JPH0582945B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing device that uses an air suction system to suck up toner clouds that cause functional stains in electrophotographic copying machines and the like.

BACKGROUND TECHNOLOGY In the dry developing device of an electrophotographic copying machine, there is a problem of functional contamination due to toner cloud.Means for preventing this toner cloud include the air pocket method (Fig. 5) and the magnetic seal method (Fig. 6). (Fig.), suction method (Fig. 7), etc.

As shown in FIG. 5, the air pocket system has air pockets 4 close to the photoreceptor 1 at the upstream end 3a and downstream end 3b of the housing 3 of the developing roll 2, which faces the photoreceptor 1 rotating in the direction of the arrow in the figure. The air pocket 4 is provided as an air flow stagnation part to prevent the toner inside the housing 3 from leaking to the outside of the developing device.

As shown in FIG. 6, in the magnetic seal method, when a two-component magnetic developer or the like is used, a permanent magnet 5 is provided at the end of the developing device housing 3 near the photoreceptor 1, and the developing By bringing the agent T into contact with the toner, leakage of toner to the outside of the developing device is prevented.

In the suction system, as shown in FIG. 7, an air suction passage 9 is formed between an inner wall 7 of the developing unit and an outer wall 8 of the developing unit as a housing, and the toner cloud between the inner wall tip 7a and the photoreceptor 1 is removed from the air suction passage 9. By suctioning in the direction of the arrow, toner is prevented from leaking to the outside of the developing device. The developing device disclosed in Japanese Patent Application Laid-Open No. 58-211770 also employs the air suction system.

Problems to be Solved by the Invention However, the above-mentioned toner cloud prevention means each have the following problems.
Among these, the air pocket method is air pocket 4.
Because of this, the developing device becomes large, and in the case of the magnetic seal method, there is a problem that the toner images on the photoreceptor 1 mix colors when the developing device has multiple color developing devices.

In addition, in the suction method, the tip 7 of the inner wall of the developing device
Toner is likely to accumulate on the photoreceptor 1, which may cause the image on the photoreceptor 1 to become blurred. To explain this point in detail, first of all, as to why toner can accumulate on the wall surface, if the developing device inner wall 7a is made of metal such as aluminum, the toner cloud in the developing device receives its own electric charge and receives from the inner wall 7. It attaches to the inner wall 7 by mirror image force,
Further, due to the characteristics of the developer, when the inner wall 7 of the developing device is electrically floating, the toner cloud adheres to the wall surface more significantly. When air suction is applied, the toner cloud in the developing device is forced to pass between the inner wall tip 7a and the photoreceptor 1, and the toner is less likely to adhere to the inner wall tip 7a than in the case where there is no air suction. Opportunities are increasing rapidly. Moreover,
If there is no air suction, the charge distribution of the toner deposited on the inner wall tip 7a is close to the charge distribution of the toner cloud inside the developing device, but when air suction is added, toner with a low charge gets on the air flow and is air-suctioned. Since the toner is easily attracted to the passage 9, a large proportion of the toner adhering to the inner wall tip 7a is highly charged.
The image on the photoreceptor 1 is likely to be distorted. This is because the toner cloud inside the developing device is forcibly sucked out to the outside, and the larger the amount of air sucked, the more the inner wall tip 7
The toner accumulation in a is significant.

The present invention has been developed in view of these problems, and it prevents toner cloud from contaminating the inside of a copying machine, and also prevents the toner cloud in the developing unit from being blown by air via the tip of the inner wall of the developing unit on the photoreceptor side. The purpose is to prevent excessive suction to the outside of the developing device and to prevent image disturbance on the photoreceptor.

Means for Solving the Problems In order to achieve the above object, the developing device of the present invention includes a housing provided on the developing roll facing the photoreceptor, the housing comprising an inner wall of the developing device and an outer wall of the developing device, and a developing device of the present invention. An air suction passage for sucking air is formed between the inner wall of the developer and the outer wall of the developer, and the inner wall of the developer is formed of a conductive material, and the inner wall of the developer is electrically suspended (not grounded and In a developing device arranged in an independent state, air suction reduces the amount of air suctioned from inside the developing device to the air suction path by air suction from the air suction path compared to the amount of air suctioned from outside the developing device to the air suction path. A quantity regulating member is provided at the tip of the inner wall of the developing device.

In a preferred embodiment of the present invention, the air suction amount regulating member is formed integrally with the inner wall of the developing device, and the distance between the tip of the outer wall of the developing device and the photoreceptor is adjusted to the tip of the air suction amount regulating member. and the photoreceptor〓
Set it to be greater than the distance.

In another preferred embodiment of the present invention, the air suction amount regulating member is bent toward the inner side of the developing unit with respect to the inner wall of the developing unit.

Function In a developing device in which the inner wall of the developing device is formed of a conductive member and is placed in an electrically floating state,
When air is sucked between the inner wall of the developer and the outer wall of the developer, the adhesion of toner to the tip of the inner wall of the developer largely depends on the amount of air passing between the inner wall of the developer and the photoreceptor, but according to the present invention, The air suction amount regulating member limits the amount of air passing through the portion between the developing unit inner wall tip (the air suction amount regulating member tip) and the photoreceptor to be smaller than the amount of air coming from the outside. This reduces the amount of toner that adheres to the tip of the inner wall of the developing device.
Unnecessary toner adhesion onto the photoreceptor is prevented, and image disturbance on the photoreceptor is prevented.

Embodiments of the present invention will be described below based on the drawings.

Embodiment 1 In FIGS. 1 and 2, an air suction amount regulating member is integrally formed at the tip of the inner wall of the developing device, and the distance between the outer wall tip of the developing device and the photoreceptor is determined by the distance between the tip of the air suction amount regulating member. The first embodiment of the present invention is shown in which the distance between the photoreceptor and the photoreceptor is set to be greater than the distance between the photoreceptor and the photoreceptor. In FIG. 1, components that are substantially the same as those in FIG. 7 are given the same reference numerals.

The housing of the developing roll 2 is connected to the inner wall 12 of the developing device.
and a developing device outer wall 8 provided on the outside thereof, and these developing device inner wall 12 and developing device outer wall 13.
An air suction passage 14 for sucking air in the direction of the arrow shown in the figure is formed between the two. As a means for sucking air, for example, a vacuum pump (not shown) is used.

At the tip of the inner wall 12 of the developing device, the tip and the photoreceptor 1 are attached.
An air suction amount regulating member (corresponding to the part protruding toward the photoreceptor 1 side compared to the developing device outer wall 13 in the figure) is integrally formed. . Inner wall of the developing device (including the air suction amount regulating member, the same applies hereinafter in this example)
12 is made of a conductive member such as aluminum, and the inner wall 12 of the developing device is placed in an electrically floating state (not grounded and electrically independent).

As shown in FIG. 2, the distance between the tip of each of the inner wall 12 and outer wall 13 of the developing device and the photoconductor 1 is the distance r1 between the tip 12a of the inner wall of the developing device and the photoconductor 1.
The distance between the developing device outer wall tip 13a and the photoreceptor 1 is
By setting r2 to a large value, relatively more air from outside the developing device is sucked than air inside the developing device, and as a result, the amount of air sucked from inside the developing device is reduced.

In the first example, when air was suctioned at a wind speed of 0.2 to 0.6 m/sec at the point A shown in Fig. 2, it was found that r2 was within the range of two to four times r1. A good image was obtained on the photoreceptor 1 with almost no staining.

The value of r1 in the first embodiment is set to 0.5 to 4 mm, more preferably 0.5 to 2 mm, and the value of r2 is set to r1
While maintaining the relationship <r2, it is set to 1 to 10 mm, more preferably 1 to 5 mm.

Embodiment 2 FIGS. 3 and 4 show a book in which an air suction amount regulating member is formed integrally with the tip of the inner wall of the developing device and bent toward the inner side of the developing device with respect to the inner wall of the developing device. 2 shows a second embodiment of the invention. In FIG. 3, components that are substantially the same as those in FIG. 7 are given the same reference numerals.

The housing of the developing roll 2 is connected to the inner wall 16 of the developing device.
and a developing device outer wall 17 provided on the garden side, and these developing device inner wall 16 and developing device outer wall 1
An air suction passage 18 for suctioning air in the direction of the arrow shown in the figure is formed between the two.

An air suction amount regulating member 16a that regulates the air flow rate is integrally formed at the tip of the inner wall 16 of the developing device. Developing device inner wall 16 and air suction amount regulating member 1
6a is made of a conductive member such as aluminum, and is connected to the developing device inner wall 16 and the air suction amount regulating member 16.
a is electrically floating (not grounded,
electrically independent).

The air suction amount regulating member 16a is integrally formed with the air suction amount regulating member 16a bent toward the inner side of the developing device.As shown in FIG. It has been extended to the extent that it does not interfere with the spikes of the developer.

In FIG. 4, the distance r1 between the photoreceptor 1 and the base of the air suction amount regulating member 16a and the distance r2 between the photoreceptor 1 and the tip of the air suction amount regulating member 16a are configured to have approximately the same value. When air was suctioned at a wind speed of 0.5 m/sec at point A shown in Figure 4, it was possible to obtain a good image on the photoreceptor 1 when the developing roll 2 was developing the image onto the photoreceptor 1. I can,
In addition, there was almost no staining caused by toner cloud on the outside of the developing device. Note that the angle θ between the developing device inner wall 16 and the air suction amount regulating member 16a is 90 degrees to
It is desirable to set it within a range of 120 degrees.

In the second embodiment, the distance r1 and the distance r2 are set to the same value, but in the present invention, they are set so that r1<r2, and as the air suction amount regulating member 16a goes from the base to the tip, It may be set so that the distance to the photoconductor gradually becomes smaller.

According to the second embodiment, an air suction amount regulating member 16a bent toward the inside of the developing device is provided at the tip of the inner wall 16 of the developing device on the side of the photoreceptor, and the amount of air suctioned from inside the developing device is controlled by the amount of air sucked from outside the developing device. By reducing the amount of toner cloud in the developing device to the outside of the developing device, only the toner cloud naturally generated inside the developing device is removed, thereby reducing the amount of toner cloud on the photoreceptor 1. Necessary toner adhesion can be prevented. In the embodiment shown in FIG. 3, since the air suction amount regulating member 16a is formed at the tip of the inner wall 16 of the developing device, the ease of assembling the housing is improved.

In the present invention, the toner cloud inside the developing device is discharged to the outside by air suction from the gap between the photoreceptor and the housing. The toner cloud inside the developing device may be removed by suctioning air through the holes.

Effects of the Invention As explained above, according to the present invention, it is possible to prevent the function of a copying machine from being contaminated by toner cloud, reduce the amount of toner adhering to the inner wall of the developing device, and reliably prevent image disturbance on the photoreceptor. be able to.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention, FIG. 2 is a schematic configuration diagram of main parts for explaining the main parts thereof, and FIG. 3 is a schematic configuration diagram showing a second embodiment of the present invention. 4 are schematic side views of the main parts thereof, and FIGS. 5, 6, and 7 are schematic configuration diagrams showing conventional examples. DESCRIPTION OF SYMBOLS 1... Photoreceptor, 2... Developing roll, 12... Inner wall of developing device, 12a... Tip portion of inner wall of developing device, 13...
...Developer outer wall, 13a...Developer outer wall tip, 1
4... Air suction passage, 16... Inner wall of developing device, 16
a...Air suction amount regulating member, 17...Developer outer wall, 18...Air suction passage.

Claims (1)

[Scope of Claims] 1. A housing is provided on the developing roll facing the photoreceptor, the housing is composed of an inner wall of the developing device and an outer wall of the developing device, and an air suction passageway that sucks air between the inner wall of the developing device and the outer wall of the developing device. In a developing device in which the inner wall of the developing device is formed of a conductive member and the inner wall of the developing device is arranged in an electrically floating state, air is drawn from the inside of the developing device to the air suction path by air suction from the air suction path. A developing device characterized in that an air suction amount regulating member is provided at the tip of an inner wall of the developing device to reduce the suction amount from the amount of air suctioned from the outside of the developing device to the air suction passage. 2. The air suction amount regulating member is integrally formed with the inner wall of the developing device, and the distance between the tip of the outer wall of the developing device and the photoconductor is equal to the distance between the tip of the air suction amount regulating member and the photoconductor. 2. The developing device according to claim 1, wherein the developing device is set to be larger than . 3. The developing device according to claim 1, wherein the air suction amount regulating member is bent toward the inner side of the developing device with respect to the inner wall of the developing device.