JPS5952266A - Electrophotographic developing device - Google Patents

Abstract

PURPOSE:To eliminate the clogging of foreign matter and a large body, to adjust the thickness of toner, and to obtain a uniform, clear picture, by fitting a toner- layer specifying blade with a slit to a developing sleeve at a specific angle. CONSTITUTION:When a photosensitive drum 4 and a magnet roll 3 are rotated clockwise and the developing sleeve 2 is rotated counter-clockwise, the toner 5 rotates counterclockwise on the whole. Then, the layer of the toner 5 is raised by rhe specifying blade 6 fitted tightly onto the sleeve 2 and only a specific amount of the toner passes through the slit 6a and is conveyed again onto the sleeve 2 by the magnetic attracting force of the roll 3. This passing amount of the toner is suppressed even when the width W of the slit 6a is large by setting the angle theta between the sleeve 2 and blade 6 to >=90 deg. and increasing the height (h) from the sleeve 2 to the slit 6a, and uniform development is performed on the sleeve 2.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electrophotographic developing device.

Conventional Structure and Problems Conventionally, magnetic toner developing devices have a regulating blade 1 and a developing device, as shown in FIG. The sleeves 2 were installed with a certain gap G1 between them. As shown in FIG. 1, when the photoreceptor drums 2 and 4 and the magnet row 3 rotate clockwise and the developing sleeve rotates counterclockwise, the toner 5 rotates counterclockwise and is regulated. Blade 1 gap G1
The electrostatic latent image is conveyed to the photoreceptor and developed.

In a developing device using an iron powder carrier with strong magnetism and large particle size, such as a two-component developing method, the gap G1 and the distance G2 between the photosensitive drum 4 and the developing sleeve 2 are relatively wide, ranging from 5 to 101B. However, recently, in order to improve image quality in component development methods and two-component development methods, microcarriers with fine particle diameters and resin carriers have been used, and the gap G
1 and spacing G2 have begun to be used in very narrow gaps of 1 wL or less. As a result, foreign matter and coarse matter, which have not been a problem in the past, have become stuck between the regulating blade 1 and the developing sleeve 2, causing a serious problem in that uniform images cannot be obtained, such as white streaks appearing on copies.

OBJECTS OF THE INVENTION The present invention obviates these conventional drawbacks.
Therefore, an electrophotographic developing device capable of obtaining uniform and clear images is provided.

Structure of the Invention In order to achieve the above object, the present invention provides a rotatable developing sleeve having a built-in rotatable magnet roll, and a lower end of a regulating blade provided with a slit hole as a regulating blade for regulating one layer of toner. The sleeve is attached in close contact with the sleeve, and the angle between the sleeve and the tangent is 90 degrees or more with respect to the toner traveling direction, and can be arbitrarily set.

With this configuration, a layer of toner blocked by the regulating blade that is in close contact with the developing sleeve is pushed upward. A certain amount of the pushed up toner passes through the slit of the regulating blade and is conveyed to the developing sleeve again. Even if the slit width is set larger than the conventional gap between the developing sleeve and the regulating blade, the amount of toner conveyed can be controlled if the angle formed by the tangent at the point of contact between the developing sleeve and the regulating blade approaches 90 degrees. Clogging caused by foreign matter or coarse matter is resolved, and uniform development becomes possible.

DESCRIPTION OF THE EMBODIMENTS An electrophotographic developing apparatus according to an embodiment of the present invention will now be described with reference to FIGS. 2, 3, and 4. The numbers in FIGS. 2 and 3 are the same as those in FIG. 1 for the same parts.

As shown in Figure 2, photosensitive drum 4, magnet row)
When V3 is rotated clockwise and the developing sleeve 2 is rotated counterclockwise, the toner 5 as a whole rotates counterclockwise. This layer of toner 5 is blocked by a regulation blade 6 that is in close contact with the top of the developing sleeve 2 and pushed up toward the top of the developing sleeve 2. The pushed-up 1-ner 6 moves as shown in Fig. 3, passes through the sleeve 6a by a certain amount, and is brought back onto the developing sleeve 2 by the magnetic attraction force of the magnet low/l/3. transported. The amount of toner 5 passing through the slit 6a is determined by the width W1 of the slit 6a.
5 1i-5 from developing sleeve 2 to slit 6a
, - Height h, and angle θ between the developing nulieve 2 and the regulating blade can be arbitrarily controlled. For example, even if the width W of the slit 6a is large, the amount of toner 5 passing through the slit can be reduced by setting the angle θ close to 90 degrees (but larger than 90 degrees) and making h large. That is, as h increases, the potential increases, and as θ approaches 90 degrees, the magnetic attraction force decreases, and the amount of toner 5 passing through the slit 61L decreases.

If θ is less than 90 degrees, the toner 5 will no longer pass through the slits 6&, making development impossible.

Therefore, in the regulating blade 6 according to the present invention, it is possible to increase the width W of the sleeve 81L corresponding to the conventional 01, and it is possible to solve the problem of blade clogging caused by foreign matter or coarse matter. However, if there is a foreign object or large object with the same size as the width W of the sleeve 1-6a, clogging may occur, but since the toner 5 moves as shown in Figure 3, clogging is relatively unlikely. . Compared to the conventional method, which passes through the developing sleeve 2 continuously even if it becomes clogged,
The height of sin θ6 7" is spread evenly while being conveyed onto the developing cleave 2 again by magnetic attraction, so that uniform development is performed and a clear image is obtained. This regulation grade 6 It is also possible to attach it to the lower part of the developing Nureve 2 depending on the direction of movement, and the shape of the slit 6a is not only a rectangle as shown in FIG. 2 but also a polygon as shown in FIGS. 4(a) to (C). You can make several to dozens of them.

Effects of the Invention As described above, the present invention provides a method in which the lower end of the regulating blade provided with a slit is attached to the developing sleeve in close contact with the developing sleeve, and the regulating blade is placed at any angle of 9 degrees or more relative to the toner traveling direction. By configuring the angle to be settable, foreign objects and coarse objects do not get stuck between the regulating blade and the developing roller, and the thickness of the toner can be adjusted, making it possible to obtain uniform and clear images.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the basic structure of a conventional electrophotographic developing device, and FIG. 2 is a perspective view showing the basic structure of an electrophotographic developing device according to an embodiment of the present invention. FIG. 3 is a partially sectional side view showing a conceptual diagram of the movement of toner in the same device, and FIGS. 4(a) to (C) are front views showing other examples of the developing blade of the same device. 2...Rotating sleeve, 3...Magnet roll, 5...Toner, 6...Regulation blade, 6a...Nurisoto. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] The rotatable device is mounted on a rotatable developing sleeve with a built-in magnetic roll, and the lower end of a regulation blade provided with a slit hole for regulating the thickness of the toner layer is attached in close contact with the developing sleeve, and the tangential line of the developing sleeve is An electrophotographic developing device in which an angle formed by the toner can be arbitrarily set at 90 degrees or more with respect to the toner traveling direction.