JPH03131880A - Developing device - Google Patents

Abstract

PURPOSE:To eliminate the deterioration of a developer such as coherence by making the agitation carrying force of an agitation carrying means in a 1st hopper relatively lower than at a position which does not face a developing sleeve. CONSTITUTION:The 1st hopper 4 supplies a developer to the peripheral surface of a developer carrier 1 and a 2nd hopper 5 supplements a developer to the 1st hopper 4. The 1st hopper 4 faces the developer carrier 1 to its overall length, the 2nd hopper 5 is provided at an extension part 4B extending out of a range A4, and the agitation carrying means 3 supplies the developer received from the 2nd hopper 5 to the developer carrier while sending it into the range 4A uniformly. Then the agitation carrying force of the agitation carrying means 3 is set smaller in the range 4A than at the extension part 4B. Therefore, the agitation carrying force becomes nearly uniform in the entire area in the 1st hopper 4. Consequently, the deterioration of the developer such as coherence is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device used in an electric f''5 device or the like, and particularly relates to a stirring and conveying means for the developer.

[Prior Art] Recently, as the need for color copying has increased, inexpensive and compact monochrome copying machines have been increasing in number. Since multiple developing devices are provided in the development device, each developing device is downsized and the developer storage space (first hopper) in each developing device is also small. In many cases, a separate developer carrier "X (second hopper) is provided to replenish the developer. In this case, the developer is supplied from the second developer to the first hopper in the developing device using the developer carrier ( Ideally, this would be done uniformly over the entire axial direction of the developing sleeve (hereinafter referred to as the developing sleeve).However, since there is not enough space above the developing device, the developing device should be extended in the length direction of the latent image carrier rather than the length of the latent image carrier. Extending it, its extension part-
A second hopper is provided at the second hopper, and developer is replenished from the second hopper to the first hopper in the developing device. The developer in the first hopper is transferred over the entire length of the developing sleeve (over the entire length in the axial direction @
). Generally, plate-shaped blades are used as the stirring and conveying means, which are attached to a shaft extending parallel to the axis of the developing sleeve at a uniform pitch in the axial direction. The plate-shaped blades rotate the developer to level the developer in the axial direction while agitating the developer and transporting the developer in the axial direction. Therefore, - once the developer is horizontal throughout the entire axial direction in the first hopper,
The developer transport effect disappears, and only stirring is performed. In addition, since the developer agitation and conveyance force due to this leveling effect is also present in the developing sleeve itself, the part of the first hopper that faces the developing sleeve (the area where the first hopper and the developing sleeve face each other) Comparing the agitation and conveyance force in the area that does not face the developing sleeve (the area of the extending portion, that is, the area outside the developing sleeve of the first hopper), the force is higher in the area where the first hopper and the developing sleeve face each other.

Generally, the developer conveying force is designed to meet the maximum consumption amount such as when copying a solid black image. Therefore, in the case of the above configuration, the stirring conveyance amount in the area of the first hopper extension is
It was designed to be equal to the maximum consumption.

[Problem to be solved by the invention] However, in the above-mentioned particular conventional device, the agitation and conveyance force in the opposing area between the first hopper and the developing sleeve becomes more than necessary, which may cause the developer to aggregate or become electrified. It was easy to cause developer deterioration phenomenon such as the developer becoming hard to clean.

The present invention solves this problem and provides a developing device in which even one agitation and conveyance means can provide appropriate agitation and conveyance force in the opposing area and the extension area between the first hopper and the developing sleep. With the goal.

[Means for Solving the Problems] According to the present invention, the above object is as follows: A developer carrier, a first hopper that supplies developer to the circumferential surface of the developer carrier, and a developer that is supplied to the first hopper. and a second hopper for replenishing the developer, the first hopper has an extending portion that faces the entire length of the developer carrier and extends outside the range, and the second hopper is provided in the extended portion. In the developing device, the developer received from the second hopper is supplied to the developer carrier by the agitation conveyance means in the first hopper while uniformly sending it out within the range indicated by L within the first hopper. This is achieved by setting the agitation and conveyance force within the above range to be lower than the agitation and conveyance force in the extension section.

[Function] In the present invention as described above, the agitation and conveyance means has the original agitation and conveyance force in the extension region, and the agitation and conveyance force of the developer sleep in the area where the first hopper and the developing sleep are opposed to each other. Together with this, the original stirring and conveying force mentioned above is ensured. As a result, the stirring and conveying force becomes almost uniform throughout the entire area within the first hopper.

[Example] The present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIG. 3, the developing device according to the first embodiment of the present invention basically consists of a developing sleeve 1 which includes a plurality of fixed magnetic poles and is driven to rotate. A magnetic blade 2 for contacting the circumferential surface of the developing sleeve 1 along the axial direction to form a uniform thin layer of developer T on the surface of the developing sleeve. In order to agitate and transport the developer T in the first hopper 4 formed facing the developing sleeve, the stirring and transporting device has a plate-shaped blade 3 attached to a rotating shaft 7 extending in the longitudinal direction of the developer T. Consists of means.

FIG. 2 is a view of the apparatus shown in FIG. 3 from the photoreceptor side, and the first hopper 4 is formed to further extend in the longitudinal direction from a portion 4A facing the developing sleeve l. A second hopper 5 that can be connected to the second hopper 4 is provided on the L side of 4B. The developer T is supplied from the second hopper 5 to the extension portion 4B of the first hopper 4, and is roughly evenly distributed by the plate-shaped blade 3 in the first hopper 4, which rotates around the rotation shaft 7.
The developing sleeve is conveyed in the axial direction from the developing sleeve to the facing portion 4A. The developer T transported in this manner is supported on the surface of the developing sleeve l by the magnetic force formed on the developing sleeve l. The developer T on the developing sleeve 11 is coated with a thin layer evenly by the magnetic plate 1 and subjected to development. When the developer in the first hopper 4 is consumed to a predetermined amount or less, the developer amount detection element 6 attached to the end face of the extension part 4B of the first hopper 4 transfers the developer from the second hopper 5 to the first hopper. A signal for supplying developer to the second hopper 5 is sent to the second hopper 5. Thereby, the amount of developer in the first hopper 4 is always maintained at a predetermined value or more.

Next, the stirring and conveying means disposed within the first hopper will be explained. The stirring and conveying means in this example is shown in Figure 1 (Δ
), (B), an oval ring-shaped blade is attached to the shaft body 7 extending across the region I in the axial direction where the first hopper 4 and the developing sleeve 3 face each other, and the region II in the extension portion 4B. 3 is attached at an angle to the axis by an arm body 3A extending in the radial direction.

At this time, the blade 3 has a perfect circle when viewed from the axial direction. In the conventional device, the blades 3 are provided at equal intervals in the axial direction as shown in FIG. 6 over the area work and area II. As a result, as mentioned above, the area written in L ■
The agitation and conveyance force exceeded the required value, causing deterioration of the developer.

In this embodiment, as shown in FIG. 1(A), in the area rr'', blades are provided at intervals of 2 to reduce the required stirring and conveying force by 1, and in the area The blades are provided at a distance larger than 2 in L so that the necessary stirring and conveying force in L is achieved.To give a specific example, the length is 30 mm and Q2 is 20 mm. However, the agitation and conveyance amount of the developer in the area I and area II in the first hopper 4 became almost equal, and the developer no longer deteriorated.

Further, as shown in FIG. 4 as a second embodiment, the mounting intervals of the blades may be set at equal intervals without changing between the area work and area II, and a difference may be provided in the radius 1 (..., R2) of the blades.

That is, R, < R2 may be satisfied. As a specific example,
When R = 12 mm and R2 = 15+u+, the same results as in the first example were obtained.

Next, as shown in FIG. 5 as a third embodiment, the mounting angle of the blades to the axis is set to 00. You may change θ2 in the range of 00 to 90°. That is, 01>0□. Specifically, by setting θ1=60° and θ2=45°, results similar to those of the first example were obtained.

[Effects of the Invention] As explained above, the present invention reduces the amount of developer by making the agitation and conveyance force of the agitation and conveyance means in the first hopper relatively low compared to the portion not facing the developing sleeve. This prevents the occurrence of developer deterioration such as aggregation, making it possible to consistently obtain high-quality images.

[Brief explanation of the drawing]

Figure 1 (^) is a top view of the stirring conveyance stage in the first embodiment of the present invention, Figure 1 (R) is a side view of Figure 1 (A), and Figure 2 is the apparatus of the first embodiment. A partial cross-sectional front view of the
Figure 4: Enlarged longitudinal sectional view of the developing sleeve portion of the device.
Figure (A) is a front view of the agitation conveyance means of the second embodiment;
4(B) is a side view thereof, 5UA(A) is a front view of the stirring conveyance means of the third embodiment, and FIG. 5(B) is a side view thereof,
Figure 6 (A) is a front view of the agitation conveyance means of the conventional device;
Figure (B) is its side view. ■...Developer carrier (developing sleeve) 3...
...Agitation conveyance means (blade) 4...First hopper 4A...Extension portion 5...Second hopper T...Developer

Claims (1)

[Scope of Claims] A first hopper comprising a developer carrier, a first hopper that supplies developer to the circumferential surface of the developer carrier, and a second hopper that supplies developer to the first hopper. has an extending portion that faces over the entire length of the developer carrier and extends outside the range, and a second hopper is provided in the extended portion. In the developing device that supplies the developer received from the hopper to the developer carrier while uniformly sending it out within the above range in the first hopper, the agitation conveyance means has an agitation conveyance force within the above range and an agitation conveyance force at the extension part. A developing device characterized by being set lower than .