JP2009157117A - Developing device and image forming apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device capable of preventing toner scattering from the inside of the developing device and forming a high-quality image free from fogging or image irregularities, and to provide an image forming apparatus equipped therewith. <P>SOLUTION: The developing device includes a developing roller 2 developing an electrostatic latent image on a surface of a photoreceptor drum 20 by supplying toner thereto, a regulating member 3 regulating a carried amount of developer on a surface of the developing roller 2, a cover member 4 provided between the photoreceptor drum 20 and the regulating member 3 above the developing roller 2 and preventing the toner scattering from the inside of the developing device 1, and a seal member 5 provided at the lower part of the cover member 4 and vibrated with rotation of the photoreceptor drum 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device and an image forming apparatus including the developing device.

  An image forming apparatus (hereinafter simply referred to as “image forming apparatus”) that forms an image using an electrophotographic method can form a high-quality image with a simple operation and is easy to maintain and manage. Widely used in printers, facsimiles and the like. The image forming apparatus includes, for example, a photosensitive drum, a charging device, an exposure device, a developing device, a transfer device, and a fixing device. The photosensitive drum is a roller-shaped member having a photosensitive layer on the surface thereof. The charging device charges the surface of the photosensitive drum to a predetermined potential. The exposure device forms an electrostatic latent image on the surface of the charged photosensitive drum. The developing device supplies toner to the electrostatic latent image on the surface of the photosensitive drum to form a toner image. The transfer device transfers the toner image on the surface of the photosensitive drum to a recording medium. The fixing device heat-fixes the toner image on the recording medium. As a result, an image is formed on the recording medium.

  In the image forming apparatus, as the developing device, a developing device including a developing tank, a developing roller, a stirring member, a regulating member, a flow plate, and the like is generally used. The developing tank rotatably supports the developing roller and the stirring member, and stores the developer in the internal space. The developing roller carries a developer on its surface and rotates, and supplies toner to the electrostatic latent image on the surface of the photosensitive drum to form (develop) the toner image. The agitating member uniformly agitates the developer in the developing tank and conveys the developer toward the developing roller. The restricting member restricts the amount of developer carried on the surface of the developing roller. As the developer, a two-component developer containing toner and carrier is mainly used.

  With the rapid spread of image forming apparatuses to a wide range of fields, various performance enhancements are required for image forming apparatuses. For example, the printing speed has been increased. The printing speed, which was 50 sheets / minute to 70 sheets / minute on A4 paper until several years ago, has now reached 100 sheets / minute to 120 sheets / minute. Such speeding up is intended to advance into the field of light printing.

  In order to cope with an increase in printing speed in the developing device, it is necessary to increase the rotation speed of the developing roller. When the developing roller rotates at a high speed, centrifugal force, air resistance, and the like are generated accordingly, and the toner is easily released from the carrier. For this reason, there arises a problem that the liberated toner is scattered outside the developing device from a gap existing between the regulating member and the photosensitive drum, thereby contaminating the inside of the image forming apparatus.

  In order to cope with the above-described problem, for example, Patent Document 1 discloses that the gap between the upper end of the peripheral wall of the developing device and the photosensitive drum is closed with a sealing material to prevent the toner from scattering from the developing tank to the outside. A technique is disclosed in which a vent hole with a filter is formed in the peripheral wall of the developer tank so as to release the internal pressure so as to be positioned in the vicinity of the developer regulating doctor.

JP-A 61-145570

  In the developing device using the technology disclosed in Patent Document 1, when development is performed using a small particle size toner having high cohesive force, the toner adheres inside the upper peripheral wall of the developing device to prevent toner scattering. There is a problem in that fogging and image unevenness in which a ball-like mark is generated on the formed image occurs due to accumulation and dropping as a lump into the developer layer on the surface of the developing roller.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a developing device capable of preventing toner scattering from the inside of the developing device and forming a high-quality image free from fogging and image unevenness. An image forming apparatus including the same is provided.

The present invention is a developing device attached to an electrophotographic image forming apparatus including a photosensitive drum on which an electrostatic latent image is formed.
A developing roller that carries a developer on its surface, rotates, supplies toner to the electrostatic latent image on the surface of the photosensitive drum, and develops the toner;
A regulating member that regulates the amount of developer carried on the surface of the developing roller;
A cover member provided above the developing roller and provided between the photosensitive drum and the regulating member to prevent toner scattering from the inside of the developing device;
And a seal member that is provided at a lower portion of the cover member and vibrates as the photosensitive drum rotates.

  In the developing device of the present invention, only one end in the short direction of the seal member is fixed to the cover member.

  In the developing device of the present invention, the seal member vibrates when the other end contacts the surface of the photosensitive drum.

Further, the developing device of the present invention is provided with an upper seal member that is provided on the upper portion of the cover member, one end portion in the short direction is fixed to the cover member, and the other end portion vibrates by contacting the surface of the photosensitive drum,
The seal member vibrates by contacting the upper seal member.

  In the developing device of the present invention, the seal member is made of urethane rubber.

  The developing device of the present invention is characterized in that the portion of the seal member that does not contact the photosensitive drum has conductivity.

  In the developing device of the present invention, the seal member has a Shore A hardness of 75 ° to 85 °.

In the developing device of the present invention, the upper seal member has an insulating property.
The present invention also provides an image forming apparatus comprising the developing device.

  According to the present invention, in a developing device mounted on an electrophotographic image forming apparatus including a photosensitive drum on which an electrostatic latent image is formed, the developing roller carries a developer on the surface and rotates. The toner is supplied to the electrostatic latent image on the surface of the photosensitive drum for development, the regulating member regulates the amount of developer carried on the surface of the developing roller, and the cover member is above the developing roller. The seal member is provided between the drum and the regulating member to prevent toner scattering from the inside of the developing device, and the seal member is provided below the cover member and vibrates as the photosensitive drum rotates.

  As described above, the toner is attached and accumulated not near the lower part of the cover member but near the lower part of the seal member provided at the lower part of the cover member, and the seal member vibrates as the photosensitive drum rotates. As a result, the toner can be gradually dropped into the developer layer on the surface of the developing roller as the seal member vibrates before the toner accumulates and becomes a lump. As a result, even when developing using a toner having a small particle size with high cohesive force, the toner adheres and accumulates in the vicinity of the lower part of the seal member and drops into the developer layer on the surface of the developing roller as a lump. Can be prevented.

  Therefore, the developing device of the present invention can prevent toner scattering from the inside of the developing device by the cover member and the seal member, and can form a high-quality image without fogging and image unevenness.

  Moreover, according to this invention, it is preferable that only a short-side direction one end part is fixed to a cover member as a base end part. As a result, the other end portion of the seal member can freely move as a free end portion, and therefore, it becomes easier to vibrate. Therefore, the toner can be more effectively dropped into the developer layer on the surface of the developing roller, and a high-quality image with less fog and image unevenness can be formed.

  According to the invention, it is preferable that the seal member vibrates when the other end contacts the surface of the photosensitive drum. As a result, since the seal member can be vibrated by utilizing the frictional force resulting from the rotation of the photosensitive drum, the toner can be more easily dropped into the developer layer on the surface of the developing roller, and the fog can be further increased. And high-quality images with little image unevenness can be easily formed.

  Further, according to the present invention, the developing device of the present invention is provided on the upper portion of the cover member, and vibrates when one end in the short direction is fixed to the cover member and the other end contacts the surface of the photosensitive drum. It is preferable that an upper seal member is provided, and the seal member vibrates by contacting the upper seal member.

  As a result, the upper seal member vibrates using the frictional force caused by the rotation of the photosensitive drum, and the vibration can be transmitted to vibrate the seal member, so that the toner can be more easily developed on the surface of the developing roller. It can be dropped into the agent layer, and a high-quality image with less fog and image unevenness can be easily formed. Further, by providing the upper seal member and the seal member in a double manner, toner scattering from the inside of the developing device can be prevented more reliably.

  Moreover, according to this invention, it is preferable that a sealing member is comprised from urethane rubber. As a result, a seal member having excellent durability can be obtained, and toner scattering from the inside of the developing device can be prevented over a long period of time, and a high-quality image free from fogging and image unevenness can be formed.

  According to the invention, it is preferable that the seal member has conductivity at a portion that does not come into contact with the photosensitive drum. As a result, the seal member is less likely to be charged, so that the toner can be prevented from being adsorbed by electrostatic force. Therefore, it is possible to prevent the toner from adhering and accumulating in the vicinity of the lower portion of the seal member, and it is possible to form a high-quality image with less fog and image unevenness.

  According to the present invention, the seal member preferably has a Shore A hardness of 75 ° to 85 °. As a result, the seal member becomes easier to vibrate, so that the toner can be more effectively dropped into the developer layer on the surface of the developing roller. Therefore, it is possible to form a high-quality image with less fog and image unevenness.

  According to the invention, the upper seal member preferably has an insulating property. As a result, it is possible to prevent the electric charge held on the surface of the photosensitive drum from leaking to the upper seal member, thereby preventing the electrostatic latent image from being disturbed. Therefore, it is possible to form a high-quality image free from image blur due to disturbance of the electrostatic latent image.

  According to the invention, the image forming apparatus of the invention is provided with the developing device, thereby preventing contamination inside the image forming apparatus due to toner scattering from the inside of the developing device, and high-quality images with little fogging and image unevenness. Can be formed.

  The present invention relates to a developing device mounted on an electrophotographic image forming apparatus including a photosensitive drum on which an electrostatic latent image is formed. The photosensitive drum rotates while carrying a developer on the surface. A developing roller that supplies toner to the electrostatic latent image on the surface for development, a regulating member that regulates the amount of developer carried on the surface of the developing roller, and a photosensitive drum and a regulating member above the developing roller. A cover member provided in between to prevent toner scattering from the inside of the developing device, and a seal member provided at a lower portion of the cover member and vibrating as the photosensitive drum rotates.

  As described above, the toner is attached and accumulated not near the lower part of the cover member but near the lower part of the seal member provided at the lower part of the cover member, and the seal member vibrates as the photosensitive drum rotates. As a result, the toner can be gradually dropped into the developer layer on the surface of the developing roller as the seal member vibrates before the toner accumulates and becomes a lump. As a result, even when developing using a toner having a small particle size with high cohesive force, the toner adheres and accumulates in the vicinity of the lower part of the seal member and drops into the developer layer on the surface of the developing roller as a lump. Can be prevented.

  Therefore, the developing device of the present invention can prevent toner scattering from the inside of the developing device by the cover member and the seal member, and can form a high-quality image without fogging and image unevenness.

  The present invention will be specifically described below with reference to embodiments, but the present invention is not particularly limited as long as it does not exceed the gist thereof.

[Development equipment]
(First embodiment)
FIG. 1 is a cross-sectional view schematically showing the configuration of the developing device 1 according to the first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a part of the developing device 1 shown in FIG. FIG. 3 is a diagram showing a magnetic force distribution of each magnetic pole in the magnet roller 12 included in the developing roller 2 which is one of the constituent members of the developing device 1 shown in FIG.

  As shown in FIG. 1 and FIG. 2, the developing device 1 carries a developer on its surface and rotates to supply toner to the electrostatic latent image on the surface of the photosensitive drum 20 for development, and developing A regulating member 3 that regulates the amount of developer carried on the surface of the roller 2, and is provided above the developing roller 2 and between the photosensitive drum 20 and the regulating member 3 to prevent toner scattering from the inside of the developing device 1. The cover member 4 to be prevented is provided, and the seal member 5 is provided below the cover member 4 and vibrates as the photosensitive drum 20 rotates. Further, the developing roller 2 and a stirring member to be described later are rotatably supported, and the developing tank 6 storing the developer in the internal space thereof, and the developer in the developing tank 6 are uniformly stirred toward the developing roller 2. The first agitating member 7, the second agitating member 8 and the conveying member 9 that are the agitating members to be conveyed in this manner, the sink plate 10 that allows the developer in the developing tank 6 to flow smoothly, and the developing tank 6 are accommodated. And a toner concentration detection sensor 11 for detecting the toner concentration. In the present embodiment, the developer is a two-component developer including toner and a carrier that is magnetic powder.

  At least a part of the developing roller 2 is rotatably supported by the developing tank 6 and is a roller-like member that is driven to rotate about an axis by a driving unit (not shown). Further, the developing roller 2 faces the photosensitive drum 20 through the opening 6 a of the developing tank 6. The developing roller 2 is provided so as to be separated from the photosensitive drum 20 with a gap, and the closest portion is a developing nip portion. In the developing nip portion, toner is supplied from an unillustrated developer layer on the surface of the developing roller 2 to the electrostatic latent image on the surface of the photosensitive drum 20. In the developing nip portion, a developing bias voltage is applied to the developing roller 2 from a power source (not shown) connected to the developing roller 2, and the developer layer on the surface of the developing roller 2 changes to the electrostatic latent image on the surface of the photosensitive drum 20. Toner transfer proceeds smoothly.

  The developing roller 2 includes a magnet roller 12 and a sleeve 13. The magnet roller 12 is supported by the developing tank wall of the developing tank 6 at both ends in the longitudinal direction, and magnetic poles N1, N2, N3, and N4 that are a plurality of bar magnets having a rectangular cross-sectional shape at the circumferential position of the developing roller 2. And magnetic poles S1, S2, and S3 are multi-pole magnetized magnet rollers that are spaced apart from each other and arranged radially in the radial direction of the developing roller 2.

  The magnetic poles are provided in the order of the magnetic pole N1, the magnetic pole S1, the magnetic pole N2, the magnetic pole S2, the magnetic pole N3, the magnetic pole N4, and the magnetic pole S3 in the reverse direction to the rotation direction of the developing roller 2 (sleeve 13).

  In the magnet roller 12, the magnetic pole N3 is preferably provided in a specific angle range on the upstream side in the rotation direction of the developing roller 2 from the magnetic pole S2 (hereinafter, simply referred to as “upstream” unless otherwise specified). Here, the angle for defining a specific angle range refers to the radius (hereinafter referred to as “radius S2”) of the developing roller 2 where the magnetic pole S2 is disposed and the developing roller 2 where the magnetic pole N3 is disposed. This is the angle θ formed by the radius in the cross section (hereinafter referred to as “radius N3”). That is, the angle range of the angle θ is 33 ° or more, and an angle formed by the radius S2 and a straight line connecting the axis of the developing roller 2 and the axis of the first stirring member 7 (hereinafter referred to as “first”). It is preferable that the angle is “the installation angle of the stirring member 7”. When the angle range of the angle θ is less than 33 °, image defects such as uneven image density tend to occur. When the angle range of the angle θ exceeds the installation angle of the first stirring member 7, the extension line of the radius N <b> 3 extends vertically downward from the axis of the first stirring member 7. As a result, the ability of the first stirring member 7 to pump the developer to the developing roller 2 is reduced, and image defects such as a reduction in image density and uneven image density are likely to occur.

  The arrangement of the magnetic poles in the magnet roller is as follows in this embodiment. The magnetic pole N1 (peak value of magnetic flux density = 105.8 mT) is provided on a straight line connecting the axis of the developing roller 2 and the axis of the photosensitive drum 20 at a position facing the photosensitive drum 20. The magnetic pole S1 (peak value of magnetic flux density = −87.0 mT) is provided at a position of 50.55 ° upstream from the magnetic pole N1. This angle is an angle formed by the radius S1 in the cross section of the developing roller 2 where the magnetic pole S1 is disposed and the radius N1 in the cross section of the developing roller 2 where the magnetic pole N1 is disposed. The same shall apply hereinafter. The magnetic pole N2 (peak value of magnetic flux density = 39.3 mT) is provided at a position of 111.33 ° upstream from the magnetic pole N1. The magnetic pole S2 (peak value of magnetic flux density = −46.9 mT) is provided at a position 153.73 ° upstream from the magnetic pole N1. The magnetic pole N3 (peak value of magnetic flux density = 52.8 mT) is provided at a position 199.40 ° upstream from the magnetic pole N1 and at a position 45.67 ° upstream (angle θ) from the magnetic pole S2. The magnetic pole N4 (peak value of magnetic flux density = 46.8 mT) is provided at a position 272.40 ° upstream from the magnetic pole N1. The magnetic pole S3 (peak value of magnetic flux density = −83.2 mT) is provided at a position 314.80 ° upstream from the magnetic pole N1. FIG. 3 shows the magnetic force distribution of each magnetic pole in the magnet roller 12.

  The sleeve 13 is a cylindrical member that is externally fitted to the magnet roller 12, is rotatably supported by the developing tank 6 and a support member (not shown), and is rotatably provided by a drive unit (not shown). The sleeve 13 is formed using a nonmagnetic material. In this embodiment, the sleeve 13 rotates counterclockwise, and the photosensitive drum 20 rotates clockwise. Accordingly, the sleeve 13 and the photosensitive drum 20 rotate in the opposite directions at the developing nip portion.

  The regulating member 3 is a plate-like member extending parallel to the axial direction of the developing roller 2, and one end portion in the short direction is supported by the developing tank 6 and the cover member 4 above the developing roller 2 in the vertical direction, and The other end is provided so as to be separated from the surface of the developing roller 2 with a gap. In this embodiment, the regulating member 3 is provided on the radial direction of the developing roller 2 (extension line of the radius of the developing roller 2), and the extension line and the radius N1 in the cross section of the developing roller 2 where the magnetic pole N1 is disposed. Is provided so that the angle formed by the angle becomes 90 °. The regulating member 3 is made of, for example, a nonmagnetic metal having elasticity such as stainless steel or aluminum, a synthetic resin, or the like. In this embodiment, a thin plate-like stainless steel is used for the regulating member 3. The regulating member 3 adjusts the transport amount of the developer by removing excess developer from the developer layer carried on the surface of the developing roller 2 and regulating the layer thickness of the developer layer to be constant. In addition, the regulating member 3 imparts electric charge to the developer that is insufficiently charged in the developer layer by rubbing between the other end portion in the short side direction and the developer layer, and develops in the developer layer. Charge the agent sufficiently.

  The cover member 4 is provided above the developing roller 2 and between the photosensitive drum 20 and the regulating member 3 and supports the regulating member 3 together with the developing tank 6. Specifically, one end of the regulating member 3 in the short direction and the vicinity thereof are supported by being sandwiched between the cover member 4 and the developing tank 6. The cover member 4 is made of a material such as synthetic resin or metal. In this embodiment, it is formed from a synthetic resin. In the cover member 4, the toner in the developer regulated by the regulating member 3 scatters outside the developing device from a gap existing between the regulating member 3 and the photosensitive drum 20, and the inside of the image forming apparatus 100 described later. Prevent contamination.

  The seal member 5 is a substantially rectangular plate member having a thickness of 0.1 mm to 0.2 mm, and is provided below the cover member 4, that is, on the developing roller 2 side. One end portion of the seal member 5 on the side close to the regulating member 3, that is, one end portion in the short direction is fixed to the cover member 4 by the double-sided tape 5a. Thus, the seal member 5 is preferably fixed to the cover member 4 with only one end portion in the short direction as a base end portion. As a result, the other end portion of the seal member 5 can freely move as a free end portion, so that it becomes easier to vibrate. Therefore, the toner can be more effectively dropped into the developer layer on the surface of the developing roller 2, and a high-quality image with less fog and image unevenness can be formed.

  Further, the other end portion of the seal member 5 serving as a free end portion is provided so as to contact the surface of the photosensitive drum 20. Thus, it is preferable that the other end portion of the seal member 5 is configured to vibrate by contacting the surface of the photosensitive drum 20. Thereby, since the seal member 5 can be vibrated using the frictional force resulting from the rotation of the photosensitive drum 20, the toner can be more easily dropped into the developer layer on the surface of the developing roller 2, This makes it easier to form a high-quality image with less fog and image unevenness.

  The constituent material of the seal member 5 is not particularly limited as long as it has elasticity, but is preferably urethane rubber. As described above, the seal member 5 is made of urethane rubber, so that the seal member 5 having excellent durability can be obtained, and toner scattering from the inside of the developing device 1 can be prevented over a long period of time, and fog and image unevenness can be prevented. High quality images can be formed.

  In addition, when the seal member 5 is made of a high resistance material, the seal member 5 is easily charged, so that the toner is easily adsorbed by electrostatic force. As a result, toner tends to adhere and accumulate in the vicinity of the lower portion of the seal member 5, and there is a possibility that a lump of toner is likely to occur. Therefore, it is preferable that the seal member 5 has conductivity at a portion that does not come into contact with the photosensitive drum 20. As a result, the seal member 5 is less likely to be charged, and it is possible to prevent toner from being adsorbed by electrostatic force. Therefore, it is possible to prevent the toner from adhering and accumulating in the vicinity of the lower portion of the seal member 5, and it is possible to form a high-quality image with less fog and image unevenness.

  Examples of a method for imparting conductivity to the seal member 5 include a method in which a conductive agent such as a quaternary ammonium salt is mixed and mixed with a material constituting the seal member 5, and a method in which the conductive material is applied to the surface by impregnation. .

  The reason why only the portion of the seal member 5 that does not come into contact with the photoconductive drum 20 is made conductive is to prevent the electric charge held on the surface of the photoconductive drum 20 from leaking to the seal member 5. Thereby, it is possible to prevent the electrostatic latent image from being disturbed, and it is possible to form a high-quality image free from image blur caused by the electrostatic latent image disorder.

  The seal member 5 preferably has a Shore A hardness (Hs) of 75 ° to 85 °. As a result, the seal member 5 is more likely to vibrate, so that the toner can be more effectively dropped into the developer layer on the surface of the developing roller 2. Therefore, it is possible to form a high-quality image with less fog and image unevenness. The Shore A hardness (Hs) indicates a value measured according to JISK6253.

  In this embodiment, the seal member 5 is a urethane rubber sheet (trade name: Esmer URS, manufactured by Nippon Matai Co., Ltd.) having a thickness of 0.1 to 0.2 mm and a Shore A hardness (Hs) of 75 to 85 °. Then, a quaternary ammonium salt (trade name: trimethyl lauryl ammonium chloride, manufactured by Wako Pure Chemical Industries, Ltd.) is applied to a portion not in contact with the photosensitive drum 20.

  FIG. 4 is a schematic view showing how toner T adheres and accumulates in the vicinity of the lower portion of the seal member 5 in the developing device 1 according to the first embodiment of the present invention. FIG. 5 shows the first embodiment of the present invention. 4 is a schematic diagram illustrating a state in which toner T adhered and accumulated near the lower portion of the seal member 5 falls due to vibration of the seal member 5 in the developing device 1 according to the embodiment. FIG.

  As shown in FIG. 4, the toner T adheres and accumulates not near the lower portion of the cover member 4, which is relatively rigid and difficult to vibrate, but near the lower portion of the seal member 5, thereby causing the toner T to adhere and accumulate on the cover member 4. Can be prevented. As shown in FIG. 5, when the photosensitive drum 20 rotates, the seal member 5 is displaced in the rotation direction of the photosensitive drum 20 by a frictional force acting between the photosensitive drum 20 and the seal member 5. And if the repulsive force (spring force) which the seal member 5 tries to return to an original form becomes larger than the said friction force, the seal member 5 will be displaced so that a displacement may become small, and will return to an original form. By repeating the above-described operation, the seal member 5 vibrates.

  Thus, the seal member 5 vibrates due to the frictional force resulting from the rotation of the photosensitive drum 20. In particular, large vibrations occur when the photosensitive drum 20 starts to rotate. As a result, the toner T adhering and accumulating in the vicinity of the lower portion of the seal member 5 falls little by little into the developer layer on the surface of the developing roller 2 before accumulating and forming a lump. As a result, even when the development is performed using a small particle size toner having a high cohesive force, the toner T adheres and accumulates in the vicinity of the lower portion of the seal member 5, and the developer layer on the surface of the developing roller 2 becomes a lump. It can be prevented from falling inside. Therefore, the developing device 1 of the present invention can prevent toner scattering from the inside of the developing device 1 by the cover member 4 and the seal member 5, and can form a high-quality image without fogging and image unevenness.

  The developing tank 6 is a substantially prismatic container member having an internal space, and rotatably supports the developing roller 2, the first stirring member 7, the second stirring member 8, and the conveying member 9, and the regulating member 3 and the flow plate 10. Etc. are directly or indirectly supported, and the developer is accommodated in the internal space. Further, in the developing tank 6, when the developing device 1 is mounted on an electrophotographic image forming apparatus 100 described later, an opening 6 a is formed on a side surface facing the photosensitive drum 20 provided in the image forming apparatus 100. A toner supply port 6 b is formed on the upper surface of the developing tank 6 in the vertical direction.

  A toner cartridge (not shown) and a toner hopper (not shown) are provided above the developing tank 6 in the vertical direction. More specifically, the toner cartridge, the toner hopper, and the developing tank 6 are provided in this order from the top to the bottom in the vertical direction. The toner cartridge is a cylindrical container member that accommodates toner in its internal space. The toner cartridge is detachably attached to a later-described image forming apparatus 100 main body to which the developing device 1 is attached. Further, the toner cartridge is driven to rotate about an axis by a driving unit (not shown) provided in the image forming apparatus 100. An elongated opening extending in the longitudinal direction is formed on the side surface of the toner cartridge in the longitudinal direction, and the toner falls from the elongated opening and is supplied to the toner hopper as the toner cartridge rotates.

  The toner hopper is provided, for example, such that a toner supply port, which is an opening formed in the bottom surface in the vertical direction, communicates in a vertical direction with a toner supply port 6 b that is an opening formed in the top surface in the vertical direction of the developing tank 6. In the toner hopper, a toner replenishing roller (not shown) is provided above the toner supply port in the vertical direction. The toner supply roller is rotatably supported by a toner hopper and is driven to rotate by a driving means (not shown). The rotation of the toner replenishing roller is controlled by a control unit (not shown) provided in the image forming apparatus 100 in accordance with the detection result of the toner concentration in the developing tank 6 by the toner concentration detection sensor 11. The toner is supplied into the developing tank 6 through the toner supply port and the toner supply port 6b by the rotation of the toner supply roller.

  Each of the first stirring member 7 and the second stirring member 8 is a roller-like member that is rotatably supported by the developing tank 6 and that can be driven to rotate around an axis by a driving unit (not shown). In the present embodiment, the first stirring member 7 rotates counterclockwise, and the second stirring member 8 rotates clockwise. The first stirring member 7 is provided at a position facing the photosensitive drum 20 through the developing roller 2 and being vertically lower than the developing roller 2. In the present embodiment, the installation angle of the first stirring member 7 that is an angle formed by the radius S2 and a straight line connecting the axis of the developing roller 2 and the axis of the first stirring member 7 is 54 °. The second agitating member 8 is provided at a position facing the developing roller 2 with the first agitating member 7 interposed therebetween and lower than the developing roller 2 in the vertical direction. The first agitating member 7 and the second agitating member 8 agitate the developer stored in the developing tank 6 to give a uniform charge to the toner, and pump up the charged developer to Send to the surroundings.

  The conveying member 9 is a roller-like member that is rotatably supported by the developing tank 6 and is rotatably driven by a driving unit (not shown). The conveying member 9 is opposed to the first stirring member 7 with the second stirring member 8 interposed therebetween, and is provided below the toner supply port 6b in the vertical direction. The conveying member 9 conveys the toner replenished into the developing tank 6 through the toner replenishing port 6 b to the periphery of the second stirring member 8.

  The flow plate 10 is a plate-like member provided in the developing tank 6 upstream of the regulating member 3 in the rotation direction of the developing roller 2 and above the first stirring member 7 and the second stirring member 8. It is. The sink plate 10 has one end in the short direction facing the surface of the developing roller 2 and having a gap, and the other end extends in a direction away from the developing roller 2. In the present embodiment, the upper surface in the vertical direction of the sink plate 10 is parallel to the horizontal direction at the end portion on the developing roller 2 side in the short direction of the sink plate 10 and the vicinity thereof, and the developing roller at other portions. It is provided to descend downward in the vertical direction as it is separated from 2. The sink plate 10 is supported by a support member 10a that is formed so as to penetrate in the longitudinal direction of the sink plate 10 at a lower portion in the vertical direction and is inserted into the through hole. By providing the flow plate 10, a smooth flow of the developer in the developing tank 6 is generated, and the occurrence of uneven charging of the toner, blocking of the toner and the like is prevented. Specifically, the developer removed from the surface of the developing roller 2 by the regulating member 3 temporarily stays in the space above the developing roller 2, but when the amount increases, the vertical upper surface of the sink plate 10 moves away from the developing roller 2. Begins to flow through. The developer flows along the upper surface of the sink plate 10, and falls toward the second stirring member 8 from the end of the sink plate 10 opposite to the developing roller 2 side in the short direction. The dropped developer is uniformly mixed with the other developer and newly supplied toner by the first stirring member 7 and the second stirring member 8, and is conveyed toward the developing roller 2.

  For example, the toner concentration detection sensor 11 is mounted on the bottom surface of the developing tank 6 below the second stirring member 8 in the vertical direction, and is provided so that the sensor surface is exposed inside the developing tank 6. The toner concentration detection sensor 11 is electrically connected to control means (not shown). The toner concentration detection sensor 11 detects the concentration of the toner stored in the developing tank 6, and the control unit rotates and drives a toner cartridge (not shown) and a toner supply roller according to the detection result by the toner concentration detection sensor 11. Then, control is performed so that toner is supplied into the developing tank 6 through a toner hopper (not shown). That is, when the control means determines that the detection result by the toner density detection sensor 11 is lower than the toner density setting value, the control means sends a control signal to the drive means for rotationally driving the toner cartridge and the toner supply roller, and the toner cartridge and the toner supply roller are turned on. Drive to rotate. As the toner concentration detection sensor 11, a general toner concentration detection sensor can be used. For example, a transmitted light detection sensor, a reflected light detection sensor, a magnetic permeability detection sensor, and the like are used. Among these, a magnetic permeability detection sensor is used. It is preferable. In this embodiment, a magnetic permeability detection sensor is used as the toner concentration detection sensor 11, and a power supply (not shown) is connected to the magnetic permeability detection sensor. The power supply applies a drive voltage for driving the magnetic permeability detection sensor and a control voltage for outputting the detection result of the toner density to the control means. Application of a voltage to the magnetic permeability detection sensor by the power source is controlled by the control means. The permeability detection sensor is a type of sensor that receives the control voltage and outputs the toner density detection result as an output voltage value. Basically, the sensitivity near the median value of the output voltage is good. It is used by applying a control voltage to obtain a voltage. Such types of magnetic permeability detection sensors are commercially available, and examples include TS-L, TS-A, TS-K (all of which are trade names, manufactured by TDK Corporation).

  The control means may be provided exclusively for the developing device 1 or may also serve as the control means provided in the image forming apparatus 100 to which the developing device 1 is attached. The control means includes, for example, a storage unit, a calculation unit, and a control unit. Detection results, setting values, image information, table data, programs, and the like by various sensors are written in the storage unit. As the storage unit, those commonly used in this field can be used, and examples thereof include a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). The calculation unit retrieves various data (print command, detection result, image information, etc.) input to the storage unit and a program for performing various controls, and performs various detections and determinations. A control part sends a control signal to an applicable apparatus according to the determination result in a calculating part, and performs operation control. A control part and a calculating part are processing circuits implement | achieved by the microcomputer provided with a central processing unit (CPU, Central Processing Unit), a microprocessor, etc., for example. The control means includes a main power supply together with the storage unit, the calculation unit, and the control unit.

  The dimensions of the regulating member 3, the first stirring member 7, the second stirring member 8, the conveying member 9, and the sink plate 10 are appropriately determined from an appropriate range according to the dimensions of the developing roller 2.

  According to the developing device 1 of the present invention, the developer stored in the developing tank 6 is conveyed upward in the vertical direction of the first stirring member 7 by the rotation of the first stirring member 7 and the second stirring member 8, and the developing roller 2 supplied to the surface. The developing roller 2 carries a developer layer on its surface and rotates. After the developer layer thickness is regulated by the regulating member 3 and the developer is charged, the developing roller 2 is statically fixed on the photosensitive drum 20 at the development nip. The toner is supplied to the electrostatic latent image and developed. After the development is completed, the developing roller 2 further rotates and receives the developer supply again. On the other hand, the developer removed from the surface of the developing roller 2 by the regulating member 3 flows in the direction away from the developing roller 2 on the upper surface in the vertical direction of the flow plate 10, and between the second stirring member 8 and the conveying member 9. Then, it is mixed again with another developer and conveyed toward the developing roller 2. In the developing tank 6, the developer circulation as described above occurs. The conveying member 9 conveys toner replenished into the developing tank 6 around the second stirring member 8 according to the detection result by the toner concentration detection sensor 11.

  Further, toner adheres and accumulates in the vicinity of the lower portion of the seal member 5, thereby preventing toner from adhering and accumulating on the cover member 4. When the photosensitive drum 20 rotates, the seal member 5 vibrates due to the frictional force resulting from this rotation. As a result, the toner that adheres and accumulates in the vicinity of the lower portion of the seal member 5 gradually falls into the developer layer on the surface of the developing roller 2 before it accumulates and forms a lump. As a result, even when development is performed using a small particle size toner having high cohesive force, the toner adheres and accumulates in the vicinity of the lower portion of the seal member 5 and becomes a lump in the developer layer on the surface of the developing roller 2. Can be prevented from falling.

  Therefore, the developing device 1 of the present invention can prevent toner scattering from the inside of the developing device 1 by the cover member 4 and the seal member 5, and can form a high-quality image without fogging and image unevenness.

  In the developing device 1, the length of the seal member 5, particularly the distance from the double-sided tape 5 a to the other end contacting the surface of the photoconductor drum 20 is the friction force generated between the photoconductor drum 20 and the seal member 5. Or the repulsive force of the seal member 5 may be adjusted as appropriate.

(Second Embodiment)
The developing device 14 according to the second embodiment of the present invention will be described below. The developing device 14 according to the second embodiment of the present invention is the same as the developing device 1 according to the first embodiment except that a part of the configuration of the seal member 5 is different and an upper seal member 15 is provided. It is the composition. Hereinafter, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components having the same configuration is omitted.

  FIG. 6 is an enlarged cross-sectional view of a part of the developing device 14 according to the second embodiment of the present invention. As shown in FIG. 6, the developing device 14 is provided with an upper seal member 15. The upper seal member 15 is a plate member having a substantially rectangular shape with a thickness of 0.1 mm to 0.2 mm, and is provided on the upper portion of the cover member 4, that is, on the opposite side to the developing roller 2. One end portion of the upper seal member 15 on the side close to the regulating member 3, that is, one end portion in the short direction is fixed to the cover member 4 by the double-sided tape 15a. Thus, it is preferable that the upper seal member 15 is fixed to the cover member 4 with only one end portion in the short direction as a base end portion. As a result, the other end portion of the upper seal member 15 can freely move as a free end portion, and thus more easily vibrates.

  The other end portion of the upper seal member 15 serving as the free end portion is provided so as to contact the surface of the photosensitive drum 20, and the other end portion of the seal member 5 serving as the free end portion is provided as the upper seal. It is provided so as to contact the member 15. As described above, the other end portion of the upper seal member 15 is configured to vibrate when contacting the surface of the photosensitive drum 20, and the other end portion of the seal member 5 is vibrated when contacting the upper seal member 15. It is preferable to be configured as described above.

  As a result, the upper seal member 15 vibrates using the frictional force resulting from the rotation of the photosensitive drum 20, and the seal member 5 can be vibrated by transmission of this vibration. 20 can be dropped into the developer layer on the surface, and a high-quality image with less fog and image unevenness can be easily formed.

  Further, as described above, the seal member 5 and the upper seal member 15 are configured to contact each other before the rotation of the photosensitive drum 20, that is, in a state where the displacement of the seal member 5 and the upper seal member 15 is zero. The seal member 5 can be vibrated more effectively. Therefore, the above-described effect can be further easily obtained.

  Further, since the area of the upper seal member 15 can be made larger than that of the seal member 5, toner scattering from the inside of the developing device 1 can be more effectively prevented. Accordingly, by providing the upper seal member 15 and the seal member 5 in a double manner, toner scattering from the inside of the developing device 1 can be more reliably prevented.

Further, if the material constituting the upper seal member 15 is a low resistance material, the charge held on the surface of the photosensitive drum 20 may leak to the upper seal member 15 and disturb the electrostatic latent image. Therefore, the constituent material of the upper seal member 15 is preferably a high resistance material, for example, a material having a volume resistivity of 10 ¹² Ω · cm or more. In view of excellent durability, urethane rubber is preferable.

  Thus, the upper seal member 15 is preferably made of a high resistance material, that is, has an insulating property. As a result, the charge held on the surface of the photosensitive drum 20 can be prevented from leaking to the upper seal member 15, so that the electrostatic latent image can be prevented from being disturbed. Therefore, it is possible to form a high-quality image free from image blur due to disturbance of the electrostatic latent image.

  The upper seal member 15 preferably has a Shore A hardness (Hs) of 75 ° to 85 °. As a result, the upper seal member 15 is more likely to vibrate, so that the toner can be more effectively dropped into the developer layer on the surface of the developing roller 2. Therefore, it is possible to form a high-quality image with less fog and image unevenness.

  In the present embodiment, a urethane rubber sheet (trade name: Esmer URS, manufactured by Nihon Matai Co., Ltd.) having a thickness of 0.1 to 0.2 mm and a Shore A hardness (Hs) of 75 to 85 ° is used as the upper seal member 15. used.

  FIG. 7 is a schematic view showing how toner T adheres and accumulates in the vicinity of the lower portion of the seal member 5 in the developing device 14 according to the second embodiment of the present invention. FIG. 8 shows the second embodiment of the present invention. 6 is a schematic diagram illustrating a state where toner T adhered and accumulated near the lower portion of the seal member 5 falls due to vibration of the seal member 5 in the developing device 14 according to the embodiment. FIG.

  As shown in FIG. 7, the toner T adheres and accumulates not near the lower part of the cover member 4, which is relatively rigid because it is relatively hard to vibrate, but near the lower part of the seal member 5, so that the toner T adheres to the cover member 4. Accumulation can be prevented. Further, since the upper seal member 15 having a large area is provided on the upper portion of the cover member, toner scattering from the inside of the developing device 14 can be more effectively prevented. Further, as shown in FIG. 8, when the photosensitive drum 20 rotates, the upper seal member 15 is displaced in the rotation direction of the photosensitive drum 20 by a frictional force acting between the photosensitive drum 20 and the upper seal member 15. And if the repulsive force (spring force) which the upper seal member 15 tries to return to the original shape becomes larger than the frictional force, the upper seal member 15 is displaced so that the displacement becomes smaller and returns to the original shape. By repeating the above operation, the upper seal member 15 vibrates.

  Thus, the upper seal member 15 is vibrated by the frictional force resulting from the rotation of the photosensitive drum 20, and the seal member 5 is vibrated when this vibration is transmitted. In particular, large vibrations occur when the photosensitive drum 20 starts to rotate. As a result, the toner T adhering and accumulating in the vicinity of the lower portion of the seal member 5 falls little by little into the developer layer on the surface of the developing roller 2 before accumulating and forming a lump. As a result, even when the development is performed using a small particle size toner having a high cohesive force, the toner T adheres and accumulates in the vicinity of the lower portion of the seal member 5, and the developer layer on the surface of the developing roller 2 becomes a lump. It can be prevented from falling inside.

  Therefore, the developing device 14 of the present invention can prevent toner scattering from the inside of the developing device 14 and can form a high-quality image without fogging and image unevenness.

  In the developing device 14, the length of the upper seal member 15, particularly the distance from the double-sided tape 15a to the other end contacting the surface of the photosensitive drum 20, and the length of the seal member 5, especially the double-sided tape 5a to the upper seal. The distance to the other end contacting the member 15 may be appropriately adjusted in consideration of the frictional force generated between the photosensitive drum 20 and the seal member 15 and the repulsive force of the seal member 5.

  As described above, the developing device 1 (14) of the present invention has the developing roller 2 that supplies toner to the electrostatic latent image on the surface of the photosensitive drum 20 and develops it, and the amount of developer carried on the surface of the developing roller 2 is adjusted. A regulating member 3 for regulating, a cover member 4 provided above the developing roller 2 and provided between the photosensitive drum 20 and the regulating member 3 to prevent toner scattering from the inside of the developing device 1 (14); The seal member 5 is provided below the cover member 4 and vibrates as the photosensitive drum 20 rotates.

  In this way, the toner adheres and accumulates not near the lower part of the cover member 4 but near the lower part of the seal member 5 provided at the lower part of the cover member 4, and the seal member 5 further rotates as the photosensitive drum 20 rotates. By being configured to vibrate, the toner can be gradually dropped into the developer layer on the surface of the developing roller 2 as the seal member 5 vibrates before the toner accumulates and becomes a lump. As a result, even when development is performed using a small particle size toner having high cohesive force, the toner adheres and accumulates in the vicinity of the lower portion of the seal member 5 and becomes a lump in the developer layer on the surface of the developing roller 2. Can be prevented from falling. Therefore, in the developing device 1 (14) of the present invention, the cover member 4, the seal member 5 and the upper seal member 15 prevent the toner from scattering from the inside of the developing device 1 (14), and there is no fogging or image unevenness. Can be formed.

[Image forming apparatus]
FIG. 9 is a cross-sectional view schematically showing the configuration of the image forming apparatus 100 of the present invention. The image forming apparatus 100 has a copy mode and a print mode. In the copy mode, a copy of the original is printed according to the image information of the original read by the scanner unit 29 described later. This is a digital copying machine that prints an image corresponding to image information from an external device connected via the printer. The image forming apparatus 100 includes a photosensitive drum 20, a charging device 21, an exposure device 22, a developing device 1 (14), a transfer device 23, a cleaning device 24, a fixing device 25, and a paper feed tray 28. The scanner unit 29 and the paper discharge tray 30 are included.

  The photosensitive drum 20 is a roller-like member having a photosensitive film on which a latent electrostatic image and, consequently, a toner image is formed. For the photosensitive drum 20, for example, a roller-shaped member including a conductive substrate (not shown) and a photosensitive film (not shown) formed on the surface of the conductive substrate can be used. As the conductive substrate, a conductive substrate having a cylindrical shape, a columnar shape, a sheet shape or the like can be used, and among them, the cylindrical conductive substrate is preferable. Examples of the photosensitive film include an organic photosensitive film and an inorganic photosensitive film. As an organic photosensitive film, a laminate of a charge generation layer, which is a resin layer containing a charge generation material, and a charge transport layer, which is a resin layer containing a charge transport material, a charge generation material and a charge transport material in one resin layer And a resin layer containing. Examples of the inorganic photosensitive film include films containing one or more selected from zinc oxide, selenium, amorphous silicon and the like. A base film may be interposed between the conductive substrate and the photosensitive film, and a surface film (protective film) for mainly protecting the photosensitive film may be provided on the surface of the photosensitive film.

  The charging device 21 is a roller-like member provided so as to be in pressure contact with the photosensitive drum 20. A power supply (not shown) is connected to the charging device 21 to apply a voltage to the charging device 21. The charging device 21 receives a voltage from a power source and charges the surface of the photosensitive drum 20 to a predetermined polarity and potential. In this embodiment, a charger-type charger is used, but the present invention is not limited to this. A charging brush-type charger, a roller-type charger, a saw-tooth charger, an ion generator, a contact-type charger such as a magnetic brush, or the like is used. Can be used.

  The exposure device 22 receives image information of a document read by the scanner unit 29 or image information from an external device, and irradiates the charged surface of the photosensitive drum 20 with signal light corresponding to the image information. As a result, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 20. For the exposure device 22, a laser scanning device including a light source is used. The laser scanning device is a device that combines, for example, a light source, a polygon mirror, an fθ lens, a reflection mirror, and the like. As the light source, for example, a semiconductor laser, an LED array, an electroluminescence (EL) element, or the like can be used.

  The developing device 1 (14) is the developing device 1 according to the first embodiment of the present invention or the developing device 14 according to the second embodiment.

  The transfer device 23 is a roller-like member that is rotatably supported by a support member (not shown), is rotatably provided by a drive means (not shown), and is provided so as to be in pressure contact with the photosensitive drum 20. For the transfer device 23, for example, a roller-shaped member including a metal cored bar having a diameter of 8 mm to 10 mm and a conductive elastic layer formed on the surface of the metal cored bar is used. As the metal forming the metal core, stainless steel, aluminum, or the like can be used. As the conductive elastic layer, a rubber material in which a conductive material such as carbon black is blended with a rubber material such as ethylene-propylene rubber (EPDM), foamed EPDM, or foamed urethane can be used. A pick-up roller and a registration roller (not shown) are fed from the paper feed tray 28 to the pressure contact portion (transfer nip portion) between the photosensitive drum 20 and the transfer device 23 in synchronism with the conveyance of the toner image by the rotation of the photosensitive drum 20. The recording medium is supplied one by one through the.

  As the recording medium passes through the transfer nip portion, the toner image on the surface of the photosensitive drum 20 is transferred to the recording medium. A power supply (not shown) is connected to the transfer device 23, and a voltage having a polarity opposite to the charging polarity of the toner constituting the toner image is applied to the transfer device 23 when the toner image is transferred to a recording medium. As a result, the toner image is smoothly transferred to the recording medium. According to the transfer device 23, the toner image on the surface of the photosensitive drum 20 is transferred to a recording medium.

  The cleaning device 24 includes a cleaning blade (not shown) and a toner storage tank (not shown). The cleaning blade is a plate-like member that is provided so as to extend in parallel with the longitudinal direction of the photosensitive drum 20 and that one end in the short-side direction is in contact with the surface of the photosensitive drum 20. The cleaning blade removes toner, paper powder, and the like remaining on the surface of the photosensitive drum 20 from the surface of the photosensitive drum 20 after the toner image is transferred to the recording medium. The toner storage tank is a container-like member having an internal space, and temporarily stores the toner removed by the cleaning blade. The surface of the photosensitive drum 20 after the toner image is transferred is cleaned by the cleaning device 24.

  The fixing device 25 includes a fixing roller 26 and a pressure roller 27. The fixing roller 26 is a roller-like member that is rotatably supported by a support member (not shown) and is rotatable around an axis line by a drive unit (not shown). The fixing roller 26 has a heating member (not shown) inside, and heats and melts the toner constituting the unfixed toner image carried on the recording medium conveyed from the transfer nip portion to fix it on the recording medium. As the fixing roller 26, for example, a roller-shaped member including a cored bar and an elastic layer is used. The core metal is formed of a metal such as iron, stainless steel, or aluminum. The elastic layer is formed of an elastic material such as silicone rubber or fluorine rubber, for example. The heating member receives heat from a power source (not shown) and generates heat. A halogen lamp, an infrared lamp, etc. can be used for a heating member.

  The pressure roller 27 is a roller-like member that is rotatably supported and is provided so as to be in pressure contact with the fixing roller 26 by a pressure member (not shown). The pressure roller 27 rotates following the rotation of the fixing roller 26. A pressure contact portion between the fixing roller 26 and the pressure roller 27 is a fixing nip portion. The pressure roller 27 promotes fixing of the toner image to the recording medium by pressing the toner in a molten state against the recording medium when the fixing roller 26 heats and fixes the toner image to the recording medium. A roller-like member having the same configuration as that of the fixing roller 26 can be used for the pressure roller 27. A heating member may also be provided inside the pressure roller 27. As the heating member, the same heating member as that in the fixing roller 26 can be used.

  According to the fixing device 25, the recording medium on which the toner image is transferred is passed through the fixing nip portion, and the toner constituting the toner image is melted and pressed against the recording medium to fix the toner image on the recording medium. Print the image. The recording medium on which the image is printed is discharged and stacked on a discharge tray 30 provided on a side surface in the vertical direction of the image forming apparatus 100 by a conveying unit (not shown).

  The paper feed tray 28 is a tray that stores recording media such as plain paper, coated paper, color copy paper, and OHP film. A plurality of paper feed trays 28 are provided, and recording media having different sizes are accommodated in the respective paper feed trays 28. The size of the recording medium includes A3, A4, B5, and B4. Further, a plurality of paper feed trays 28 may contain the same size recording medium. A recording medium is fed one by one in synchronization with the toner image on the surface of the photosensitive drum 20 being conveyed to the transfer nip portion by a pickup roller (not shown), a conveyance roller, and a registration roller.

The scanner unit 29 includes a document set tray (not shown), an automatic document feeder (RADF,
Reversing Automatic Document Feeder) is provided, and a document reading device (not shown) is provided. The automatic document feeder conveys a document placed on a document set tray to a document placement table of a document reading device. The document reading device includes a document placing table, a document scanning device, a reflecting member, a photoelectric conversion device (Charge Coupled Device, hereinafter referred to as “CCD”) line sensor, and the like. Image information is read every plural lines, for example every ten lines. The document placing table is a glass plate-like member for placing a document for reading image information. The document scanning device includes a light source (not shown) and a first reflecting mirror, and reciprocates at a constant speed V in parallel along the lower surface in the vertical direction of the document placement table, and forms an image forming surface of the document placed on the document placement table. Irradiate light. A reflected light image is obtained by light irradiation. The light source is a light source for irradiating a document placed on the document table. The first reflecting mirror reflects the reflected light image toward the reflecting member. The reflecting member includes a second reflecting mirror, a third reflecting mirror, and an optical lens (not shown), and forms a reflected light image obtained by the document scanning device on the photoelectric conversion element line sensor. The reflection member reciprocates at a speed of V / 2 following the reciprocation of the document scanning device. The second and third reflecting mirrors reflect the reflected light image so that the reflected light image faces the optical lens. The optical lens forms a reflected light image on the photoelectric conversion element line sensor. The CCD line sensor includes a CCD circuit (not shown) that photoelectrically converts a reflected light image formed by the optical lens into an electric signal, and outputs an electric signal as image information to an image processing unit in the control means. The image processing unit converts image information input from an external device such as a document reading device or a personal computer into an electrical signal and outputs the electrical signal to the exposure device 22.

  As described above, the image forming apparatus 100 of the present invention includes the developing device 1 (14) of the present invention, thereby preventing contamination inside the image forming apparatus 100 due to toner scattering from the inside of the developing device 1 (14), and A high-quality image with little fogging and image unevenness can be formed.

1 is a cross-sectional view schematically showing a configuration of a developing device according to a first embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view illustrating a part of the developing device illustrated in FIG. 1. It is a figure which shows magnetic force distribution of each magnetic pole in the magnet roller contained in the developing roller which is one of the structural members of the developing device shown in FIG. FIG. 3 is a schematic diagram illustrating a state in which toner adheres and accumulates in the vicinity of a lower portion of a seal member in the developing device according to the first embodiment of the present invention. FIG. 3 is a schematic diagram illustrating a state in which toner that has adhered and accumulated near the lower portion of the seal member falls due to vibration of the seal member in the developing device according to the first embodiment of the present invention. It is sectional drawing which expands and shows a part of developing apparatus which is the 2nd Embodiment of this invention. FIG. 6 is a schematic diagram illustrating a state in which toner adheres and accumulates in the vicinity of a lower portion of a seal member in a developing device according to a second embodiment of the present invention. In the developing device according to the second embodiment of the present invention, the toner that has adhered and accumulated near the lower portion of the seal member falls down due to the vibration of the seal member. 1 is a cross-sectional view schematically showing a configuration of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,14 Developing device 2 Developing roller 3 Control member 4 Cover member 5 Seal member 6 Developing tank 7 First stirring member 8 Second stirring member 9 Conveying member 10 Sink plate 11 Toner density detection sensor 12 Magnet roller 13 Sleeve 15 Upper seal member DESCRIPTION OF SYMBOLS 20 Photosensitive drum 21 Charging means 22 Exposure means 23 Transfer means 24 Cleaning means 25 Fixing means 26 Fixing roller 27 Fixing roller 27 Pressure roller 28 Paper feed tray 29 Scanner part 30 Paper discharge tray 100 Image forming apparatus

Claims (9)

A developing device attached to an electrophotographic image forming apparatus including a photosensitive drum on which an electrostatic latent image is formed,
A developing roller that carries a developer on its surface, rotates, supplies toner to the electrostatic latent image on the surface of the photosensitive drum, and develops the toner;
A regulating member that regulates the amount of developer carried on the surface of the developing roller;
A cover member provided above the developing roller and provided between the photosensitive drum and the regulating member to prevent toner scattering from the inside of the developing device;
A developing device, comprising: a seal member provided at a lower portion of the cover member and vibrating as the photosensitive drum rotates.   The developing device according to claim 1, wherein the seal member is fixed to the cover member only at one end portion in the short direction.   The developing device according to claim 2, wherein the seal member vibrates when the other end contacts the surface of the photosensitive drum. Provided on the upper part of the cover member, provided with an upper seal member that vibrates when one end in the short direction is fixed to the cover member and the other end contacts the surface of the photosensitive drum,
The developing device according to claim 1, wherein the seal member vibrates by contacting the upper seal member.   The developing device according to claim 1, wherein the seal member is made of urethane rubber.   The developing device according to claim 1, wherein a portion of the seal member that does not contact the photosensitive drum has conductivity.   The developing device according to claim 1, wherein the seal member has a Shore A hardness of 75 ° to 85 °.   The developing device according to claim 4, wherein the upper seal member has an insulating property.   An image forming apparatus comprising the developing device according to claim 1.

Images