JPH0583776U - Developing device for electrophotographic copying machine - Google Patents

Abstract

(57) [Summary] [Purpose] The rotation support of the feed screws 20 and 21 for stirring and dispersing the developer in the developing device 26 is always good. [Structure] The feed-direction end portions 24a of the feed fins 24, 25,
Since the inclination direction of 25a is opposite to the inclination direction of the other portions, the feeding direction of the developer at the end portions 24a, 25a is opposite to the other portions, whereby the developer is inclined in this direction. Many stay near the boundary where the direction is reversed. Therefore, it is possible to prevent the bearings 22 and 23 from being buried in the developer.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a developing device that supplies a developer to a photosensitive drum of an electrophotographic copying machine to visualize an electrostatic latent image on the photosensitive drum.

[0002]

[Prior Art]

 As a developing device of a conventional electrophotographic copying machine, for example, a case installed near a photosensitive drum and containing a developer therein, and a device arranged in the case and rotating about an axis parallel to the photosensitive drum are used. The magnetic roller that supplies the developer in the case to the photosensitive drum is placed inside the case with both ends rotatably supported by the case, and extends parallel to the photosensitive drum and is located inside the case. A pair of feed screws with spiral feed fins are formed on the outer periphery of the part, and by rotating these both feed screws, the developer in the case is transferred in the opposite direction to stir and disperse, and It is known that the electrostatic latent image on the photosensitive drum is visualized by the developer toner supplied by the magnetic roller.

[0003]

[Problems to be solved by the device]

 However, in such a conventional developing device for an electrophotographic copying machine, the feed fins of each feed screw are inclined in the same direction over the entire length, that is, from the feed direction start end to the feed direction end. , The developing agent is successively fed near the end of the feed fin in the feed direction by the feed screw, so that a large amount of the developer stays near the end of the feed direction rather than near the beginning of the feed fin in the feed direction. . Here, a bearing for rotatably supporting the feed screw in the case is provided at the position where such a large amount of developer stays, that is, at the end of the feed screw. There is a problem in that the bearing may be buried and, as a result, the developer may enter the bearing and the rotational support of the bearing may become defective.

It is an object of the present invention to provide a developing device of an electrophotographic copying machine, which can always favorably support the rotation of a feed screw by a bearing.

[0005]

[Means for Solving the Problems]

 For this purpose, the case installed near the photosensitive drum and containing the developer inside it, and the developer inside the case exposed to light by rotating around an axis parallel to the photosensitive drum are arranged inside the case. The magnetic roller that supplies the drum and the both ends are rotatably supported by the case are arranged inside the case, and extend in parallel with the photosensitive drum, and are spirally formed on the outer periphery of the portion located inside the case. A pair of feed screws with feed fins are provided, and by rotating both feed screws, the developer in the case is transferred in the opposite direction to stir and disperse, and the developer supplied by the magnetic roller is also used. In the developing device of an electrophotographic copying machine in which the electrostatic latent image on the photosensitive drum is visualized by the toner of the developer, the end of the feed fin of the feed screw in the feed direction is terminated. The inclination direction of section, can be accomplished by an inclined direction opposite to the direction of feed fins at other sites.

[0006]

[Action]

 Now, it is assumed that the developer in the case is supplied to the photosensitive drum by the magnetic roller, and the electrostatic latent image on the photosensitive drum is visualized as a toner image by the toner of the developer. At this time, since the pair of feed screws arranged in the case rotate together, the feed fins formed on the feed screws cause the developing agent in the case to move from the feed direction start end side to the feed direction end side, respectively. Be transferred. Here, since the feed directions of the pair of feed screws are opposite to each other, this developing agent is agitated and dispersed in the case. Then, as described above, when the feeding screw rotates and the developer is successively fed toward the end of the feed direction, a large amount of developer tends to stay near the end of the feed fin in the feed direction. The inclination direction of the feed fin end of each feed screw is opposite to the feed fin inclination direction of the other part, so the developer feed direction at the end part of each feed fin is different from that of the other part. That is, the feed direction is opposite to the feed direction at the start end portion and the central portion, and as a result, a large amount of the developer stays near the boundary where the tilt direction reverses. This prevents the bearing that rotatably supports the feed screw from being buried in the developer, and makes it possible to constantly support the rotation of the feed screw by the bearing.

[0007]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1, 2 and 3, reference numeral 11 denotes a photosensitive drum which is rotated in the direction of the arrow by a motor (not shown), and an electrostatic latent image of a document is formed on the outer peripheral surface of the photosensitive drum 11. A box-shaped case 12 extending parallel to the axis of the photosensitive drum 11 is installed in the vicinity of the photosensitive drum 11, here immediately before, and a developer consisting of a carrier and toner is stored in the case 12. ing. Reference numeral 15 denotes a magnetic roller extending parallel to the axis of the photosensitive drum 11. The magnetic roller 15 is arranged in contact with the developer in the case 12, and its both ends are provided with bearings 16 on the side wall of the case 12. The magnetic roller 15 can be rotated about an axis parallel to the photosensitive drum 11 when it receives a driving force from a motor (not shown). A part of the magnetic roller 15 projects rearward from an opening 17 formed at the rear end of the case 12 and contacts the outer peripheral surface of the photosensitive drum 11. As a result, the developer contained in the case 12 is supplied to the photosensitive drum 11 by the magnetic roller 15, whereby the toner in the developer adheres to the photosensitive drum 11 and the electrostatic latent on the photosensitive drum 11 is caused. The image is visualized as a visible toner image.

A pair of feed screws 20 and 21 are arranged in the case 12 in front of the magnetic roller 15, and the feed screws 20 and 21 extend parallel to the axis of the photosensitive drum 11. Further, both axial ends of the feed screws 20 and 21 are rotatably supported on the side wall of the case 12 via bearings 22 and 23, whereby when a driving force from a motor (not shown) is received, These feed screws 20 and 21 can rotate about an axis parallel to the photosensitive drum 11, and in the case of this embodiment, they can rotate in opposite directions as indicated by arrows. Further, spiral feed fins 24, 25 are formed on the outer peripheries of the feed screws 20, 21 located inside the case 12, respectively, and these feed fins 24, 25 are in the same direction in this embodiment. It is inclined. When the feed screws 20 and 21 rotate, the developer in the case 12 is transported by the feed fins 24 and 25 from the feed direction start end side toward the feed direction end side. Here, since the feed screws 20 and 21 rotate in the opposite directions as described above, and the feed fins 24 and 25 are inclined in the same direction, the developer in the case 12 is directed in the longitudinal direction of the case 12. And the developer is agitated / dispersed in the case 12. In addition, the end portions 24a and 25a of the feed fins 24 and 25 in the feed direction (the feed fins 24 and 25 at the right end portion in FIG. 2 for the feed screw 20 and the left end portion in FIG. 2 for the feed screw 21) are The inclination direction is opposite to the inclination direction of the other portions, that is, the feed direction starting ends 24b and 25b and the feed direction central portions 24c and 25c. The case 12, the magnetic roller 15, and the feed screws 20 and 21 described above constitute a developing device 26 as a whole.

A toner supply box 31 is installed above the developing device 26, and the toner supply box 31 is fixed to the upper surface of the case 12. The toner supply box 31 stores a large amount of toner to be supplied to the developing device 26. Reference numeral 32 is a screw hole provided in the lower portion of the toner supply box 31, and the screw hole 32 extends parallel to the axis of the photosensitive drum 11. A supply screw 33 is housed in the screw hole 32, and the supply screw 33 is driven by a motor (not shown) to rotate. When the replenishing screw 33 rotates, the toner in the toner replenishing box 31 is sent through the screw hole 32 toward the hole bottom. Reference numeral 35 denotes a large number of replenishment holes 35 formed in the upper wall of the case 12 for communicating the screw hole 32 with the inside of the case 12, and in this embodiment, seven replenishment holes 35. It is located between the toner inside the supply box 21 and the toner. Further, these replenishment holes 35 are provided at predetermined intervals in the longitudinal direction of the developing device 26, and the toner sent from the toner replenishing box 31 by the replenishing screw 33 into the case 12 of the developing device 26. Lead.

Next, the operation of the embodiment of the present invention will be described. Now, as the magnetic roller 15 rotates, the developer in the case 12 is supplied to the photosensitive drum 11, and the electrostatic latent image on the photosensitive drum 11 is visualized as a visible toner image by the toner of the developer. And At this time, since the pair of feed screws 20 and 21 arranged in the case 12 are both rotated by the motor, the feed fins 24 and 25 formed on the feed screens 20 and 21 remove the developer in the case 12. The material is transferred from the feed direction start end side to the feed direction end side. Here, since the feed fins 24 and 25 of the pair of feed screws 20 and 21 are inclined in the same direction and the feed screws 20 and 21 are rotated in opposite directions, the feed screws 20 and 21 are not rotated. The feeding directions are opposite to each other, and as a result, the developer is agitated and dispersed while circulating in the case 12.

Then, as described above, when the feed screws 20 and 21 rotate and the developer is successively fed toward the end of the feed direction, a large amount of developer stays near the end of the feed fins 24 and 25 in the feed direction. In this embodiment, the inclination direction at the feed direction end portions 24a and 25a (only 50 mm in length in this embodiment) of the feed fins 24 and 25 of the feed screws 20 and 21 is The other portions, that is, the feed direction starting ends 24b and 25b and the feed direction central portions 24c and 25c are set in the opposite direction to the tilt direction. As a result, the developer feeding direction at the feeding direction end portions 24a, 25a of the feeding fins 24, 25 is opposite to the feeding direction of the other portions, whereby the developer is reversed in its inclination direction. In the vicinity of the boundary, that is, in the vicinity of the boundary between the feeding direction central portions 24c and 25c and the feeding direction end portions 24a and 25a, a large amount of water is retained. Therefore, the bearings 22 and 23 for rotatably supporting the feed screws 20 and 21 on the case 12, particularly the right-side bearing 22 in FIG. 2 for the feed screw 20 and the left-side bearing 23 in FIG. 2 for the feed screw 21. Therefore, the situation in which the toner is buried in the developer is prevented, and the rotation support of the feed screws 20 and 21 by the bearings 22 and 23 is always good.

[0012]

[Effect of the device]

 As described above, according to this invention, the rotation support of the feed screw by the bearing can always be made good.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II of FIG.

3 is a sectional view taken along the line II-II of FIG.

[Explanation of symbols]

 11 ... Photosensitive drum 12 ... Case 15 ... Magnetic roller 20, 21 ... Feed screw 24, 25 ... Feed fin

Claims (1)

[Scope of utility model registration request] 1. A case installed near a photosensitive drum and containing a developer therein, and a developer disposed in the case and rotated about an axis parallel to the photosensitive drum to remove the developer in the case from the photosensitive drum. And a magnetic roller that is disposed inside the case with both ends rotatably supported by the case and that extends parallel to the photosensitive drum and that has spiral feed fins on the outer periphery of the portion located inside the case. A pair of feed screws formed is provided, and by rotating these both feed screws, the developer in the case is transferred in the opposite direction to agitate and disperse, and by the toner of the developer supplied by the magnetic roller, In the developing device of the electrophotographic copying machine which visualizes the electrostatic latent image on the photosensitive drum, at the feed direction end portion of the feed fin of each feed screw. The oblique, the developing device of an electrophotographic copying machine, characterized in that an inclined direction opposite to the direction of feed fins at other sites.