JPH0389282A - Developing device - Google Patents

Abstract

PURPOSE:To prevent developer from blown down and to prevent the developer from accumulation by neighboring a terminal wall plane confronting with a developing sleeve to the developing sleeve, and separating a carrier pole confronting wall plane from the developing sleeve. CONSTITUTION:The terminal wall plane 13a confronting with the developing sleeve 3 of a developing casing terminal 13 between the main pole N1 of a developing aperture part (c) and a carrier pole S2 neighboring to the main pole N1 is comparatively neighbored to the sleeve 3. Also, a recessed part is formed on the carrier pole confronting wall plane 13b confronted with the pole S2 adjacently to the wall plane 13a, which is comparatively separated from the developing sleeve 3. The shape of the wall plane following from the wall plane 13a to the plane 13b is formed in the one almost fitted in the crest shape of the developer formed extending from the pole N1 to the pole S2. Therefore, even when a difference between the pressure inside and outside a developing device is generated by the fast rotation of the sleeve 3, the blow down of the developer can be prevented from occurring. Also, it is possible to prevent the developer whose crest is cut, accumulating and forming a lump.

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an improvement of a developing device used in an image forming device such as a copying machine or a laser beam printer, and in particular to a 3JI which eliminates the problem of developer blowing out from the developing device due to high-speed rotation of a developing sleeve. The invention relates to an imaging device.

[Prior art]

FIG. 2 is a front cross-sectional view showing a developing device used in the above-mentioned image forming apparatus, especially a fundoshi copying machine.As shown in FIG. A developing sleeve 3 made of an aluminum cylinder or the like (the direction of rotation is indicated by an arrow , and a magnetic permeability sensor 5a that is fixedly provided in the vicinity of the developing sleeve 3. Here, Nl, S2°, N3.
S4. S3. N2 and 31 respectively indicate the polarity and center of the magnet attached to the magnet holding member, N1 is the main pole, 52. N3. S4 is a transport pole, S3 is a developer stripping pole, and N2 and 31 are pumping poles. The magnetic permeability sensor 5a is provided on the ear cutting board. Further, a guide plate 7 facing the magnetic permeability sensor 5a is for guiding the cut developer on the front end side, and rectifies Fi, 8.
8. It is integrally formed with the return plate 9 that includes... The baffle plate 8 is mounted on the return plate 9 at a slight angle with respect to the plane of the figure in order to deflect the developer returned from the guide plate 7 in the axial direction of the developing sleeve 3. The developer returned by the return plate 9 is transferred to the stirring roller 1.
0 and returned to the developing sleeve 3 by the conveying roller (1). Such a stirring roller 10. tl
) The feed roller (1) constitutes the agent supply means. The titration element of the developing device 1a as described above is surrounded by the developing casing 12. However, the above developer casing 12
is a developing opening C in a portion corresponding to the main pole and its vicinity.
is formed. [Problems to be Solved by the Invention] In the conventional developing casing 12 as described above, when the developing sleeve 3 rotates at high speed in the direction of arrow There is a problem in that the developer blows out from the gap between the developing casing 12 and the opposing developing casing 12. Japanese Patent Publication No. 58-1639
The dry developing device described in Japanese Patent No. 69 is intended to solve this problem, and an elastic sealing member made of urethane foam or the like is attached to the developer blowing portion. However, according to the inventor's experiments, it was not possible to avoid the drawback that the sealing member as described above has the problem that the developer adheres to and accumulates in the sealing member, and that the developer sometimes forms a lump and squirts out to the outside. Therefore, it is an object of the present invention to provide a structure of a developer casing that eliminates the above-mentioned blow-out of developer and at the same time prevents accumulation of developer. [Means for Solving the Problems] In order to achieve the above object, the present invention includes a main pole that is provided adjacent to a photoconductor and faces at least the photoconductor, and a transport pole that is adjacent to this main pole. A magnet holding member that is fixedly held, a developing sleeve that rotates around the magnet holding member, an agent supply means that supplies ylA developer to the developing sleeve, and a developing opening that corresponds to the main pole and its vicinity. In a developing device comprising at least the developing sleeve and a developing casing that encloses the agent supplying means, the developing device is provided with a developing device between the main pole of the developing opening and the transport pole adjacent to the main pole. The end wall surface of the casing end facing the developing sleeve is brought relatively close to the developing sleeve, and a recess is formed in the transport pole facing wall surface adjacent to the end wall surface and opposite to the transport pole to separate the developing sleeve from the developing sleeve. tIll is a developing device characterized by being relatively isolated.
It has been a. [Effect]. Therefore, the shape of the end of the developer opening of the developer casing follows the shape of the developer attached to the developer sleeve in this area, and since it is entirely formed of a part of the developer casing, the developer does not accumulate. This method does not cause any problems, and at the same time, no developer blows out. (Example) Next, examples embodying the present invention will be described to provide an understanding of the present invention. FIG. 1 is a front sectional view showing a developing device according to an embodiment of the present invention. In addition, the following example is only an example of embodying the present invention,
The same reference numerals are used for elements that are not intended to limit the technical scope of the present invention and are common to elements constituting the conventional developing device shown in FIG. 2, and their explanations will be omitted. The embodiment shown in 1vlJ is different from the conventional example shown in FIG. The end wall surface 13a of the end portion 13 facing the 1Jl image sleeve is brought relatively close to the developing sleeve 3 (the gap is narrowed), and the transport surface is adjacent to the end wall surface 13a and faces the transport pole S2. 0, which is a point where a recess is formed in the polar opposite wall surface 13b and is relatively isolated from the developing sleeve 3.
Although the recess shown in the figure is stepped, it may also be formed into a smooth recess.
The shape of the wall surface continuing from the transport pole opposing surface 13b is the main pole N1.
The shape almost matches the spike shape of the developer formed from the top to the transport pole S2. That is, the developer stands up in the largest spikes at the main pole N1, becomes flattened once from the main pole to the transport pole, and then stands up again in large spikes at the transport pole S, so that the above-mentioned gap is The width is matched to the spike shape of the developer. Therefore, by rotating the developing sleeve 3 at high speed,
Even if there is a difference in pressure between the inside and outside of the developing device, since the end wall surface 13a of the gap is narrow, the problem of developer blowing out from this portion is eliminated. Also,
Since the wall surface 13a13b is formed to approximate the shape of spikes of developer and is formed integrally with the developer casing 13, there is no problem that the spiked developer accumulates and forms a lump. [Effects of the Invention] Since the present invention is configured as described above, the problem of developer blowing out from the developing device is solved, and the inconvenience caused by developer accumulation is also solved at the same time.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a developing device according to an embodiment of the present invention, and FIG. 2 is a view corresponding to FIG. 1 showing a conventional developing device. [Explanation of symbols] ■...Developing device 3...Developing sleeve 4.
... Magnet holding member 5 ... Magnetic permeability sensor 6 ...
Ear cutting board 7... Guide plate 12... Developing casing 13... Opening end 13a... End wall surface 13b... Wall surface opposite transport pole

Claims (1)

[Claims] (1) A magnet holding member provided adjacent to the photoreceptor and fixedly holding at least a main pole facing the photoreceptor and a transport pole adjacent to the main pole; a rotating developing sleeve; a developer supplying means for supplying developer to the developing sleeve; and a developing casing surrounding the developing sleeve and the developer supplying means except for the main pole and the developing opening corresponding to the vicinity thereof. A developing device comprising: an end wall surface facing the developing sleeve at an end between the main pole of the developing opening and a transport pole adjacent to the main pole is brought relatively close to the developing sleeve; The developing device is further characterized in that a recess is formed in a wall surface facing the transport pole adjacent to the end wall surface and facing the transport pole so as to be relatively isolated from the developing sleeve.