JP5579012B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device used in an image forming apparatus such as a copying machine, a printer, and a facsimile machine, and an image forming apparatus using the same.

  An example of this type of image forming apparatus is an electrophotographic type. In this type of apparatus, an electrostatic latent image is formed on the surface of the photosensitive drum, the electrostatic latent image on the surface of the photosensitive drum is developed with toner, a toner image is formed on the surface of the photosensitive drum, and the toner image is exposed to light. The toner image is fixed on the recording paper by transferring it from the body drum to the recording paper or the like and heating and pressurizing the recording paper.

  For fixing the toner image on the recording paper, for example, a fixing device as shown in FIG. In this fixing device, the heating roller 101 and the pressure roller 102 are pressed against each other, the rollers 101 and 102 are rotated, and the recording sheet P is conveyed while being guided between the rollers 101 and 102. The toner image is fixed on the recording paper P by heating and pressing. 6 (a) and 6 (b), the opening / closing body 103 is rotatably supported around the shaft 103a, the opening / closing body 103 is provided so as to be opened / closed, the opening / closing body 103 is opened, and each roller 101, The recording paper jammed between 102 can be removed.

  Such a fixing device usually has a lifetime, and is replaced with a new one when the lifetime is reached. However, if a heating roller or a pressure roller is exposed in a state where a new fixing device is placed on a desk or the like in order to replace the fixing device, the rollers are scratched or dusty. Sometimes.

  FIG. 7 is a cross-sectional view showing a state where the fixing device of FIG. 6 is placed on a flat placement surface. As shown in FIG. 7, when the opening / closing body 103 is opened in a state where the fixing device is placed on a flat placement surface, the rollers 101 and 102 are exposed, and scratches, dust, and the like are exposed to the rollers 101 and 102. Stick.

  For this reason, in Patent Document 1, an entrance guide is rotatably provided at the opening of the fixing device, and the entrance guide is biased by a spring. When the fixing device is detached from the image forming apparatus, the entrance guide is rotated by the spring and the opening of the fixing device is closed by the entrance guide, so that the heating roller and the pressure roller inside the fixing device are not exposed. When the fixing device is mounted on the image forming apparatus, the entrance guide of the fixing device moves against the abutting portion on the image forming apparatus side, the opening of the fixing device is opened, and the recording paper is fixed through the opening. It can be installed inside the apparatus.

JP 2003-295655 A

  However, in Patent Document 1, it is necessary to provide an urging means such as an inlet guide and a spring on the fixing device side, and to provide an abutting portion on the image forming device side, which increases the number of parts and complicates the configuration. was there.

  Accordingly, the present invention has been made to solve the above-described problems, and has a simple configuration, and a fixing device in which the fixing roller is not exposed when placed on a desk or the like, and the fixing device An object of the present invention is to provide an image forming apparatus including the above.

In order to solve the above problems, a fixing device of the present invention is a fixing device that is detachable from an image forming apparatus, and can be opened and closed to fix a fixing member that fixes a toner image on a sheet. A fixing device in which the fixing member is exposed by opening the opening / closing member, and the opening / closing member can be opened and closed when the fixing device is mounted on the image forming apparatus and in use. The position of the center of gravity of the opening / closing body is located on the opening side of the opening / closing body with respect to the supporting shaft, and the bottom surface of the fixing device is flat when the fixing device is detached from the image forming apparatus. to when it is placed, said bottom surface for use posture lifted in the closing direction of the closing body, the mounting position of the center of gravity of said movable member to pair before Symbol shaft is in the closed side of the opening and closing member become the postures and such so that shape That.

In the present invention, when the fixing device is placed on a flat surface, the bottom surface of the fixing device for use orientation of the fixing device is placed posture raised in the closing direction of the closing body. In this mounting posture , the center of gravity of the opening / closing body is on the closing side of the opening / closing body with respect to the shaft that supports the opening / closing body so that the opening / closing body can be opened / closed. Rotate and close. Therefore, when the fixing device is placed on a flat surface, the opening / closing body is closed and the fixing member is not exposed. For this reason, in a state where a new fixing device is placed on a desk or the like in order to replace the fixing device, the fixing roller is not exposed and the fixing roller is not scratched or dusty.

Further, the bottom surface of the fixing device, when the fixing device is placed on a flat surface, bottom surface relative to usage posture of the fixing device is lifted in the closing direction of the closing body, in the mounting postures Do that shape Therefore, the configuration of the fixing device is not complicated.

In addition , when the fixing device is in use, the center of gravity of the opening / closing body with respect to the shaft is on the opening side of the opening / closing body.

  Thus, when the fixing device is in use, the position of the center of gravity of the opening / closing body with respect to the shaft is on the opening side of the opening / closing body, so the opening / closing body is opened.

Further, in the fixing device of the present invention, the shape of the pre-Symbol bottom is obtained by forming a protrusion that abuts against the flat surface on one side of the bottom surface.

In this case, the shape of the bottom surface of the fixing device only slightly changed, it is Rukoto lift the bottom surface of the placed on a flat surface fixing device in the direction of closing of the closing body.

  In the fixing device of the present invention, the shaft is provided horizontally.

  In this case, the weight of the opening / closing body effectively acts as a moment around the axis, and the opening / closing body rotates reliably around the axis to open and close.

  Furthermore, in the fixing device of the present invention, the opening / closing body is also used as a conveyance guide for the sheet.

In this case, the number of parts of the fixing device can be reduced.
For example, the fixing member is a heating roller that conveys and heats the sheet. Alternatively, the fixing member is a pressure roller that conveys and pressurizes the sheet.

  On the other hand, the image forming apparatus of the present invention includes the fixing device of the present invention, and has the same effects as the fixing device of the present invention.

According to the fixing device of the present invention, when the fixing device is placed on a flat surface, the bottom surface of the fixing device is placed posture raised in the closing direction of the closing body against the use position of the fixing device. In this mounting posture , the center of gravity of the opening / closing body is on the closing side of the opening / closing body with respect to the shaft that supports the opening / closing body so that the opening / closing body can be opened / closed. Rotate and close. Therefore, when the fixing device is placed on a flat surface, the opening / closing body is closed and the fixing member is not exposed. For this reason, in a state where a new fixing device is placed on a desk or the like in order to replace the fixing device, the fixing roller is not exposed and the fixing roller is not scratched or dusty.

Further, the bottom surface of the fixing device, when the fixing device is placed on a flat surface, bottom surface with respect to the use state of the fixing device is lifted in the closing direction of the closing body, in the mounting postures Do that shape Therefore, the configuration of the fixing device is not complicated.

1 is a cross-sectional view illustrating an image forming apparatus to which an embodiment of a fixing device of the present invention is applied. FIG. 2 is a cross-sectional view illustrating a fixing device of the present embodiment. FIG. 3 is a cross-sectional view showing a state in which an opening / closing body of the fixing device in FIG. 2 is opened. 2A is a diagram schematically showing a state in which the fixing device of FIG. 2 is mounted on the image forming apparatus and the door is closed, and FIG. 3B is a diagram schematically showing a state in which the door is opened. FIG. 3 is a cross-sectional view showing a state where the fixing device of FIG. 2 is placed on a flat placement surface such as a desk. (A) is sectional drawing which shows the conventional fixing device, (b) is sectional drawing which shows the state which opened the opening-closing body of the fixing device of (a). It is sectional drawing which shows the state which mounted the fixing device of FIG. 6 on the flat mounting surface.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an image forming apparatus to which an embodiment of a fixing device of the present invention is applied. The image forming apparatus 100 is a so-called multi-function machine having a scanner function, a copying function, a printer function, a facsimile function, and the like, and transmits an image of a document read by the document reading device 101 to the outside (corresponding to a scanner function). The image of the read original or the image received from the outside is recorded and formed on a recording sheet in color or single color (corresponding to a copying function, a printer function, and a facsimile function).

  The image forming apparatus 100 includes a document reading device 101 and a document transport unit 42 for reading a document image. The document reading device 101 reads the document image conveyed by the document conveying unit 42. In the document conveying section 42, when a document is set on the document set tray 41, the document pickup roller 44 is pressed against the document surface and rotated, the document is pulled out from the document set tray 41, and the document is pulled out from the suction roller 45 and the separation pad 46. After passing between the sheets, the sheets are separated one by one and then conveyed to the conveyance path 47.

  In this conveyance path 47, the leading edge of the document abuts on the document registration roller 49, the leading edge of the document is aligned in parallel with the document registration roller 49, and then the document is transported by the document registration roller 49 and read by the reading guide 51. Passes between the glasses 52. Further, the document is conveyed by the conveyance roller 57 and is discharged to the paper discharge tray 59 via the paper discharge roller 58.

  In the document reading apparatus 101, when the document passes between the reading guide 51 and the reading glass 52, the light from the light source of the first scanning unit 53 is irradiated on the surface of the document through the reading glass 52, and the reflected light is read by the reading glass 52. The reflected light is reflected by the mirrors of the first and second scanning units 53 and 54 and guided to the imaging lens 55, and the image of the original is converted by the imaging lens 55. An image is formed on a CCD (Charge Coupled Device) 56. The CCD 56 reads a document image and outputs image data indicating the document image.

  In addition, it is possible to read a document placed on the platen glass 61. The document conveying section 42 is pivotally supported on the back side of the lower document reading apparatus 101 by a hinge (not shown) and opened and closed by moving the front portion up and down. When the document conveying section 42 is opened, the document table glass 61 is opened, and a document can be placed on the document table glass 61. When a document is placed and the document transport unit 42 is closed, the first and second scanning units 53 and 54 are moved in the sub-scanning direction, and the document on the document glass 61 is moved by the light source of the first scanning unit 53. The surface is exposed, reflected light from the document surface is guided to the imaging lens 55 by the mirrors of the first and second scanning units 53 and 54, and an image of the document is formed on the CCD 56 by the imaging lens 55. . At this time, the first and second scanning units 53 and 54 are moved while maintaining a predetermined speed relationship with each other, and reflection of the document surface → the first and second scanning units 53 and 54 → the imaging lens 55 → the CCD 56 is performed. The positional relationship between the first and second scanning units 53 and 54 is always maintained so that the length of the optical path of the light does not change, whereby the focus of the original image on the CCD 56 is always maintained accurately.

  The entire image of the original read in this way is sent and received as image data to the laser exposure apparatus 1 of the image forming apparatus 100, and the image is printed on recording paper in the image forming apparatus 100.

  The image forming apparatus 100 includes a laser exposure device 1, a developing device 2, a photosensitive drum 3, a charger 5, a cleaner device 4, an intermediate transfer belt device 8, a fixing device 12, and a paper transport path for printing an image on a recording paper. S, a paper feed tray 10, a paper discharge tray 15, and the like.

  The image data handled in the image forming apparatus 100 uses data corresponding to a color image using each color of black (K), cyan (C), magenta (M), yellow (Y), or a single color (for example, black). This is in accordance with the monochrome image. For this reason, four each of the developing device 2, the photosensitive drum 3, the charger 5, and the cleaner device 4 are provided so as to form four types of images corresponding to the respective colors, and black, cyan, magenta, and yellow are respectively provided. Four image stations Pa, Pb, Pc, and Pd are configured in association with each other.

  The photosensitive drum 3 has a photosensitive layer on its surface. The charger 5 is a charging means for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. In addition to a contact type roller type or brush type charger, a charger type charger is used. .

  The laser exposure apparatus 1 is a laser scanning unit (LSU) provided with a laser diode and a reflection mirror, and exposes the surface of the uniformly charged photosensitive drum 3 according to image data and corresponds to the image data on the surface. An electrostatic latent image is formed.

  The developing device 2 develops the electrostatic latent image on the photosensitive drum 3 with toner (K, C, M, Y), and forms a toner image on the surface of the photosensitive drum 3. The cleaner device 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  The intermediate transfer belt device 8 disposed above the photosensitive drum 3 includes an intermediate transfer belt 7, an intermediate transfer belt drive roller 21, a driven roller 22, an intermediate transfer roller 6, and an intermediate transfer belt cleaning device 9. .

  The intermediate transfer belt drive roller 21, the intermediate transfer roller 6, the driven roller 22, etc. stretch and support the intermediate transfer belt 7, and move the intermediate transfer belt 7 in the direction of arrow C.

  The intermediate transfer roller 6 is rotatably supported in the vicinity of the intermediate transfer belt 7 and is pressed against the photosensitive drum 3 via the intermediate transfer belt 7.

  The intermediate transfer belt 7 is formed in an endless belt shape using a film having a thickness of about 100 μm to 150 μm.

  The toner images on the respective photosensitive drums 3 are sequentially transferred to the intermediate transfer belt 7 so as to be color toner images on the intermediate transfer belt 7. The transfer of the toner image from the photosensitive drum 3 to the intermediate transfer belt 7 is performed by the intermediate transfer roller 6 that is in pressure contact with the back surface of the intermediate transfer belt 7. A high voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 6 in order to transfer the toner image. The intermediate transfer roller 6 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). A high voltage can be uniformly applied to the recording paper by this conductive elastic material.

  As described above, the toner images on the surface of the respective photosensitive drums 3 are stacked on the intermediate transfer belt 7 and become a color toner image indicated by the image data. This color toner image is transported together with the intermediate transfer belt 7 and transferred onto the recording paper by the transfer roller 11 a of the secondary transfer device 11 in contact with the intermediate transfer belt 7.

  The intermediate transfer belt 7 and the transfer roller 11a of the secondary transfer device 11 are pressed against each other to form a nip region. Further, the transfer roller 11a of the secondary transfer device 11 has a voltage for transferring the toner image of each color on the intermediate transfer belt 7 onto a recording sheet (high polarity (+) opposite to the toner charge polarity (-)). Voltage) is applied. Further, in order to constantly obtain the nip region, either the transfer roller 11a of the secondary transfer device 11 or the intermediate transfer belt drive roller 21 is made of a hard material (metal or the like), and the other is a soft material such as an elastic roller. (Elastic rubber roller, foaming resin roller, etc.).

  In addition, the toner image on the intermediate transfer belt 7 may not be completely transferred onto the recording paper by the secondary transfer device 11, and the toner may remain on the intermediate transfer belt 7. Causes color mixing. Therefore, the residual toner is removed and collected by the intermediate transfer belt cleaning device 9. The intermediate transfer belt cleaning device 9 is provided with, for example, a cleaning blade as a cleaning member that comes into contact with the intermediate transfer belt 7 to remove residual toner, and the intermediate transfer belt is driven by a driven roller 22 at a portion where the cleaning blade comes into contact. 7 The back side is supported.

  The paper feed tray 10 is a tray for storing recording paper, and is provided below the image forming apparatus 100 to supply the recording paper in the tray.

  The image forming apparatus 100 has an S-shaped sheet conveyance path S for sending the recording sheet supplied from the sheet feeding tray 10 to the sheet discharge tray 15 via the secondary transfer device 11 and the fixing device 12. Is provided. Along the paper transport path S, a paper pick-up roller 16, a paper registration roller 14, a fixing device 12, a transport roller 13 for transporting recording paper, a paper discharge roller 17, and the like are arranged.

  The paper pick-up roller 16 is a calling roller that is provided at the end of the paper feed tray 10 and supplies recording paper from the paper feed tray 10 to the paper transport path S one by one. The conveyance roller 13 is a small roller for promoting and assisting conveyance of the recording paper, and a plurality of the conveyance rollers 13 are provided.

  The paper registration roller 14 temporarily stops the recording paper that has been conveyed, aligns the leading edge of the recording paper, and is on the intermediate transfer belt 7 in the nip region between the intermediate transfer belt 7 and the transfer roller 11 a of the secondary transfer device 11. The recording paper is conveyed in a timely manner in accordance with the rotation of the photosensitive drum 3 and the intermediate transfer belt 7 so that the color toner image is transferred onto the recording paper.

  For example, the paper registration roller 14 detects the color toner image on the intermediate transfer belt 7 in the nip area between the intermediate transfer belt 7 and the transfer roller 11a of the secondary transfer device 11 based on the detection output of a pre-registration detection switch (not shown). The recording paper is transported so that the leading edge is aligned with the leading edge of the image forming area of the recording paper.

  The fixing device 12 includes a heating roller 31 and a pressure roller 32 that are fixing members. The heating roller 31 and the pressure roller 32 sandwich and convey the recording paper that has passed through the nip region between the intermediate transfer belt 7 and the transfer roller 11a of the secondary transfer device 11.

  The heating roller 31 is controlled so as to reach a predetermined fixing temperature based on the detection output of a temperature detector (not shown), and the toner transferred onto the recording paper by thermocompression bonding with the pressure roller 32. It has a function of fusing, mixing, and pressing an image to thermally fix the image on a recording sheet.

  The recording paper after fixing the toner images of the respective colors is discharged face down onto the paper discharge tray 15 by the paper discharge roller 17.

  Incidentally, in the image forming apparatus 100, the side wall on the side where the paper transport path S is provided is a door 71 that can be opened and closed. The door 71 is supported so as to be slidable in the direction of arrow A, and can be opened and closed by sliding the door 71. When the door 71 is opened, the fixing device 12 can be replaced, and the recording paper jammed in the paper transport path S can be easily removed.

  The fixing device 12 has a lifetime, and the performance of the fixing device 12 gradually deteriorates. For this reason, for example, when the operating time of the fixing device 12 or the number of fixing processes reaches a certain value, it is considered that the life of the fixing device 12 has been reached, and the fixing device 12 is replaced.

  However, if the heating roller 31 and the pressure roller 32 are exposed in a state in which a new fixing device 12 is placed on a desk or the like in order to replace the fixing device 12, these rollers 31, 32 are exposed. May be scratched or dusty.

  Therefore, in the fixing device 12 of the present embodiment, an opening / closing body that covers the rollers 31 and 32 is provided, and when the fixing device 12 is placed on a desk or the like, the opening / closing body is automatically closed, The rollers 31 and 32 are not exposed.

  FIG. 2 is a cross-sectional view showing the fixing device 12 of the present embodiment. The fixing device 12 includes a main body casing 81, and a heating roller 31 and a pressure roller 32 provided inside the main body casing 81. The heating roller 31 and the pressure roller 32 are pressed against each other inside the main body casing 81, and a nip region is formed between the rollers 31 and 32. For example, the heating roller 31 is driven to rotate, and the pressure roller 32 is driven to rotate.

  The heating roller 31 is a three-layered roller in which an elastic layer is provided on the outer surface of the core metal, and a release layer is formed on the outer surface of the elastic layer. For the core metal, for example, a metal such as iron, stainless steel, aluminum, copper, or an alloy thereof is used. Silicon rubber is used for the elastic layer, and fluorine resin such as PFA (copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether) or PTFE (polytetrafluoroethylene) is used for the release layer.

  Inside the heating roller 31 (inside the metal core), a heater lamp (halogen lamp) as a heat source for heating the roller 31 is provided.

  Similarly to the heating roller 31, the pressure roller 32 is also composed of a metal core such as iron, stainless steel, aluminum, copper, or an alloy thereof, an elastic layer such as silicon rubber on the surface of the metal core, and further thereon. The roller has a three-layer structure composed of a release layer such as PFA or PTFE.

  The main body casing 81 has openings 81a and 81b on the upper and lower sides thereof. The recording sheet passes through the nip region between the intermediate transfer belt 7 and the transfer roller 11a of the secondary transfer device 11 in FIG. 1, and is then guided to the nip region between the rollers 31 and 32 through the lower opening 81b. Heated and pressurized by the rollers 31 and 32, and further conveyed through the upper opening 81a.

  Here, the main body casing 81 of the fixing device 12 includes a top plate 82, a side plate 83, a left side bottom plate 84, a right side bottom plate 85, and an opening / closing body 86, and each of the rollers 31 and 32 that supports both ends of the shaft. It has a side wall (not shown). The right bottom plate 85 is formed with a protrusion 87 protruding downward.

  The left bottom plate 84 and the right bottom plate 85 are spaced apart from each other, and a lower opening 81b is formed between them. Moreover, the top plate 82 and the opening / closing body 86 are also separated from each other, and an upper opening 81a is formed between them. The guide member 82a of the top plate 82 and the guide member 86a of the opening / closing body 86 are disposed to face each other via the upper opening 81a, and the recording paper is guided by these guide members 82a and 86a.

  The opening / closing body 86 is formed by integrating a guide member 86a, a side plate 86b, and an arm portion 86c. The end of the arm portion 86c is supported rotatably around a horizontal shaft 86d, and the entire opening / closing body 86 is a shaft 86d. It is supported so that it can rotate freely. The rotation of the opening / closing body 86 is restricted by a stopper (not shown) in both the counterclockwise direction and the clockwise direction.

  When the opening / closing body 86 rotates counterclockwise to the limit position by the stopper, the guide member 86a faces the guide member 82a of the top plate 82, and the peeling claw 86e integrally fixed to the guide member 86a has the pressure roller 32. It is positioned in the vicinity of the surface.

  Further, as shown in FIG. 3, when the opening / closing body 86 rotates clockwise to another limit position by the stopper, the guide member 86a is separated from the guide member 82a of the top plate 82, and the space between the guide members 82a and 86a is large. The peeling claw 86e is separated from the pressure roller 32 surface.

  FIG. 4A shows a state in which the fixing device 12 is attached to the image forming apparatus 100 and the door 71 is closed. The door 71 is slidably supported by a slide rail 72, a rail guide or the like (not shown), and is moved in the direction of arrow A to be opened and closed. When the door 71 is closed, the opening / closing body 86 of the fixing device 12 is pushed by the pressing member 73 provided inside the door 71, and the opening / closing body 86 rotates counterclockwise to the limit position by the stopper to close. Thus, the opening / closing body 86 does not open. The holding member 73 is a coil spring or the like.

  FIG. 4B shows a state in which the door 71 is opened. When the door 71 is opened, the fixing device 12 is exposed, and the fixing device 12 can be attached and detached. Further, since the pressing member 73 inside the door 71 is separated from the opening / closing body 86 of the fixing device 12, the opening / closing body 86 is opened by rotating clockwise to another limit position by the stopper. It is possible to remove the recording paper jammed.

  As shown in FIGS. 2 to 4, when the fixing device 12 is mounted on the image forming apparatus 100 (the usage state of the fixing device 12), the vertical passing through the center of gravity G of the opening / closing body 86 regardless of opening / closing of the opening / closing body 86. The line V1 is on the right side (opening side of the opening / closing body 86) of the vertical line V2 passing through the shaft 86d of the opening / closing body 86. For this reason, the opening / closing body 86 tends to rotate and rotate clockwise around the shaft 86d by its own weight. Therefore, when the door 71 is opened, the opening / closing body 86 of the fixing device 12 is also opened, and the recording paper jammed between the rollers 31 and 32 of the fixing device 12 can be quickly removed.

  Next, a state when a new fixing device 12 is placed on a desk or the like and prepared in order to replace the fixing device 12 will be described.

  FIG. 5 shows a state where the fixing device 12 is placed on a horizontal flat surface such as a desk. As is apparent from FIG. 5, when the fixing device 12 is placed on a horizontal flat surface 91 such as a desk, the protrusion 87 of the right bottom plate 85 of the fixing device 12 comes into contact with the placement surface 91 to fix. The right bottom plate 85 of the device 12 is lifted from the placement surface 91, and the fixing device 12 is inclined. At this time, the vertical line V1 passing through the center of gravity position G of the opening / closing body 86 is on the left side (closed side of the opening / closing body 86) of the vertical line V2 passing through the shaft 86d of the opening / closing body 86. The shaft 86d is horizontal and parallel to the flat surface 91, and the weight of the opening / closing body 86 acts as a moment around the shaft 86d. For this reason, the opening / closing body 86 closes quickly by rotating counterclockwise around the shaft 86d by its own weight.

  Therefore, when a new fixing device 12 is placed on a desk or the like to be replaced in order to replace the fixing device 12, the opening / closing body 86 is not inadvertently opened, and the rollers 31 and 32 are exposed. In addition, the rollers 31, 32 are not scratched or dusty. Since the rollers 31 and 32 are provided with an elastic layer near the surface as described above, they are easily damaged and dust, and it is effective to inhibit the opening / closing body 86 from opening. .

  Here, the state in which the fixing device 12 is tilted is defined with respect to the fixing device 12 in use, which is mounted on the image forming apparatus 100. For example, in the usage state of the fixing device 12 as shown in FIG. 4A, the side plate 83 of the fixing device 12 is substantially parallel to the vertical line, but in the mounting state of the fixing device 12 as shown in FIG. Since the side plate 83 of the fixing device 12 is inclined with respect to the vertical line, it can be said that the fixing device 12 is inclined. Even in other non-movable parts of the fixing device 12, the angle with respect to the vertical line changes between the usage state and the mounting state of the fixing device 12, so that the usage state and the mounting state can be distinguished.

In the fixing device 12 described above, when the fixing device 12 is placed on the flat surface 91, the fixing device 12 is inclined with respect to the usage state of the fixing device 12. That is, when the fixing device 12 is placed on the flat surface 91, the fixing device 12 is inclined as compared with the posture in the use state. In this inclined state, the center of gravity G of the opening / closing body 86 is on the closing side of the opening / closing body 86 with respect to the shaft 86d that supports the opening / closing body 86 so that the opening / closing body 86 can be opened / closed. The opening / closing body 86 rotates around the shaft 86d and closes. Therefore, in a state where the fixing device 12 is placed on the flat surface 91, the opening / closing body 86 is closed and the fixing member 12 is not exposed. For this reason, in a state where a new fixing device 12 is placed on a desk or the like in order to replace the fixing device 12, the heating roller 31 and the pressure roller 32 (fixing roller) are not exposed, and the fixing roller There will be no scratches or dust.
Further, since the bottom surface of the fixing device 12 only has a shape in which the fixing device 12 is inclined with respect to the use state of the fixing device 12 when the fixing device 12 is placed on the flat surface 91. There is no complication of the configuration.
Specifically, when the fixing device 12 is in use, the vertical line V1 passing through the center of gravity G of the opening / closing body 86 is on the right side of the vertical line V2 passing through the shaft 86d of the opening / closing body 86. The body 86 is rotated by its own weight in the clockwise direction about the shaft 86d and opened, so that the recording paper jammed between the rollers 31 and 32 of the fixing device 12 can be quickly removed. When the fixing device 12 is placed on a horizontal flat surface, the vertical line V1 passing through the center of gravity G of the opening / closing body 86 is on the left side of the vertical line V2 passing through the shaft 86d of the opening / closing body 86, and Since 86 is closed by rotating counterclockwise about a horizontal shaft 86d by its own weight, the rollers 31, 32 are not damaged or dust.

  Further, since only the protrusion 87 is provided on the right bottom plate 85 of the fixing device 12, the number of parts is not significantly increased and the configuration is not complicated.

  Furthermore, since the guide member 86a is integrated with the opening / closing body 86, the increase in the number of parts and the complexity of the configuration can be suppressed.

  As mentioned above, although the embodiment of the present invention has been described in detail, the present invention is not limited to the above-described embodiment, and even if a design change or the like in a category not departing from the gist of the present invention is performed, It is included in the scope of the present invention.

  For example, instead of the protrusion 87 of the right bottom plate 85, another member may be provided so that the fixing device 12 placed on the flat surface is inclined. Alternatively, the fixing device 12 may be inclined by changing the angle of the entire bottom plate with respect to the side plate 83.

  In addition, although a heating roller and a pressure roller (fixing roller) are illustrated as the fixing member, an endless fixing belt is bridged, and a nip area is formed between the fixing belt and the roller. The present invention can also be applied to a fixing device that heats and pressurizes a recording sheet while sandwiching and conveying the recording sheet.

DESCRIPTION OF SYMBOLS 1 Laser exposure apparatus 2 Developing apparatus 3 Photosensitive drum 4 Cleaner apparatus 5 Charger 8 Intermediate transfer belt apparatus 10 Paper feed tray 11 Secondary transfer apparatus 12 Fixing apparatus 15 Paper discharge tray 42 Document conveyance part 71 Door 81 Main body case 82 Top Plate 83 Side plate 84 Left side bottom plate 85 Right side bottom plate 86 Opening and closing body 86d Shaft 87 Projection part 100 Image forming apparatus 101 Document reading apparatus

Claims (7)

A fixing device detachable from an image forming apparatus , comprising: a fixing member that fixes a toner image on a sheet; and an openable / closable opening / closing member that covers the fixing member, and the fixing by opening the opening / closing member. A fixing device in which a member is exposed,
When the fixing device is attached to the image forming apparatus and in use, the fixing device is installed in a usage posture in which the center of gravity of the opening / closing body is on the opening side of the opening / closing body with respect to the shaft that supports the opening / closing body. Has been
The bottom surface of the fixing apparatus, when the fixing device is mounted on a flat surface is detached from the image forming apparatus, the bottom surface with respect to the use orientation is raised in the direction of closing of the closing body, pre-Symbol fixing device center of gravity of the opening and closing member against the shaft, characterized in that it is a so that shape, such as setting attitude in a closed side of said opening and closing member. The fixing device according to claim 1 ,
Shape before Symbol bottom, a fixing device, characterized in that by forming a protrusion that abuts against the flat surface on one side of the bottom surface. The fixing device according to claim 1 or 2 ,
The fixing device is characterized in that the shaft is provided horizontally. A fixing device according to any one of claims 1 to 3 , wherein
The fixing device, wherein the opening / closing body is also used as a conveyance guide for the sheet. A fixing device according to any one of claims 1 to 4 , wherein
The fixing device, wherein the fixing member is a heating roller that conveys and heats the sheet. A fixing device according to any one of claims 1 to 5 , comprising:
The fixing device, wherein the fixing member is a pressure roller that conveys and pressurizes the sheet. An image forming apparatus comprising the fixing device according to any one of claims 1 to 6 .

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