JP2006106171A - Developing apparatus, image forming unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing apparatus capable of removing useless space which may be generated after engaging a biaxial side agitation member with the upper and lower cases of a developing housing by forming the shape of the engaged upper and lower cases of the developing housing like a cylindrical shape under a speed-up tendency, capable of improving charging/agitating properties by removing staying positions of a developer and capable of preventing the generation of irregular charging, irregular agitation, irregular density in the horizontal width direction and toner scattering, and to provide an image forming apparatus provided with the developing apparatus. <P>SOLUTION: The developing apparatus comprises a biaxial agitating/carrying member 1 provided with a partition wall 5 for dividing the member 1 into two sections to circulate a flow of a developer 10 into the upper and lower cases 7, 2 of the developing housing and a toner feeding port 4 for supplying toner from the outside. The shape of the engaged upper and lower cases 7, 2 of the developing housing is a cylindrical shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device in an electrophotographic process, such as a copying machine, a facsimile machine, and a printer, and an image forming apparatus provided with the developing device.

Conventionally, it has been proposed to devise various shapes of the conveying / stirring member in order to improve charging and stirring properties of newly supplied toner in the developing unit in the image forming apparatus (see, for example, Patent Documents 1 and 2). ).
In the above prior art, for example, in Patent Document 1, charging and stirring properties are improved by devising the shape of the conveying / stirring member. Further, in Patent Document 2, it is a basic configuration that a guide shape of the developer is provided in a portion of the casing facing the developing sleeve.
FIG. 7 is a sectional view showing a conventional developing unit. FIG. 8 is a cross-sectional view showing a state where the developer is filled in the developing casing of the conventional developing unit of FIG. 7 and 8, when the developer 10 is put in the upper and lower developing casings 2 and 7, the developer 10 stays at a location 12 when the developer 10 is transported and stirred by the stirring member 1, and the transport and stirring is performed.・ This is one of the causes that adversely affect the chargeability.
Japanese Patent Laid-Open No. 10-10852 JP 2002-287472 A

However, recent electrophotographic image forming apparatuses have been increased in speed, and in the case of the two-component development system, the newly supplied toner moves without being charged / stirred with the developer so that the newly replenished toner slides on the developer. This is one of the causes of density unevenness in the left-right width direction and toner scattering due to uneven charging and uneven stirring.
Therefore, in view of the above-described circumstances, the object of the present invention is to make the shape after the fitting of the upper and lower cases of the developing housing into a cylindrical shape in such a high speed, so that the biaxial stirring member and Eliminates unnecessary space after fitting the upper and lower cases of the developer housing case, and eliminates stagnant developer, improving charging and stirring ability, preventing uneven charging and uneven stirring, uneven density in the horizontal direction, It is an object of the present invention to provide a developing device that prevents toner scattering and an image forming apparatus including the developing device.

In order to solve the above problems, the invention described in claim 1 is a biaxial agitating / conveying member provided with a partition that bisects the developer flow in the upper and lower cases of the developing housing. In a developing device having a toner replenishing port for supplying toner from the outside, the shape when the upper and lower cases of the developing housing covering the biaxial stirring / conveying member are fitted is a cylindrical shape Features the device.
The invention according to claim 2 is characterized in that the developing device according to claim 1 is characterized in that the biaxial stirring / conveying member and the cylindrical cross-sectional center positional relationship after fitting the upper and lower cases are the same. To do.
According to a third aspect of the present invention, the difference between the outer diameter of the biaxial stirring / conveying member and the inner diameter of the cylindrical shape after fitting the upper and lower cases is 2.5 mm or less. Features a developing device.
According to a fourth aspect of the present invention, there is provided the developing device according to the first aspect, wherein minute irregularities are formed on the cylindrical inner surfaces after the upper and lower cases are fitted.
According to a fifth aspect of the present invention, the developing device according to the first aspect is characterized in that minute irregularities are formed on the surface of the biaxial stirring / conveying member.
According to a sixth aspect of the present invention, the developing device according to the first aspect is provided with the constitution of the fourth aspect and the constitution of the fifth aspect at the same time.
According to a seventh aspect of the present invention, there is provided an image forming unit of PCU or AIO on which the developing device according to any one of the first to sixth aspects is mounted.
According to an eighth aspect of the invention, there is provided an image forming apparatus including the developing device according to any one of the first to sixth aspects or the image forming unit according to the seventh aspect.

  According to the present invention, the developer / toner is not retained in a useless space in the casing, and the toner and the developer are easily charged and stirred, thereby preventing uneven charging and uneven stirring. It is possible to provide a developing device with less scattering and an image forming apparatus including the developing device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a top view of a developing unit according to an embodiment of the present invention and a cross-sectional view of a main component. Toner is replenished into the developing housing 11 from the toner replenishing port 4 formed in the lower case 2 of the developing housing 11 composed of the lower case 2 and the upper case 7, and a biaxial agitating / conveying member (hereinafter, agitating / conveying member). ) The developer 10 is conveyed in the direction of the arrow in the figure while being conveyed, stirred and charged at 1.
In general, a developing device (developing unit) has a developing housing 11 that opens to face a photoreceptor (not shown) that carries a latent image, and this developing housing 11 has a rotating shaft around it. A magnet member (not shown) having a plurality of magnetic poles formed thereon is fixed and arranged.
Further, a developing roller 6 carrying a two-component developer and a layer thickness regulating doctor (not shown) for regulating the layer thickness of the developer pumped up by the developing roller 6 are accommodated. The upper and lower cases 7 and 2 of the developing housing 11 have two parallel agitating / conveying members 1 and both agitating / conveying members (shafts) so that the developer flow by the agitating / conveying members 1 circulates. A partition wall 5 is provided that bisects (except at both ends in the direction). Further, the developing housing 11 has a toner supply port 4.
In FIG. 1, both ends of the agitating / conveying member 1 are supported by bearings 3 by upper and lower cases 7 and 2 of the developing housing 11, and a developer flow circulates by a central partition (partition) 5 of the developing housing 11. Are arranged in half.

FIG. 2 is a cross-sectional view for explaining the first embodiment of the developing housing and the agitating / conveying member of the developing unit according to the embodiment of the present invention in the AA section of FIG. As shown in FIG. 2, each part of the upper case 7 and the lower case 2 constituting the developing housing 11 is formed in a semicircular shape, and is configured so as to be cylindrical after the upper and lower cases 7 and 2 are fitted. is doing.
The agitating / conveying member 1 is arranged in the cylindrical portion, arranged so that the center position relationship between the cylindrical portion and the agitating / conveying member 1 is the same, and the outer shape a of the agitating / conveying member 1 and the cylindrical shape are arranged. The dimensional difference of the inner diameter b is set to 2.5 mm or less.
According to this, the cylindrical portion after the upper and lower cases 7 and 2 are fitted to each other and the conveying / stirring member 1 can be configured in a well-balanced manner, and the newly supplied toner is easily charged and stirred with the developer 10. Therefore, it is possible to provide a developing device that prevents uneven charging and uneven stirring, and minimizes left / right density unevenness and toner scattering.
FIG. 3 is a cross-sectional view showing a state where the developing unit of FIG. 2 is filled with a developer. With this configuration, as shown in FIG. 3, the developer 10 is disposed in a well-balanced manner in the cylindrical shape constituted by the upper and lower cases 7 and 2 and the agitation / conveyance member 1, and is wasted during conveyance / agitation. It is conveyed, stirred, and charged without creating a staying location (reference numeral 12 in FIG. 8 describing the conventional example).
Unnecessary space between the cylindrical portion formed by fitting the upper and lower cases 7 and 2 and the conveying / stirring member 1 is eliminated, and the newly supplied toner and the developer 10 are easily charged and agitated. In addition, it is possible to provide a developing device that prevents stirring unevenness and causes less left-right density unevenness and toner scattering.

FIG. 4 is a cross-sectional view for explaining a second embodiment of the developing housing and the agitating / conveying member of the developing unit according to the embodiment of the present invention in the AA section of FIG. By providing the concave and convex portions 8 on the inner walls of the upper and lower cases 7 and 2 at a predetermined circumferential pitch or at an arbitrary pitch, the coefficient of friction with the concave and convex portions 8 is increased when the developer 10 is conveyed and stirred. To improve the chargeability.
The upper and lower cases 7 and 2 can improve the frictional force between the inner wall of the cylindrical portion after fitting and the developer 10, and the newly replenished toner and the developer 10 can be easily charged and agitated. Further, it is possible to provide a developing device that prevents stirring unevenness and causes less left-right density unevenness and toner scattering.
FIG. 5 is a cross-sectional view illustrating a third embodiment of the developing housing and the agitating / conveying member of the developing unit according to the embodiment of the present invention in the AA section of FIG. By providing the uneven portion 9 on the surface of the spiral blade of the conveying / stirring member 1, the coefficient of friction with the uneven portion 9 is increased during the conveyance / stirring of the developer 10 to improve the charging property.
The frictional force between the surface of the conveying / stirring member 1 and the developer 10 can be improved, and the newly supplied toner and the developer 10 are easily charged and stirred, preventing uneven charging and uneven stirring, and uneven density on the left and right sides. Therefore, it is possible to provide a developing device with less toner scattering.

FIG. 6 is a cross-sectional view for explaining a fourth embodiment of the developing housing and the agitating / conveying member of the developing unit according to the embodiment of the present invention in the AA section of FIG. By providing the concave and convex portions 8 on the upper and lower cases 7 and 2 and the concave and convex portions 9 on the conveying / stirring member 1, the coefficient of friction with the concave and convex portions 8 and 9 is increased when the developer 10 is conveyed and stirred. , Improve the chargeability. That is, this embodiment has a configuration in which the configurations of FIGS. 4 and 5 are combined.
The upper and lower cases 7, 2, the inner wall of the cylindrical portion after fitting, the surface of the conveying / stirring member 1 and the developer 10 can be improved in friction, and the newly replenished toner and developer 10 are charged. It is easy to stir, prevents charging unevenness and stirring unevenness, and can provide a developing device with little left-right density unevenness and toner scattering.
According to the present invention, it is possible to provide an image forming unit such as a PCU or AIO that is equipped with a developing device that prevents uneven charging and uneven stirring and has less lateral density unevenness and toner scattering.
According to the present invention, it is possible to provide an image forming apparatus equipped with an image forming unit such as a PCU or AIO that prevents uneven charging and uneven stirring, and uneven left-right density unevenness and toner scattering.

The figure which looked at the developing unit which concerns on embodiment of this invention from the top, and sectional drawing of the main structure part. Sectional drawing explaining the 1st Embodiment of the image development housing and stirring / conveyance member of the image development unit which concerns on embodiment of this invention in the AA cross section of FIG. FIG. 3 is a cross-sectional view showing a state where a developer is filled in the developing unit of FIG. 2. Sectional drawing explaining 2nd Embodiment of the image development housing and stirring / conveyance member of the image development unit which concerns on embodiment of this invention in the AA cross section of FIG. Sectional drawing explaining 3rd Embodiment of the image development housing and stirring / conveyance member of the image development unit which concerns on embodiment of this invention in the AA cross section of FIG. Sectional drawing explaining the 4th Embodiment of the image development housing and the stirring and conveyance member of the image development unit concerning embodiment of this invention in the AA cross section of FIG. Sectional drawing which shows the conventional image development unit. Sectional drawing which shows the state which filled the developing agent in the conventional image development unit of FIG.

Explanation of symbols

1 Biaxial stirring / conveying member (stirring / conveying member)
2 Lower case of developing housing 4 Toner replenishment port 5 Central partition of developing housing 6 Developing roller 7 Upper case of developing housing 8 Concavity and convexity (upper and lower cases of developing housing)
9 Concavity and convexity parts (for conveying and stirring members)
10 Developer 11 Developer Housing 12 Developer Location

Claims (8)

  A developer housing constructed by combining the upper case and the lower case, a biaxial agitating / conveying member disposed in the developing housing, and the biaxial agitating / conveying member being divided into two parts to allow the developer to flow In a developing device having a partition wall to be circulated and a toner replenishing port for supplying toner from the outside to the inside of the developing housing, the developing housing has a cylindrical shape that rotatably supports a biaxial agitating / conveying member inside A developing device.   The developing device according to claim 1, wherein a center position of the biaxial stirring / conveying member and a center position of a cross section of the cylindrical portion after the upper and lower cases are fitted to each other.   2. The developing device according to claim 1, wherein a difference between an outer diameter of the biaxial stirring / conveying member and an inner diameter of the cylindrical portion after the upper and lower cases are fitted is 2.5 mm or less.   2. The developing device according to claim 1, wherein minute irregularities are formed on an inner surface of the cylindrical portion after the upper and lower cases are fitted.   2. The developing device according to claim 1, wherein minute irregularities are formed on the surface of the biaxial stirring / conveying member.   The developing device according to claim 1, wherein the unevenness according to claim 4 and the unevenness according to claim 5 are provided at the same time.   An image forming unit for PCU or AIO, wherein the developing device according to any one of claims 1 to 6 is mounted. An image forming apparatus comprising the developing device according to any one of claims 1 to 6 or the image forming unit according to claim 7.

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