JPS608868A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a developer from scattering from an opening part which faces the photosensitive body of a developing device by providing an air flow guide plate along a developing roll from near a development part, and providing a discharge opening for air in the side wall of the air flow guide plate at a larger interval from the developing roll. CONSTITUTION:The air flow guide plate 10 is provided along the downstream- side surface in the rotational direction of the developing roll 7 so that the distance increases gradually, and the discharge opening 11 for air is formed in the housing-side wall at a widened distance position. When the rotating sleeve 6 of the developing roll 7 rotates as shown by an arrow B, air flowing along the surface of the developing roll 7 does not flow into a developer 8 banking at the bottom part and the pressure in the space C of the bottom part rises, so that air flows out of the housing 2 through the discharge opening 11. Consequently, the air is sucked from outside of the housing near the opening part into the housing, so no developer scatters from the opening part.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing device used in an electrostatic recording device such as an electrophotographic copying machine.

Conventional configuration and its problems In conventional developing devices for electrostatic recording devices such as electrophotographic copying machines, powdered developers such as carriers and toner are stirred and mixed within the housing of the developing device, so that particles of several microns are mixed. A portion of the carrier and toner, which have a particle size of several tens of microns, floats in the air inside the housing of the developing device. Floating powder does not easily fall under its own weight, and when air flows out from inside the housing of the developing device, the above-mentioned floating powder such as carrier and toner flows out and damages the surrounding area of the developing device and the electrostatic recording device. It had the disadvantage of staining the inside.

Conventionally, in order to prevent the air inside the developing device from leaking out through the opening facing the photoreceptor, the end surface of the opening of the developing device housing was placed extremely close to the surface of the photoreceptor, or the end surface of the housing was placed very close to the surface of the photoreceptor. It was made into a labyrinth-like shape. 1. In the conventional method, a tape-like seal made of fibers is attached to the end face of the casing, and the tip of the fibers is lightly rubbed against the surface of the photoreceptor to prevent air leakage inside the casing of the developing device. I tried not to come out.

However, the surface of the developing ale is rough because the developer is attracted by magnetic force.

Since the developing roll is rotated at 200°F or 4°Ofl, the developing roll functions as a cross-flow fan and has a ventilation effect. It had the disadvantage that it was not possible to completely prevent leakage.

FIG. 1 is a cross-sectional view of the main parts of a conventional example, in which 1 is a photosensitive drum, 2 is a housing of a developing device, with an open part facing the photosensitive drum 1, and 3 is a lid, which is placed on top of the housing 2. Inside the housing 2, a fixed shaft 4 is fixed to the side wall 2a of the housing.
A plurality of magnets 6 are fixed at predetermined intervals on the fixed shaft 4, and a non-magnetic rotating sleeve 6 surrounding the magnets 6 is rotatably supported to constitute a developing roll 7.

A developer 8 is a mixture of carrier and toner, which is stirred and mixed by a stirring means 9, and the carrier and toner are adsorbed onto the rotating sleeve 6 while being frictionally charged with each other. When the developer 8 is attracted onto the rotating sleeve 6, the developer 8 stands up in spikes due to the magnetic force of the magnet 5.

The photosensitive drum 10 is rotated in the direction of arrow B.
Rub the surface and develop. When the rotating sleeve 6 of the developing roll 7 rotates, air on the surface of the developing roll 7 flows in the direction of arrow E as a laminar flow. At the bottom of the housing 2 of the developing device, the developer 8 adhering to the surface of the developing roll 7 enters into the developer 8 that had already sagged at the bottom. The air that flows out does not enter the developer 8 that had already settled at the bottom, and the pressure in the bottom space C remains high. Finally, as shown by the arrow, the high-pressure air comes to the bottom of the casing 2 and leaks out of the casing from the opening of the casing. Even if a multi-stage labyrinth packing 2b is provided at the opening of the housing, it has the disadvantage that it eventually leaks and the entire area around the developing device has to be cured.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a developing device which eliminates the drawbacks of the above-mentioned conventional examples and effectively prevents the developer from scattering from the opening facing the photoreceptor of the developing device.

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides an airflow guide plate near the developing section that develops the surface of the photoconductor so as to be spaced apart from the developing roll, and to control the airflow. Position 1 where the distance between the guide plate and the developing roll has increased
It is constructed by providing an air outlet in the 111 wall.

DESCRIPTION OF EMBODIMENTS The present invention will be described in detail below based on illustrated embodiments. Second
The figure is a sectional view of essential parts of a developing device according to an embodiment of the present invention, and the same parts as those explained in FIG. 1 of the conventional example are given the same reference numerals.

In the embodiment shown in FIG. 2, a magnetic brush formed on the developing roll 7 rubs the surface of the photosensitive drum 1 at an opening facing the photosensitive drum 1 to perform development. In the present embodiment, the airflow guide plate 10 is arranged so that the interval gradually increases from the vicinity of the developing portion to the downstream surface of the developing roll 7 in the rotational direction as it goes downstream from the developing roll in the rotational direction.
is fixed to the housing 2. Further, in this embodiment, a gas discharge port 11 is provided in the side wall 2a of the housing of the developing device at a position where the airflow guide plate 10 is spaced apart from the developing roll.

In this embodiment, when the rotating sleeve 6 of the developing roll 7 rotates in the direction of arrow B, the air on the surface of the developing roll 7 flows in the direction of arrow E as a laminar flow. At the bottom of the casing 2 of the developing device, the developer 8 that had adhered to the surface of the developing roll 7 falls off the bottom in advance and enters the developer 8. The air flowing in does not enter the developer 8 that had previously accumulated at the bottom, and the pressure in the bottom space C increases. Then, the air flows out from the air outlet 11 to the outside of the casing 2 as shown by the arrow F. When air flows from the arrow E to the arrow F and toward the air discharge +Z]11 from the opening of the casing, the air opens as shown by the arrow G.
Since a flow of air is generated that is drawn into the housing from outside the housing near the opening, air containing floating developer powder such as toner and carrier does not leak out from the opening, but rather clean air enters.

FIG. 3 is a perspective view showing the inside of the developing device of this embodiment with the lid 3 removed, and the same parts as shown in FIGS. 1 and 2 are given the same reference numerals.

FIG. 4 is a front view of another embodiment of the present invention, partially shown in cross section. Reference numeral 12 denotes a dust collector, and a hole 13 is provided below the dust collector, which is connected to communicate with the air outlet 11 of the developing device. The dust collector 12 is box-shaped, with a collision plate 12 protruding inside.

A filter 14 is provided on one side to allow air to escape, and the air containing fine particles of toner and carrier that flows out from the air outlet 11 of the developing device as shown by arrow F is collected. The liquid passes through the device 12 through bends as shown by the arrow H, passes through the filter 14, and is discharged to the outside as shown by the arrow I. The hole 13 of the dust collector acts as an orifice and causes a pressure change in the airflow flowing out from the developing device as shown by arrow F.

Fine particles such as toner and carrier, which are heavier than air, fall downward. Further, in the dust collector 12, since the air flows in a curved manner as shown by the arrow H, fine particles of toner and carrier adhere to and accumulate on the inner wall surface of the dust collector 12 and the collision plate 12&. Furthermore, the filter 14 collects any fine particles remaining in the airflow.

FIG. 6 is a sectional view of a main part showing still another embodiment of the present invention. This is an integrated structure of an airflow guide plate and a housing.
Components that are the same as those shown in FIGS. 1 to 4 are designated by the same reference numerals.

In this embodiment as well, when the developing roll 7 rotates in the direction of the arrow B, the pressure in the bottom space C of the casing becomes high, and the air containing fine particles of toner and carrier floating flows out of the casing from the air outlet 11 as shown by the arrow F. On the other hand, clean air flows into the housing from outside the housing near the opening of the housing as shown by arrow G.

Effects of the Invention As described in detail, according to the present invention, developer powder such as toner and carrier does not leak out from the casing of the developing device, but rather prevents the casing facing the photoreceptor from leaking out. In the department,
Since clean air can be sucked into the inside of the housing from the outside, developer is not scattered from inside the developing device unlike in the conventional case, and this has the effect of keeping the inside of a device such as a copying machine clean.

By rotating the developing roll, a ventilation effect can be obtained, so even if it is connected to a dust collector, it can simply be a box-shaped one, which has the advantage of not having to provide a suction means in the dust collector itself. .

The airflow guide plate is placed near the developing section where the photoreceptor is developed, so as to be spaced from the developing roll, but the airflow guide plate is placed on the surface of the photoreceptor at a distance of, for example, 1 mm.
There is no need to approach the following by 1, and there is an advantage that the developing device according to the present invention can be mass-produced. Unfortunately, the photoconductor is replaced when it reaches the end of its lifespan, but there is also the advantage that there is no need to damage the surface of the photoconductor by applying it to a nearby housing or labyrinth packing, as in the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a conventional developing device, FIG. 2 is a sectional view of a main part of an embodiment of the present invention, and FIG. 3 is a perspective view of the same embodiment.
FIG. 4 is a front view of another embodiment of the invention, and FIG. 5 is a sectional view of a main part of still another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Photosensitive drum, 2... Housing of developing device, 5... Magnet, 6... Rotating sleeve, 7... Development 8... Developer, 9... Stirring means, 10... Air flow guide plate, 11... Air discharge port. Name of agent: Patent attorney Toshio Nakao and 1 other person7 Figure 2 (□---) Figure 3 β

Claims (3)

[Claims] (1) A casing of a developing device having an opening facing the surface of the photoreceptor, a developing roll, and a vicinity of the developing section where the surface of the photoreceptor is developed by rubbing 1 with a magnetic brush formed on the developing roll. an airflow guide plate disposed so that the interval gradually increases from the developing roll as it goes downstream in the rotational direction of the developing roll, and the developing roll of the airflow guide plate; A developing device comprising a gas discharge port provided on a side wall of the casing at a position where the distance from the casing is increased. (2) The developing device according to claim (1), characterized in that the airflow guide plate and the casing are integrally constructed. (3) The developing device according to claim (1), wherein the gas discharge port is connected to a dust collector that collects floating fine powder.