The exposure device 20 forms an electrostatic latent image corresponding to each color on the image carrier 22 by exposing the surface of the image carrier 22 charged by the charger 23 according to each color. The exposure device 20 incorporates a light source that emits a laser beam, a polygon mirror that scans and reflects the laser beam, and optical elements (for example, a lens, a mirror, etc.) for guiding the laser light of the reflected laser beam to the image carrier 22.

[0029] The developing device 21 forms a toner image by visualizing the electrostatic latent image formed on the surface of each image carrier 22 with toner of each color (Y, M, C, K) supplied from the toner cartridge T. By causing the developing device 21 to fly the toner onto the image carrier 22, toner is supplied to the electrostatic latent image formed on the surface of the image carrier 22, and a toner image is formed on the surface of the image carrier 22.

[0030] The image carrier 22 has an electrostatic latent image formed on its surface and is rotationally driven in a predetermined direction by the drive of a main motor (not shown). By the rotational drive of the image carrier 22, the toner image visualized on the image carrier 22 is conveyed to the intermediate transfer member 3.

[0031] The charger 23 uniformly charges the surface of the image carrier 22 to a predetermined potential. For the charger 23, for example, a contact type charger (such as a roller type or a brush type) or a charger type charger is used.

[0032] The cleaning unit 24 removes and collects the toner remaining on the surface of the image carrier 22 after development and image transfer.

[0033] The intermediate transfer member 3 is disposed above the image carrier 22, and the toner images of each color formed on the surface of the image carrier 22 are once transferred thereto. The intermediate transfer member 3 includes an intermediate transfer belt 30, a driving roller 31, a driven roller 32, and a primary transfer roller 33.

[0034] The intermediate transfer belt 30 is an endless belt rotated in a predetermined direction and is suspended by the driving roller 31 and the driven roller 32. The outer surface of the intermediate transfer belt 30 is in contact with the image carrier 22. The toner images of each color visualized on the image carrier 22 are sequentially superimposed and transferred onto the intermediate transfer belt 30. The toner image transferred onto the intermediate transfer belt 30 is conveyed to the secondary transfer portion 4 by the rotation of the intermediate transfer belt 30. The intermediate transfer belt 30 is formed of, for example, a film having a thickness of about 100 μm to 150 μm.

[0035] The driving roller 31 is a roller that is rotationally driven in a predetermined direction by the driving of a belt motor (not shown), and is provided on the right end side of the intermediate transfer member 3 (see FIG. 2). By the rotational driving of the driving roller 31, the intermediate transfer belt 30 is rotated.

[0036] The driven roller 32 is a roller rotatably provided along the intermediate transfer belt 30 (see FIG. 2). The driven roller 32 is rotated according to the rotation of the intermediate transfer belt 30.

[0037] The primary transfer rollers 33 are arranged in a row so as to correspond to the image carrier 22 via the intermediate transfer belt 30 (see FIG. 2). When a transfer bias is applied to the primary transfer roller 33, the toner image on the image carrier 22 is transferred to the intermediate transfer belt 30. This transfer bias is a high-voltage transfer bias having a polarity opposite to the charging polarity of the toner (for example, a minus electrode), for example, a plus electrode.

[0038] On the outer peripheral surface of the primary transfer roller 33, a conductive elastic material (for example, a material made of EPDM, foamed urethane, etc.) is provided. By providing this conductive elastic material, it becomes possible to uniformly apply a high voltage to the intermediate transfer belt 30. Hereinafter, the transfer of the toner images of respective colors formed on the image carrier 22 onto the intermediate transfer belt 30 is referred to as "primary transfer".

[0039] The secondary transfer unit 4 transfers the toner images of respective colors primarily transferred onto the intermediate transfer belt 30 onto the sheet. The secondary transfer unit 4 has a secondary transfer roller 40 provided at a transfer site where the sheet and the intermediate transfer belt 30 face each other. A voltage for transferring the toner images of respective colors on the intermediate transfer belt 30 onto the sheet, that is, a voltage having a polarity opposite to the charging polarity of the toner (for example, a minus electrode), for example, a plus electrode, is applied to the secondary transfer roller 40. Hereinafter, the transfer of the toner images of respective colors transferred onto the intermediate transfer belt 30 onto the sheet is referred to as "secondary transfer".

[0040] The fixing device 5 fixes the toner image on the sheet by heating and melting the toner image secondarily transferred onto the sheet and fixing it on the sheet, and is provided on the downstream side of the secondary transfer portion 4 in the sheet conveyance path S. The configuration of the fixing device 5 will be described later.

[0041] The sheet storage unit 6 is disposed at the lower part of the image forming apparatus A and has a cassette 60 for storing sheets used for image formation. The sheet storage unit 6 may have a plurality of cassettes 60. Further, each of the plurality of cassettes 60 may store sheets of any material and size.

[0042] The sheet roller group 7 includes a pickup roller 7a, conveyance rollers 7b to 7d, and a registration roller 7e.

[0043] The pickup roller 7a pulls out the uppermost recording sheet (sheet) of the sheet stack in the sheet storage unit 6 and conveys it to the sheet conveyance path S. The conveyance rollers 7b to 7d convey the sheet along the sheet conveyance path S. The registration roller 7e temporarily stops the sheet conveyed from the sheet storage unit 6 and aligns the leading edges of the sheets. These sheet roller groups 7 are each rotationally driven by the drive of a motor (not shown).

[0044] The sheet discharge unit 70 is provided at the upper part of the image forming apparatus A and picks up the printed sheet face down.

[0045] In addition to the above configuration, the image forming apparatus A is provided with a control unit (not shown) that controls each of the above-described components according to an input operation by the user or the like.

[0046] With the image forming apparatus A as described above, printing on a sheet is performed as follows. First, the image forming unit 2 forms a toner image based on the image data generated by the image reading unit 1 or supplied from an external device. This toner image is primarily transferred to the intermediate transfer member 3. During this time, the sheet is pulled out from the sheet storage unit 6 by the pickup roller 7a, conveyed to the registration roller 7e by the conveyance roller 7b, and then conveyed to the secondary transfer unit 4 by the registration roller 7e. Subsequently, the secondary transfer unit 4 secondarily transfers the toner image primarily transferred onto the intermediate transfer belt 30 to the sheet. The fixing device 5 fixes the toner image secondarily transferred onto the sheet to the sheet. Thereafter, the sheet is conveyed by the conveyance roller 7d and discharged onto the sheet discharge unit 70, thereby completing the printing on the sheet.

[0047] -Fixing Device and Structure around the Fixing Device- Hereinafter, the fixing device 5 and its surrounding structure will be described.

[0048] FIG. 2 is a schematic cross-sectional view showing the configuration of the fixing device 5 in Embodiment 1.

[0049] The fixing device 5 includes a fixing member 50, a heat source 51, a support member 52, a nip forming member 53, a pressing member 54, and a peeling member 55 (see FIG. 2).

[0050] The fixing member 50, together with the pressing member 54, sandwiches and conveys the sheet in the F direction from the paper feeding portion 5a to the paper discharging portion 5b. In the present embodiment, the fixing member 50 is an endless belt rotatable in the G1 direction (see FIG. 2), and both ends thereof are rotatably supported by a frame (not shown). For the fixing member 50, for example, a metal having a predetermined thickness (e.g., about 30 μm to 100 μm) or a silicone rubber layer having a predetermined thickness (e.g., about 100 μm to 300 μm) is formed on a polyimide (PI) substrate, and a fluororesin layer having a predetermined thickness (e.g., about 20 μm to 30 μm) is further formed on the upper layer. This fluororesin layer is formed, for example, by laminating PFA tubes or applying a fluororesin.

[0051] The heat source 51 heats the fixing member 50 and is built in the fixing member 50 (see FIG. 2). In the present embodiment, the heat source 51 is a lamp heater, and both ends thereof are supported by a frame (not shown).

[0052] The support member 52 supports the nip forming member 53, is formed in an inverted T shape in cross-section (see FIG. 2), and both ends thereof are supported by a frame (not shown). On the outer surface of the support member 52 facing the heat source 51, a reflecting member 56 for reflecting the heat radiation from the heat source 51 toward the fixing member 50 is provided. The reflecting member 56 is formed of a metal material such as aluminum in a plate shape, and the surface of the reflecting member 56 is mirror-finished in order to efficiently reflect the heat radiation from the heat source 51 to the fixing member 50.

[0053] The nip forming member 53 forms a fixing nip region FN between the pressing member 54 and the fixing member 50 and is disposed on the inner peripheral surface of the fixing member 50 (see FIG. 2). The nip forming member 53 is supported from the inside of the fixing member 50 by the support member 52 while being fixed to the bottom surface of the support member 52. The nip forming member 53 is formed of, for example, a high-rigidity heat-resistant resin material [for example, liquid crystal polymer (LCP: Liquid Crystal Polymer), polyether ether ketone (PEEK: Poly Ether Ether Ketone), polyphenylene sulfide (PPS: Poly Phenylene Sulfide), etc.] or a high-elasticity heat-resistant resin material (for example, a rubber material). Further, the nip forming member 53 may be provided with an elastic layer (for example, a rubber layer such as silicone rubber) on the surface of the nip forming member 53 formed of a high-rigidity heat-resistant resin material.

[0054] On the bottom surface of the nip forming member 53, that is, the surface that slidably contacts the fixing member 50, a sliding contact sheet 57 for reducing the friction against the fixing member 50 is attached (see Fig. 2). The sliding contact sheet 57 is adhered to the nip forming member 53 with, for example, an adhesive or an adhesive member. Further, the sliding contact sheet 57 is formed from, for example, a glass fiber material (such as a glass cloth) coated with a fluororesin such as PTFE (Poly Tetra Fluoro Etylene) (such as a glass cloth sheet). The thickness of the sliding contact sheet 57 is set to about 0.1 mm to 0.5 mm, for example.

[0055] The pressing member 54 is pressed against the nip forming member 53 from the outside of the fixing member 50 and, together with the fixing member 50, sandwiches and conveys the sheet in the F direction from the paper feeding section 5a to the paper discharging section 5b. Both ends thereof are rotatably supported by a frame (not shown). Further, the pressing member 54 is configured to be rotationally driven in the G2 direction by the rotational driving force of a rotational driving section (driving motor) (not shown) (see Fig. 2). The pressing member 54 is, for example, a member in which an elastic member (such as a sponge rubber or a solid rubber such as silicone rubber) with a predetermined thickness (about 6 mm, for example) and a hardness of about 35 degrees to 40 degrees is formed on a metal base such as aluminum, and a fluororesin layer is further formed on the upper layer of the elastic member. This fluororesin layer is formed by, for example, laminating PFA tubes or applying a fluororesin.

[0056] The separating member 55 separates the sheet that has passed between the fixing member 50 and the pressing member 54 from the fixing member 50 to prevent the sheet from winding around the fixing member 50, and is provided in the vicinity of the fixing member 50 in the paper discharging section 5b (see Fig. 2).

[0057] With the fixing device 5 as described above, the toner image secondarily transferred onto the sheet is fixed to the sheet as follows. First, the sheet conveyed to the paper feed section 5a is sandwiched between the fixing member 50 and the pressure member 54. When the pressure member 54 is rotationally driven in the G2 direction, the fixing member 50 is driven to rotate passively in the G1 direction along with the rotational drive. When the sheet is nipped and conveyed in the F direction toward the paper discharge section 5b by the pressure member 54 and the fixing member 50, it passes through the fixing nip region FN and receives heat from the heat source 51 via the fixing member 50, so that the toner image is fixed to the sheet.

[0058] Note that the structure of the fixing device 5 is not limited to the above. For example, a so-called belt fixing method in which a pressure roller is pressed against a structure in which a fixing belt is suspended on a plurality of rollers (for example, a fixing roller and a heating roller) may be used.

[0059] FIG. 3 is a schematic cross-sectional view showing the fixing device 5 and the structure around it in Embodiment 1. FIG. 4 is a schematic cross-sectional view showing the case where the fan β in FIG. 3 is replaced with an intake fan. FIG. 5 is a schematic cross-sectional view showing the elastic member P.

[0060] The fixing device 5 as described above is provided in the first space S1 on one side partitioned by the partition wall 8 while being stored in the housing H (see FIG. 3). Openings Ha and Hb are provided in the housing H of the fixing device 5. Subsequently, the partition wall 8 and the first space S1 and the second space S2 defined by the partition wall 8 will be described.

[0061] The image forming apparatus A includes a partition wall 8 that partitions the space (see FIG. 3). The partition wall 8 is formed of, for example, a synthetic resin or the like. In the present embodiment, the partition wall 8 partitions the space in the Y direction. A first space S1 is defined on one side of the partition wall 8, and a second space S2 is defined on the other side of the partition wall 8.

[0062] The partition wall 8 is provided with openings 80 (80a, 80b). In the present embodiment, the openings 80 include openings 80a and 80b arranged so as to face the openings Ha and Hb of the housing H along the X direction. In the present embodiment, the opening 80 is a rectangular through-hole.

[0063] As described above, the fixing device 5 is provided in the first space S1 (see FIG. 3).

[0064] In the second space S2, fixing temperature measuring means 9 (9a, 9b) for non-contact measurement of the fixing temperature of the fixing device 5 facing the opening 80 is provided. The fixing temperature measuring means 9 is composed of a fixing temperature measuring means 9a facing the opening 80a and a fixing temperature measuring means 9b facing the opening 80b. In the present embodiment, the fixing temperature measuring means 9 measures the surface temperature of the fixing member 50. In the present embodiment, the fixing temperature measuring means 9 is composed of a thermopile element.

[0065] Also, in the present embodiment, an air flow path α communicating with the outside of the image forming apparatus A is further provided in the second space S2 (see FIG. 3). In the present embodiment, the air flow path α is provided along the X direction. One end of the air flow path α communicates with the space in which the toner cartridge T (see FIG. 1) is accommodated, and the other end communicates with the outside of the image forming apparatus A via the fan β. Thereby, the second space S2 on the other side of the partition wall 8 can be effectively utilized. In the present embodiment, the fan β is an exhaust fan, and the flow direction D1 of the air flowing through the air flow path α is along the +X direction (see FIG. 3).

[0066] Incidentally, if air flows between the first space S1 and the second space S2 through the opening 80, the air hits the fixing temperature measuring means 9 facing the opening 80, and there is a risk that the temperature measured by the fixing temperature measuring means 9 deviates from the actual fixing temperature of the fixing device 5 due to this air. In the present embodiment, in particular, since the inside of the air flow path α becomes negative pressure by the fan β that exhausts air from the air flow path α, air flows from the first space S1 to the second space S2 through the opening 80. Due to the air flow from the first space S1 to the second space S2 through the opening 80, the heat discharge of the fixing member 50 heated by the heat source 51 in the first space S1 is promoted, and the hot air heated by this heat hits the fixing temperature measuring means 9, so there is a risk that the temperature measured by the fixing temperature measuring means 9 becomes higher than the actual fixing temperature of the fixing device 5.

[0067] Therefore, the image forming apparatus A includes a blocking means for blocking the air flow between the first space S1 and the second space S2 through the opening 80. Specifically, as the blocking means, the fixing temperature measuring means 9a and 9b are fitted so as to close the openings 80a and 80b, respectively (see FIG. 3). By such a blocking means, the air flow between the first space S1 and the second space S2 through the opening 80 is blocked, and the air is prevented from hitting the fixing temperature measuring means 9, so that the temperature deviation between the measured temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5 can be suppressed.

[0068] Note that, as shown in FIG. 4, even when the fan β is an intake fan and, for example, the air flow direction D2 of the air flowing through the air flow path α is along the -X direction, the functions and effects of the blocking means are the same as described above. When the fan β is an intake fan, the inside of the air flow path α becomes a positive pressure due to the fan β that intakes air from the air flow path α. If the blocking means is not used, air will flow from the second space S2 to the first space S1 through the opening 80. Due to such air flow from the second space S2 to the first space S1 through the opening 80, the air flowing through the air flow path α in the second space S2 hits the fixing temperature measuring means 9, so there is a risk that the temperature measured by the fixing temperature measuring means 9 will be lower than the actual fixing temperature of the fixing device 5. Therefore, by using the blocking means in the same manner as above, the air flow between the first space S1 and the second space S2 through the opening 80 is blocked. Thus, even when the fan β is an intake fan, the temperature deviation between the measured temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5 can be suppressed.

[0069] Note that the partition wall 8 may be a part of the housing H of the fixing device 5.

[0070] Note that the fixing temperature measuring means 9 may measure the temperature of a pressurizing member or the like according to the structure of the fixing device 5. In this case as well, the functions and effects of the blocking means are the same as described above.

[0071] Note that, as shown in FIG. 5, an elastic member P made of resin, rubber, or the like may be provided between the inner peripheral side surface of the opening 80 and the fixing temperature measuring means 9 in order to improve the air flow blocking property.

[0072] (Embodiment 2) Hereinafter, only the differences from the above-described Embodiment 1 will be described for Embodiment 2.

[0073] FIG. 6 is a schematic cross-sectional view showing the fixing device 5 and the surrounding structure in Embodiment 2. FIG. 7 is a schematic plan view showing the blocking rib 91 in Embodiment 2. FIG. 8 is a schematic plan view of the mounting plate 90 viewed from the second space S2 side in Embodiment 2. FIG. 9 is a schematic plan view showing a state where the positioning hole 900 is located outside the inner peripheral edge of the blocking rib 91.

[0074] In Embodiment 2, in the second space S2, a mounting plate 90 (90a, 90b) which is offset from the partition wall 8 and to which the fixing temperature measuring means 9 is attached is further provided (see FIG. 6). The mounting plate 90 (90a, 90b) is composed of a mounting plate 90a to which the fixing temperature measuring means 9a is attached and a mounting plate 90b to which the fixing temperature measuring means 9b is attached. In the present embodiment, the mounting plate 90 is composed of a substrate on which the fixing temperature measuring means 9 composed of a thermopile element is mounted on the mounting surface facing the first space S1 side. Thereby, not only can a thermopile element be used for the fixing temperature measuring means 9, but also the fixing temperature measuring means 9 can be mounted on the mounting plate 90 in advance, which facilitates assembly, effectively utilizes the substrate, and reduces the number of parts compared to the case of separately attaching a substrate to the mounting plate 90. Further, on the mounting plate 90, chip resistors, connectors, etc. are mounted as necessary together with the fixing temperature measuring means 9.

[0075] In the present embodiment, blocking ribs 91 (91a, 91b) functioning as blocking means are erected from the outer peripheral edge of the opening 80 of the partition wall 8 to the mounting plate 90 (see FIG. 6). The blocking rib 91 is composed of a blocking rib 91a that blocks the flow of air passing through the opening 80a and a blocking rib 91b that blocks the flow of air passing through the opening 80b. In the present embodiment, the blocking rib 91 is formed in a rectangular tube shape (see FIGS. 7 and 8). Further, in the present embodiment, the blocking rib 91 is integrally formed with the partition wall 8. Thereby, the number of parts can be reduced.

[0076] The mounting plate 90 is abutted against the blocking rib 91 by fixing both side portions thereof by means of mounting plate fixing portions 92 extending from the partition wall 8 side (see FIG. 8). The mounting plate fixing portions 92 have interference claws 920 that regulate the movement of the mounting plate 90 toward the second space S2 side and interfere with the mounting plate 90 in order to bring the mounting plate 90 into contact with the blocking rib 91. The mounting plate fixing portions 92 are attached to, for example, the blocking rib 91 or the partition wall 8. The mounting plate fixing portions 92 are formed of, for example, synthetic resin or the like.

[0077] Due to the blocking rib 91 as described above, the air flow between the first space S1 and the second space S2 through the opening 80 is blocked, and the air is prevented from hitting the fixing temperature measuring means 9. Therefore, the temperature deviation between the measured temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5 can be suppressed.

[0078] In addition to the above configuration, in the present embodiment, a positioning pin 912 for positioning the mounting plate 90 protrudes from the first side wall 910 of the blocking rib 91 toward the mounting plate 90 side (see FIGS. 7 and 8). The positioning pin 912 is formed in a columnar shape. Further, on the second side wall 911 facing the first side wall 910 of the blocking rib 91, an extension portion 913 extends in a direction away from the first side wall 910, and a positioning pin 914 protrudes from the extension portion 913 (see FIGS. 7 and 8). The positioning pin 914 is formed in an oblong columnar shape. Furthermore, the mounting plate 90 is provided with a positioning hole 900 through which the positioning pin 912 is inserted and a notch portion 901 through which the positioning pin 914 is inserted and which is notched in a substantially U shape (see FIG. 8). The positioning hole 900 is closed by the positioning pin 912 in a state where the mounting plate 90 is positioned by the blocking rib 91 (see FIG. 8). Thereby, since the air is prevented from hitting the fixing temperature measuring means 9 through the positioning hole 900, the temperature deviation between the measured temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5 can be suppressed.

[0079] Note that the shape of the opening 80 is not limited to the above, and may be, for example, a circular, elliptical, or oblong through-hole. Note that the blocking rib 91 may be formed separately from the partition wall 8 and fixed to the partition wall 8 by a fastening member such as a screw (not shown). Further, the shape of the blocking rib 91 is not limited to the above, and for example, it may be formed in a cylindrical shape, an elliptical cylindrical shape, an oblong cylindrical shape, or a shape adapted to the opening 80.

[0080] Note that, as shown in FIG. 9, the positioning hole 900 may be located outside the inner peripheral side edge of the blocking rib 91 in a state where the mounting plate 90 is positioned by the blocking rib 91. Thereby, since air is prevented from hitting the fixing temperature measuring means 9 through the positioning hole 900, the temperature deviation between the measured temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5 can be suppressed.

[0081] (Modification of Embodiment 2) Hereinafter, a modification of the above-described Embodiment 1 will be described.

[0082] FIG. 10 is a schematic cross-sectional view showing the partition wall 8 and the surrounding structure in Modification 1 of Embodiment 2. FIG. 11 is a schematic cross-sectional view of the blocking rib 91 viewed from above in Modification 2 of Embodiment 2. FIG. 12 is a schematic cross-sectional view of the blocking rib 91 viewed from the rear in Modification 2 of Embodiment 2. FIG. 13 is a schematic cross-sectional view showing the partition wall 8 and the blocking rib 91 in Modification 3 of Embodiment 2.

[0083] As in Modification Example 1 shown in FIG. 10, among the partition walls 8, the partition wall cover portion 8a, which is a portion of the region including the openings 80 (80a, 80b), may be configured to be detachable from the image forming apparatus main body together with the fixing temperature measuring means 9, the mounting plate 90, and the blocking rib 91. The partition wall cover portion 8a is fixed to the partition wall 8 by a fastening member such as a screw (not shown). Since the partition wall cover portion 8a is configured to be detachable from the image forming apparatus A, it becomes possible to pre-assemble the fixing temperature measuring means 9, the mounting plate 90, and the blocking rib 91 to the partition wall cover portion 8a outside the image forming apparatus A and then assemble the assembled unit to the partition wall 8. Therefore, compared with the case where the fixing temperature measuring means 9, the mounting plate 90, and the blocking rib 91 are directly attached to the partition wall 8 respectively, the assembly becomes easier.

[0084] Also, as in Modification Example 2 shown in FIGS. 11 and 12, a fixing portion 915 for fixing to the partition wall 8 may be continuously provided at the edge portion of the blocking rib 91. The fixing portion 915 is formed in a flange shape, for example. Thereby, the blocking rib 91 can be easily fixed to an arbitrary position of the partition wall 8. In this Modification Example 2, the mounting plate 90 is abutted against the blocking rib 91 by a mounting plate fixing portion 92 attached to the blocking rib 91.

[0085] Furthermore, as in Modification Example 3 shown in FIG. 13, by combining Modification Example 1 and Modification Example 2, the fixing portion 915 of the blocking rib 91 may be fixed to the partition wall cover portion 8a of the partition wall 8. Thereby, both the effects of Modification Example 1 and the effects of Modification Example 2 can be enjoyed.

[0086] (Embodiment 3) Hereinafter, regarding Embodiment 3, only the points different from Embodiment 2 will be described.

[0087] FIG. 14 is a schematic cross-sectional view showing the partition wall 8 and the blocking rib 91 in Embodiment 3. FIG. 15 is a schematic plan view of the partition wall 8 and the blocking rib 91 in FIG. 14 viewed from the second space S2 side.

[0088] In Embodiment 3, the partition wall 8 is provided with an air induction port 81 that guides air in a direction away from the fixing temperature measuring means 9 facing the opening 80 (see FIGS. 14 and 15). Specifically, the air induction port 81 is arranged at a position separated by a predetermined distance from one side of the opening 80. Due to such an air induction port 81, air circulation occurs between the first space S1 and the second space S2 through the air induction port 81, and this air flow path is necessarily formed in a direction away from the opening 80. Thereby, it is possible to prevent air from hitting the fixing temperature measuring means 9 and suppress the temperature deviation between the measurement temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5. Further, when the fan β is an exhaust fan, since the hot air heated by the heat of the fixing member 50 in the first space S1 is actively discharged through the air induction port 81 (see FIG. 6), it is possible to suppress the dew condensation of the fixing temperature measuring means 9 caused by the temperature difference between the temperature of this hot air and the fixing temperature measuring means 9.

[0089] Also, in Embodiment 3, a substantially flange-shaped fixing portion 915 fixed to the partition wall 8 is provided at the edge portion of the blocking rib 91 (see FIGS. 14 and 15). A locking claw 916 locked to the air induction port 81 is continuously provided at the edge of one side portion of the fixing portion 915 close to the air induction port 81. The width of the locking claw 916 is set smaller than the width of the air induction port 81 (see FIG. 15). One side portion of the fixing portion 915 is fixed to the partition wall 8 by the locking claw 916, while the other side portion of the fixing portion 915 is fixed to the partition wall 8 on the opposite side of the air induction port 81 with respect to the opening 80 by a screw Q (see FIGS. 14 and 15). Thereby, compared with the case where both side portions of the fixing portion 915 are fixed with fastening members such as screws, the number of fastening members can be reduced and the cost can be suppressed.

[0090] (Embodiment 4) Hereinafter, regarding Embodiment 4, only the points different from the above Embodiment 2 will be described.

[0091] FIG. 16 is a schematic cross-sectional view showing the fixing device 5 and the surrounding structure in Embodiment 4. FIG. 17 is a schematic cross-sectional view showing the case where the fan β in FIG. 16 is replaced with an intake fan.

[0092] In Embodiment 4, the mounting plates 90 (90a, 90b) extend downstream of the air flow direction D1 of the air flowing in the air flow path α with respect to the blocking rib 91 (see FIG. 16). Further, on the mounting surface of the substrate constituting the mounting plate 90 on the downstream side of the blocking rib 91 in the flow direction D1, connection means 93 (93a, 93b) connectable to an external device are mounted (see FIG. 8). This mounting surface is the surface on which the fixing temperature measuring means 9 is mounted, and in Embodiment 2, it faces the first space S1 side. In Embodiment 2, the connection means 93 is composed of connection means 93a attached to the mounting plate 90a and connection means 93b attached to the mounting plate 90b. In the present embodiment, the connection means 93 is composed of a connector.

[0093] In the air flow path α, a hood 94 (94a, 94b) is provided which opens on the downstream side of the air flow direction D1 of the air flowing in the air flow path α and covers the fixing temperature measuring means 9 and the mounting plate 90 (see FIG. 16). The hood 94 is composed of a hood 94a covering the fixing temperature measuring means 9a and the mounting plate 90a and a hood 94b covering the fixing temperature measuring means 9b and the mounting plate 90b. The hood 94 has a side wall portion 940 formed in a substantially U shape as viewed from the flow direction D1, and a bottom wall portion 941 connected to the edge of the side wall portion 940 so as to close the opening of the side wall portion 940 on the upstream side of the flow direction D1. The hood 94 is fixed to the partition wall 8 by a fastening member such as a screw (not shown). The hood 94 is formed of, for example, synthetic resin or the like.

[0094] With the provision of the hood 94 as described above, not only is it possible to prevent the air flowing in the flow direction D1 from hitting the fixing temperature measuring means 9, but also the air hitting the mounting plate 90 is inhibited. Therefore, the influence of the air on the fixing temperature measuring means 9 via the mounting plate 90 can be reduced, and the temperature deviation between the measured temperature measured by the fixing temperature measuring means 9 and the actual fixing temperature of the fixing device 5 can be suppressed. In particular, when the fixing temperature measuring means 9 is composed of a thermopile element, the fixing temperature measuring means 9 is provided with an environmental temperature sensor (not shown). Here, when air hits the mounting plate 90, which is the substrate on which the fixing temperature measuring means 9 is mounted, the environmental temperature sensor is cooled, and thus the temperature measured by the fixing temperature measuring means 9 may deviate from the actual fixing temperature of the fixing device 5. In this regard, by covering the fixing temperature measuring means 9 and the mounting plate 90 with the hood 94, cooling of the environmental temperature sensor can be prevented, and temperature deviation of the fixing temperature measuring means 9 can be suppressed.

[0095] Further, since the hood 94 opens on the downstream side of the flow direction D1 of the air flowing in the air flow path α, that is, on the side where the connecting means 93 is attached to the mounting plate 90, an operator can access the connecting means 93 from this opening. For example, the insertion and removal of the connector constituting the connecting means 93 becomes easy, and good workability can be ensured.

[0096] As shown in FIG. 17, even when the fan β is an intake fan and, for example, the flow direction D2 of the air flowing through the air flow path α is along the -X direction, the hood 94 can be used with an opening on the downstream side in the flow direction D2. In this case, as also shown in FIG. 17, if the mounting plate 90 extends downstream of the blocking rib 91 in the flow direction D2 and the connecting means 93 (93a, 93b) is mounted on the mounting surface of the substrate constituting the mounting plate 90 downstream of the blocking rib 91 in the flow direction D2, good workability can be ensured as described above, which is even better.

[0097] The above-described embodiments and examples are illustrative in all respects and are not intended to be a basis for a limiting interpretation. Therefore, the technical scope of the present invention is not construed only by the above-described embodiments and examples, but is defined based on the description in the claims. Also, all changes within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0098] A Image forming apparatus 1 Image reading unit 2 Image forming unit 3 Intermediate transfer body 4 Secondary transfer unit 5 Fixing device 50 Fixing member 51 Heat source 52 Support member 53 Nip forming member 54 Pressing member 55 Peeling member 8 Partition wall 80 Opening 9 Fixing temperature measuring means 90 Mounting plate 91 Blocking rib 92 Mounting plate fixing part 93 Connecting means 94 Hood S1 First space S2 Second space α Air flow path β Fan D1,D2 Flow direction

Claims

1. An image forming apparatus including a partition wall that partitions a space, wherein in a first space on one side of the partition wall, a fixing device that fixes by heating and pressing is provided, an opening is provided in the partition wall, in a second space on the other side of the partition wall, fixing temperature measuring means for non - contact measurement of the fixing temperature of the fixing device facing the opening of the partition wall, an air flow path that communicates with the outside of the image forming apparatus and through which air flows along the partition wall, a mounting plate that is offset from the partition wall into the air flow path and on which the fixing temperature measuring means is mounted, a blocking rib erected from the outer peripheral edge of the opening of the partition wall to the mounting plate is provided, and the blocking rib is fixed to the partition wall by a fastening member, blocks air flowing along the partition wall, and inhibits air from hitting the fixing temperature measuring means, a fixing portion for fixing to the partition wall is continuously provided at an edge portion of the blocking rib characterizing the image forming apparatus.

2. The image forming apparatus according to claim 1, wherein a portion of the partition wall including the opening is configured to be detachable from the image forming apparatus main body together with the fixing temperature measuring means, the mounting plate, and the blocking rib.

3. The image forming apparatus according to claim 1 or claim 2, wherein a positioning pin for positioning the mounting plate protrudes from the blocking rib toward the mounting plate side, a positioning hole through which the positioning pin is inserted is formed in the mounting plate, and the positioning hole is blocked by the positioning pin in a state where the mounting plate is positioned by the blocking rib.

4. The image forming apparatus according to any one of claims 1 to 3, wherein a positioning pin for positioning the mounting plate protrudes from the blocking rib toward the mounting plate side, a positioning hole through which the positioning pin is inserted is formed in the mounting plate, and the positioning hole is located outside the inner peripheral side edge of the blocking rib in a state where the mounting plate is positioned by the blocking rib.

5. The image forming apparatus according to any one of claims 1 to 4, wherein the fixing temperature measuring means is composed of a thermopile element, and the mounting plate is composed of a substrate on which the fixing temperature measuring means is mounted.

6. The image forming apparatus according to claim 1, wherein An image forming apparatus, characterized in that a hood is provided in the air flow path, which opens on the downstream side in the flow direction of the air flowing in the air flow path and covers the mounting plate.

7. The image forming apparatus according to any one of Claims 1 to 3, in the second space on the other side of the partition wall, an air flow path communicating with the outside of the image forming apparatus is provided, the fixing temperature measuring means is composed of a thermopile element, the mounting plate extends downstream in the flow direction of the air flowing in the air flow path from the blocking rib and is composed of a substrate on which the fixing temperature measuring means is mounted on the mounting surface, on the mounting surface of the substrate constituting the mounting plate on the downstream side in the flow direction from the blocking rib, connection means connectable to an external device is mounted, An image forming apparatus, characterized in that a hood is provided in the air flow path, which opens on the downstream side in the flow direction of the air flowing in the air flow path and covers the fixing temperature measuring means and the mounting plate.

8. The image forming apparatus according to any one of Claims 1 to 7, wherein the partition wall is provided with an air guiding port for guiding air in a direction away from the fixing temperature measuring means facing the opening.

Images