JP7635565B2 - Developing device, and image forming apparatus equipped with developing device - Google Patents

Description

The present invention relates to a developing device that is installed in an image forming device such as a copier or multifunction device.

Electrophotographic image forming devices are equipped with a developing device that develops an electrostatic latent image on a photosensitive drum with toner. The developing device has a developing roller that is rotatably supported within its housing, and performs development by supplying toner contained within the housing from the developing roller to the photosensitive drum.

This type of developing device is provided with a side seal to prevent toner from leaking from the axial end of the developing roller (see Patent Document 1). The side seal is provided in a curved state along the outer peripheral surface of the axial end of the developing roller.

JP 2018-060028 A

However, because conventional side seals are made by bending a sheet member made of felt or the like into a curved shape, when the seal member is bent, its end face (longitudinal end face) is inclined relative to the seal surface. This occurs because the curvature of the inner part close to the outer periphery of the developing roller is different from that of the outer part away from the outer periphery. For this reason, when the end face comes into contact with another seal member while the developing device is installed, the contact surfaces do not come into close contact with each other, and gaps are created between the contact surfaces, which can cause developer such as toner to leak out.

The object of the present invention is to provide a developing device capable of realizing high sealing performance in a sealing member that prevents leakage of developer, and an image forming device equipped with the developing device.

The developing device according to one aspect of the present invention is a developing device that is mounted on an image forming apparatus, and includes a housing capable of accommodating a developer therein, a developing roller rotatably provided in the housing, carrying the developer on its outer peripheral surface and rotating in a predetermined rotation direction, and a seal member that is bent in a curved shape along the outer peripheral surface of the developing roller and is interposed in a gap between an axial end of the outer peripheral surface and the housing, and is in sliding contact with the outer peripheral surface. The seal member is formed by providing at least two sheet members in layers, and includes a first sheet member that is disposed on the outer peripheral surface side, and a second sheet member that is disposed outside the first sheet member. When the seal member is in an unbent state, among the seal ends on the downstream side of the rotation direction of the seal member, the second downstream end of the second sheet member protrudes beyond the first downstream end of the first sheet member.

An image forming apparatus according to another aspect of the present invention includes the developing device and an apparatus main body that detachably supports the developing device, and the apparatus main body has another seal member that abuts against the seal end of the seal member and presses against the seal end when the developing device is attached.

According to the present invention, it is possible to achieve high sealing performance in the sealing member that prevents leakage of developer.

FIG. 1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the top cover of the image forming apparatus according to the embodiment of the present invention is open. FIG. 3 is a cross-sectional view showing the internal structure of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a perspective view showing an image forming unit included in the image forming apparatus according to the embodiment of the present invention. FIG. 5 is a perspective view showing the image forming apparatus according to the embodiment of the present invention, showing a state in which the image forming unit is removed from the apparatus main body. FIG. 6 is a perspective view showing a drum unit provided in the image forming apparatus according to the embodiment of the present invention. FIG. 7 is a diagram showing a cross-sectional structure of a drum unit provided in an image forming apparatus according to an embodiment of the present invention, and is a cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view showing the internal structure of the image forming apparatus according to the embodiment of the present invention, showing a state in which the drum unit is attached to the apparatus main body. FIG. 9 is a perspective view of the developing device according to the embodiment of the present invention, as viewed from the front left side. FIG. 10 is a perspective view of the developing device according to the embodiment of the present invention, as viewed from the rear right side. FIG. 11 is a plan view of the developing device according to the embodiment of the present invention. FIG. 12 is a cross-sectional view taken along line XII-XII of FIG. 9, showing the internal structure of the developing device according to the embodiment of the present invention. FIG. 13 is a partial enlarged view of the left side of the developing device according to the embodiment of the present invention. FIG. 14 is a left side view of the developing device according to the embodiment of the present invention with the side cover removed. FIG. 15 is an enlarged perspective view of the right side of the developing device according to the embodiment of the present invention. FIG. 16 is a perspective view showing a state in which the shaft cover is removed from the right side of the developing device according to the embodiment of the present invention. FIG. 17 is an enlarged detailed view of the left end portion of the developing roller in FIG. FIG. 18 is a cross-sectional view taken along a cutting plane passing through a side seal provided in the developing device in FIG. FIG. 19 is a perspective view showing the side seal in an unbent state. FIG. 20 is a schematic diagram showing a state in which the side seal and the other seal member are in pressure contact with each other when the developing device is mounted.

Below, an embodiment of the present invention will be described with reference to the drawings as appropriate. The embodiment described below is merely one embodiment of the present invention, and does not limit the technical scope of the present invention. Furthermore, for the sake of convenience, the following description will use the up-down direction 7, the front-rear direction 8, and the left-right direction 9 shown in each figure. Note that in Figures 1 to 5, the vertical direction is defined as the up-down direction 7 in the installed state in which the image forming device 10 is usable (the state shown in Figure 1), and the front-rear direction 8 and the left-right direction 9 (width direction 9) are defined in this installed state.

[First]
1 to 3 show an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 is an apparatus having at least a printing function, for example, a printer that forms a single-color image on a sheet such as printing paper according to an electrophotographic method. The image forming apparatus 10 prints an image on printing paper based on image data input from the outside via a communication unit (not shown). The image forming apparatus 10 is not limited to a single-color printer, and may be a color printer that forms a color image. The image forming apparatus 10 may also be a multifunction machine that has various functions such as a facsimile and a copier in addition to the printing function.

Figures 1 and 2 are perspective views showing the exterior of the image forming device 10, with Figure 1 showing the top cover 12 and front cover 13 in a closed state, and Figure 2 showing the top cover 12 and front cover 13 in an open state. Figure 3 is a cross-sectional view showing the internal structure of the device body 11. Note that the top cover 12 is not shown in Figure 3.

As shown in Figures 1 and 2, the image forming device 10 is formed in a generally rectangular parallelepiped shape that is elongated in the width direction 9, and includes a device body 11 to which each unit that performs image forming processing is attached, a top cover 12 provided on the top of the device body 11, and a front cover 13 provided on the front of the device body 11.

As shown in FIG. 2, an opening 21 that leads to the inside is formed in the upper part of the device body 11, and a top cover 12 is provided so that this opening 21 can be opened and closed. The top cover 12 is supported so as to be openable and closable between an open position (position shown in FIG. 2) that opens the opening 21 and a closed position (position shown in FIG. 1) that closes the opening 21, centered on a hinge 24 provided at the rear end of the upper part of the device body 11. When the top cover 12 is rotated upward (opening direction) to open the opening 21, the image forming unit 50 and other components mounted inside the device body 11, which will be described later, are exposed. In this state, the user can remove the developing device 70 supported by the image forming unit 50 from inside the device body 11.

In addition, an opening 22 that leads to the inside is formed at the bottom of the front of the device body 11, and a front cover 13 is provided so that this opening 22 can be opened and closed. The front cover 13 is supported around a hinge 25 provided at the lower end of the front side of the device body 11 so that it can be opened and closed between an open position (position shown in FIG. 2) that opens the opening 22, and a closed position (position shown in FIG. 1) that closes the opening 22. When the front cover 13 is rotated forward (opening direction) to open the opening 22, it becomes possible to set printing paper inside the device body 11 through the opening 22.

As shown in FIG. 3, the image forming device 10 mainly comprises an image forming unit 50, a fixing section 31, a paper feed tray 32, a feeding unit 33, an LSU (Laser Scanner Unit) 34, a paper discharge tray 35 (see FIG. 1), a number of transport rollers 37 provided in a transport path 36, and a discharge roller 38 provided at the end of the transport path 36. These are attached inside the device body 11 including the cover of the outer frame of the image forming device 10 and the internal frame. In FIG. 3, the path indicated by the dashed line extending upward from the feeding unit 33 is the transport path 36.

Figure 4 is a perspective view showing the image forming unit 50. The image forming unit 50 forms images according to an electrophotographic method, and includes a drum unit 60 and a developing device 70. In this embodiment, the image forming unit 50 is detachably supported on the device body 11 so that it can be replaced.

When the developer stored in the developing device 70 becomes empty, it is necessary to replace it with another developing device 70 filled with developer. Therefore, in this embodiment, the developing device 70 is supported by the device body 11 so as to be detachable from the device body 11. Specifically, the developing device 70 is detachably mounted to the drum unit 60 (an example of a mounting member) mounted to the device body 11. The developing device 70 is also removed as necessary when performing maintenance on the inside of the image forming device 10. Figures 2 and 3 show the image forming unit 50 mounted to the device body 11. Figure 5 shows the image forming unit 50 removed from the device body 11.

Figure 6 is a perspective view showing the drum unit 60. Also, Figure 7 is a cross-sectional view of the section VII-VII in Figure 6, showing the cross-sectional structure of the drum unit 60.

As shown in Figures 6 and 7, the drum unit 60 includes a photosensitive drum 61, a charging section 62, a transfer roller 63, and a housing 64. The photosensitive drum 61, the charging section 62, and the transfer roller 63 are supported by the housing 64. In addition, the developing device 70 is detachably supported by a developing support section 65 that is integrally provided on the housing 64.

The housing 64 is, for example, a molded product made of synthetic resin, and has a first base frame 641 extending in the left-right direction 9, and a pair of support frames 642 erected on both ends of the first base frame 641 in the left-right direction 9. Each support frame 642 is formed, for example, in a plate shape. Each support frame 642 is formed of an insulating material that does not conduct electricity. Each support frame 642 extends in the front-rear direction 8, and the photosensitive drum 61 and the transfer roller 63 are supported rotatably in a state of being pressed against each other at the rear part of each support frame 642. In addition, a charging unit 62 is attached to the upper part of the rear part of each support frame 642. The charging unit 62 is arranged to face the outer circumferential surface of the photosensitive drum 61, and is attached so as to span each support frame 642.

As shown in Figures 6 and 7, the developer support part 65 is integrally formed on the front side of the housing 64. The developer support part 65 has a second base frame 651 formed forward from the first base frame 641 across the paper passage opening 66 (see Figure 7), and a front plate 652 that constitutes the front part of each support frame 642. When the developer device 70 is attached to the developer support part 65, the lower surface 716 (see Figure 12) of the developer device 70 is supported by the second base frame 651. In this case, the lower surface 716 is the supported surface supported by the drum unit 60.

The paper passage opening 66 is a through opening formed between the first base frame 641 and the second base frame 651, through which the printing paper fed from the paper feed tray 32 is inserted and guided toward the transfer position between the photosensitive drum 61 and the transfer roller 63.

When the image forming operation is started with the image forming unit 50 attached to the device main body 11, the photosensitive layer on the surface of the photosensitive drum 61 is charged to a uniform potential by the charging section 62. In addition, the LSU 34 scans the photosensitive drum 61 with laser light according to the image data. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 61. A bias voltage is applied to the photosensitive drum 61 and the developing roller 74 (see FIG. 10) of the developing device 70, and an electric field with a predetermined potential difference that can transfer toner from the developing roller 74 to the photosensitive drum 61 is formed between the photosensitive drum 61 and the developing roller 74. Due to the potential difference, toner is attached to the electrostatic latent image from the developing roller 74, and a toner image is formed on the photosensitive drum 61. An electric field with a predetermined potential difference is also formed between the photosensitive drum 61 and the transfer roller 63. Due to this potential difference, the toner image on the photosensitive drum 61 is transferred to the printing paper fed from the paper feed tray 32. The printing paper with the toner image transferred is transported to the fixing unit 31.

The fixing unit 31 is provided downstream of the image forming unit 50 in the conveying direction of the print paper. The fixing unit 31 fixes the toner image transferred to the print paper to the print paper by heat. The fixing unit 31 includes a heating roller and a pressure roller. The heating roller is heated by a heating means such as an induction heater during the fixing operation. The pressure roller is urged toward the heating roller by an elastic member. As the print paper passes through the fixing unit 31, the toner is heated and melted while the print paper is pressed by the fixing unit 31, and adheres to the print paper. As a result, the toner image is fixed to the print paper, and an image is formed on the print paper.

Discharge rollers 38 are provided downstream of the fixing unit 31 in the transport direction. The discharge rollers 38 discharge the print paper, on which the image has been fixed by the fixing unit 31, to the paper output tray 35 (see FIG. 1).

The photosensitive drum 61 of the drum unit 60 deteriorates and wears as the photosensitive layer on its surface is repeatedly formed with images. When the photosensitive layer deteriorates, its charging property deteriorates, and when it wears, it is no longer charged to a predetermined potential, resulting in a deterioration in image quality. Therefore, the photosensitive drum 61 needs to be replaced at a predetermined replacement timing. Therefore, in this embodiment, the drum unit 60 is supported by the device body 11 so that it can be attached and detached from the device body 11 so that the photosensitive drum 61 can be replaced. The drum unit 60 is also removed as necessary when performing maintenance on the inside of the image forming device 10. Here, FIG. 8 is a cross-sectional view showing a state in which only the drum unit 60 of the image forming unit 50 is attached to the device body 11. Therefore, the developing device 70 is not shown in FIG. 8.

As shown in FIG. 8, guide grooves 111 are formed on the inner surfaces 15 on both sides of the left-right direction 9 of the device body 11 to guide the drum unit 60 when the drum unit 60 is attached to the inside of the device body 11 through the opening 21. The guide grooves 111 also guide the drum unit 60 toward the opening 21 when the drum unit 60 is removed from the device body 11, making it easy to remove. The guide grooves 111 extend diagonally downward and rearward from an insertion opening 113 that is funnel-shaped in cross section and formed on the upper edge of the inner surface 15. Note that while FIG. 8 shows the guide groove 111 formed on the right inner surface 15A, a similarly shaped guide groove 111 is also formed on the opposite left inner surface 15B (see FIG. 5).

The guide groove 111 is formed so that the degree of inclination gradually becomes gentler toward the mounting position of the drum unit 60 (the position shown in FIG. 8, hereinafter referred to as the unit mounting position). Specifically, the guide groove 111 has a first groove 111A formed in a substantially straight line from the insertion opening 113 to a first bending point P1, a second groove 111B that is inclined more gently than the first groove 111A from the first bending point P1 to a second bending point P2, and a third groove 111C that is inclined more gently than the second groove 111B from the second bending point P2 to the unit mounting position.

As shown in FIG. 6, the drum unit 60 is provided with a guide member 644 that is inserted into the guide groove 111 when the drum unit 60 is attached to the device body 11 and when the drum unit 60 is removed from the device body 11. The guide member 644 is provided on the outer surface of each of a pair of support frames 642 that constitute the housing 64. The guide member 644 is a boss-shaped or pin-shaped member that is provided vertically on the outer surface of the support frame 642.

The guide member 644 is provided on the rear side of the outer surface of the support frame 642. The drum unit 60 is inserted until the guide member 644 is positioned at the end of the guide groove 111.

As shown in FIG. 8, another guide groove 112 branching off from guide groove 111 is formed on the inner surface 15A. FIG. 8 shows guide groove 112 formed on the right inner surface 15A, but a similar guide groove 112 is also formed on the opposite, left inner surface 15B. Like guide groove 111, guide groove 112 guides drum unit 60 to the unit mounting position when drum unit 60 is mounted inside device body 11 from opening 21, and guides drum unit 60 toward opening 21 when drum unit 60 is removed from device body 11.

The guide groove 112 extends diagonally downward and rearward from the first bending point P1 in the guide groove 111. The guide groove 112 is formed so that it gradually widens diagonally rearward from the upper end opening 114, which is the connecting portion with the guide groove 111. In other words, the guide groove 112 is formed in a generally flared shape from the upper end opening 114 diagonally rearward.

The upper groove wall surface of the guide groove 112 is a guide surface 112A for guiding a bearing portion 77 (see Figures 13 and 15) of the developing device 70, which will be described later, toward a mounting position P11 determined on the drum unit 60 when the developing device 70 is attached to the device body 11. The guide surface 112A is generally parallel to the second groove 111B of the guide groove 111.

The lower groove wall surface of the guide groove 112 is a guide surface 112B for guiding a guide member 645 (see FIG. 6) provided on the drum unit 60, described below, downward when the drum unit 60 is attached to the device body 11. When the developing device 70 is attached to the device body 11, this guide surface 112B also guides guide portions 78, 791 (see FIG. 13, FIG. 15) provided on the developing device 70, described below, downward.

As shown in FIG. 6, the drum unit 60 is provided with a guide member 645 that is inserted into the guide groove 112 when the drum unit 60 is attached to the device body 11 and when the drum unit 60 is removed from the device body 11. The guide member 645 is erected on the outer surface of each of the pair of support frames 642 that constitute the housing 64. The guide member 645 is a boss-shaped or pin-shaped member that is erected vertically on the outer surface of the support frame 642.

On the outer surface of the support frame 642, the guide member 645 is provided forward of the guide member 644. When the drum unit 60 is attached to the device body 11, the guide member 644 is first inserted into the guide groove 111 from the insertion opening 113, and then the guide member 645 is inserted into the guide groove 111. During the installation process of the drum unit 60, the guide member 644 is guided from the first groove 111A through the second groove 111B and along the third groove 111C toward the unit installation position (position shown in FIG. 8). On the other hand, when the guide member 645 reaches the first bending point P1 of the guide groove 111 during the installation process of the drum unit 60, it enters the guide groove 112 from the upper end opening 114 and is guided generally downward along the guide surface 112B of the guide groove 112.

When the drum unit 60 is inserted up to the unit mounting position shown in FIG. 8, the drum unit 60 is locked at the unit mounting position by a locking mechanism (not shown). In other words, the drum unit 60 is positioned at the unit mounting position. When an unlocking member (not shown) provided on the device body 11 is operated, the locking mechanism is released. This makes it possible to remove the drum unit 60 upward from the unit mounting position and take it out from the opening 21.

7, the support frame 642 is formed with a guide groove 646 for guiding the bearing portion 77 (see FIGS. 13 and 15) of the developing device 70 to the mounting position P11, and a stopper 647 provided at the end of the guide groove 646. The guide groove 646 is formed in the support frame 642 so as to separate the support frame 642 into a rear portion and a front plate 652 on the front side. When the bearing portion 77 is guided to the mounting position P11, the stopper 647 positions the bearing portion 77 at that position P11. When the developing device 70 is attached to the device body 11, the stopper 647 abuts against the bearing portion 77, and the movement of the bearing portion 77 in the insertion direction is restricted by the stopper 647. This positions the developing device 70 on the drum unit 60. The developing device 70 is also locked to the drum unit 60 by a locking mechanism (not shown) provided in the drum unit 60. When the lock release lever 67 on the drum unit 60 is operated, the locking mechanism is released. This allows the developing device 70 to be removed upward from the device body 11 and taken out from the opening 21.

Figure 9 is a perspective view of the developing device 70 as seen from the front left side, Figure 10 is a perspective view of the developing device 70 as seen from the rear right side, and Figure 11 is a plan view of the developing device 70. Also, Figure 12 is a cross-sectional view of section XII-XII in Figure 11, showing the cross-sectional structure of the central portion of the developing device 70.

The developing device 70 adheres toner to the electrostatic latent image on the photoreceptor drum 61, and develops the electrostatic latent image with toner to form a toner image as a visible image on the surface of the photoreceptor drum 61. As shown in FIG. 12, the developing device 70 includes a housing 71 (an example of a housing), an agitating member 72, a supply roller 73 (an example of a rotating member), and a developing roller 74 (an example of a rotating member). The agitating member 72, the supply roller 73, and the developing roller 74 are rotatably supported by the housing 71.

The housing 71 is, for example, a molded product made of synthetic resin. As shown in Figures 9 to 11, the housing 71 is formed in a shape that is long in the left-right direction 9 (longitudinal direction). A developer including toner is contained inside the housing 71. In other words, the housing 71 not only serves as a case that supports the developing roller 74 and the like, but also serves as a developer container (also called a toner container) that contains the developer.

As shown in FIG. 12, the stirring member 72 is disposed on the front side inside the housing 71. The stirring member 72 is rotatably supported by a pair of support frames 711 (see FIG. 9 to FIG. 11) provided on both sides of the housing 71 in the left-right direction 9 (axial direction). The pair of support frames 711 (an example of a pair of support members) constitute each side surface of the housing 71 on both sides in the left-right direction 9.

At both ends in the width direction of the shaft member 721 of the stirring member 72, a support shaft 722 (see FIG. 14) is provided that is rotatably supported by the support frame 711. The left support shaft 722L of the stirring member 72 is rotatably supported in a bearing hole (not shown) formed in the left support frame 711L. As shown in FIG. 14, the support shaft 722L passes through the bearing hole and protrudes to the outside of the support frame 711L. A transmission gear 82, which will be described later, is attached to the support shaft 722L.

As shown in FIG. 12, the shaft member 721 of the stirring member 72 is provided with a film-shaped paddle portion 723 that is perpendicular to the shaft member 721. When a rotational driving force is input from the outside to the stirring member 72, the stirring member 72 rotates, and the developer contained in the housing 71 is stirred by the paddle portion 723. When the developer is stirred by the stirring member 72, an electric charge is imparted to the toner contained in the developer.

As shown in FIG. 9, a side cover 75 is attached to the support frame 711L on the left side of the housing 71.

Figure 13 is a partially enlarged view of the left side of the developing device 70. Figure 14 is a left side view of the developing device 70 with the side cover 75 removed.

As shown in FIG. 13, the side cover 75 is attached to the support frame 711L so as to cover the left side of the support frame 711L. As shown in FIG. 14, a transmission mechanism 80 consisting of multiple gears 81-85 is provided inside the side cover 75, that is, between the side cover 75 and the support frame 711L. Each of the gears 81-85 constituting the transmission mechanism 80 is rotatably supported by the support frame 711L.

As shown in FIG. 14, the transmission mechanism 80 has an input section 76 to which a driving force is input from the outside. That is, the input section 76 is provided on the support frame 711L. The input section 76 is, for example, a shaft joint (coupling). The side cover 75 is formed with a cylindrical tube section 751 (see FIG. 13) that penetrates the input section 76 and exposes it to the outside. As shown in FIG. 13, when the side cover 75 is attached to the support frame 711L, the input section 76 is exposed to the outside through the tube section 751.

When the developing device 70 is attached to the device body 11, a drive output unit (not shown) provided on the device body 11 is connected to the input unit 76. As a result, the rotational drive force of a drive source such as a motor is input to the input unit 76 via the drive output unit. The input unit 76 has an input gear 81 (see FIG. 14) that is provided coaxially with the input unit 76. In other words, the transmission mechanism 80 has an input gear 81. When the rotational drive force is input to the input unit 76, the input gear 81 transmits the rotational drive force to the other transmission gears 82 to 85 that make up the transmission mechanism 80.

As shown in FIG. 14, the transmission mechanism 80 has a plurality of transmission gears 82-85. Each of the transmission gears 82-85 is disposed on the outer surface of the support frame 711L. The transmission gear 82 is attached to the support shaft 722L of the agitator 72 and transmits the rotational driving force to the agitator 72. The transmission gear 83 is attached to the end of the rotation shaft 732 (an example of a second support shaft) of the supply roller 73 and transmits the rotational driving force to the supply roller 73. The transmission gear 84 is attached to the end of the rotation shaft 742 (see FIG. 12) of the development roller 74 and transmits the rotational driving force to the development roller 74. The transmission gear 85 is rotatably supported by the support frame 711L in a state of meshing with the transmission gear 82. The transmission gear 85 transmits the rotational driving force to the rotation member 90 provided on the support frame 711L.

When the rotational driving force is input to the input portion 76 and transmitted from the input gear 81 to the other transmission gears 82 to 85 that constitute the transmission mechanism 80, the rotational driving force is transmitted to the agitating member 72, the supply roller 73, the developing roller 74, and the rotating member 90, causing the agitating member 72, the supply roller 73, the developing roller 74, and the rotating member 90 to rotate.

As shown in FIG. 12, the supply roller 73 is disposed in front of the developing roller 74 (in the direction opposite to the insertion direction of the developing device 70) and disposed behind the stirring member 72. The supply roller 73 is a roller member that rotates while carrying the toner contained in the developer on its outer circumferential surface. The supply roller 73 is rotatably supported by a pair of support frames 711. When the supply roller 73 is rotated, it carries the developer contained in the housing 71 on its outer circumferential surface and transports the developer to a position facing the developing roller 74.

The supply roller 73 has a cylindrical roller body 731 made of a conductive elastic material, and a conductive rotating shaft 732 arranged at the center of the roller body 731. The roller body 731 is formed of an elastic material such as urethane with an appropriate amount of carbon scattered therein. The rotating shaft 732 is a conductive metal shaft. Both ends of the rotating shaft 732 are rotatably supported in bearing holes (not shown) provided in a pair of support frames 711. A predetermined bias (hereinafter referred to as a supply bias) is applied to the supply roller 73 to carry charged toner on the outer circumferential surface and to move the toner from the supply roller 73 to the developing roller 74.

In this embodiment, when the developing device 70 is attached to the device body 11, the supply bias is applied to the rotating shaft 732 of the supply roller 73 from a supply terminal 117 (see FIG. 8) provided on the device body 11. Specifically, the supply terminal 117 is provided at a position where it contacts a guide portion 791 (see FIGS. 15 and 16) described below when the developing device 70 is attached, and when the developing device 70 is attached to the device body 11, the guide portion 791 contacts the supply terminal 117, and the supply bias is applied from the supply terminal 117 to the rotating shaft 732 via the guide portion 791, the guide member 79, and the connecting portion 792.

The developing roller 74 is disposed on the rear side inside the housing 71. The developing roller 74 is a roller member that rotates while carrying the toner contained in the developer on its outer circumferential surface. The developing roller 74 is rotatably supported by a pair of support frames 711. An opening 713 that exposes the developing roller 74 to the outside is formed on the rear side of the housing 71. When the developing device 70 is attached to the device main body 11, the developing roller 74 faces the photosensitive drum 61 with a specified gap between them.

The developing roller 74 has a cylindrical roller body 741 made of a conductive elastic material and a conductive rotating shaft 742 (an example of a first support shaft) arranged at the center of the roller body 741. The roller body 741 is formed of an elastic material such as urethane with carbon appropriately dispersed therein. The rotating shaft 742 is a conductive metal shaft. Both ends of the rotating shaft 742 are rotatably supported by bearings 77 (77L, 77R) provided on a pair of support frames 711 (see FIG. 11). A predetermined bias (hereinafter referred to as a developing bias) is applied to the developing roller 74 to move the toner from the supply roller 73 to the developing roller 74. The potential difference between the developing bias and the supply bias causes the charged toner to be supplied from the supply roller 73 to the developing roller 74.

In this embodiment, when the developing device 70 is attached to the device body 11, the developing bias is applied to the rotating shaft 742 of the developing roller 74 from a supply terminal 116 (see FIG. 8) provided on the device body 11. Specifically, the supply terminal 116 is provided at a position where it contacts a bearing portion 77R (see FIG. 15) described below when the developing device 70 is attached, and when the developing device 70 is attached to the device body 11, a guide portion 77R2 (see FIG. 15) of the bearing portion 77R contacts the supply terminal 116, and the developing bias is applied from the supply terminal 116 to the rotating shaft 742 via the guide portion 77R2.

As shown in FIG. 14, a bearing portion 77L (an example of a first bearing portion) is provided on the support frame 711L. The bearing portion 77L is formed integrally with the support frame 711L and has a cylindrical guide portion 77L1 (an example of a first guide portion) that protrudes outward from the outer side surface of the support frame 711L. The left shaft end of the rotating shaft 742 is inserted into a bearing hole formed inside the bearing portion 77L, thereby supporting the shaft end so that it can rotate. In this embodiment, the guide portion 77L1 of the bearing portion 77L, together with a guide portion 77R2 of the bearing portion 77R described below, also serves as a guide member for guiding the developing device 70 to the mounting position P11 determined on the drum unit 60 during the process of mounting the developing device 70 to the apparatus main body 11.

As shown in FIG. 13, the side cover 75 is provided with a guide portion 78 formed integrally therewith. The guide portion 78 is provided at a position spaced a predetermined distance forward (in the direction opposite to the insertion direction of the developing device 70) from the bearing portion 77L (its guide portion 77L1). The guide portion 78 is a cylindrical member that protrudes outward from the outer side surface of the side cover 75. In this embodiment, the guide portion 78 guides the front end portion of the developing device 70 downward together with a guide portion 791 of a guide member 79 described later during the process of mounting the developing device 70 to the apparatus main body 11.

Figure 15 is an enlarged perspective view of the right side of the developing device 70.

As shown in FIG. 15, a bearing portion 77R (an example of a first bearing portion) is provided on the support frame 711R. The bearing portion 77R is an example of a first guide portion. The bearing portion 77R has a cylindrical portion 77R1 formed integrally with the support frame 711R, and a guide portion 77R2 (an example of a first guide portion) that is guided when the developing device 70 is attached to the apparatus main body 11. The cylindrical portion 77R1 protrudes outward from the outer side surface of the support frame 711R. The right shaft end portion 742R of the rotating shaft 742 is inserted into the inner hole of the cylindrical portion 77R1, thereby supporting the shaft end portion 742R for rotation.

When the rotating shaft 742 is inserted into the cylindrical portion 77R1, the shaft end 742R passes through the cylindrical portion 77R1 and is exposed to the outside. A cylindrical guide portion 77R2 is attached to this exposed portion. The guide portion 77R2 is formed, for example, from a conductive material. In this embodiment, the guide portion 77R2 is a guide portion for guiding the developing device 70 to the mounting position P11 determined on the drum unit 60 during the process of mounting the developing device 70 to the apparatus main body 11.

As shown in FIG. 15, the support frame 711R is provided with a guide portion 791. Specifically, a guide member 79 made of a conductive material is fixed to the support frame 711R, and the guide portion 791 is integrally formed with the guide member 79. The guide portion 791 is an example of a second guide portion.

Figure 16 is a perspective view showing the state where the shaft cover 712 (see Figure 15) has been removed from the right side of the developing device 70. As shown in Figure 16, a bearing hole is formed in the support frame 711R to support the right shaft end 732R of the rotating shaft 732 of the supply roller 73, and the shaft end 732R is inserted into this bearing hole. A shaft cover 712 (see Figure 15) is attached to the outer surface of the support frame 711R so as to cover the shaft end 732R. Note that in Figure 15, the member surrounded by a thick solid line is the shaft cover 712.

As shown in FIG. 16, the guide member 79 is attached to the outer surface of the support frame 711R. In FIG. 16, the member surrounded by a thick solid line is the guide member 79. The guide member 79 is formed from a conductive member and has a guide portion 791 and a connecting portion 792. The connecting portion 792 connects to the shaft end portion 732R that protrudes outward from the support frame 711R, thereby electrically connecting the conductive rotating shaft 732 and the conductive guide member 79.

The guide portion 791 is provided at a position spaced a predetermined distance forward from the bearing portion 77R. The guide portion 791 is a cylindrical member that protrudes outward from the outer side surface of the support frame 711R. In this embodiment, the guide portion 791 guides the front end portion of the developing device 70 downward during the process of mounting the developing device 70 to the device main body 11.

As shown in Figures 15 and 16, the support frame 711R is provided with a cap member (lid member) 714 that closes a toner filling port formed in the support frame 711R. The toner filling port is connected to the inside of the housing 71, and toner is filled into the inside through the toner filling port.

As described above, the developing device 70 of this embodiment has bearings 77 (77L, 77R) provided on a pair of support frames 711. Therefore, when the developing device 70 is inserted into the device body 11 with the drum unit 60 attached to the device body 11, the guide portion 77L1 of the bearing portion 77L and the guide portion 77R2 of the bearing portion 77R provided on the developing device 70 are guided along the guide surface 112A of the device body 11 toward the mounting position P11 (see FIG. 8).

Specifically, when the guide portion 77L1 and the guide portion 77R2 inserted into the guide groove 111 from the insertion opening 113 reach the first bending point P1 of the guide groove 111, the guide portion 77L1 and the guide portion 77R2 enter the guide groove 112 from the upper end opening 114. Thereafter, they are guided along the guide surface 112A of the guide groove 112 toward the mounting position P11. When the guiding by the guide surface 112A ends and the guide portion 77L1 and the guide portion 77R2 enter the guide groove 646, they are guided to the mounting position P11 by the guide groove 646. Then, when the guide portion 77L1 and the guide portion 77R2 are guided to the mounting position P11, the guide portion 77L1 and the guide portion 77R2 are restricted by the stopper 647 at the position P11.

In addition, when the developing device 70 is mounted in the device body 11, the guide portions 78, 791 enter the guide groove 112 and are guided generally downward along the guide surface 112B of the guide groove 112.

This positions the developing device 70 in the drum unit 60, and the developing device 70 is locked to the drum unit 60 by a locking mechanism (not shown).

In addition, in the developing device 70 of this embodiment, the guide portion 77L1 provided on the bearing portion 77L and the guide portion 77R2 provided on the shaft end portion 742R are used as members that are guided when the developing device 70 is attached. In other words, the bearing portions 77L and 77R also serve as guide members for the developing device 70 when it is attached to or detached from the apparatus main body 11. This makes it possible to reduce the number of members provided on the side portions of the developing device 70, and as a result, it is possible to realize a more compact housing 71 for the developing device 70.

In addition, in this embodiment, when the developing device 70 is attached, the guide portion 791 contacts the supply terminal 117, and the supply bias is applied from the supply terminal 117 to the rotating shaft 732 via the guide portion 791, the guide member 79, and the connecting portion 792. Also, the guide portion 77R2 of the bearing portion 77R contacts the supply terminal 116, and the developing bias is applied from the supply terminal 116 to the rotating shaft 742 via the guide portion 77R2. In other words, the guide member 79 also serves as a power receiving terminal (power receiving portion) for the supply bias, and the bearing portion 77R also serves as a power receiving terminal (power receiving portion) for the developing bias. Therefore, it is no longer necessary to provide each power receiving terminal on the side portion of the developing device 70, and the number of members provided on the side portion can be further reduced. As a result, the housing 71 of the developing device 70 can be made even more compact.

[Second]
Hereinafter, the side seal 40 (one example of the seal member of the present invention) provided in the developing device 70 will be described with reference to Figs. 17 to 21. Fig. 17 is an enlarged detailed view of the left end of the developing roller 74 in Fig. 10. Fig. 18 is a cross-sectional view taken along a cutting plane passing through the side seal 40 in Fig. 17. Fig. 19 is a perspective view showing the side seal 40 in an unbent state. Fig. 20 is a schematic view showing a state in which the side seal 40 and another seal member 68 are pressed into contact when the developing device 70 is installed.

As shown in FIG. 17, the developing device 70 is provided with a side seal 40. The side seal 40 is a member that seals the gap between the axial end 741A (area surrounded by a dashed line) on the outer circumferential surface of the developing roller 74 and the housing 71 to prevent toner from leaking from the gap. In this embodiment, a side seal 40 is provided at each of both axial ends of the developing roller 74.

As shown in FIG. 18, the side seal 40 is bent in a curved shape along the outer peripheral surface of the roller body 741 of the developing roller 74, and is provided in the gap between the axial end 741A of the outer peripheral surface and the housing 71. The inner surface 40A of the side seal 40 is in contact with the surface of the end 741A. Therefore, when the developing roller 74 rotates in a predetermined rotation direction D11 during the developing operation, the side seal 40 slides against the end 741A. The outer surface 40B of the side seal 40 is in contact with the bottom surface 71A of the housing 71. The bottom surface 71A is the inner surface of the lower edge portion 713A of the opening 713 in the housing 71.

The side seal 40 is provided in the gap while being compressed in the thickness direction. In the side seal 40, one end 401 (an example of the seal end of the present invention) is located near the lower edge 713A, and the other end 402 is located upstream of the end 401 in the direction of rotation D11.

The side seal 40 is made up of at least two layered sheet members, specifically an inner sheet 41 (an example of the first sheet member of the present invention) arranged on the end 741A side, and an outer sheet 42 (an example of the first sheet member of the present invention) arranged outside the inner sheet 41. Furthermore, the side seal 40 has a three-layer structure in which three sheet members are stacked, with an intermediate sheet 43 (an example of the third sheet member of the present invention) provided between the inner sheet 41 and the outer sheet 42.

The inner sheet 41 is a sheet member formed, for example, from a nonwoven fabric. The inner sheet 41 is preferably formed from a felt that has a higher sliding property than the outer sheet 42. The outer sheet 42 is a porous member, a sheet member formed from a relatively soft material. The outer sheet 42 is preferably formed from a sponge member or urethane foam that has appropriate elasticity and flexibility. In this embodiment, the thickness of the outer sheet 42 is thicker than the thickness of the inner sheet 41, for example, it is formed to be two to four times the thickness of the inner sheet 41.

The intermediate sheet 43 is a sheet member formed of a harder material than the inner sheet 41 and the outer sheet 42. The intermediate sheet 43 is formed thinner than the inner sheet 41 and the outer sheet 42, and is, for example, a film-like resin sheet formed of PET resin. Both longitudinal end faces of each of the sheets 41 to 43 are cut vertically.

As shown in FIG. 19, when the side seal 40 is in an unbent state, the sheets 41 to 43 have different lengths. Specifically, the outer sheet 42, which is located on the outermost side, is the longest, followed by the middle sheet 43, and the inner sheet 41 is the shortest.

The sheets 41 to 43 are partially joined to each other. Specifically, at the contact surface between the sheets of the side seal 40, the joint area R1 on the end 402 side (the contact surface on the upstream side of the rotation direction D11) is joined by an adhesive member. In this embodiment, with the end 402 of the side seal 40 aligned, approximately one-third of the contact surface on the end 402 side is joined. The adhesive member may be a double-sided tape or adhesive. Meanwhile, at the contact surface, the portion on the end 401 side (the contact surface on the downstream side of the rotation direction D11) excluding the joint area R1 is not joined.

As described above, the lengths of the sheets 41 to 43 are different, and the end 402 of each sheet 41 to 43 is joined with the end 402 aligned. Therefore, a step is generated for each sheet 41 to 43 at the end 401 of the side seal 40. Specifically, in the unbent state shown in FIG. 19, the end 421 of the outer sheet 42 (an example of the second end of the present invention) protrudes beyond the end 431 of the intermediate sheet 43. Also, the end 431 of the intermediate sheet 43 protrudes beyond the end 411 of the inner sheet 41 (an example of the first end of the present invention). The protruding direction is the right side of the paper in FIG. 19, and is the downstream side of the rotation direction D11 or the opening 713 side when installed in the gap.

The end 401 of the side seal 40 is pressed against another seal member 68 (see FIG. 17) provided on the housing 71 of the developing device 70. As shown in FIG. 17, the seal member 68 is provided at a position facing the end 401 on the bottom surface 71A. In FIG. 17, the seal member 68 is indicated by a broken line. The seal member 68 is bonded to the bottom surface 71A by an adhesive member. When the developing device 70 is attached to the drum unit 60 inside the device main body 11, the seal member 68 abuts against a seal member (not shown) provided on the drum unit 60 with a predetermined pressing force. As a result, the seal member 68 seals the gap between the opening 713 and the housing 64 of the drum unit 60. In addition, the seal member 68 and the end 401 abut against each other and press against each other, thereby sealing the gap between the seal member 68 and the end 401.

As described above, the lengths of the sheets 41 to 43 of the side seal 40 are different. Therefore, when the side seal 40 is installed in a curved state in the gap between the end 741A of the roller body 741 and the housing 71, the tapered protrusions 41A, 42A, and 43A appear at the end 401. Here, the protrusion 41A of the inner sheet 41 corresponds to the inner corner of the end 411. The protrusion 42A of the outer sheet 42 corresponds to the inner corner of the end 421. The protrusion 43A of the intermediate sheet 43 corresponds to the inner corner of the end 431. Such protrusions 41A, 42A, and 43A are caused by the difference in curvature of each surface of the sheets 41 to 43 due to the curved shape, since only the joint region R1 on the end 402 side is joined in each sheet 41 to 43.

In this embodiment, as shown in Figure 20, the protrusion amounts of the ends 411, 421, and 431 of each sheet 41-43 are determined so that the straight line connecting the tips of each protrusion 41A, 42A, and 43A is parallel to the contact surface 68A of the seal member 68. These protrusion amounts are designed appropriately depending on the material and thickness of each sheet 41-43, the range of the joined area, the size of the roller body 741, the longitudinal length of the side seal 40, etc.

When the side seal 40 is attached, the protrusions 41A, 42A, and 43A appear on each sheet 41 to 43. When the developing device 70 is attached to the drum unit 60, the protrusions 41A, 42A, and 43A come into contact with the contact surface 68A of the seal member 68, and are pressed against each other, causing the protrusions 41A, 42A, and 43A to sink into the seal member 68. This makes it difficult for gaps to form between the end 401 of the side seal 40 and the seal member 68 when the developing device 70 is attached. As a result, toner is prevented from leaking from the gap, and high sealing performance can be achieved.

In the above embodiment, the side seal 40 has three sheets 41 to 43, but the present invention is not limited to this configuration. For example, the side seal 40 may have at least two sheet members among the sheets 41 to 43. Therefore, when the side seal 40 is composed of an inner sheet 41 and an intermediate sheet 43, the inner sheet 41 corresponds to the first sheet member, and the intermediate sheet 43 corresponds to the second sheet member. Also, when the side seal 40 is composed of an intermediate sheet 43 and an outer sheet 42, the intermediate sheet 43 corresponds to the first sheet member, and the outer sheet 42 corresponds to the second sheet member.

In addition, in the above embodiment, an example was described in which the developing device 70 is attached to the drum unit 60 attached to the image forming device 10, but the present invention is also applicable when the housing 64 of the drum unit 60 is formed integrally with the device body 11 of the image forming device 10.

10: Image forming apparatus 11: Apparatus main body 40: Side seal 40A: Inner surface 40B: Outer surface 41: Inner sheet 41A: Protruding portion 42: Outer sheet 42A: Protruding portion 43: Intermediate sheet 43A: Protruding portion 50: Image forming unit 60: Drum unit 70: Developing device 71: Housing 74: Developing rollers 401, 402: Ends 411, 421, 431: Ends

Claims (5)

A developing device;
an apparatus main body that detachably supports the developing device,
The developing device is
A housing capable of accommodating a developer therein;
a developing roller that is rotatably provided in the housing, carries the developer on an outer circumferential surface thereof, and is rotated in a predetermined rotation direction;
a seal member that is bent in a curved shape along the outer circumferential surface of the developing roller, is interposed in a gap between an end of the outer circumferential surface in an axial direction and the housing, and is in sliding contact with the outer circumferential surface,
the seal member is formed by providing at least two sheet members in a layered manner, and includes a first sheet member disposed on the outer circumferential surface side and a second sheet member disposed on an outer side of the first sheet member,
When the seal member is in an unbent state, a second end of the second seat member on the downstream side in the rotation direction of the seal member protrudes more than a first end of the first seat member on the downstream side,
The device body includes:
an image forming apparatus including another seal member that abuts against and presses the seal end of the seal member when the developing device is attached; 2 . The image forming apparatus according to claim 1 , wherein the contact surfaces between the sheet members are joined at an upstream side in the rotation direction and are not joined at a downstream side. The sealing member includes a third sheet member provided between the first sheet member and the second sheet member,
3. The image forming apparatus according to claim 1, wherein the third sheet member is made of a material harder than the first sheet member and the second sheet member. 4. The image forming apparatus according to claim 1, wherein the first sheet member is made of a nonwoven fabric, and the second sheet member is made of a porous soft material. The image forming apparatus according to claim 4 , wherein the second sheet member is thicker than the first sheet member.