JPS59123865A - Developing device - Google Patents

Abstract

PURPOSE:To feed an always fresh developer on a sleeve by removing a developer on the sleeve with a scraper installed below a magnetic brush developing roll and magnets equal to each other in polarity. CONSTITUTION:A toner is replenished from a replenishing device 2 in the direction of arrow E, mixed with a developer from a slope 7a and a density detector 18 through a mixing means 19, and further mixed with a developer removed from the sleeve of a developing roll 9 with a mixing means 14. At that time, a magnet supporting shaft 11 and magnets 12B, 12C equal to each other in polarity are installed in the sleeve, and the developer is once securely removed from the surface of the sleeve. The developer after mixing is further sent between partition walls 7 and controlled to a prescribed amt. with a branching member 17, and conveyed with plural mangets 12D, 12E, 12A to a developing section to develop an electrostatic latent image on an electrostatic drum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing device such as a dry type copying machine or facsimile machine using a two-component developer, and more particularly to a developing device having a function of efficiently stirring and mixing carrier and toner.

Conventional groove formation and its problems Conventionally, a developing device using a two-component developer is equipped with a magnetic brush developing roll and a stirring member such as a stirring blade or a stirring screw in the housing of the developing device, and the developer is stirred in advance. The carrier and toner are stirred and mixed by a member, and are initially charged by friction, and are adsorbed on the surface of a magnetic brush developing roll in contact with π1, forming a magnetic brush and slidingly contacting the surface of the photosensitive drum to perform a salt-like process. However, according to the conventional example in which a magnetic brush developing roll and a stirring member coexist in the same space of the housing of the developing device, the toner supplied from the toner replenishing device such as a toner hopper into the current mining device is not sufficiently stirred and mixed. There was a drawback that the magnetic brush was attracted to the developing roll (sliding contact with the δ optical drum, forming a partially uneven density area.Also, when the magnetic brush was in sliding contact with the surface of the photosensitive drum) Toner lumps that are insufficiently stirred and mixed hit the photosensitive drum and scatter on the surface of the photosensitive drum, contaminating the image height and the inside of the copying machine.Also, the agitation and mixing of the carrier and toner is often caused by the agitation blade or tl. This is done by rotating a stirring member such as a stirring screw in the developing device, so the higher the number of copies per minute, the higher the developing speed and the higher the number of rotations of the stirring member. Therefore, there was a drawback that the super-dynamic torque increased and a motor with high power consumption was required.Furthermore, since stirring was carried out only in the rotating part of the stirring member, one stirring and mixing progressed little by little, and all the developing parts were mixed. There was a drawback that it took time for the agent to be stirred and mixed uniformly.

OBJECTS OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a developing device that efficiently stirs and mixes toner and carrier.

In order to achieve the above object, the present invention includes a housing having a first IJO port facing the photosensitive drum and a second IJO opening facing the toner 'f'+G feeding device; A magnetic brush developing roll disposed near the opening, a first developer stirring and mixing means disposed below the second opening in the housing, and a first developer stirring and mixing means disposed at the bottom of the housing. a second developer stirring and mixing means; a partition wall disposed between the magnetic brush developing roll and the first developer stirring and mixing means in the housing;
a developer flow branching member positioned above the magnetic brush developing roll and forming a gap of a predetermined height between the magnetic brush developing roll and the surface of the magnetic brush developing roll; The developer adsorbed on the surface is moved from below to above in the partition side portion, and the second developer agitating and mixing means mixes the developer from the first developer agitating and mixing means. The developer is stirred and mixed with the developer from the magnetic brush developing roll that has been developed.
The developer flow branching member is configured to branch the developer transported upward through the partition wall by the magnetic brush developing roll into the first opening and the second opening.

Embodiment Figure 1 shows a sectional view of an embodiment of the present invention.Q)
(2) is a toner supply device, (3) is a developing device according to the present invention, and (4) is a housing of the developing device (3). The housing (4) has a first opening (5) facing the photosensitive drum (1), and a replenishment port (2) for the toner replenishment device (2).
1)2 openings (6) opposite to 2a) are provided. (7) is a partition wall that partitions the inside of the housing (4) into a space on the photosensitive drum (1) side and a space on the toner replenishing device (2) side. (9) is a magnetic brush developing roll, and photosensitive drum (1)
It is rotatably supported in the space on the side. The sex appeal brush developing roll (9) includes a cylindrical sleeve (11) and a Ki stone support member θυ provided through the inside of this sleeve QQ.
It is composed of a plurality of magnets (12A) to (12E) arranged in the same direction, and a magnetic brush is formed on the surface of the sleeve 00.

The sleeve QO is configured to be rotated in the direction of the arrow (6), but the magnet support member Ov is fixedly supported on the housing (4) side. A scraper al is provided near the inner bottom of the casing (4), and its tip is close to the surface of the sleeve 01. O◆ is a second agent stirring and mixing means provided at the bottom of the housing (4), which includes a 1゛11 body a9 rotated in the direction of the arrow (B) and an M protruding from the outer periphery of this shaft body 09.
It is composed of N & protrusions 011. Oη is a developer flow branching member supported by the housing (4) at a position above the sleeve cut, and a gap (a) of a predetermined height is provided between its lower surface and the surface of the sleeve 01, and its lower rear surface is It is formed in a concave portion (17a). In addition, the partition wall (7)
The upper surface is a sloped portion (7a) located approximately diagonally rearward of the developer flow branching member aη, and the lower end of the sloped portion (7a) extends to a position approximately below the second opening (6). . Barrel 0 is within the above slope part <'ra> and the surface is the slope part (7a)
A developer concentration detection sensor buried flush with the surface detects the temperature of the developer flowing down on the slope portion (7a). 4 is a first developer stirring and mixing means provided in the space on the side of the toner replenishing device, which is composed of an upper uneven stirring and mixing device (1) and a lower stirring and mixing device 1);
In addition, each stirring state tool (!1J (jυ is the rotation axis (20a)
Screw (20b) (2t
b) is provided. Note that the upper stirring mixer) and the lower stirring mixer Q) are rotated in opposite directions to each other as shown by arrows (C) and (D). Therefore, the housing (
The empty space on the toner replenishing device d side in 4) serves as a stirring and mixing chamber for the current enemy agent.

The gradient is a protruding member that protrudes inward from the rear wall (4a) of the housing (4) at a position between the upper stirring mixer (E) and the lower stirring mixer 0υ. The flow of the agent will be explained based on FIG.

First, toner is dropped from the toner replenishing device (2) into the second opening (6) of the housing (4) as shown by arrow (E). Then, the toner joins the developer sliding down the slope portion (7a) of the partition wall (7) and falls onto the first developer stirring and mixing means OI. The combined toner and developer are stirred and mixed by the upper stirring mixer (1) rotating in the direction of the arrow (C), and fall onto the lower stirring mixer Qp via the protruding member (A) of the housing (4). This lower stirring mixer Qυ rotates in the direction of arrow (D) 7 to further stir and mix the toner and developer. In this way, the developer mixed with toner is at the bottom along the lower inclined surface (side) of the housing (4), and the developing agent is moved by the second developer agitating mixing means 0→ rotating in the direction of the arrow (arrow). The developer is stirred and mixed with the developer scraped off by the scraper 03 from the surface of the developing roll (9).

A fixed amount of the developer is attracted to the surface of the sleeve OQ by the magnetic force of the magnet (12C), and moves upward as the sleeve OQ rotates.

Excess developer is returned to the second opening (6) side by the developer flow branching member oi. 'f! The developer that has passed through the gap (a) between the 7Ae agent flow branching member α and the sleeve OQ further rotates together with the sleeve 00, stands up by the magnetic force of the magnet (12A), forms a magnetic brush, and is applied to the photosensitive drum ( 1)
The electrostatic latent image on the photosensitive drum (1) is developed with toner by sliding the surface thereof. Then, the developing agent that has been developed is further moved downward by the rotation of the sleeve OL#, and is moved to the scraper 03.
The developing agent is scraped off by the second developer stirring and mixing means θ and mixed with the developing agent that has fallen from the lower inclined surface (4b) of the housing (4) and used for development. Ru. By the way, the developer concentration detection sensor 01G uses a coil magnet with an iron core, and detects the change in magnetic permeability due to the amount of toner in the developer flowing on the surface as the inkkutance of the coil. In case of shortage, operate the toner supply device (2) to fill the second opening (
June toner? The toner density of the developer in the developing device (3) is kept constant. Note that the slope section <'t
Since the meteor of the developer flowing through a) remains constant,
There is no noise due to fluctuations in movement, and the detection Tr1 degree is high.

Also, the magnet (12B) in the magnetic brush developing roll (9)
(12C) are made to have the same polarity so that the developer adsorbed on the sleeve aI repel each other, and after developing the photosensitive drum (1), the developer gas is removed from the sleeve OI at the position where it is scraped off by the scraper 03. It is designed to make it easier to leave. By the way, in the above embodiment, the first
Each stirring and mixing tool 61x (2υ
Although it has been described as a Kescrew type, it has, for example, plate-like blades or protrusions (it may also be a lead agitating type).

Effects of the Invention As detailed above, according to the developing device of the present invention, toner 1
117 Because the toner supplied from the supply device to the developing device is stirred and mixed during development, the stirring and mixing chamber and the magnetic brush developing roll are separated by a partition wall. +IJ h'i It is possible to prevent the toner from being adsorbed onto the brush developing roll without being sufficiently stirred and there is an advantage that an image with partially uneven density is not formed. Furthermore, in the present invention, in addition to the first developer stirring and mixing member J, the developer is stirred and mixed by the second developer stirring and mixing means having protrusions, so that the toner does not remain in the magnetic brush as a lump. This has the advantage that toner lumps do not scatter on the surface of the photosensitive drum. In addition, at the bottom of the m body, the existing agent from the stirring mixing chamber and the developer scraped from the surface of the magnetic brush roll are mixed, and the mixture is sent upward by the magnetic brush developing roll and separated by the developer flow branching member. The tgjs of the rice developer from the stirring and mixing chamber returns to the stirring and mixing chamber, so the stirring and mixing is repeated and the toner developer is 1'l tIiI
It has the advantage of being able to mix thoroughly. Since the efficiency of stirring and mixing is high, even in a high-speed continuous machine, the number of rotations of the first and second developer stirring and mixing members is relatively low, and the rotation drive motor consumes less power. There is a flJ point where a motor is sufficient.

Further, compared to the conventional method, there is an advantage that the developer in the developing device can be quickly and uniformly mixed and combined.

In the present invention, since the flow rate of the developer on the slope portion of the upper end of the partition wall is kept constant, there is no noise due to flow rate fluctuations, and there is an advantage that the detection accuracy of the sensor is high.

In addition, in this product, a scraper is installed below the first roll, and a magnet (12B) and (12C) are installed.
Since the developer is dropped from the top of the sleeve and collected at the bottom of the housing with the same polarity, the same developer is always metabolized without being adsorbed on the sleeve, so there is a second developer on the sleeve. There is an advantage that the developer stirred and mixed by Company I is newly adsorbed by the stirring and mixing means.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall sectional view, and FIG. 2 is an explanatory diagram showing the flow of developer. (1)...Photosensitive drum, (2)...Toner supply device, (3)...Developing device, (4)...xH body, (5)
...first opening, (6)...second opening, (7).
...Partition wall, (7a)...Slope portion, (9)...Magnetic brush developing roll, a...Scraper, 0→...Second
Developer stirring and mixing means, θ'I)...Developer flow branching member, (17a)...Concave portion, 0 Enoki...Densing agent concentration detection sensor, 01...First developer stirring and mixing means , to)・
...Top stirring mixer, QO...Lower stirring mixer Agent Yoshihiro Morimoto 1st cause 2nd figure

Claims (1)

[Claims] 1. A housing having an xlfJ opening facing the photosensitive drum and a second opening facing the toner supply device, and a magnetic brush disposed near the first opening in the housing. a developing roll; a first developer stirring and mixing means disposed below the second opening in the casing; and a second developer stirring and mixing means disposed at the bottom of the casing. and a partition wall disposed at the same time between the magnetic brush developing roll and the first developer stirring and mixing means in the housing, and a partition wall located above the magnetic brush developing roll and between the surface of the magnetic brush developing roll. a developer flow branching member forming a gap of a predetermined height, and the rotating direction of the magnetic brush developing roll moves the developer adsorbed on the surface from below to above in the partition side portion. The second developer stirring and mixing means is configured to stir and mix the developer from the first developer stirring and mixing means and the developer from the magnetic brush developing roll which has been developed. A developing device characterized in that the developer flow branching member is configured to branch the developer conveyed upward through the gap between the magnetic brush developing roll and the partition wall into a first opening and a second opening. . 2. The developing device according to claim 1, wherein the developer flow branching member is configured to restrict bubbling of the developer conveyed to the 1980th section by the magnetic brush developing roll.