JPH0725804Y2 - Development device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a developing device used in an electrophotographic copying machine or the like, and more particularly, to a peripheral surface of a developer carrying carrier, which is provided with a stirring means. The present invention relates to a developing device that is attracted to and transported by a developer, develops the electrostatic image of the image forming body into a toner image by the transported developer, and returns the remaining developer to the developer pool again.

[Conventional technology]

In the developing device as described above, the toner is supplied to the developer pool by feeding the toner from the toner hopper into the first mixing chamber extending in the developing width direction, and then the toner is first fed from the toner and the developer pool.
The developer entering the mixing chamber is sent by a screw conveyor in one direction of the developing width direction to be mixed, and the mixed developer is dropped in the second mixing chamber extending in the developing width direction during the conveyance and at the end thereof. Then, the developer is sent together with the developer in the second mixing chamber by a screw conveyor in a direction opposite to the direction in which the first mixing chamber is conveyed, and the developer is mixed therewith to connect to the developer reservoir provided along the conveyance path. A developing device which is carried out by sending the toner from the developer to the developer reservoir is disclosed in, for example, Japanese Patent Laid-Open No. 58-1639.
Known from the '68 publication. In such a developing device, the developer fed to the developer reservoir on the end side of the conveyance of the first mixing chamber, that is, the start side of the conveyance of the second mixing chamber is the developer having a high toner concentration from the first mixing chamber. It becomes a developer with a large proportion, and the variation in the toner concentration of the developer in the developing width direction becomes large, or the toner is not sufficiently mixed, so that the toner is not sufficiently charged in the developer pool. However, there is a problem that uneven development may occur in the developing width direction.

[Problems to be solved by the device]

The present invention has been made in order to solve the above-mentioned problem, and the toner sent out from the second mixing chamber to the developer reservoir is sufficiently mixed even at the start side of the conveyance of the second mixing chamber,
An object of the present invention is to provide a developing device that does not cause unevenness in development in the developing width direction due to uneven toner concentration of the developer in the developing width direction or insufficient mixing of toner.

[Means for Solving the Problems]

According to the present invention, the toner is sent from the toner hopper to the first mixing chamber extending in the developing width direction, and the screw conveyor of the first mixing chamber together with the developer coming into the first mixing chamber from the developer reservoir having a stirring means. In the developing width direction, the mixed developer is mixed in one direction, and the mixed developer falls into the second mixing chamber extending in the developing width direction at the middle and the end of the conveyance, and is mixed with the developer in the second mixing chamber. In the developing device in which the toner is replenished by being mixed and sent out to the developer reservoir while being sent in the direction opposite to the feeding direction of the second mixing chamber by the screw conveyor, the end of the conveyance of the first mixing chamber The developing device is characterized in that an agitating blade substantially parallel to the axis of the screw conveyor is provided on the upstream side of the screw conveyor of the second mixing chamber that conveys the developer dropped from the part. To achieve the above object by forming.

[Action]

That is, in the developing device of the present invention, since the agitating blades substantially parallel to the axis of the screw conveyor are provided on the upstream side of the screw conveyor in the second mixing chamber, the second end to the second end of the first mixing chamber are conveyed. The developer dropped into the mixing chamber is first mixed well with the developer in the second mixing chamber by the stirring blade, and when it is delivered to the developer pool, the developer and toner delivered from the other portion in the developing width direction. The difference in density is reduced, and the toner contained in the developer is sufficiently charged in the developer pool, so that uneven development in the development width direction is eliminated and uniform development is achieved. .

〔Example〕

 Hereinafter, the present invention will be described with reference to illustrated examples.

1 and 2 are a partial sectional view and a plan view of an electrophotographic recording apparatus showing an example of a developing device of the present invention, and FIG. 3 is an XX line in FIG.
FIG. 4 is a view on arrow, and FIG. 4 is a view on arrow YY in FIG.

In this developing device A, the developer carrier 4 having the magnet body 1 which is stationary inside rotates in the arrow direction, and the developer reservoir 4 has the stirring means 3 which rotates in the arrow direction.
The developer is adsorbed on the surface by the magnetic force of the magnetic pole and is conveyed, and the layer thickness of the developer is regulated by the layer thickness regulating member 5, and the image carrier B approaches the developer conveying carrier 2 by the developer layer. In the developing area, the electrostatic image of the image forming body B is developed into a toner image, and the remaining developer passing through the developing area is again stored in the developer pool 4
To return to. As a result, the toner concentration of the developer in the developer pool 4 decreases, so that the toner needs to be replenished to the developer pool 4 for stable development. This toner replenishment is performed as follows.

The toner in the toner container is dropped into the toner hopper 6 shown by the one-dot chain line in FIG. 2 from the inlet 6a shown by the dotted line, and the toner in the toner hopper 6 is moved by the screw conveyor 7 provided at the bottom of the toner hopper 6. The toner is conveyed in the direction of the one-dot chain line and is fed to the one end side of the first mixing chamber 8 extending in the developing width direction. The toner sent into the first mixing chamber 8 is conveyed to the other end side by the screw conveyor 9. The upper part of the first mixing chamber adjacent to the developer pool 4 is opened so as to receive the developer in the developer pool 4 stirred by the stirring means 3.
The stirring means 3 is also provided with a stirring blade 3b composed of a surface including a shaft and a long axis of the elliptical inclined blade 3a in addition to the elliptic inclined blade 3a so that the developer is well scattered to the first mixing chamber 8 side. There is. Therefore, the developer in the developer reservoir 4 is also well fed into the first mixing chamber 8, and the screw conveyor 9 mixes the toner from the toner hopper 6 and the developer from the developer reservoir 4 together and moves them to the other end side. Transport.

The developer in the first mixing chamber 8 being mixed and conveyed is sequentially dropped from the dropping holes 10 provided side by side along the conveying path to the second mixing chamber 11 below and in parallel with the first mixing chamber 8 and the other end. The developer conveyed to the side drops into the second mixing chamber 11 through the last dropping hole 10n provided on the other end side. The drop hole 10 and the last drop hole 10n have a larger hole area on the downstream side of the conveyance so that the toner replenishment amount to the developer reservoir 4 is made uniform in the developing width direction, and therefore the developer drop amount is smaller. It is provided to be many. The developer that has fallen into the second mixing chamber 11 is conveyed by the screw conveyor 12 in the direction opposite to that of the developer in the first mixing chamber 11 together with the developer that has entered from the developer reservoir 4, and is mixed, and sequentially developed while being conveyed. It is sent to the medicine reservoir 4. As a result, the toner is supplied to the developer reservoir 4.

The above is the same as in the developing device described in Japanese Patent Laid-Open No. 58-163968, and as it is, the developer fed into the developer reservoir 4 is the first portion of the conveyance by the screw conveyor 12, that is, the right portion of FIG. (1) Mixing of toner having a high toner concentration falling from the mixing chamber 11 tends to be insufficient. Therefore, the stirring blade 12 that is substantially parallel to the axis of the screw conveyor 12 is provided on the starting side of the screw conveyor 12 conveyance.
b is also provided so that the developer falling from the dropping holes 10 and 10n into the second mixing chamber 11 at the end of the conveyance of the first mixing chamber 8 is sufficiently mixed with the developer in the second mixing chamber 11 first. I am trying to let you. As a result, it is possible to solve the problem of uneven development density between the portion corresponding to the right side of FIGS. 2 and 3 in the developing width direction and the other portions.

The developing device of the present invention is not limited to the illustrated example, but the toner hopper is provided in parallel with the first mixing chamber so that the toner is evenly fed from the toner hopper along the conveying path of the first mixing chamber. Alternatively, a partition wall having a developer passage distributed along the transfer passage of the second mixing chamber may be provided between the second mixing chamber and the developer reservoir.

[Effects of the Invention] The developing device of the present invention is provided with the stirring blade substantially parallel to the axis of the screw conveyor at the upstream side of the screw conveyor in the second mixing chamber, so that uneven development in the developing width direction occurs. Has the effect of reducing

[Brief description of drawings]

1 and 2 are a partial sectional view and a plan view of an electrophotographic recording apparatus showing an example of a developing device of the present invention, and FIG. 3 is an XX line in FIG.
FIG. 4 is a view on arrow, and FIG. 4 is a view on arrow YY in FIG. DESCRIPTION OF SYMBOLS 1 ... Magnet body, 2 ... Developer conveyance carrier 3 ... Stirring means, 4 ... Developer reservoir 5 ... Layer thickness control member, 6 ... Toner hopper 7,9 ... Screw conveyor 8 ... 1st mixing chamber, 10, 10n ... Drop Hole 11 ... Second mixing chamber, 12 ... Screw conveyor 12b ... Stirring blade

Claims (1)

[Scope of utility model registration request] 1. A screw in a first mixing chamber together with a developer fed from a toner hopper into a first mixing chamber extending in a developing width direction and entering the first mixing chamber from a developer reservoir having a stirring means. The developer is sent in one direction in the developing width direction by a conveyor to be mixed, and the mixed developer falls into the second mixing chamber extending in the developing width direction at the middle and end portions of the conveyance, and the developer in the second mixing chamber In the developing device in which the toner is replenished by being mixed and sent out to the developer reservoir while being sent in the direction opposite to the feeding direction of the first mixing chamber by the screw conveyor, A developing device, wherein an agitating blade that is substantially parallel to the axis of the screw conveyor is provided on the upstream side of the screw conveyor in the second mixing chamber that conveys the developer dropped from the end portion.