JPS6049372A - Developing device of copying machine - Google Patents

Abstract

PURPOSE:To improve the ability of a developing device in with mode to convey a developer by providing a magnet roll for developer conveyance between a developing roll and a paddle for supplying the developer thereto, and supplying the developer onto the developing roll. CONSTITUTION:The developer 3 scooped up with the paddle 4 is conveyed by the magnet roll 5 for developer conveyance to a magnet N3 positioned at the upper part of the back surface of an upper developing roll 2a, and then guided to magnets S2 and N2, and S1 and N1 provided to the upper developing roll 2a and magnets N2 and S2, N1 and S1, and N3 provided to a lower developing roll 2b, so that it falls between a photosensitive body 1 and the developing rolls 2a and 2b. Therefore, the back surface conveyance of the developer 3 by the developing rolls 2a and 2b is eliminated, and it is therefore unnecessary to arrange magnets on the back surface sides of the developing rolls 2a and 2b, i.e. between magnets N3 and N1 of the upper developing roll 2a and magnets N2 and N3 of the lower developing roll 2b.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a developing device for a copying machine, and particularly to a developing device that carries out development by conveying a developer while forming a magnetic brush on the surface of a developing roll. Regarding.

[Prior art]

Conventionally, in this type of developing device, as shown in FIGS. 1 and 2, the set position of the developing rolls (2a) and (2b) is at the 3 o'clock or 9 o'clock position with respect to the photoreceptor (1). , and the developing rolls (2a) and (2b) are connected to the photoreceptor (1
) A so-called with mode developing device is known, which performs development by rotating in the same direction as the image forming apparatus. In such a Wiz mode developing device, the flow (3a) of the developer (3) that is conveyed while forming a magnetic brush on the surface of the developing roll (za) (2b).
Since the direction of is the same as the rotational direction of the photoreceptor, there is less disturbance in the flow (8a) of the developer (3), and its conveyance is smoother. In addition to little deterioration of the developer, there is no development due to stains on the back surface, and it is also capable of uniformly reproducing wide-area images. 1. However, in this type of developing device, the paddle (4
) The developer (3) scooped up by the developer roll (2a
) (2b), goes around above the developing roll (2a) located above, and then descends between the photoreceptor (1) and the developing rolls (2a) and (2b). For this reason, the conveyance of the developer (3) is poor, and the developing roll (2a)
Selection of magnetic pole and magnetic force (2b) and two developing rolls (2a)
) (2b), it becomes difficult to select the roll interval. Moreover, since the developer (3) is conveyed from the rear side of the developing rolls (2a) and (2b), the number of red mats incorporated into the developing rolls (2a and 2b) increases. As shown, seven magnets are required for the upper developing roll (2a), and eight magnets are required for the lower developing roll (2b), which means that the developing roll has a larger diameter. (
2a) (2b) are required, and as a result, photoreceptor (1)
It was difficult to improve the developing performance by disposing a large number of developing rolls at the 3 o'clock or 9 o'clock position.

[Purpose of the invention]

Accordingly, an object of the present invention is to eliminate the need for rear conveyance of the developer on the developing roll in a Witzu mode developing device, reduce the number of magnets incorporated in the developing roll, and make the developing roll small in diameter, thereby increasing the It is an object of the present invention to provide a developing device for a copying machine in which a large number of developing rolls are arranged at the 8 o'clock or 9 o'clock position to improve developing performance.

[Structure of the invention]

That is, the present invention provides a developing device in which the developing roll is set at a special 3 o'clock or 9 o'clock position relative to the photoreceptor of a copying machine, and the developing roll rotates in the same direction as the photoreceptor to perform development. A magnetic roll for transporting the developer is provided between the developing roll and the paddle that scoops up the developer and supplies it to the developing roll, and the developer supplied from the paddle is supplied to the upper part of the developing roll by this Madai Tsutrol. This is a developing device. This developing device (according to 2)
Since the magnet roll transports the developer to the upper part of the developing roll, it is possible to eliminate the back transport of the developing roll, and also to omit the magnet on the back side of the developing roll.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The developing device of the present invention will be specifically described below based on embodiments shown in accompanying drawings.

3 and 4, a developing device according to an embodiment of the present invention is shown. The tax source device shown in this embodiment has a photoreceptor (1) similar to the conventional developing device shown in FIG.
There is a pair of upper and lower developer rolls (z
a, ) (2b) are arranged, and these developing rolls (2a) and (2b) both rotate in the same direction as the photoreceptor (1), and the developer (3) is transferred to the upper developing roll (2a). ) and the photoconductor (1) and each developing roll (2).
a) (2b) between these developing rolls (2a) (2b).
In the so-called with mode, development is performed by descending while forming a magnetic blank on the surface of b).
), and the upper developing roll (
2a) and developer (3) and place them on each developing roll (2).
Between the paddle (4) that supplies the paddle (2b) to a), there is a magnetic roll for conveying the developer that conveys the developer (3) scooped up by the paddle (4) to the upper part of the upper developing roll (2a). (5) is provided.

In this embodiment, as shown in FIG. 4, the magnets incorporated in each of the developing rolls (2a) and (2b) are located at the upper rear side of the developer transporting magnet roll (5) for the upper developing roll (2a). 5 in the order of N3 → S2 → N2 → 31-+N from the front lower part of the photoreceptor (1) side.
The lower developing roll (zb) +
Regarding the second, five wires are arranged in the order of N2→S2→N1→84-+N3 from the upper front surface to the lower front surface on the photoreceptor (1) side.

Then, the developer (3) scooped up by the paddle (4) is transferred to the developer conveying Madai roll (
5) to the red sea bream N3 located on the upper back side of the upper developing roll (2a), and then each red sea bream N2 provided on the upper developing roll (2a). N2
゜Sl, N1 and valley magnet N21 provided on the lower developing roll (2b) S21 N1+ S1+ N3
The photoreceptor (1) and each developing roll (2a) (2
b) descend between

Therefore, according to this embodiment, as is clear from a comparison between FIG. 1 and FIG. As is clear from the comparison between and Fig. 4, each developing roll (
2a) Magnets N3 and N on the back side of (2b), that is, on the upper developing roll (2a) in FIG.
1 and in the lower developing roll (2b)) It is no longer necessary to install a magnet between N2 and N3, and it is no longer necessary to install a magnet between N2 and N3. The number decreases.

〔Effect of the invention〕

As described above, the developing device of the present invention (according to 2), between the developing roll and the paddle that supplies developer to this developing roll (2), a magnetic roll for conveying developer is provided to supply the developer to the upper part of the developing roll. This eliminates the need for the developer to be transported from the back of the developing roll, which improves the developer transportability.Also, since the developer no longer needs to be transported from the back of the developing roll, the developer does not need to be transported from the back of the developing roll. There is no need to install a magnet on the back side of the
By designing the diameter of the developing roll to be small, it is possible to arrange as many as 8 to 5 developing rolls at the 8 o'clock or 9 o'clock position of the photoconductor, and it is possible to improve the developing performance. , it is possible to eliminate the drawbacks in Wiz mode development.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing a conventional developing device, FIG. 2 is an explanatory view showing the arrangement of magnets in each developing roll (-) in FIG. 1, and FIGS. 1 and 2 showing such a developing device.
...Development roll (3) ...Developer (4) ...
・・・Paddle (5)・・・Madai・ttororuj acid for conveying developer? ! )≦j Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] The setting position of the developing roll relative to the photoreceptor is clock 0')8
In a developing device of a copying machine in which the developing roll rotates in the same direction as the photoconductor to perform development, the developing roll is positioned between the developing roll and a paddle that scoops up developer and supplies it to the developing roll. 1. A developing device for a copying machine, characterized in that a magnetic roll for conveying developer is provided, and the magnetic roll supplies developer supplied from a paddle to an upper part of the developing roll.