JPS59154474A - Developing device - Google Patents

Abstract

PURPOSE:To maintain the quality of copy high and stable by providing a developer uniforming member having a magnetic force generating member along the surface of a developer carrier and off from the surface of the developer carrier and thereby forming a uniform layer of developer. CONSTITUTION:The uniforming member 8 consists of a nonmagnetic cover 8A that faces peripheral face of a sleeve 3 and a magnet 8M. The cover 8A is not ferromagnetic, and the magnet 8M is a fixed magnet provided on the opposite side of the side in which the cover 8A faces the sleeve 3, and the magnetic pole faces the sleeve 3. Magnetic developer D that passes the area of the uniforming member 8 is disturbed by interaction of magnetic field formed by a magnetic roll 4 and magnetic field formed by the uniforming member 8. Further, the developer is moved laterally by pressing force of succeeding magnetic developer D carried out from a controlling plate 7. Thus, distribution of thickness of magnetic developer on the sleeve 3 is made uniform and used to develop electrostatic latent image on the photosensitive drum. By this way, problem of clogging can be evaded and stable pictures can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a parent image device that develops an electrostatic latent image formed on an electrostatic image carrier using a magnetic developer.

Conventional technology In a developing device using a magnetic powder developer, for example, a developing device for an electrophotographic close-up photocopying machine using a dry tool method, a thin developer layer is formed on a developer conveying member (developing sleeve). death,
This developer layer is conveyed to a developing area to develop an electrostatic latent mark formed on an electrostatic image carrier (for example, a photoreceptor drum).

In particular, when developing with a two-component developer using -component magnetic toner or a micro-gear, there is a spike regulating plate that regulates the thickness of the developer layer, and a spike regulating plate that closely opposes the regulating plate and The distance between the developing sleeve, which is generally non-magnetic and which carries the developer, is approximately 0.2 to 1.0 mm. It is necessary to maintain a minute gap of OT+M.

Since this gap is minute, small aggregates and foreign matter such as paper powder, etc., may occur in the developer passing through this gap.
If dust, lint, etc. are present, they will clog the gap between the regulating plate and the developing sleeve, causing so-called clogging, and this clogging will impede the conveyance of the developer. There will be areas where there is no developer or areas where the developer is thin compared to other areas, so if you develop in this state, the image will be white or thin by +%rlj. This has the drawback that so-called white sushi occurs, which significantly impairs copy quality.

Furthermore, once clogging occurs, it is difficult to remove the phenomenon agent agglomerates, etc., and the restoration work is troublesome and maintenance is complicated.

In order to solve the above-mentioned drawbacks (a), conventional methods have been used to provide a foreign matter removal section (a) or to make the height of the magnetic excitation of the developer uniform at the developing position.

As an example, according to Japanese Unexamined Patent Publication No. 53-63022, the current 1! J! There is a proposal to equalize the height of the magnetic excitation of the phenomenon agent up to the position. However, this proposal has the following problems, which have not yet been fully resolved.

(1) It is difficult to achieve uniformity if the time required for the agent to be sent between the panicle stand regulating portion and the current position is short.

(2) The magnetic pole plate essentially becomes a second spike control plate,
Foreign matter stuck in this magnetic pole plate causes similar problems.

(3) The setting of the magnetic pole plate is delicate; if it is too far away, it will have no effect at all, and if it is too close, it will promote unevenness in the developer layer.

(4) The white streaks occur even when the magnetic poles rotate.

As another measure to prevent clogging, removing foreign matter such as paper dust mixed into the developer is disclosed in JP-A-57-116 in Example and 12.
Publication No. 373 has been proposed. According to this method, foreign matter in the developer is combed out after development, but the trapping effect is insufficient, and furthermore, it cannot fundamentally solve clogging of foreign matter caused by contamination in other parts. In particular, the developer refluxed from the cleaning device and put into the developing device contains a large amount of foreign matter such as paper dust, but the above proposal is completely ineffective.

Purpose of the Invention The present invention has been made in view of the above problems, and includes:
A spike regulation plate that regulates the thickness of the developer layer. By completely removing the uneven thickness of the developer layer caused by foreign matter stuck in the narrow gap in the developing sleeve that transports the developer before it reaches the development area, a uniform developer layer is formed.
The purpose of this invention is to provide a developing device that can stably maintain high copy quality.

Structure of the Invention It is an object of the present invention to provide a spike regulating portion (8) that is formed on a developer carrier having a magnet inside and regulates spikes of developer magnetically excited to be conveyed to a development area. (3) A developer layer homogenizing member having a magnetic force generating member is disposed between the image area, along the developer carrying surface, and spaced apart from the developer carrier surface. achieved by the device.

According to the present invention, even if the thickness of the developer conveyed onto the developing sleeve is uneven due to foreign matter clogging the narrow gap between the spike control plate and the developing sleeve, the developer layer can be made uniform. By causing the developer to rise up due to the action of the member, a completely uniform thickness of the developer layer is formed before it reaches the image area, producing high-quality copies without white streaks or unevenness. The purpose is to provide

EXAMPLES The present invention will be described in detail below. FIG. 1 shows a schematic configuration of an example of a developing device embodying the present invention.

In Fig. 1, reference numeral 1 indicates an electrostatic image carrier (hereinafter referred to as an image carrier), such as a photosensitive drum, which rotates in the poetic direction. A non-magnetic agent carrier (hereinafter referred to as sleeve) 3 that is rotationally driven by
A magnetic roll 4, for example called a mag roll, which rotates clockwise around a rotating shaft 5 inside this sleeve 3, a hook 6 that accommodates a developer and supplies the developer to the sleeve 3, and the sleeve a spike regulating plate (hereinafter referred to as a regulating plate) 7 that mechanically regulates the height of magnetic excitation of a developer layer formed on the circumferential surface of the sleeve 3; A developer layer homogenizing member 8 (hereinafter referred to as a homogenizing member) is provided between the developer layer A and the developer layer 3, which is spaced apart from the surface of the slit 3. Further, the equalizing member 8 includes a non-magnetic cover 8A facing the circumferential surface of the sleeve 3 and a magnet 8M. Cover 8A
is not a ferromagnetic material, but is non-magnetic or paramagnetic, and is made of, for example, synthetic resin or a metal such as brass or aluminum.

The magnet 8M is a fixed magnet provided on the opposite side of the cover 88 facing the sleeve 3, and its magnetic pole faces toward the sleeve 3. That is, the lines of magnetic force caused by this magnet 8M reach the circumferential surface of the sleeve 30. Therefore, when the magnetic developer material conveyed onto the non-magnetic sleeve 3 passes through this magnetic field, it It is moved by the interaction between the magnetic field and the magnetic field of the magnetic roll 4.

The magnetic roll 4 consists of several magnetic poles arranged alternately, N-pole to 8-pole. The magnetic roll 4 and the sleeve 3 rotate relative to each other, and the magnetic roll 4 may be fixed to the main body of the copying machine and only the sleeve 4 may be rotated counterclockwise. Alternatively, the sleeve 4 may be fixed and only the magnetic roll 3 rotated counterclockwise (.) Among the above-mentioned systems, the 40-rotation magnetic roll system is most preferred for component development.

A two-component developer, such as a magnetic carrier and a non-magnetic toner, a magnetic carrier and a magnetic one. It refers to a two-component phenomenon such as ``na'' or ``na''.

The surface of the sleeve 3 and the tip of the regulation plate 7! 11'' and the distance a between the surface of the sleeve 3 and the equalizing member 8 facing thereto.
The relationship between b>a is as follows. Further, the equalizing member 8 is currently 1. J: 1. to device 2 and other parts. '
jl may be determined -(-, but in order to correctly maintain the relationship between a and b, it is better to identify or incorporate it into the regulation plate 7.

FIGS. 2(a) to (e) are cross-section 11'Ij diagrams showing various magnet arrangements in the equalizing section 8, and the number/x, <
(d) A magnet having both NS and NS poles, as indicated by diagonal lines (1 to 1), is arranged in a part of the magnet. That is, ta> The figure shows a rubber magnet whose surface is magnetized alternately. (b) Figure and (d) (8
7J is a structure in which a plurality of magnets, such as rubber magnets, magnetized in the thickness direction are arranged sparsely or densely. In the figure (C), the magnetic pole directions of adjacent magnets are arranged in opposite directions. . (e) In the figure, NS rubber magnets whose surfaces are alternately magnetized are opposed to the sleeve surface, and a cover is installed on the back side. 4)

FIG. 3(a) (13) shows another embodiment of the equalizing member 8, in which FIG. 3(a) shows a perspective view and FIG. 3(b) shows a developed view. This is a device in which magnets magnetized in diagonal directions are arranged in parallel. According to this, since the direction of the two magnetic fields acts obliquely with respect to the direction of rotation of the sleeve 30, the magnetic flux agent conveyed through the sleeve 31 moves in an oblique direction.

Although FIG. 1 shows the bias source 9 that applies to the sleeve 3 at t6, it can be changed as appropriate depending on the plug of the photoreceptor (static polarity), the magnetic flux agent used, etc. Methods such as grounding may be used.

The operation of the present invention device configured as described above will be explained with reference to FIG.

The magnetic material in the upper hopper (5) is magnetically held on the circumferential surface of the sleeve 3 and conveyed counterclockwise by the action of the relatively rotating sleeve 3 and magnetic roll 40.Sleeve 3 After the height of the magnetic material (magnetic brush) formed on the circumferential surface of the magnetic brush is regulated by the regulating plate 7;
It is transported to an area facing the forming member 8. The magnetic developer passing through the area of the homogenizing member 8 is caused by the magnetic roll 4
Due to the interaction between the magnetic field formed by the homogenizing member 8 and the magnetic field formed by the homogenizing member 8, the magnetic field of the barrel is disturbed, and the master plate 7 is also carried out. The homogenization f~) also moves in the lateral direction while passing through the region of the L material 8,
This causes the magnetic developer 9 to be placed on the sleeve 3.
The thickness D is equalized. Therefore, when it passes through the equalizing member 8 and reaches the white area, the magnetic excitation of the agent in the longitudinal direction of the sleeve 3 is in a negative state. Uniformly distributed magnetic flux
The additive reaches the developing area and is applied to the developing edge of the electrostatic latent image on the photoreceptor drum of the electrostatic image carrier 1, etc., which moves in the direction of the arrow.

As a result, even if the regulating plate is clogged with foreign matter, developer coagulation, etc. and there is a region on the sleeve where the magnetic material is low or has no magnetic waves, the magnetic material will be uniformly distributed while passing through the area of the equalizing member. Therefore, clogging problems can be avoided and stable images can be obtained.

The equalizing member of the present invention is effective in both the magnetic pole fixed sleeve rotating type and the magnetic pole rotating sleeve fixed type, but the effect is particularly remarkable in the magnetic sleeve dual rotating type.

FIG. 4 is a sectional view showing another embodiment of the present invention. In the embodiment shown in FIGS. 1 to 3, the cover 8A and the magnet 8M are integrated at a temperature of .degree. C., but they may be separated. In FIG. 4, the same magnetic pole of the magnet 18M faces the sleeve 3 surface so as to form a repulsive magnetic field, and the opposite magnetic pole is fixed to the magnetic member 1.8B. The magnets 18M that form the repulsive magnetic field may be two magnets arranged in parallel, or one magnet may be provided with a cutout hole on the side facing the sleeve 3.

FIG. 5 is a stop view and a plan view showing an embodiment of a magnet that forms a repulsion magnetic field by the magnetic force generating member itself in the equalizing member. 3. A hole 28H is bored in the fixed magnet 28M. , a repulsive magnetic field is formed near the hole. Several holes 28H are arranged in the longitudinal direction of the fixed magnet 28M, and the size and spacing of the holes 2811 are set so as to equalize the j9 unevenness of the magnetic developer. Multiple rows of holes 28H with several single rows like this! , 1- may be arranged. Alternatively, the holes 28H may be not only circular but also oval or elongated, and their arrangement may be diagonally parallel, vertically parallel, etc. 71
[ru. Moreover, FIG. 6 is a -E view and a plan view showing an example of the magnet 38M fitted with the notch groove 38H.

A repulsive magnetic field is formed by these holes or grooves, and the magnetic field is distributed in the longitudinal direction of the magnet. , the developer layer is homogenized.

It goes without saying that the present invention is not limited to the above embodiments. Note that the equalizing member 8 only needs to be provided close to the circumferential surface of the sleeve 3, so it may not be integrated with the regulating plate 7 or the developing device 2.

Further, by moving the equalizing member 8 back and forth in the longitudinal direction of the sleeve, the developer layer equalizing member becomes even larger.

DETAILED DESCRIPTION OF THE INVENTION According to the developing device of the present invention (, 7I), (1) Even if the gap between the regulating plate and the sleeve is clogged with foreign matter, the sleeve surface caused by this clogging is The areas where there is no developer are completely eliminated by the magnetic force of the developer layer homogenizing member that has a magnetic force generating member, and a uniform developer layer is obtained, ensuring long-term high-quality copies without white streaks or density unevenness. can be stably provided.

(2) Furthermore, since this can be achieved with a simple configuration, a low-floor developing device can be provided.

(3) The mixing action of the developer agent is carried out while passing through the developer layer homogenizing member. Secondly, it is possible to obtain a more homogeneous developer, and it is possible to obtain stable copies over a long period of time. can.

(4) It is easy to set the developer layer uniformity member, and its setting tolerance is wide, so assembly workability is good.

As described above, the developing device according to the present invention has the advantage that a more uniform thin layer of developer can be easily formed on the sleeve at all times and a high-quality and uniform developed image can be obtained compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a developing device according to the present invention, a perspective view and a developed view showing another embodiment of the leveled material, and FIG. 4 is a cross-sectional view showing still another embodiment of the present invention. . O Yukiin, Oa Kan IJ O, etc. 4 boys, 1) 1) 3 rebellion, 5, 4 years old, and Toshi. 1... Electrostatic forging carrier 2... Developing device 3... Currently agent phase special 4... Magnetic roll 7... Ear standing regulation plate 8.18 River developer agent layer leveling Member 8A, 18A °°゛Cover 8M, 18M, -
28M, 38M... Magnet A... Guchen area
D...Magnetic current iron agent Yoshimi Kuwahara Figure 1 551-

Claims (3)

[Claims] (1) The developer is formed on a developer carrier having a magnet therein and is conveyed to the fJl image area.
A developing device characterized in that a developer layer equalizing section having a magnetic force generating member is disposed along the surface of the developer carrier and spaced apart from the surface of the developer carrier. (2) The magnetic force generating member is configured such that the direction of the magnetic field within the developer magnetic excitation formation region on the developer carrier is oblique to the rotating direction of the developer carrier. A developing device according to claim 1. (3) The developing device according to claim 1 or 2, wherein the developing device is an equalizing member provided so that the magnetic force generating member itself forms a repulsive magnetic force.