JPH0442262A - Developing device for electrophotographic device - Google Patents

Abstract

PURPOSE:To stop the transportation of a developer from the sleeve surface of a magnet roll and to detach the developer from a photosensitive body by disposing one magnetic pole in the magnet roll and a member for suppressing the amt. of the developer to be transported in the positions where both face each other and in the relative positional relation thereof. CONSTITUTION:The stationary magnetic pole in the magnet roll 2 is rotationally moved via a link by the excitation of a solenoid 9 and the N3 magnetic pole 4 is so positioned as to come to the position where the magnetic pole nearly faces a regulating member 5 at the time of non-development. The developer 7 in this state cannot pass the gap between the front end of the regulating member 5 and a sleeve 6. The developer 7 sticking to the sleeve 6 surface of the magnet roll 2 is easily removed in this way to prevent the contact of the photosensitive body 8 and the developer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a developing device in an electrophotographic apparatus.

[Background of the idea]

Conventionally, when performing two-color or multicolor printing, in order to prevent color mixture from occurring due to contact between the developer and the photoreceptor, the developing device itself was moved away from the photoreceptor, and a magnetic roll that controlled development was used. Efforts were made to prevent the developer from coming into contact with the photoreceptor. However, in this prior art, in order to move the developing device itself, the developing device and the main body of the electrophotographic apparatus must have a moving mechanism, which makes the developing device complicated and increases cost.

Furthermore, it is difficult to reproduce the precision of the gap between the photoreceptor and the roll between the magnet 1 during printing, and there is a problem that the stability of printing quality deteriorates.

[Purpose of invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to easily remove the developer adhering to the sleeve surface of the magnetic roll, thereby preventing contact between the photoreceptor and the developer.

[Summary of the idea]

In this invention, in a magnet roll having a rotating sleeve and a fixed magnetic pole inside the sleeve, the magnetic field of the developer on the sleeve facing the magnetic pole is directed in the normal direction of the sleeve, and Focusing on the formation of a magnetic brush, the present invention is devised to stop the flow of developer by arranging a restraining member at a position facing the magnetic brush portion.

[Example of idea]

Specific examples according to the present invention are shown in FIGS. 1, 2, and 3. Normally, when developing a photoconductor, as shown in FIG. is located approximately at the center of the two poles in the circumferential direction. In this state, the flow rate of the developer 7 on the rotating sleeve 6 is adjusted in the gap between the tip of the regulating member 5 and the sleeve 6, and the required amount of developer 7 is distributed between the photoreceptor 8 and the sleeve 6. is transported and contributes to development.

During non-development, as shown in FIG. 2, the fixed magnetic pole inside the magnetic screw 1-○-2 is rotated via the link by the excitation of the solenoid 9, so that the N3 magnetic pole 4 comes to a position almost opposite the regulating member 5. become.

In this state, the developer 7 cannot pass through the gap between the tip of the regulating member 5 and the sleeve 6. In FIG. 3, the above-mentioned developing machine 1 is designated as A developing machine 10, and the developing machine for developing 1 hener of a different color from A developing machine 10 is designated as B developing machine 11. The N3 magnetic pole 4 inside the magnetic screw 1-roll 2 of the A developing machine 10 is rotated by the above-described mechanism to a position almost facing the regulating member 5, and the developer 7 is not conveyed on the sleeve 6 and comes into contact with the photoreceptor 8. At this time, development is performed in the B developing machine 11 and color mixing in the A developing machine 10 can be prevented. Furthermore, when developing with the A developing machine 10, the above-mentioned mechanism is used to convey the developer on the sleeve of the A developing machine 10 in reverse, and eliminate the developer on the sleeve of the B developing machine 11. By doing this, it is possible to prevent the mixing of two colors.

Another embodiment according to the present invention is shown in Fig. 4.5.6. 1st
In the embodiment shown in FIG. 4, the fixed magnetic pole in the magnet roll 2 is rotated to move the N3 magnetic pole 4 to the position facing the regulating member 5, whereas the regulating member 5 is moved as shown in FIG. Similar effects can be obtained even if the magnetic pole 4 and the regulating member 5 are arranged to face each other. As shown in FIG. 5, the member 12 for suppressing the flow of developer is installed separately from the developing member 5. When stopping the flow of developer, the member 12 for suppressing the flow of developer is
A similar effect can be obtained even if the structure moves to a position facing the magnetic pole 4.

In addition, in the first embodiment, Agnet 1-Role 2
Although the fixed magnetic poles inside are rotated integrally by the solenoid 9, the same effect can be obtained even if the structure is such that only the N3 magnetic pole near the regulating member 5 is moved and facing the regulating member 5 as shown in Fig. 6. .

[Effect of idea]

According to the present invention, one magnetic pole inside the magnetic screw 1 roll and the member for suppressing the amount of developer to be conveyed are arranged in opposing positions in the relative positional relationship, thereby allowing the developer to be conveyed from the sleeve surface of the magnetic roll. Since the developer can be separated from the stopper photoreceptor, color mixing can be prevented during development in two-color or multi-color printing. Furthermore, compared to the prior art, there is no need to slide the developing device itself, and the structure of the developing device can be simplified and the cost can be reduced. Furthermore, the gap between the developing device and the photosensitive drum can be kept constant without changing due to movement of the developing device, and stable printing can be performed.

[Brief explanation of drawings]

Figures 1 and 2.3 are cross-sectional views showing one embodiment of the developing device according to the present invention. Figure 1 is for development, Figure 2 is for non-development, and Figure 3 is for two-color development. This shows the relationship between development conditions. 4.5.6 is a sectional view showing another embodiment of the developing device according to the present invention. In the figure, 1 is a developing machine, 2 is a magnetic roll, and 3 is a developing machine.
is a magnetic pole (S), 4 is a magnetic pole (N), 5 is a regulating member, 6 is a sleeve, 7 is a developer, 8 is a photoreceptor, 9 is a solenoid, 1
0 indicates developing machine A, 11 indicates developing machine B, and 12 indicates a restraining member. Name of applicant for utility model registration Hitachi Koki Co., Ltd. Figure 13, Figure 14, Figure 10

Claims (1)

[Scope of Claims] 1. A developing device for an electrophotographic device having a sleeve that rotates inside the developing device and a magnet roll having a fixed magnetic pole that does not rotate inside the sleeve and forming a magnetic brush, The magnetic poles inside the magnet roll and the developer suppressing member are small so that the magnetic poles inside the magnet roll and the developer suppressing member flowing on the rotating sleeve on the outer periphery of the magnet roll can be arranged in a positional relationship that substantially opposes each other. A developing device for an electrophotographic apparatus, characterized in that at least one side of the developing device is movable. 2. The regulating member is disposed between two magnetic poles inside the magnet roll in the upper circumferential direction of the sleeve of the magnet roll during development, and when stopping development, the inhibiting member is sandwiched in the sleeve circumferential direction. 2. The developing device for an electrophotographic apparatus according to claim 1, wherein the developing device is movably disposed near one position facing one of the magnetic poles. 3. Claim 2 characterized by having means for rotationally moving a magnetic pole inside the magnet roll when stopping development and arranging this magnetic pole near a position facing the restraining member.
A developing device in the electrophotographic apparatus described above. 4. The developing device for an electrophotographic apparatus according to claim 1, wherein the restraining member also serves as a regulating member that regulates the developer flowing on the magnet roll.