JPH0219166U

JPH0219166U -

Info

Publication number: JPH0219166U
Application number: JP12626488U
Authority: JP
Priority date: 1988-03-28
Filing date: 1988-09-29
Publication date: 1990-02-08

Description

[Brief explanation of drawings]

第１図は本考案に係る現像装置の一例を示す断
面図、第２図は現像スリーブ内のマグネツトによ
り形成される磁束密度分布を示す説明図、第３図
は別の実施例の現像装置の要部を示す断面図、第
４図及び第５図は現像スリーブ内のマグネツトに
より形成される磁束密度分布を示す説明図、第６
図はさらに別の実施例の現像装置を示す断面図、
第７図は同上実施例における現像スリーブ内のマ
グネツトにより形成される磁束密度分布を示す説
明図、第８図は従来の現像装置の一例を示す断面
図、第９図は同上現像装置における現像スリーブ
内のマグネツトにより形成される磁束密度分布を
示す説明図、第１０図はベタ画像にラジイドを生
じることを説明するための図、第１１図はネガ画
像にラジイドを生じることを説明するための図で
ある。１，１１……現像スリーブ、Ｂ，Ｃ……直線、
Ｍ……主極、Ｔ……搬送極、ＭＢ１，ＭＢ２……
磁気ブラシ、Ｏ……中心、θ……角度、Ｅ，Ｆ…
…線、Ｈ，Ｉ……交点、Ｏ_１……現像スリーブの
中心、Ｌ_１，Ｌ_２……直線、α……角度。 FIG. 1 is a sectional view showing an example of the developing device according to the present invention, FIG. 2 is an explanatory diagram showing the magnetic flux density distribution formed by the magnet in the developing sleeve, and FIG. 3 is a sectional view of the developing device of another embodiment. 4 and 5 are explanatory diagrams showing the magnetic flux density distribution formed by the magnet in the developing sleeve.
The figure is a sectional view showing a developing device of yet another embodiment.
FIG. 7 is an explanatory diagram showing the magnetic flux density distribution formed by the magnet in the developing sleeve in the above embodiment, FIG. 8 is a sectional view showing an example of a conventional developing device, and FIG. 9 is a developing sleeve in the same developing device. Fig. 10 is an explanatory diagram showing the magnetic flux density distribution formed by the magnet in the image, Fig. 10 is an illustration to explain that radicals occur in a solid image, and Fig. 11 is an illustration to explain that radicals occur in a negative image. It is. 1, 11...Developing sleeve, B, C...straight line,
M...Main pole, T...Carrier pole, MB1, MB2...
Magnetic brush, O...center, θ...angle, E, F...
... Line, H, I ... Intersection, O ₁ ... Center of developing sleeve, L ₁ , L ₂ ... Straight line, α ... Angle.

Claims

[Claims for Utility Model Registration] (1) A two-component developer disposed in a rotationally driven developing sleeve and used to visualize an electrostatic latent image formed on a latent image carrier. In a dry type developing device of an image forming apparatus, the dry type developing device of an image forming apparatus has a main pole for forming a magnetic brush on the developing sleeve, and a transport pole located downstream of the main pole with respect to the moving direction of the latent image carrier. A straight line passing through the center of the magnetic flux density distribution due to the main pole in the circumferential direction and the center of the developing sleeve, and a straight line passing through the developing sleeve portion showing the peak of the magnetic flux density distribution due to the transport pole in the circumferential direction of the developing sleeve and the center of the developing sleeve. A dry type developing device characterized in that the angle formed by the two is set to 25 degrees or less. 2. The dry developing device according to claim 1, further comprising contact prevention means for preventing the magnetic brush of the two-component developer formed by the transport pole from coming into contact with the latent image carrier. (3) A dry developing device according to claim 2, characterized in that a gap between the developing sleeve and the contact prevention means is set so that the magnetic brush of the two-component developer formed by the transport pole rubs against the contact prevention means. . (4) A magnetic brush of a two-component developer, which is disposed inside the rotationally driven developing sleeve and is used to visualize the electrostatic latent image formed on the latent image carrier, is placed on the developing sleeve. In the developing device of an image forming apparatus equipped with a main pole, the strength of the magnetic field in the normal direction of the developing sleeve due to the main pole is measured on the surface of the developing sleeve, and the value is expressed outward in the normal direction of the developing sleeve. Considering the magnetic flux density distribution shown above, among the intersections of the arc centered at the center of the developing sleeve and the lines on both sides of the magnetic flux density distribution, which pass through approximately 1/2 of the maximum value of the distribution, Dry development characterized in that the main pole is configured such that the angle formed by a straight line connecting one intersection point and the center of the developing sleeve and a straight line connecting the other intersection point and the center of the developing sleeve is 30 degrees or less. Device.