JPH07111597B2 - Development device - Google Patents

Description

Description: TECHNICAL FIELD The present invention conveys a two-component magnetic developer in a developer chamber while carrying it on a developer carrying member by the action of magnetic force, and uses the carried developer to carry a latent image. A developing device for visualizing an electrostatic latent image formed on a body, and a replenishment pipe for guiding toner from the outside into the developer chamber, and a replenishment pipe internally provided for conveying the toner in the replenishment pipe. The developer feeding member is provided, and the developer containing the carrier in the developer chamber is taken into the replenishment pipe from the developer inlet formed in the replenishment pipe, and this is mixed with the toner in the replenishment pipe to improve its fluidity. The present invention relates to a developing device that replenishes toner by discharging the toner sent from the outside of the developer chamber and the developer taken into the replenishment pipe to the developer chamber through an outlet formed in the replenishment pipe.

2. Description of the Related Art A developing device of the above type used in an image forming apparatus such as a copying machine or a printer is conventionally known. In this type of developing device using a two-component developer having a toner and a carrier, the toner is sequentially transferred to the latent image carrier and consumed, so that it is necessary to replenish the toner in the developer chamber as necessary. is there. Therefore, the above-mentioned replenishment pipe is provided, and the toner outside the developer chamber is replenished into the developer chamber through this pipe.

At that time, since the toner is inferior in fluidity to the carrier,
If only the toner is sent through the replenishment pipe, the conveyance may be hindered. For this reason, a developer inlet is provided in the replenishment pipe, the developer containing the carrier in the developer chamber is introduced into the replenishment pipe through the inlet, and this is mixed with the toner sent from outside the developer chamber, and its fluidity is improved. And transport it,
It is desirable to discharge these from the outlet of the supply pipe.

However, if only the inlet is provided in the replenishment pipe, the efficiency of taking in the developer from here is poor, and it is not possible to introduce a sufficient amount of the developer into the replenishment pipe, resulting in the fluidity of the developer in the replenishment pipe. It is difficult to sufficiently increase the desired value.

The object of the present invention is to provide a developing device of the type described at the beginning capable of increasing the amount of the developer taken into the replenishing pipe and increasing the fluidity of the toner in the pipe with a simple structure. To provide.

To achieve the above object, the present invention provides a developing device of the type described at the beginning, in which at least a part of the developer feeding member is made of a magnetic material, and the developer on the developer transporting member is provided in the replenishing pipe. The developer inlet of the replenishing pipe is arranged so as to face the surface of the developer transporting member, and at least a part of the magnetic material portion of the developer transporting member is used to transport the developer. We propose a configuration that is placed within the range.

Embodiment Hereinafter, an embodiment in which the present invention is applied to a rotary developing device having a plurality of developing devices will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a developing unit of the developing device supported by the copying machine main body 2. The developing unit 1 has at least one, in the example shown, three developing devices 3, 3R, 3B incorporated therein, and the developer chambers 4, 4R, 4B of the developing devices 3, 3R, 3B are made of aluminum or the like. 3 of casing member 5 made of non-magnetic material
It is divided by one partition wall 6, 6R, 6B and two end walls fixed to both ends in the longitudinal direction.

Each developer chamber 4, 4R, 4B has different color developer 9, 9R, 9B
(For example, black, red, and blue developers) are stored. Cyan, yellow, and magenta toner developers may be stored in the developer chambers to form a full-color image, and the developer chambers of the same color may be stored. Is also possible. Each developer room
As the developer 9,9R, 9B contained in 4,4R, 4B, a two-component developer having a carrier and a toner, at least a part of which is a magnetic developer is used. .
The first to third developing units 3, 3R, 3B are arranged radially around the central axis O of the developing unit 1, but their structures are all the same.

The developing unit 1 is rotatably supported around the central axis O, and is provided to each developing device. The developing roller 1 is described below.
0, 10R, 10B rotate to a predetermined developing position to perform a developing operation, respectively. FIG. 1 shows a state in which the developing roller 10 of the first developing device 3 occupies the developing position.

In FIG. 1, a developer conveying member provided in the first developing device 3, the developing roller 10 in the example shown in the drawing has two partition walls.
The latent image carrier, which is rotatably supported by the main body 2 of the copying machine and partially exposed from the opening formed by 6, 6R, occupies a predetermined developing position with respect to the photosensitive drum 11. The developing roller 10 is positioned parallel to the photosensitive drum 11 with a predetermined minute gap. Instead of the photoconductor drum, a latent image carrier composed of a photoconductor belt may be used, and depending on the model of the image forming apparatus, a latent image carrier composed of a dielectric belt or a dielectric drum may be used.

An impeller 16 having a large number of blades 15 is provided inside the developer chamber 4.
The impeller 16 is rotationally driven in the counterclockwise direction in FIG. 1, whereby the developer in the developer chamber 4, that is, the toner and the carrier are agitated and supplied to the developing roller 10. By stirring the toner and the carrier, the toner is triboelectrically charged to a predetermined polarity.

Inside the developing roller 10, a magnet 21 having a magnetic pole composed of an S pole and an N pole is fixedly arranged in the casing member 5 of the developing unit 1 as shown by S and N in FIG. As a result, when the developing roller 10 is rotationally driven counterclockwise in FIG. 1, the magnetic developer 9 supplied to the developing roller 10 is carried on the surface of the developing roller 10 by the magnetic force of the magnet 21 and is rotated counterclockwise. Be transported to. The conveyed developer is scraped by a doctor blade 22 fixed to the casing member 5, and a predetermined amount of the developer that has passed through the blade 22 is sent to the photosensitive drum 11 with its layer thickness regulated.

On the other hand, the photosensitive drum 11 is rotationally driven in the clockwise direction in FIG. 1, and an electrostatic latent image corresponding to the image of the original document (not shown) is also formed on the surface thereof by the charging / exposure means (not shown). ing. When this electrostatic latent image reaches the opposing development area D between the photoconductor drum 11 and the developing roller 10, the charged toner in the developer also conveyed to this area D is electrostatically transferred to the electrostatic latent image, The electrostatic latent image is visualized. The visible image is transferred onto a transfer paper (not shown) by a transfer device (not shown), and the transferred visible image is fixed by a fixing device (not shown). The developer that has passed through the developing area D is returned to the inside of the developer chamber 4.

As described above, in the illustrated developing device, the two-component magnetic developer 9 in the developer chamber 4 is carried while being carried on the developing roller 10 by the action of the magnetic force, and the carried developer is used to convey the photoconductor drum. It is configured to visualize the electrostatic latent image formed on 11.

The magnetized state of the magnet 21 provided in the developing roller 10 is such that two magnets (S pole in the example in the figure) in the magnet portion T corresponding to the downstream side of the developing area D when viewed in the rotation direction of the roller 10 are magnetized. Are adjacent to each other. Therefore, the developer that has passed through the developing area D and is carried to the portion T having the same polarity is peeled off from the surface of the developing roller 10 by the repulsive action of the magnetic poles having the same polarity. This is because when the developer passes through the developing area D, the toner is transferred to the electrostatic latent image on the photosensitive drum 11 and the amount of toner is reduced. This is because it is mixed with another developer in the agent chamber 4.

By the way, when the above-described developing operation is performed, the toner in the developer is sequentially consumed as the operation proceeds. For this reason, it is necessary to replenish the developer in the developer chamber 4 with toner. For this purpose, as shown in FIG. 2, a replenishment pipe 122 made of a non-magnetic material is arranged in the developer chamber 4 so as to extend parallel to the developing roller 10. The replenishment pipe 122 extends to the outside of the developer chamber and is connected to a toner tank of a toner supply device (not shown) provided outside the developer chamber. In the supply pipe 122, a developer feeding member including a feeding screw shaft 217 provided with a spiral screw is rotatably provided internally, and by rotating the shaft 217,
The toner sent from the toner tank to the supply pipe 122 is
The toner is conveyed toward the developer chamber 4, and is discharged into the developer chamber through an outlet 124 that is formed in the lower region of the replenishment pipe 122 with an appropriate interval. A feeding member other than the screw shaft 217,
For example, a wire wound in the shape of a coil spring may be used.

As described above, the replenishment toner is fed into the developer chamber 4 through the replenishment pipe 122, but at that time, the toner has poor fluidity as compared with the carrier. Therefore the feed screw shaft 217
If only the toner flows in the replenishment pipe 122 due to the rotation of, the transportability of the toner deteriorates.

Therefore, in the developing device shown in the figure, a large number of developer inlets 123 arranged at an appropriate pitch are formed in the replenishing pipe 122, and the developer 9 in the developer chamber 4 is introduced into the pipe from here, and the feeding screw is fed. The rotation of the shaft 217 is configured to mix and agitate the taken-in developer and the toner supplied from the toner tank. Since the carrier is present in the taken-in developer, the developer containing the replenishment toner agitated in the replenishment pipe 122 can have its fluidity enhanced, and thus the replenishment pipe is
It is smoothly transported inside 122 and discharged from the outlet 124 to the outside of the pipe.

As described above, the illustrated developing device includes the replenishment pipe 122 that guides the toner from the outside into the developer chamber 4, and the feeding screw shaft 217 that is provided inside the replenishment pipe 122 and that conveys the toner in the pipe. The developer inlet 12 formed in the supply pipe 122
Replenishment pipe 1 containing developer containing carrier in developer chamber 4 from 3
The toner introduced into the replenishment pipe 122 is mixed with the toner in the replenishment pipe 122 to enhance its fluidity, and the toner sent from the outside of the developer chamber 4 and the developer introduced into the replenishment pipe 122 are fed to the replenishment pipe 122. The toner is replenished by discharging the toner from the formed outlet 124 to the developer chamber 4.

However, as described above, if only the supply pipe having the developer intake port is provided in the developer chamber, the amount of the developer that can be introduced from the intake port is limited, which causes There is a possibility that the fluidity of the developer cannot be sufficiently increased due to insufficient carrier amount.

Therefore, in the developing device of this example, as shown in FIG. 1 and FIG. 2, at least a part of the feed screw shaft 217 provided in the replenishment pipe 122, that is, the whole or a part thereof is made of a magnetic material. The replenishment pipe 1 is configured so that the developer on the developing roller 10 can be taken into the replenishment pipe 122.
The developer inlet 123 of 22 is disposed opposite to the surface of the developing roller 10, and at least a part of the magnetic material portion of the feeding screw shaft 217 is a magnetic field for carrying the developer, that is, a range of the magnetic force of the magnet 21. It is located inside.

According to this configuration, the feeding screw shaft 217 is connected to the magnet 21.
The developer on the developing roller 10 is attracted to the feeding screw shaft 217 by the magnetic force and is supplied through the developer inlet 123 facing the developing roller 10 to the replenishment pipe 122.
Actively taken in. Therefore, the amount of developer taken into the replenishment pipe 122 increases, and a large amount of carrier is fed into this. Therefore, the developer in the replenishment pipe 122 is effectively improved in fluidity, smoothly flows in the pipe, and flows out from the outlet 124 to the developer chamber 4 as shown by an arrow in FIG.

Further, in this example, the developer inlet 123 of the replenishing pipe 122 is arranged at the portion of the developing roller 10 where the developer is peeled off as described above (the lower part of the developing roller 10 in the example of the figure). Therefore, the developer repelled from the developing roller 10 and peeled off is more positively taken into the replenishing pipe 122 through the intake port 123, and the fluidity of the developer in the pipe is further enhanced. Further, since the developer separated from the developing roller 10 has a low toner concentration with a small amount of toner components immediately after passing through the developing area D, that is, a high carrier mixing ratio, it can be taken into the replenishing pipe 122. If so, the ratio of the carrier component in the pipe can be increased, and the fluidity of the developer in the supply pipe can be further improved. Moreover, it is possible to effectively supply the toner to the developer having a low toner concentration separated from the developing roller 10 and mix them.

The developer flowing out from the outlet 124 of the supply pipe 122 is agitated by the impeller 16 and scattered around it. In order to enhance the scattering effect, a wire (not shown) may be spirally wound around the outer circumference of the impeller 16 and the developer may be sent in a direction perpendicular to the paper surface of FIG. it can.

By making the magnetic poles adjacent to each other the same as described above, instead of forming a peeling means for peeling the developer on the developing roller, peeling is performed by a separator that scrapes off the developer on the developing roller 10 as known per se. Even when the means is configured, the same effect can be obtained by disposing the intake port 123 of the supply pipe 122 so as to face the peeling position.

The above-described configuration shown in FIGS. 1 and 2 is different from the other developing devices 3R, 3R.
The same applies to B as well, and thus the duplicated description will be omitted.

The present invention is not limited to the rotary developing device, but can be widely applied to a developing device having one developing device and a developing device in an image forming apparatus such as a printer other than a copying machine. Also,
When the developer carrying member is a member other than the developing roller, for example, a carrying belt, or the developer carrying member does not rotate, the magnet provided therein rotates, or both of them rotate. It is also applicable to.

Effect According to the present invention, the developer containing the carrier is taken into the replenishment pipe for guiding the toner from the outside to the developer chamber and is mixed with the toner in the replenishment pipe, so that the fluidity is improved. be able to. Not only that, at least a part of the developer feeding member is made of a magnetic material, and at least a part of the magnetic material portion of the feeding member is arranged in the range of magnetic force for conveying the developer. At the same time, since the developer inlet of the replenishment pipe is arranged to face the surface of the developer transport member, the two-component magnetic developer on the developer transport member is acted on by magnetic force toward the developer transport member. It is attracted and is positively taken into the supply pipe from the developer intake. Therefore, a large amount of developer can be taken into the supply pipe, and the fluidity of the developer in the supply pipe can be improved. In this way, it is possible to reliably prevent the trouble that the conveyance of the replenishment toner sent through the replenishment tube is obstructed.

[Brief description of drawings]

FIG. 1 is a sectional view of a developing device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line WW in FIG. 4,4R, 4B ... Developer chamber, 9,9R, 9B ... Developer 122 ... Replenishment pipe, 123 ... Developer intake port 124 ... Outlet

Claims (1)

[Claims] 1. A two-component magnetic developer in a developer chamber is carried while being carried by a developer carrying member by the action of magnetic force, and the carried developer is used to form an electrostatic latent image formed on a latent image carrier. A developing device for visualizing an image, comprising a replenishment pipe for introducing toner from the outside into the developer chamber, and a developer feeding member provided in the replenishment pipe for conveying toner in the pipe. , The developer containing the carrier in the developer chamber is taken into the replenishment pipe from the developer inlet formed in the replenishment pipe, mixed with the toner in the replenishment pipe to enhance its fluidity, and sent from outside the developer chamber. In a developing device for replenishing toner by discharging the toner and the developer taken into the replenishing pipe to an developer chamber through an outlet formed in the replenishing pipe, at least a part of the developer feeding member is made of a magnetic material. The developer on the developer transport member. The developer inlet of the replenishing pipe is arranged to face the surface of the developer conveying member so as to be taken into the replenishing pipe, and at least a part of the magnetic material portion of the developer feeding member conveys the developer. The developing device is arranged within the range of the magnetic force.