Image forming device

Abstract

To provide an image forming device capable of stably ensuring grounding via a hinge mechanism for rotatably fitting a door to a device body.SOLUTION: A hinge plate 41 has a conductive abutment 60. A support plate 51 has a conductive abutted part 70 abbutable against the abutment 60. The abutment 60 and the abutted part 70 abut against each other when a front door 40 is closed, and are separated from each other when the front door 40 is opened. The abutment 60 collides with and abut against the abutted part 70 when the front door 40 is closed. When the abutment 60 abuts against the abutted part 70, the abutted part 70 is elastically deformed to come into contact with the abutment 60 at fixed contact pressure. Specifically, in addition to grounding by contact between the lower end surface of an upper cylindrical part 111 of the support plate 51 affected by application of a load of the front door 40 when the front door 40 is in a closed state and the upper end surface of a lower cylindrical part 112 of the hinge plate 41, grounding is ensured by abutment between the abutment 60 provided in a door side plate part 412 and the abutted part 70 provided in a body side plate part 512.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus such as a printer, a copier, a facsimile, or a multifunction machine. [Background technology]

[0002] Image forming devices such as printers, copiers, facsimiles, and multifunction devices are provided with a door that can be opened and closed on the device body. An operator can access the device body by opening the door to replace or clean various units housed in the device body, or remove recording material stuck in the conveying path. The door is rotatably attached to the device body by a hinge (Patent Document 1). A holding mechanism is provided on the free end side of the door, for example, by a magnet to hold the door to the device body in a closed state (Patent Document 2). When the door is made of resin, a reinforcing metal plate is attached to the back side of the door to ensure the durability and rigidity of the door.

[0003] Incidentally, when the door is made of metal or when the door is made of resin and is reinforced with a reinforcing metal plate, it is necessary to ground (earth) them to the ground. This is because, if they are conductors and are not grounded, they may function as antennas that receive and re-radiate electromagnetic waves (called radiation noise) that are generated from electronic circuits, motors, etc. and propagate through the air. Conventionally, a conductive hinge mechanism is used, and grounding is ensured by contacting the lower end surface of a cylindrical upper cylinder part in which a hinge pin is fitted in a support plate attached to the device body with the upper end surface of a cylindrical lower cylinder part in which a hinge pin is fitted in a hinge plate attached to the door and rotatable relative to the support plate with the hinge pin as a rotation axis. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-187815 A [Patent Document 2] JP 2017-108018 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the door is held in the closed state by the holding mechanism, the lower end surface of the upper cylinder part and the upper end surface of the lower cylinder part may not be in electrical contact with sufficient contact pressure. This is because a small gap is provided between the lower end surface of the upper cylinder part and the upper end surface of the lower cylinder part to facilitate smooth rotation, and the state of contact between them is affected by the load applied by the door when it is closed. As a result, in the past, when the door was held in the closed state, the grounding was insufficient, and there was a risk that the metal door or the reinforcing sheet metal would become a source of radiation noise.

[0006] In view of the above problems, the present invention aims to provide an image forming apparatus that can ensure stable grounding via a hinge mechanism that rotatably attaches the door to the device body, even when the door is held in a closed position. [Means for solving the problem]

[0007] An image forming apparatus according to one embodiment of the present invention is an image forming apparatus that forms an image on a recording material, the image forming apparatus comprising: an apparatus main body having an opening formed therein, the apparatus main body having a conductive frame; a door that is arranged to be able to open and close the opening of the apparatus main body and has at least a metal part; a rod-shaped hinge pin, a conductive support part having a first fixing part fixed to the frame and a cylindrical first fitting part that is rotatably fitted to the hinge pin; a second fixing part fixed to the door, and a cylindrical second fitting part that is arranged coaxially with the first fitting part and is rotatably fitted to the hinge pin, the conductive hinge part being conductively connected to the metal part, the hinge part having a conductive abutment part, the support part having a conductive abutted part that can abut against the abutment part, the abutment part and the abutted part abutting when the door is closed. Effect of the Invention

[0008] According to the present invention, even if the door is held in a closed position, stable grounding can be ensured via the conductive support part and the conductive hinge part that rotatably attach the door to the device body. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an image forming apparatus according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 4A is a perspective view showing a state in which an image forming unit is pulled out, and FIG. 4B is a perspective view showing a state in which an intermediate transfer belt unit is pulled out. [Figure 4] FIG. 2 is a diagram for explaining an outline of a hinge mechanism. [Diagram 5] (a) is an enlarged view showing the magnetic catch portion and the door switch plate, and (b) is an enlarged view showing the suction portion and the insertion portion. [Figure 6] FIG. 13 is a top cross-sectional view showing the inside of the reinforcing sheet metal with the front door closed. [Figure 7] (a) A diagram to explain the load applied when the front door is open, (b) A diagram to explain the load applied to the upper hinge mechanism, and (c) A diagram to explain the load applied to the lower hinge mechanism. [Figure 8] (a) A diagram to explain the load applied to the hinge mechanism when the front door is closed, (b) A diagram to explain the load applied to the upper hinge mechanism, and (c) A diagram to explain the load applied to the lower hinge mechanism. [Figure 9] 1A and 1B are perspective views showing the hinge mechanism of the first embodiment, in which FIG. [Figure 10] 13A and 13B are perspective views showing a hinge mechanism of a second embodiment, in which (a) the front door is open and (b) the front door is closed. [Figure 11] 13A and 13B are perspective views showing an upper support plate of the second embodiment, in which (a) is seen from the inside and (b) is seen from the outside. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] <Image forming device> The present embodiment will be described below. First, the image forming apparatus of the present embodiment will be described with reference to Figs. 1 to 3(c). As shown in Fig. 1, the image forming apparatus 1 is an electrophotographic full-color printer, and has an apparatus main body 1A. The apparatus main body 1A is provided with an original reading device 160 for reading image information of an original, a display unit capable of displaying various information, and an operation unit 80 having keys for inputting various information according to an operator's operation. In this specification, the side on which an operator stands when operating the operation unit 80 is referred to as the "front (or front side)" and the opposite side is referred to as the "rear side". Fig. 1 shows the image forming apparatus 1 as viewed from the front.

[0011] The image forming apparatus 1 of this embodiment is an intermediate transfer type full-color printer in which image forming units SY, SM, SC, and SK that form yellow, magenta, cyan, and black toner images are housed in the apparatus main body 1A and are arranged facing an intermediate transfer belt 7. The image forming apparatus 1 forms a toner image on a recording material S in accordance with image data from a document reading device 160 provided above the apparatus main body 1A or an external device (not shown) such as a personal computer. Examples of the recording material S include sheet materials such as paper, plastic film, and cloth. The image forming units SY to SK may be provided in the apparatus main body 1A so that an operator can attach and detach them from the front.

[0012] The conveying process of the recording material S in the image forming apparatus 1 will be described. The recording material S is stored in a stacked form in one or more (three in this example) cassettes 4, and is supplied one sheet at a time to a conveying path 64 by a supply roller 5 in accordance with the image formation timing. The recording material S supplied by the supply roller 5 is conveyed to a registration roller 36 arranged in the middle of the conveying path 64. Then, the registration roller 36 performs skew correction and timing correction on the recording material S, and the recording material S is sent to a secondary transfer section ST. The secondary transfer section ST is formed by a secondary transfer inner roller 34 and a secondary transfer outer roller 35 that face each other with the intermediate transfer belt 7 in between, and is a nip section that transfers a toner image from the intermediate transfer belt 7 onto the recording material S by applying a predetermined pressure force and a secondary transfer bias.

[0013] The process of forming an image sent to the secondary transfer station ST at the same timing as the process of conveying the recording material S to the secondary transfer station ST described above will be described. First, the image forming units SY to SK will be described. However, since the image forming units SY to SK for each color are basically the same except for the color of the toner, the following description will be given by taking the black image forming unit SK as an example.

[0014] The image forming unit SK mainly includes a photosensitive drum 3K as a photosensitive member, a charging device 10K, a developing device 20K, and a drum cleaner 15K. The surface of the photosensitive drum 3K, which is rotated by a drive motor (not shown), is uniformly charged in advance by the charging device 10K, and then an electrostatic latent image is formed on the surface by an exposure device 2K, which is driven based on image data. The developing device 20K develops the electrostatic latent image formed on the photosensitive drum 3K with toner contained in the developer. As a result, a toner image is formed on the photosensitive drum 3K.

[0015] Thereafter, a predetermined pressure and a primary transfer voltage are applied by primary transfer roller 30K, which is disposed opposite image forming unit SK with intermediate transfer belt 7 interposed therebetween, and the toner image formed on photosensitive drum 3K is primarily transferred onto intermediate transfer belt 7. Primary transfer residual toner remaining on photosensitive drum 3K after primary transfer is collected by drum cleaner 35K.

[0016] The intermediate transfer belt 7 is an endless belt that is stretched by a tension roller 32, a drive roller 33, and a secondary transfer inner roller 34, and is moved at a speed corresponding to the rotation speed of the photosensitive drums 3Y to 3K by the drive roller 33 that is driven to rotate by a motor or the like. The image forming process of each color, which is processed in parallel by the image forming units SY to SK of each color described above, is performed at a timing when the image forming process of each color is sequentially superimposed on the toner image of the color that has been primarily transferred onto the intermediate transfer belt 7 upstream in the moving direction. As a result, a full-color toner image is finally formed on the intermediate transfer belt 7 and is conveyed to the secondary transfer section ST. Secondary transfer residual toner that remains on the intermediate transfer belt 7 after passing through the secondary transfer section ST is collected from the intermediate transfer belt 7 by a belt cleaner device 39. The primary transfer rollers 30Y to 30K, the intermediate transfer belt 7, the tension roller 32, the drive roller 33, the secondary transfer inner roller 34, the belt cleaner device 39, and the like may be provided in the apparatus main body 1A as an intermediate transfer belt unit 800 so that an operator can attach and detach it from the front.

[0017] Through the above-mentioned conveying process and image forming process, the timing of the recording material S and the full-color toner image coincides at the secondary transfer section ST, and secondary transfer is performed in which the toner image is transferred from the intermediate transfer belt 7 to the recording material S. Thereafter, the recording material S is conveyed to the fixing device 8, where the toner image is fixed to the recording material S by applying heat and pressure.

[0018] In the case of a single-sided mode in which a toner image is formed only on one side of the recording material S, the recording material S on which the toner image is fixed by the fixing device 8 is guided to the discharge conveying path 65 and is discharged outside the apparatus main body 1A by the discharge rollers 37. On the other hand, in the case of a double-sided mode in which a toner image is formed on both sides of the recording material S, the recording material S on which the toner image is fixed by the fixing device 8 is inverted in the reversing conveying path 66, and then conveyed toward the registration rollers 36 through the double-sided conveying path 67. Thereafter, the recording material S undergoes the same process as in the single-sided mode, a toner image is formed on the other side by the fixing device 8, and then the recording material S is guided to the discharge conveying path 65 and finally discharged outside the apparatus main body 1A by the discharge rollers 37. In the case of this embodiment, a finisher unit 150 that performs post-processing such as stapling on the recording material S discharged from the apparatus main body 1A is connected to the apparatus main body 1A, so that the recording material S that has been post-processed by the finisher unit 150 is placed on the discharge tray 154.

[0019] The device body 1A is made of metal and is composed of a plurality of frames, such as a front plate on the front side, a rear plate provided on the rear side and supporting the image forming units SY to SK together with the front plate, a stay connecting the front plate and the rear plate, and a support supporting the front plate and the rear plate. As shown in FIG. 2, an opening 1B is formed in the device body 1A, and a front door 40, the surface of which is a part of the exterior of the device, is provided in the opening 1B so as to be able to be opened and closed. The front door 40 is formed of a non-conductive material such as resin, and a reinforcing metal plate 43 is attached to the rear surface of the front door 40 as a metal part to ensure the durability and rigidity of the front door 40. The front door 40 may be made of metal, in which case the reinforcing metal plate 43 may not be attached.

[0020] The front door 40 is provided by hinge mechanisms 110, 120 (see FIG. 4 described later) so as to be rotatable in the direction of arrow A. Since the front door 40 is provided on the apparatus main body 1A so as to be openable and closable, an operator can open the front door 40 and pull out, to the outside, the image forming units SY-SK and the intermediate transfer belt unit 800 housed within the apparatus main body 1A to clean or replace them.

[0021] Fig. 3(a) shows the state in which the image forming units SY-SK have been pulled out from the apparatus main body 1A, and Fig. 3(b) shows the state in which the intermediate transfer belt unit 800 has been pulled out from the apparatus main body 1A after the image forming units SY-SK have been removed. In this way, by allowing the image forming units SY-SK and the intermediate transfer belt unit 800 to be pulled out towards the front of the apparatus, the operator can easily access each unit.

[0022] In this embodiment, hinge mechanisms (110, 120) are used to provide the front door 40 to the apparatus body 1A so that it can be opened and closed. The outline of the hinge mechanisms (110, 120) will be described with reference to FIG. 4. As shown in FIG. 4, in this embodiment, the front door 40 is provided rotatably on the apparatus body 1A by two hinge mechanisms (110, 120) arranged vertically above and below. These hinge mechanisms (110, 120) rotate around rod-shaped hinge pins (53, 54) as rotation axes, with support plates (51, 52) as support parts attached to the frame 1C of the apparatus body 1A and hinge plates (41, 42) as hinge parts attached to the front door 40. In response to this, the front door 40 rotates relative to the apparatus body 1A. An operator can attach or detach the front door 40 to or from the apparatus main body 1A by inserting or removing the hinge pins (53, 54) of the hinge mechanisms (110, 120).

[0023] The support plates (51, 52) and the hinge plates (41, 42) are preferably formed so as to ensure an opening area that does not interfere with the drawing out of the image forming units SY to SK and the intermediate transfer belt unit 800 from the apparatus main body 1A when the front door 40 is opened. In this embodiment, the support plates (51, 52) and the hinge plates (41, 42) are formed to a thickness approximately equal to the thickness of the frame 1C to which the support plates (51, 52) are attached, in order to minimize the projected area from the front side. In this embodiment, the hinge mechanisms (110, 120) are disposed at two locations, one above the other, for the purpose of grounding, which will be described later, and to ensure the rigidity and strength of the thin support plates (51, 52) and the hinge plates (41, 42) to support the heavy front door 40. Therefore, if the front door 40 is heavier, more hinge mechanisms may be provided.

[0024] <Retention mechanism> In this embodiment, a holding mechanism is provided for holding the front door 40 in the closed state on the apparatus main body 1A when the front door 40 is closed. A known holding mechanism may be used, but as an example, a holding mechanism that uses a magnet will be described with reference to Figures 5(a) and 5(b) and Figure 4.

[0025] The holding mechanism of this embodiment is composed of a pair of holding parts, that is, a magnetic catch part 44 and an adsorption part 56. As shown in Fig. 4, the front door 40 is provided with hinge plates (41, 42) on one end side in the width direction perpendicular to the rotation axis of the hinge pins (53, 54), and with a magnetic catch part 44 on the other end side (free end side). As shown in Fig. 5(a), the magnetic catch part 44 has a magnet 44a.

[0026] On the other hand, the apparatus main body 1A is provided with an adhesion part 56 made of, for example, iron, as shown in Fig. 5(b). The adhesion part 56 is disposed at a position where it comes into contact with the magnet 44a of the magnetic catch part 44 provided on the front door 40 when the front door 40 is closed. When the magnet 44a comes into contact with the adhesion part 56, it is attached to the adhesion part 56 by magnetic force. As a result, the front door 40 is held by the apparatus main body 1A in the closed state unless it is pulled by a force greater than or equal to the magnetic force of the magnet 44a.

[0027] As shown in Fig. 5(a), a door switch plate 45 protruding inward from the rear surface of the front door 40 may be provided above the magnet catch portion 44 on the free end side of the front door 40. As shown in Fig. 5(b), the device main body 1A is provided with an insertion section 57 having an insertion opening into which the tip of the door switch plate 45 is inserted when the front door 40 is closed. A sensor (not shown) capable of detecting that the door switch plate 45 is inserted into the insertion opening is provided inside the insertion section 57. This sensor makes it possible to detect that the front door 40 is closed.

[0028] <Grounding> As described above, in this embodiment, the reinforcing metal plate 43 is attached to the back surface of the resin front door 40. Recently, in order to further compactify the device, the distance between the reinforcing metal plate 43 and the electronic board 72 on which electronic components such as a driver board and the motor 73 mounted on the device main body 1A is reduced when the front door 40 is closed, as shown in Fig. 6. In this case, if the grounding of the reinforcing metal plate 43 is unstable, the reinforcing metal plate 43 becomes an antenna for radiated noise and relays the radiated noise generated from the electronic components on the electronic board 72 and the motor 73, which may cause other electronic components to malfunction.

[0029] Therefore, generally, the conductive member constituting the product needs to be grounded to be electrically stable. However, it is difficult to prevent a conductive member having a large area from becoming an antenna of radiated noise by simply grounding it to the ground at one point and making it the same potential as the ground level, and it is necessary to ground it at multiple points to prevent it from becoming an antenna of radiated noise. When the reinforcing metal plate 43, which is a conductive member having a large area, is arranged on the front door 40 as in this embodiment, it is preferable to ground the reinforcing metal plate 43 to the ground at multiple points, since the reinforcing metal plate 43 does not become an antenna of radiated noise, but rather has the effect of shielding the radiated noise. On the other hand, if the reinforcing metal plate 43 cannot be grounded to the ground at multiple points with respect to the device main body 1A, the reinforcing metal plate 43 may become an antenna of radiated noise and may become a source of radiated noise. Therefore, when considering the grounding of the reinforcing metal plate 43 provided on the front door 40 that is rotatably supported by the device main body 1A, it is preferable to ground it at multiple points (two points in this case) of the hinge mechanism (110, 120) since it is not necessary to provide a member for grounding.

[0030] However, when grounding is performed via the hinge mechanism (110, 120), the manner in which the load of the front door 40 is applied to the hinge mechanism (110, 120) has an effect. Conventionally, depending on the manner in which the load of the front door 40 is applied to the hinge mechanism, the grounding by the upper hinge mechanism was unstable, and the grounding of the reinforcing sheet metal 43 was substantially only at one point by the lower hinge mechanism. Here, the manner in which the load of the front door 40 is applied to the hinge mechanism (110, 120) will be described with reference to Figs. 7(a) to 8(c).

[0031] FIG. 7(a) is a diagram for explaining the load applied to the hinge mechanism (110, 120) when the front door 40 is in an open state. FIG. 7(b) is a diagram for explaining the load applied to the upper hinge mechanism 110 when the front door 40 is in an open state. FIG. 7(c) is a diagram for explaining the load applied to the lower hinge mechanism 120 when the front door 40 is in an open state. FIG. 8(a) is a diagram for explaining the load applied to the hinge mechanism (110, 120) when the front door 40 is in a closed state. FIG. 8(b) is a diagram for explaining the load applied to the upper hinge mechanism 110 when the front door 40 is in a closed state. FIG. 8(c) is a diagram for explaining the load applied to the lower hinge mechanism 120 when the front door 40 is in a closed state.

[0032] When the front door 40 is open, as shown in FIG. 7(a), the load F applied to the center of gravity of the front door 40 is received by a load f1 applied vertically to the lower hinge mechanism 120 and a horizontal load f2 applied to the upper hinge mechanism 110. The horizontal load f2 is a moment load centered on the lower hinge mechanism 120, and is calculated by the distance X from the center of gravity of the front door 40 to the hinge mechanism 120 and the distance Y from the hinge mechanism 120 to the hinge mechanism 110. When the front door 40 is open, as shown in FIG. 7(b), the load f2 is applied to the upper cylinder portion 111 and the lower cylinder portion 112 of the hinge mechanism 110, and as shown in FIG. 7(c), the load f1 is applied to the upper cylinder portion 121 and the lower cylinder portion 122 of the hinge mechanism 120, so that a sufficient load is applied to both as an electrical contact pressure.

[0033] On the other hand, when the front door 40 is closed, as shown in Fig. 8(a), the load F applied to the center of gravity of the front door 40 is received by a load f1' applied vertically to the lower hinge mechanism 120, a load f3 related to the vertical direction to the magnetic catch portion 44, and a horizontal load f2' applied to the upper hinge mechanism 110. When the front door 40 is closed, the horizontal load f2 applied to the hinge mechanism 110 when the front door 40 is open (see Fig. 7(a)) is partially offset by a moment in the opposite direction received from the load f3, and becomes a lower load f2'. In this manner, when the front door 40 is in the closed state, as shown in Fig. 8(b), a load f2' is applied to the upper cylinder portion 111 and the lower cylinder portion 112 of the hinge mechanism 110, and as shown in Fig. 8(c), a load f1' is applied to the upper cylinder portion 121 and the lower cylinder portion 122 of the hinge mechanism 120. In this case, in the upper hinge mechanism 110, as shown in Fig. 8(b), a gap is generated between the lower end surface of the upper cylinder portion 121 and the upper end surface of the lower cylinder portion 122, making it difficult to obtain sufficient electrical contact pressure.

[0034] <Hinge mechanism> Therefore, in this embodiment, stable ground contact is ensured via the hinge mechanism (110, 120) regardless of the load applied by the front door 40 when the front door 40 is closed. The hinge mechanism of this embodiment will be described below with reference to Figs. 9(a) and 9(b) using the hinge mechanism 110 as an example. Fig. 9(a) shows the front door 40 in an open state, and Fig. 9(b) shows the front door 40 in a closed state.

[0035] As shown in Fig. 9(a) and Fig. 9(b), the support plate 51 is formed into a substantially L-shape by, for example, pressing, and has a main body side fixing part 511 as a first fixing part fixed to the frame 1C, a cylindrical upper cylinder part 111 as a first fitting part rotatably fitted to the hinge pin 53, and a main body side plate part 512 as a plate part connecting the main body side fixing part 511 and the upper cylinder part 111. The main body side fixing part 511 has a fastening hole through which a fastening member such as a screw passes, and the main body side fixing part 511 is fixed to the frame 1C by the fastening member. The main body side plate part 512 is extended from the main body side fixing part 511 toward the front of the device main body 1A. The upper cylinder part 111 is formed by curling one end of the main body side plate part 512 into a cylindrical shape.

[0036] On the other hand, the hinge plate 41 is formed into a substantially L-shape by general-purpose press processing, and has a door-side fixing portion 411 as a second fixing portion fixed to the front door 40, a cylindrical lower cylinder portion 112 as a second fitting portion provided coaxially with the upper cylinder portion 111 and rotatably fitted to the hinge pin 53, and a door-side plate-like portion 412 connecting the door-side fixing portion 411 and the lower cylinder portion 112. The door-side fixing portion 411 has a fastening hole through which a fastening member such as a screw passes, and the door-side fixing portion 411 is fixed to the front door 40 by the fastening member so as to be conductively connected to the reinforcing sheet metal 43. In the case of this embodiment, the support plate 51 and the hinge plate 41 are fixed so that the upper cylinder portion 111 of the support plate 51 is located vertically above the lower cylinder portion 112 of the hinge plate 41. The lower cylinder portion 112 is formed by curling one end of the door-side plate-like portion 412 into a cylindrical shape. The front door 40 is opened and closed by the door side plate portion 412 rotating relative to the main body side plate portion 512 around the hinge pin 53 inserted into the upper cylinder portion 111 and the lower cylinder portion 112 as a rotation axis.

[0037] In this embodiment, the hinge plate 41 has a conductive abutment portion 60, and the support plate 51 has a conductive abutted portion 70 that can abut against the abutment portion 60. The abutment portion 60 is provided on the door side plate portion 412, and the abutted portion 70 is provided on the main body side plate portion 512, so that the abutment portion 60 and the abutted portion 70 abut when the front door 40 is closed and are separated when the front door 40 is opened. The abutment portion 60 is formed in a long beam shape on the door side plate portion 412, and an abutment surface that abuts against the abutted portion 70 is formed on a tip portion that is bent in a crank shape toward the outside of the front door 40 in the width direction of the front door 40.

[0038] 9(b), the contact portion 60 abuts against the contacted portion 70 when the front door 40 is closed. When the contact portion 60 abuts against the contacted portion 70, the contacted portion 70 elastically deforms and comes into contact with the contact portion 60 at a constant contact pressure. In order to make this possible, the main body side plate portion 512 is formed with an elastic deformation portion 512a that elastically deforms when abutted against the contact portion 60.

[0039] In the present embodiment, the elastic deformation portion 512a is an area surrounded by a slit 95 formed in a concave shape in a part of the main body side plate-like portion 512. The elastic deformation portion 512a is formed so that the amount of elastic deformation is larger on the upper cylinder portion 111 side than on the main body side fixed portion 511 side, and the tip portion on the upper cylinder portion 111 side serves as the abutment portion 70. Even if the abutment portion 70 is provided at the tip portion of the elastic deformation portion 512a formed by opening the slit 95 in the main body side plate-like portion 512 in this way, the slit 95 has a closed shape, so that the rigidity and strength required to support the front door 40, which is the basic function of the support plate 51, is ensured.

[0040] The elastic deformation portion 512a is formed in a long beam shape. As a result, even if the support plate 51 is formed of a conductive material that does not have spring properties, sufficient contact pressure with the contact portion 60 can be generated within the range of elastic deformation without plastic deformation when the contact portion 60 contacts it. For example, when the support plate 51 is formed of an electrogalvanized steel plate with a thickness of 1.6 mm, the elastic deformation portion 512a is formed in a beam shape with a length of about 30 mm and a width of 8 mm. Then, the designed interference amount of the contact portion 60 with the contacted portion 70 is set to about 0.2 mm to 0.7 mm. In such a case, by changing the designed interference amount of the contact portion 60 with the contacted portion 70, when the contact portion 60 contacts the contacted portion 70, a contact pressure of "5N to 18N" can be generated while suppressing the deformation of the contacted portion 70 within the range of elastic deformation, and thus a contact pressure sufficient for grounding can be ensured. The amount of interference between the contact portion 60 and the contacted portion 70 can be adjusted by changing the length of the portion of the contact portion 60 that is bent into a crank shape.

[0041] It is preferable that a protruding portion 70a that protrudes from the surface of the elastically deforming portion 512a and abuts against the abutting portion 60 is formed at the tip of the elastically deforming portion 512a that becomes the abutted portion 70. By forming the protruding portion 70a, the abutment position between the abutting portion 60 and the abutted portion 70 and the amount of interference at the time of abutment are stabilized. Furthermore, by forming the protruding portion 70a, the abutted portion 70 functions as a durable and stable contact point.

[0042] Although an example has been shown here in which the elastically deforming elastic portion 512a is formed on the main body side plate-like portion 512, the contact portion 60 of the hinge plate 41 may be formed to be elastically deformable. That is, it is sufficient that either the support plate 51 or the hinge plate 41 has an elastically deforming portion that elastically deforms when the contact portion 60 and the contacted portion 70 come into contact with each other.

[0043] As described above, in this embodiment, the hinge plate 41 has a conductive abutment portion 60, the support plate 51 has a conductive abutted portion 70 that can abut against the abutment portion 60, and the abutment portion 60 and the abutted portion 70 abut when the front door 40 is closed, and are separated when the front door 40 is opened. When the abutment portion 60 abuts against the abutted portion 70, the abutment portion 70 elastically deforms and contacts the abutment portion 60 with a constant contact pressure. That is, in this embodiment, in addition to grounding by contact between the lower end surface of the upper cylindrical portion 111 of the support plate 51, which is affected by the load applied by the front door 40 when the front door 40 is closed, and the upper end surface of the lower cylindrical portion 112 of the hinge plate 41, grounding by contact between the abutment portion 60 provided on the door side plate portion 412 and the abutted portion 70 provided on the main body side plate portion 512 is ensured. As a result, even if the front door 40 is held in a closed state by the holding mechanism, stable grounding can be ensured via the conductive support plate 51 and the conductive hinge plate 41 that rotatably attach the front door 40 to the device main body 1A.

[0044] [Second embodiment] Next, a hinge mechanism according to a second embodiment will be described with reference to Fig. 10(a) to Fig. 11(b). In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0045] As shown in Fig. 10(a) and Fig. 10(b), in the second embodiment, as in the first embodiment, the hinge plate 41 has a conductive abutment portion 60, and the support plate 51A has a conductive abutted portion 70 that can abut against the abutment portion 60. The abutment portion 60 is provided on the hinge plate 41 on the front door 40 side as in the first embodiment, and the hinge plate 41 may have the same configuration as in the first embodiment. Then, as in the first embodiment, the abutment portion 70 and the abutment portion 60 abut when the front door 40 is closed, and are separated when the front door 40 is open. When the abutment portion 60 abuts against the abutment portion 70, the abutment portion 70 elastically deforms and comes into contact with a certain contact pressure, functioning as an electrical contact.

[0046] However, in the second embodiment, unlike the first embodiment, the abutment portion 70 is formed not on the main body side plate-like portion 512 of the support plate 51A, but on the intermediate cylinder portion 113 provided vertically below the upper cylinder portion 111 so that the hinge pin 53 can be fitted therein. As shown in Figs. 11(a) and 11(b), the intermediate cylinder portion 113 as the third fitting portion is formed by curling one end of the main body side plate-like portion 512 into a cylindrical shape, with a gap 90 between the upper cylinder portion 111 and the intermediate cylinder portion 111 in the vertical direction. The intermediate cylinder portion 113 is formed into a beam shape whose vertical length is shorter than the vertical length of the upper cylinder portion 111. In this embodiment, the abutment portion 70 is disposed below the curled portion of the main body side plate-like portion 512 in the intermediate cylinder portion 113.

[0047] 10(b), when the front door 40 is closed, the contact portion 60 butts against the contacted portion 70. When the contact portion 60 abuts against the contacted portion 70, the intermediate tube portion 113 elastically deforms, and the contact portion 60 and the contacted portion 70 come into contact with each other at a constant contact pressure.

[0048] In the second embodiment, the surface of the contact portion 70 against which the contact portion 60 contacts may be the contact surface 71 shown in FIG. 11(b). In this case, when the front door 40 is closed, the contact portion 60 does not abut against the contact portion 70, but rubs against the contact surface 71 of the contact portion 70. As the contact portion 60 rubs against the contact surface 71, the contact portion 70 elastically deforms, and the contact portion 70 contacts the contact portion 60 in the elastically deformed state. The contact portion 70 elastically deforms toward the door side plate portion 412 so as to contact the contact portion 60 with a constant contact pressure when the front door 40 is closed.

[0049] As described above, in the second embodiment, similarly to the first embodiment, even if the front door 40 is held by the holding mechanism in a closed state, stable grounding can be ensured via the conductive support plate 51 and the conductive hinge plate 41 that rotatably mount the front door 40 to the apparatus main body 1A. Also, in the second embodiment, the contact position between the contact portion 60 and the contacted portion 70 can be made closer to the rotation center than in the first embodiment. Therefore, the length from the rotation center to the contact portion 60 can be shortened, and the opening area of ​​the opening 1B (see FIG. 2) that does not interfere with the drawing out of the image forming units SY to SK and the intermediate transfer belt unit 800 from the apparatus main body 1A when the front door 40 is opened can be ensured.

[0050] In the above-described first and second embodiments, the contact portion 70 is provided on the support plate 51 (51A) on the apparatus main body side, and the contact portion 60 is provided on the hinge plate 41 on the front door 40 side, but this is not limited to the above. For example, the contact portion 70 may be provided on the hinge plate 41, and the contact portion 60 may be provided on the support plate 51 (51A). In addition, the lower hinge mechanism 120 may have the same configuration as the above-described upper hinge mechanism 110, or both the hinge mechanisms 110 and 120 may have the same configuration as described above. [Explanation of symbols]

[0051] 1...image forming apparatus, 1A...apparatus main body, 1B...opening, 1C...frame, 40...door (front door), 41...hinge portion (hinge plate), 43...metal portion (reinforcing sheet metal), 44...holding portion (magnet catch portion), 51 (51A)...support portion (support plate), 53...hinge pin, 56...holding portion (adsorption portion), 60...contacted portion, 70...contact portion, 70a...protruding portion, 95...slit, 111...first fitting portion (upper cylinder portion), 112...second fitting portion (lower cylinder portion), 113...third fitting portion (middle cylinder portion), 411...second fixing portion (door side fixing portion), 511...first fixing portion (main body side fixing portion), 512...plate-shaped portion (main body side plate-shaped portion), 512a...elastic deformation portion, S...recording material

Claims

1. In an image forming apparatus that forms an image on a recording material, A conductive frame, A first support portion is provided on the frame and is electrically conductive with the frame, A door that, when opened, allows access to the interior of the image forming apparatus, Metal parts and A second support portion which is conductive to the metal portion, and which is rotatably connected to the first support portion around a pivot axis and supports the door, A door having a contact portion that conducts electricity with the metal portion and conducts electricity when the door is closed, and contacts the first support portion, The door is equipped with a holding mechanism that maintains the closed state, An image forming apparatus characterized by the following:

2. The contact portion is provided on the second support portion, The image forming apparatus according to feature 1.

3. The contact portion and the first support portion separate when the closed door is opened. The image forming apparatus according to feature 2.

4. The first support portion has an elastically deformable portion that elastically deforms when it comes into contact with the contact portion. The image forming apparatus according to feature 1.

5. The first support portion includes a first fixing portion fixed to the frame, a cylindrical first fitting portion fitted onto the pivot shaft, and a plate-shaped portion connecting the first fixing portion and the first fitting portion. The second support portion comprises a second fixing portion fixed to the door and a cylindrical second fitting portion provided coaxially with the first fitting portion and fitted onto the pivot shaft. The plate-like portion has a slit formed in a part of it, and the region surrounded by the slit is the elastically deformable portion. The image forming apparatus according to feature 4.

6. The elastically deformable portion has a protruding portion that extends from the surface of the elastically deformable portion and contacts the contact portion. The image forming apparatus according to feature 4.

7. The first support portion includes a first fixing portion fixed to the frame, a cylindrical first fitting portion fitted onto the pivot shaft, a plate-like portion connecting the first fixing portion and the first fitting portion, and a cylindrical third fitting portion arranged on the plate-like portion coaxially with the first fitting portion and with a gap between them, and fitted onto the pivot shaft. The elastic deformation portion is provided in the third fitting portion, The image forming apparatus according to feature 4.

8. The aforementioned door is formed of a non-conductive material, The door is provided on the inside and includes a reinforcing sheet metal to reinforce the door. The image forming apparatus according to feature 1.

9. The holding mechanism comprises a pair of holding parts that hold the door to the device body when the door is closed, The door has the second support portion provided at one end and one of the pair of retaining portions provided at the other end, with respect to a direction perpendicular to the rotation axis of the pivot shaft. The main body of the device is provided with the other of the pair of holding parts. The image forming apparatus according to feature 1.

10. An image forming apparatus for forming an image on a recording material, A conductive frame, A first support portion is provided on the frame and is electrically conductive with the frame, A door that, when opened, allows access to the interior of the image forming apparatus, Metal parts and A door having a second support portion which is conductive to the metal portion, and which is rotatably connected to the first support portion about a pivot axis and supports the door, The door is equipped with a holding mechanism that maintains the closed state, The first support portion has a contact portion that contacts the second support portion and conducts electricity when the door is closed. An image forming apparatus characterized by the following:

Images