JPS5821278A - Developing device using magnetic brush - Google Patents

Abstract

PURPOSE:To eliminate the need for fine adjustment of the clearance between a doctor blade and a non-magnetic sleeve by providing a stripping part and regulating holes for the developer to the doctor blade. CONSTITUTION:A stripping part 17a provided in the leading end part of a doctor blade 17 abuts on a non-magnetic sleeve 14 and strips a magnetic toner 15. Plural regulating holes 19 for regulating the rate of passage of the dammed up toner 15 are punched to the part 17a in the leading end part of the blade 17. If the number and sizes of the regulating holes are suitably selected by using the doctor blade formed in such a way, the amt. of the magnetic toner conveyed on a sleeve 13 is made uniform. Thus the need for fine adjustment of the clearance between the doctor blade and the non-magnetic sleeve is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic brush driving device used for developing an electrostatic latent image.

In recent years, image forming apparatuses using component magnetic developers (hereinafter also referred to as magnetic toners) have come close to being practically comparable to conventional so-called two-component magnetic developers. 0
However, there are still many technical problems remaining in the -component system 40, especially the equipment related to the developing and imaging system. It is necessary to ensure and maintain a high level of accuracy on the order of 100 to 1,000 parts, which makes adjustment difficult and poses a major obstacle to stabilizing quality. For example, J11
Taking as an example a general magnetic brush braking device as shown in the figure, a main body 6 includes a columnar magnetism generating means (hereinafter also referred to as a magnet roll) 1 having a plurality of magnetic poles, and a magnetic brush f'Lt- It includes at least a non-magnetic sleeve 2 that surrounds and rotates, and a doctor blade 4 that is provided opposite to the doctor blade 4. However, since the gap between the non-magnetic sleeve 2 and the doctor blade 4 provided opposite thereto is normally used between a2 and aSm0, The gap is small, and as shown by the arrow in the middle, foreign matter such as magnetic toner gets stuck in the gap, cutting off the conveyance of the magnetic toner 30 that follows, resulting in color streaks and poor image quality.・Also, the tolerance of this gap is ±103~a0
1■ It required a range S, required accuracy of 0%O, and had many drawbacks such as being troublesome to manufacture. Adjustment of mold between doctor blade and non-magnetic sleeve
There is no need to do this at all, and the accuracy tolerance of the doctor blade tip is reduced, and the amount of magnetic toner conveyed can be adjusted accurately without any jig by simply replacing the doctor blade with a doctor blade with a different regulation hole size. It is an object of the present invention to provide a magnetic push developing device which is extremely simple in construction, and which facilitates the supply of highly reliable %A products at low cost.

This invention will be explained with reference to an embodiment shown in the drawings.

FIG. 2 is a sectional view showing an embodiment of the magnetic push developing device of the present invention, and FIG. II3 is a perspective view showing a part of the doctor blade. In each 111, 10 is a magnetic brush developing device, and this magnetic push developing device 10 is arranged at a position adjacent to a photoreceptor 11 made of selenium or the like.

At the lower opening of the main body 12 of the magnetic brush developing device 10, a cylindrical magnetism generating means having a plurality of magnetic poles, such as a magnet ring 13, is configured to be rotated in the direction of arrow A by appropriate means. . A non-magnetic sleeve 14 is arranged to surround the outer periphery of the magnet rail 15. This non-magnetic sleeve 14 is configured to be rotatable in the direction of arrow B by appropriate means so as to convey the magnetic toner disposed on the non-magnetic sleeve 14 to the current area of the first photoreceptor 11. A doctor blade 17 is attached to the outlet 11 of the magnetic toner 15 storage l116 of the main body 12 with a screw or other fixing ^18.
The doctor blade 170 is made of aluminum, brass, etc.
The peeling 1117g at the tip of the doctor blade 17 is marked on the non-magnetic sleeve 14 so that the magnetic toner 15 can be peeled off. A plurality of regulation holes 19 are drilled to regulate the amount of water passing through. The regulating holes 19 of the doctor blade 17 are arranged in a line in the axial direction KG of the non-magnetic sleeve 14 as shown in Figure 3. In this case, the regulation hole 19 of this doctor blade 15
After passing through zero, the magnetic toner 15 causes unevenness in am, but in order to reduce am and rt, the positions of the regulating holes 19 are shifted and arranged in two rows as shown in FIG. Good too. Furthermore, these multiple OJL holes 19
is the 6th wj! As shown in A, the area of the exit part of the magnetic toner 154D is larger than the area of the entrance part. This is a rounding to prevent the magnetic toner 150 passing through the regulation hole 19 from clogging. ◎Furthermore, the doctor blade 17 (D peeling part 17gtfj14 as shown in figure 10
0 to 200 pmOv 1. CNT non-magnetic sleeve 14 may be configured to be marked with lines. With this configuration, the occurrence of scratches on non-magnetic sleeve 14D can be further prevented. Regulation of the doctor blade 17 'Where is hole 1.9? Although it is preferable to provide the control holes 19 in the spike area of the Dunnett roll 13-, this is not strictly determined and may be provided at an appropriate position.The size, arrangement, etc. of the regulation holes 19 are
It is determined as appropriate depending on conditions such as the magnetic toner 15 to be used, the magnetic pole and rotation speed of the magnet roll 13, and the rotation speed of the non-magnetic sleeve 140. For example, the photoreceptor 11
When I is α4■ between and non-magnetic spring 9-14 #1
In order to develop a latent image of 1000 ports, the regulation holes 19 for K are t5-long, and 0-value holes are provided at 4-5-inch intervals. The Dunnett lock 13 uses a 10-pole tube with a magnetic force of 750 gauss on a non-magnetic sleeve 14, rotates at a rotation speed of 11,000 RP, and has a diameter of ! 11■ Non-magnetic sleeve 141
Rotating at 200 RPM gave a suitable result.K1117m is a schematic lK@ diagram showing the operating condition II of the magnetic toner, and this is the regulating hole 1? The magnetic toner 15 that has passed through the t
As the thickness increases, the thickness becomes uniform, and if the thickness is set at 011 minutes as a strong area, a smooth and smooth development result can be obtained.

It should be noted that the above embodiments are merely examples, and it goes without saying that each member can be replaced with another member having the IIIp4-o function.

Since this invention is constructed as described above, there is no need to fine-tune the gap between the doctor blade and the non-magnetic sleeve, and the accuracy tolerance of the tip of the doctor grade is reduced, and the size of the regulating hole can be reduced. By simply replacing the doctor blade with a new one, you can accurately adjust the amount of magnetic toner conveyed without a jig, and the diameter of the multiple regulating holes can be made larger than the gap between the doctor blade and the non-magnetic sleeve. Therefore, the probability of clogging with foreign matter such as fixed magnetic toner can be reduced.

In addition, it has excellent effects such as being extremely simple in structure and capable of supplying products with high reliability and performance at low cost.

[Brief explanation of the drawing]

3111 is a sectional view showing an example of a conventional magnetic push developing device, FIG. 2 is a sectional view showing an embodiment of the magnetic push developing device of the present invention, and FIG. 3 is a perspective view showing a part of a doctor blade. Figure 4 is a sectional view showing another example of doctor grade, JIIs figure is a partial perspective view showing still another example of doctor grade, 1m6 figure is a sectional view showing still another example, FIG. 2 is an explanatory diagram showing the working state of the magnetic brush developing device of the present invention. DESCRIPTION OF SYMBOLS 1... Cylindrical magnetism generating means, 2... Non-magnetic sleeve, 93... Magnetic developer, 4... Doctor grade, 5... Photoreceptor. 170 19I7

Claims (1)

[Scope of Claims] 11) A magnetic brush developing device having a cylindrical magnetism generating means and a non-magnetic sleeve surrounding the magnetic field, at least one of which is rotatably provided. The developer is conveyed on the non-magnetic sleeve as it rotates [
#A magnetic push developing device characterized by disposing a doctor blade having a peeling portion for peeling off the magnetic sleeve from above and a plurality of regulating holes for allowing a predetermined amount of developer to pass through. (2) The strip of the doctor blade that contacts the non-magnetic sleeve is made of a material with lower hardness than the non-magnetic sleeve.
The magnetic brush developing device according to claim 1, which produces one image. (3) The # regulation hole is formed so that the area of the mouth part is larger than the area of the entrance part of the developer. The one-shot brush according to claim 1 or 1I21, characterized in that the brush is arranged so as to form a magnetic brush of uniform thickness, my device 0