JP2006301281A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device which achieves smooth circulation of developer and uniformly and sufficiently electrifies toner even if a large amount of toner is replenished at once, consequently does not causes an image defect such as surface fogging nor contamination due to toner scattering or the like and which therefore can meet the need of increasing an image forming speed, and to provide an image forming apparatus including the developing device. <P>SOLUTION: The developing device 1 includes a developing tank 2 having a toner replenishing port 3, a developing roller 4, a stirring roller 5, a toner receiving roller 6, a first layer thickness regulating member 8, a second layer thickness regulating member 9, a flow board 10, a first staying prevention member 11, a second staying prevention member 12 and a toner sensor 13, wherein the toner receiving roller 6 is provided below the toner replenishing port 3 and only the toner receiving roller 6 is present as a member around the toner replenishing port 3 inside the developing tank 2, and a brush roller is used as the toner receiving roller 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  The electrophotographic system is widely used in image forming apparatuses such as a copying machine, a printer, and a facsimile because an image having a good image quality can be formed relatively easily. In general, an image forming apparatus using an electrophotographic method is based on image information by irradiating light to a charged surface of a photosensitive drum and charging means for uniformly charging the surface of the photosensitive member containing a photoconductive substance. An exposure unit that forms an electrostatic latent image, a developing unit that supplies toner contained in the developer to the electrostatic latent image on the surface of the photosensitive drum to form a toner image, and a toner image carried on the surface of the photosensitive drum Transfer means for transferring the toner image onto the surface of the recording medium, and fixing means for fixing the toner image on the recording medium to the recording medium by heating, pressing, or the like.

  The developing means includes, for example, a developing tank having an opening and a toner replenishing port and containing a developer containing toner and a carrier, and facing the surface of the photosensitive drum through the opening of the developing tank. A developing roller that is rotatably provided and carries a developer layer on the surface thereof, and a stirring roller that is spaced apart from the developing roller within the developing tank and is rotatably provided to supply the developer to the periphery of the developing roller. A toner receiving roller that is spaced apart from the agitating roller and rotatably provided below the toner replenishing port of the developing tank and feeds toner replenished from the toner replenishing port to the periphery of the agitating roller; A developing device is used that includes a layer thickness regulating member that is provided so as to be spaced apart from each other and that equalizes the thickness of the developer layer on the surface of the developing roller.

  According to the conventional developing device, the toner supplied from the toner replenishing port is fed around the agitation roller by the toner receiving roller, and the toner and the developer around the agitation roller are made uniform by the rotation driving (agitation) of the agitation roller. And the toner is charged by contact friction between the toner and the carrier contained in the developer. The developer containing the charged toner is conveyed around the developing roller and is carried on the surface of the developing roller to form a developer layer. In this developer layer, after excess developer is removed by the layer thickness regulating member, toner is supplied to the electrostatic latent image on the photosensitive drum to form a toner image. On the other hand, the developer removed by the layer thickness regulating member is returned to the periphery of the stirring roller and mixed with the toner supplied from the toner supply port again. A series of these operations (development operations) are repeatedly executed to form a toner image obtained by adding toner to the electrostatic latent image.

  In a conventional developing device, a paddle roller including a shaft member and a plate-like member provided in the radial direction of the shaft member is used as the toner receiving roller. Although the paddle roller does not cause any particular problems in normal development operations, the recent remarkable increase in image formation speed has caused problems such as image defects such as background fog and scattering of toner to the outside of the developing device. There is a risk of doing so. That is, when image formation is performed at high speed, particularly when image formation is performed at high speed and continuously, a large amount of toner is consumed in a short time. Therefore, in order to cope with an increase in the image forming speed, it is necessary to supply a large amount of toner to the developing tank in a short time. A large amount of toner contains particulate matter in which the toner is hardened, and the particulate matter is not crushed into fine toner particles even when subjected to stirring by a paddle roller, and is supplied as it is to the periphery of the stirring roller. . Moreover, in the granular material, the toner particles stick to each other due to the heat in the developing tank, and even when subjected to stirring by the stirring roller, the toner particles may not be crushed, resulting in insufficient mixing with the developer, and charging of the toner. It causes a defect. The toner charging failure may cause inconveniences such as the above-described image failure and toner scattering.

  In addition, there has been proposed a developing device in which a toner charging member such as a brush roller is provided between a toner supply port and a toner receiving roller inside the developing tank (see, for example, Patent Document 1). In this developing device, a plurality of brush rollers in which fiber hairs are radially implanted on the peripheral surface of the shaft member are provided inside the developing tank of the toner replenishing port so that the rotation regions of the respective fiber hairs overlap each other. It is intended to improve the charging property. When the amount of toner to be replenished is not so large, this developing device improves the charging property of the toner in the developing tank and improves the mixing property of the toner and the developer. However, when a large amount of toner is replenished in a short time in order to perform image formation at a high speed, a structure having a relatively large number of constituent members including a plurality of brush rollers and a toner receiving roller is adopted. It becomes an obstacle that prevents smooth circulation, mixing of the toner and the developer, etc., and the amount of charge necessary and sufficient for the developing operation is often not given to the toner. As a result, it is inevitable that image defects such as background fogging and toner scattering will occur. Also, it is not preferable to increase the number of constituent members because productivity, maintenance management, and the like are lowered and the developing device is increased in size.

  Accordingly, there is a need for a developing device that can cope with an increase in image forming speed in an electrophotographic image forming apparatus. More specifically, even if the toner replenishment amount is remarkably increased, the charge imparting property to the toner is further improved without impairing the mixing property between the developer and the toner and without causing the charging failure of the toner. An improved developing device is required.

JP-A-5-216341

  An object of the present invention is a developing device used in an electrophotographic image forming apparatus, in which a developer smoothly circulates in the developing device and a large amount of toner is replenished in the developing device at once. Including a developing device that can uniformly and sufficiently charge the toner, and that can cope with an increase in the image forming speed, and that the image is defective even if image formation is performed at high speed. An object of the present invention is to provide an image forming apparatus in which contamination due to scattering hardly occurs.

  As a result of intensive research in order to solve the above problems, the present inventor does not provide a charging member such as a brush roller in addition to the toner receiving roller, but uses a brush roller as the toner receiving roller, so that a desired developing device can be used. Was found and the present invention was completed.

The present invention
A developer tank having an opening and a toner replenishing port and containing a two-component developer containing toner and carrier;
A developing roller which is rotatably provided facing the surface of the photosensitive drum through the opening of the developing tank and carries a developer layer on the surface;
A stirring roller that is spaced apart from the developing roller inside the developing tank and is rotatably provided, and stirs the developer and supplies the developer to the developing roller;
A toner receiving roller that is spaced apart from the stirring roller inside the developing tank and is rotatably provided, and feeds toner supplied from the toner supply port to the periphery of the stirring roller;
A developing device that supplies toner to an electrostatic latent image formed on the surface of the photosensitive drum for development, and a layer thickness regulating member that regulates the layer thickness of the developer layer on the surface of the developing roller.
Toner receiving roller
A cylindrical shaft member;
The developing device is a brush roller configured to include a plurality of fiber bristles provided to protrude in the radial direction of the shaft member.

The developing device of the present invention is
Above the developing roller and the stirring roller in the developing tank, provided to extend in the direction from the developing roller to the stirring roller,
It further includes a flow plate for guiding the circulation of the developer in the developing tank.

The developing device of the present invention is
The image forming apparatus further includes voltage applying means for applying a bias voltage to the toner receiving roller.

The developing device of the present invention is
The voltage applied to the toner receiving roller is
The voltage applied to the developing roller is equal to or smaller than the voltage applied to the developing roller.

The developing device of the present invention is
The toner receiving roller is driven to rotate counterclockwise around its axis.

The developing device of the present invention is
Provided to contact the toner receiving roller,
A scraping member for removing toner adhering to the toner receiving roller is included.

The present invention also provides
Photosensitive drum having a photosensitive layer capable of forming an electrostatic latent image based on image information on the surface, charging means for charging the surface of the photosensitive drum, and image information obtained by irradiating the charged photosensitive drum surface with light. , An exposure unit that forms an electrostatic latent image based on the above, a developing unit that supplies toner to the electrostatic latent image on the surface of the photosensitive drum to form a toner image, and a toner image on the surface of the photosensitive drum is transferred to a recording medium An image forming apparatus including a transfer unit and a fixing unit that fixes a toner image on the recording medium to the recording medium,
Development means
An image forming apparatus characterized by being one of the developing devices described above.

  According to the present invention, a developer tank having an opening and a toner replenishing port and containing a developer containing toner and a carrier, a developing roller carrying a developer layer on the surface thereof, and stirring and developing of the developer A stirring roller for supplying to the roller, a toner receiving roller for feeding toner supplied from the toner supply port to the periphery of the stirring roller, and a layer thickness regulating member for regulating the layer thickness of the developer layer on the surface of the developing roller; In the developing device in which only the toner receiving roller is disposed around the toner replenishing port in the developing tank, a cylindrical shaft member and a plurality of fiber bristles protruding in the radial direction of the shaft member are provided as the toner receiving roller. If the toner replenished from the toner replenishing port contains particulate matter that has solidified the toner, the particulate matter is uniformly crushed. And the toner and developer receiving agitation by La are uniformly mixed, capable of sufficiently charging a toner. Further, by using only a brush roller as a toner receiving roller as a roller provided in the vicinity of the toner supply port, even if a large amount of toner is supplied in a short time, the circulation of the toner is not hindered, and the toner is smooth. To the periphery of the stirring roller. Therefore, the toner and the developer are mixed uniformly, and the toner is charged with a sufficient charge necessary for the developing operation, and the developer with the toner uniformly adhered to the surface of the carrier is stably supplied to the periphery of the developing roller. And high-quality images can be formed.

  According to the present invention, the brush roller as a toner receiving roller extends in a direction from the developing roller to the stirring roller above the developing roller and the stirring roller in the developing tank, and adjusts the flow of the developer in the developing tank. It is particularly suitable for a developing device including a flow plate. By adopting this configuration, the respective constituent members inside the developing tank interact with each other to realize a smoother circulation of the developer, and the charge imparting property to the toner and the replenished toner and developer even under high-speed image formation. A developing device having excellent mixing properties with the toner can be obtained.

  According to the present invention, the developing device of the present invention includes voltage applying means for applying a bias voltage to the toner receiving roller, and the toner receiving roller has a bias voltage (preferably equal to or higher than the voltage applied to the developing roller). By applying a low voltage, the charge imparting property to the toner is further improved, the adhesion of the developer to the surface of the developing roller is improved, and a developer layer in which the toner is uniformly adhered is formed.

  According to the present invention, in the developing device of the present invention, the toner receiving roller is driven to rotate counterclockwise around the axis thereof, thereby allowing the toner to be mixed with the developer and feeding the toner to the periphery of the stirring roller. The property (transportability) is further improved, and smoother circulation of the developer is realized.

  According to the present invention, in the developing device of the present invention, the clogging of the toner in the toner receiving roller is prevented by providing the scraping member that contacts the toner receiving roller and removes the toner adhering to the toner receiving roller. Therefore, the compatibility with high-speed image formation is further enhanced.

  According to the present invention, it is possible to form a high-quality image free of image defects such as background fog, including the developing device of the present invention, and to form an electrophotographic image without causing toner scattering in the device. An apparatus is provided.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a developing device 1 according to a first embodiment of the present invention.

  The developing device 1 of the present invention includes a two-component developer (hereinafter, particularly referred to as “toner” unless otherwise specified) and a magnetic carrier (hereinafter, simply referred to as “carrier” unless otherwise specified). Unless otherwise noted, the developer is simply referred to as “developer”), and in an electrophotographic image forming apparatus (not shown), toner is supplied to the electrostatic latent image on the surface of the photosensitive drum 14 and developed to form a toner image. Execute development operation.

  The developing device 1 has an opening 2a and a toner supply port 3, and includes a developing roller 4, a stirring roller 5, a toner receiving roller 6, a first layer thickness regulating member 8, a second layer thickness regulating member 9, a flow plate 10, A developing tank 2 containing the first retention preventing member 11 and the second retention preventing member 12 and storing a developer (not shown), and a part of the opening 2 a of the developing tank 2 is directed outward of the developing tank 2. The developing roller 4 that is exposed so as to face and be close to the photosensitive drum 14 is separated from the developing roller 4 on the side opposite to the photosensitive drum 14 with respect to the developing roller 4 with a predetermined interval. A toner receiving roller that is a brush roller provided at a predetermined interval on the side opposite to the developing roller 4 and on the side opposite to the developing roller 4 with respect to the stirring roller 5 and provided below the toner supply port 3. 6, the first layer thickness regulating member 8 and the second layer thickness regulating member 9 provided so as to be separated from the surface of the developing roller 4 with a predetermined interval, and the first layer thickness regulating member 8. And a flow plate 10 provided above the developing roller 4 and the stirring roller 5, a first plate provided to face the developing roller 4 and the first layer thickness regulating member 8 and to be supported by the top plate 2 b of the developing tank 2. A retention preventing member 11, a second retention preventing member 12 provided so as to be supported by the first layer thickness regulating member 8 below the first layer thickness regulating member 8, and a toner for detecting the toner concentration in the developing tank 2. And the sensor 13.

  That is, the developing device 1 is characterized in that only the toner receiving roller 6 is provided around the toner supply port 3 in the developing tank 2 and a brush roller is used as the toner receiving roller 6. Further, in the developing device having the flow plate 10 as in the developing device 1, if a brush roller is used as the toner receiving roller 6, the developer circulation in the developing tank 2 is further improved, and the toner charging property, toner This is particularly preferable since the mixing property of the carrier and the carrier is further improved.

  As described above, the developing tank 2 is a hollow container made of a synthetic resin that stores a developer. Toner replenishment for replenishing toner is provided above the toner receiving roller 6 on the top plate 2b that is a developing tank wall. A mouth 3 is formed. A toner storage container (toner hopper) (not shown) and a replaceable toner cartridge (not shown) are provided outside the toner supply port 3, and toner is supplied according to the toner concentration (or toner consumption amount) inside the developing tank 2.

  The developing roller 4 is a cylindrical member provided so as to be rotatable around its axis by a driving means (not shown). The developing roller 4 has a plurality of magnetic poles therein, and a developer is magnetically attracted to the surface thereof. The developer layer that does not. The plurality of magnetic poles provided inside the developing roller 4 makes the developer layer carried on the surface of the developing roller 4 into a magnetic brush shape in which the developer is linked in a spike shape. Since a DC superimposed AC voltage is applied between the developing roller 4 and the photosensitive drum 14 and an alternating electric field is generated in the developing region, only toner having a charge from the magnetic brush-shaped developer layer on the surface of the developing roller 4 is generated. Is attached to the electrostatic latent image on the surface of the photoconductive drum 14, whereby the developing operation is executed.

  The stirring roller 5 is a cylindrical member provided so as to be rotatable around its axis in conjunction with the developing roller 4 by driving means (not shown). By rotation (stirring) of the stirring roller 5, the toner in the developer and the carrier are rubbed, and the contact friction at that time causes the toner to have a sufficient charge necessary for developing the electrostatic latent image on the surface of the photosensitive drum 14. Is granted. The agitation roller 5 imparts sufficient charge to the toner as described above, and uniformly mixes the toner and the carrier, and removes the developer in a state where the charged toner uniformly adheres to the surface of the carrier. Send to the surroundings.

The toner receiving roller 6 is a brush roller configured to include a cylindrical shaft member 6a and a plurality of fiber bristles 6b provided so as to protrude in the radial direction of the shaft member 6a. It is provided so as to be able to be rotated in the direction of, i. Here, the counterclockwise direction means a direction in which the toner is supplied from the top to the bottom in the vertical direction with respect to the stirring roller 5. For example, a cylindrical shaft member 6a having a diameter of 20 mm and a length of 40 mm is used. The length of the fiber bristles 6b is, for example, 15 mm. For the material of the fiber bristles 6b, a high resistance conductive resin having a volume resistance value of 10 ⁶ to 10 ⁹ Ω · cm is preferably used. Specific examples thereof include those obtained by subjecting the surface of polyamide such as nylon 12 or nylon 6 to a surface coating treatment with a polymer material such as polymethyl methacrylate (PMMA) or an inorganic material such as silica. The fiber bristles 6b is, the thickness is 6 to 16 denier, density is in the range of 25,000 to 100,000 present / inch ^2. By using such a brush roller, even if the toner is replenished in a solid state, it can be crushed almost uniformly, so that the toner can be prevented from being clogged around the toner replenishing port 3. Further, by rotating the toner receiving roller 6 counterclockwise, the toner is easily fed to a relatively wide space region mainly between the stirring roller 5 and the toner receiving roller 6. On the other hand, the developer also flows over the upper surface of the flow plate 10 from the developing roller 4 to the stirring roller 5 and is fed to a relatively wide space region between the stirring roller 5 and the toner receiving roller 6. Mixing of the toner and the developer is likely to occur, and the mixing property of the toner and the developer is improved. The toner replenished into the developing tank 2 from the toner replenishing port 3 is rubbed against the fiber bristles 6a by the counterclockwise rotation of the toner receiving roller 6 and given a certain amount of charge, and then the stirring roller 5 and toner receiving It is fed to a relatively wide space area between the roller 6 and mixed with the developer. Here, when a certain amount of charge is applied to the toner, the rotation of the stirring roller 5 makes it easy to apply a necessary and sufficient amount of charge to the toner.

  The first layer thickness regulating member 8 is a plate-like member formed integrally with the flow plate 10 and having a substantially V-shaped cross section. Further, the first layer thickness regulating member 8 is provided on the surface of the developing roller 4 so as to be spaced apart with a predetermined interval. The first layer thickness regulating member 8 makes the layer thickness of the developer layer on the surface of the developing roller 4 uniform. Specifically, the first layer thickness regulating member 8 removes excess developer on the surface of the developing roller 4. The developer to be removed flows along the surface of the first layer thickness regulating member 8 and is supplied to the upper surface of the flow plate 10.

  The second layer thickness regulating member 9 is a plate-like member provided so that one end has a predetermined space on the surface of the developing roller 4 and is separated, and the other end is supported by the top plate 2 b of the developing tank 2. . The second layer thickness regulating member 9 removes a part of the developer from the developer layer made uniform by the first layer thickness regulating member 8, and changes the layer thickness of the developer layer to the electrostatic surface of the photosensitive drum 14. The layer thickness is adjusted to be suitable for applying toner to the latent image. As a result, an appropriate amount of toner uniformly adheres to the electrostatic latent image, and the developing operation is reliably performed. The developer removed by the second layer thickness regulating member 9 flows through the space between the end of the flow plate 10 and the first stay prevention member 11 and is fed onto the flow plate 10. The second layer thickness regulating member 9 also has a function of changing the flow direction of the developer removed by the first layer thickness regulating member 8.

  The flow plate 10 extends in the direction from the developing roller 4 toward the stirring roller 5 above the developing roller 4 and the stirring roller 5, and is a plate-like member provided integrally with the first layer thickness regulating member 8 in the present embodiment. It is. The flow plate 10 is preferably provided so as to be inclined so that one end portion on the developing roller 4 side is positioned higher in the vertical direction than the other end portion (that is, the end portion on the stirring roller 5 side). . This further facilitates the circulation of the developer. The toner removed from the surface of the developing roller 4 by the first layer thickness regulating member 8 and the second layer thickness regulating member 9 is fed to the end of the flow plate 10 on the developing roller 4 side, and flows on the upper surface of the flow plate 10. Then, the toner is fed to a relatively wide space between the stirring roller 5 and the toner receiving roller 6 and mixed with the toner.

  The first stay prevention member 11 is in contact with the second layer thickness regulating member 9 in the space between the top plate 2 b of the developing tank 2 and the developing roller 4 and the first layer thickness regulating member 8. It is provided so as to be separated from the layer thickness regulating member 8 with a predetermined interval and supported by the top plate 2 b of the developing tank 2. By providing the first stay prevention member 11, the developer removed by the first layer thickness regulating member 8 and the second layer thickness regulating member 9 is removed from the top plate 2 b of the developing tank 2 and the second layer thickness regulating member 9. It is prevented from staying in the space between them, and an auxiliary function for smoothly circulating the developer in the developing tank 2 is achieved.

  The second stay prevention member 12 is formed in the space below the flow plate 10 (hereinafter simply referred to as “lower space”) formed by the first layer thickness restriction member 8 and the flow plate 10. It is provided to be supported by the flow plate 10. By providing the second stay prevention member 12, the developer removed from the surface of the developing roller 4 by the first layer thickness regulating member 8 enters the lower space and is prevented from staying without being circulated. The developer staying in the lower space is melted and fixed by the heat in the developing tank 2 or the like, and adversely affects the circulation of the developer, the chargeability of the toner, and the like.

  The toner sensor 13 is mounted on the bottom surface of the developing tank 2 below the stirring roller 5, and is provided so that the sensor surface is exposed inside the developing tank 2. The toner sensor 13 is electrically connected to a CPU (not shown) that controls various operations of the image forming apparatus when the developing device 1 is incorporated in an electrophotographic image forming apparatus (not shown). Then, the toner concentration in the developing tank 2 is detected by the toner sensor 13, and the detection result is stored in the CPU. The CPU determines whether toner can be supplied to the developing tank 2 based on the detection result. When it is determined that the toner needs to be replenished, a control signal is sent to replenish the toner into the developing tank 2 from a toner storage container (not shown) via the toner replenishing port 3.

  According to the developing device 1, the toner replenished from the toner replenishing port 3 is charged to some extent by the counterclockwise rotation of the toner receiving roller 6 that is a brush roller, and the stirring roller 5 and the toner receiving roller 6. The developer that has flowed over the flow plate 10 is also fed to the relatively wide space area between the two and the toner and the developer. The rotation of the stirring roller 5 further uniformly mixes the toner and the developer, and the toner is charged with a sufficient amount of charge necessary for the developing operation, and is supplied as a developer around the developing roller 4. This developer magnetically adheres to the surface of the developing roller 4, and a developer layer containing an excessive amount of developer is formed for the developing operation. The excess amount of developer is formed by the first layer thickness regulating member 8 and the second layer. It is removed by the thickness regulating member 9, is fed onto the flow plate 10, flows over the flow plate 10, and is mixed with the toner. This series of operations is repeatedly executed, and the electrostatic latent image is developed (toner image).

  FIG. 2 is a cross-sectional view schematically showing the configuration of the developing device 15 according to the second embodiment of the present invention. The developing device 15 is similar to the developing device 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  The developing device 15 includes a power supply 16 that is a voltage applying unit that applies a bias voltage to the toner receiving roller 6. By applying a bias voltage to the toner receiving roller 6, the toner replenished from the toner replenishing port 3 is more reliably charged and further subjected to agitation by the agitation roller 5, so that the entire toner has a sufficient amount necessary for the developing operation. Since the charge is evenly applied, image defects due to poor charging of the toner are less likely to occur. Note that the bias voltage applied to the toner receiving roller 6 is preferably equal to or smaller than the bias voltage applied to the developing roller 4. As a result, the charge imparting property to the toner is enhanced and the toner adhesion property to the developing roller 4 is improved, which contributes to the formation of a higher quality image over a long period of time. Therefore, even if a large amount of toner is supplied in a short time, charging failure of the toner hardly occurs and is suitable for increasing the image forming speed.

  Also in the developing device 15, like the developing device 1, the developer circulates and the toner is replenished, and the developing operation is repeatedly executed.

  FIG. 3 is a cross-sectional view schematically showing the configuration of the developing device 20 according to the third embodiment of the present invention. The developing device 20 is similar to the developing device 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  The developing device 20 includes a scraping member 21 that is a plate-like member provided so that one end is in contact with the fiber bristles 6 a of the toner receiving roller 6 and the other end is supported by the top plate 2 b of the developing tank 2. Features. The scraping member 21 comes into contact with the fiber bristles 6a of the toner receiving roller 6 by the rotation of the toner receiving roller 6, and removes the toner that has entered between the fiber bristles 6a. By providing the scraping member 21, clogging of the toner between the fiber bristles 6a in the toner receiving roller 6 can be prevented without impairing the toner feeding performance to the periphery of the stirring roller 5, and therefore the fiber bristles 6a and The charge imparting property to the toner due to the contact of the toner is not lowered, and a high-quality image can be formed over a long period.

  In the developing device 20, as in the developing device 1, the developer circulates and the toner is replenished, and the developing operation is repeatedly executed.

  In FIG. 3, the developing device 20 is connected to a toner hopper 25 for supplying toner to the developing tank 2, and the toner hopper 25 is connected to a toner cartridge 31 that supplies toner to the toner hopper 25.

  The toner hopper 25 has a hopper body 26 that is a hollow container-like member made of a hard synthetic resin. The hopper body 26 is provided with a hopper replenishing port 27 on the toner hopper side for replenishing toner to the developing tank 2, so that the hopper replenishing port 27 and the toner replenishing port 3 on the developing tank 2 side are aligned. And provided adjacent to the developing tank 2.

  Inside the hopper body 26, the toner supply roller 28 provided immediately above the hopper supply port 27, the toner supply roller 29 for supplying toner to the toner supply roller 28, and the toner contained in the hopper body 25 are stirred. The agitating blade member 30 that is then transported is rotatably mounted. As the toner supply roller 28, for example, a sponge roller in which a coating layer made of a sponge-like elastic body is formed on the surface of a shaft member such as a cored bar is used.

  The toner accommodated in the hopper body 26 is largely stirred by the rotation of the stirring blade member 30 and is conveyed to the toner supply roller 29, and is supplied to the toner supply roller 28 by the rotation of the toner supply roller 29. . The toner replenishing roller 28 replenishes the toner supplied into the developing tank 2 through the hopper replenishing port 27 and the developing tank toner replenishing port 3. The toner hopper 25 is supplied with toner from the toner cartridge 31.

  An image forming apparatus according to another embodiment of the present invention includes a photosensitive drum having a photosensitive layer capable of forming an electrostatic latent image based on image information on a surface, and charging means for charging the surface of the photosensitive drum to a predetermined potential. And an exposure unit that exposes the charged surface of the photosensitive drum to form an electrostatic latent image based on image information, and a developer that supplies toner to the electrostatic latent image on the surface of the photosensitive drum to form a toner image. Development means in an electrophotographic image forming apparatus comprising: a transfer means for transferring a toner image on the surface of the photosensitive drum onto a recording medium; and a fixing means for fixing the toner image on the surface of the recording medium to the recording medium. The developing device of the present invention described above is used.

  As the photosensitive drum, for example, a photosensitive drum having an organic photosensitive layer formed on a metal core surface can be used. The organic photosensitive layer may be a laminate of a charge generation layer and a charge transport layer, or may contain a charge generation material and a charge transport material in one layer. As the charging means, for example, a charging roller, a corona charger or the like can be used. For example, a laser light source can be used as the exposure means. As the transfer means, for example, a system using a transfer roller or the like can be adopted. As the fixing unit, for example, a system using a combination of a pressure roller and a heating roller can be employed.

  The image forming apparatus of the present invention can adopt the same configuration as that of a conventional electrophotographic image forming apparatus except that the above-described developing apparatus of the present invention is used as a developing unit. That is, any image forming apparatus using the developing device of the present invention is included in the image forming apparatus of the present invention.

1 is a cross-sectional view schematically showing a configuration of a developing device according to a first embodiment of the present invention. It is sectional drawing which shows typically the structure of the image development apparatus which is 2nd Embodiment of this invention. It is sectional drawing which shows typically the structure of the developing device which is 3rd Embodiment of this invention.

Explanation of symbols

1, 15, 20 Developing device 2 Developing tank 2a Opening 2b Top plate 3 Toner replenishing port 4 Developing roller 5 Stirring roller 6 Toner receiving roller 8 First layer thickness regulating member 9 Second layer thickness regulating member 10 Flow plate 11 First Residence prevention member 12 Second residence prevention member 13 Toner sensor 14 Photosensitive drum 16 Power supply 21 Scraping member

Claims (7)

A developer tank having an opening and a toner replenishing port and containing a two-component developer containing toner and carrier;
A developing roller which is rotatably provided facing the surface of the photosensitive drum through the opening of the developing tank and carries a developer layer on the surface;
A stirring roller that is spaced apart from the developing roller inside the developing tank and is rotatably provided, and stirs the developer and supplies the developer to the developing roller;
A toner receiving roller that is spaced apart from the stirring roller inside the developing tank and is rotatably provided, and feeds toner supplied from the toner supply port to the periphery of the stirring roller;
A developing device that supplies toner to an electrostatic latent image formed on the surface of the photosensitive drum for development, and a layer thickness regulating member that regulates the layer thickness of the developer layer on the surface of the developing roller.
The toner receiving roller
A cylindrical shaft member;
A developing device comprising a brush roller configured to include a plurality of fiber bristles provided to protrude in a radial direction of the shaft member. Above the developing roller and the stirring roller in the developing tank, provided to extend in the direction from the developing roller to the stirring roller,
2. The developing device according to claim 1, further comprising a flow plate for guiding circulation of the developer in the developing tank.   3. The developing device according to claim 1, further comprising voltage applying means for applying a bias voltage to the toner receiving roller. The voltage applied to the toner receiving roller is
The developing device according to claim 1, wherein the developing device is equal to or smaller than a voltage applied to the developing roller. The toner receiving roller
The developing device according to claim 1, wherein the developing device is driven to rotate counterclockwise around the axis. Provided to contact the toner receiving roller,
The developing device according to claim 1, further comprising a scraping member that removes toner adhering to the toner receiving roller. Photosensitive drum having a photosensitive layer capable of forming an electrostatic latent image based on image information on the surface, charging means for charging the surface of the photosensitive drum, and image information obtained by irradiating the charged photosensitive drum surface with light. , An exposure unit that forms an electrostatic latent image based on the above, a developing unit that supplies toner to the electrostatic latent image on the surface of the photosensitive drum to form a toner image, and a toner image on the surface of the photosensitive drum is transferred to a recording medium An image forming apparatus including a transfer unit and a fixing unit that fixes a toner image on the recording medium to the recording medium,
Development means
An image forming apparatus comprising the developing device according to claim 1.

Images