JPH0359687A - Developing machine for electrophotographic device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a developing machine for an electrophotographic apparatus.

[Conventional technology]

Dry developing machines are widely used in electrophotographic devices used in printers and copying machines. A dry developing machine is a device that performs development by conveying a developer, which is magnetic powder, using a magnetic roll with a built-in magnet. The developer also contains toner, which is a fine powder for forming characters and graphics. Since this toner is fine and lightweight, with a diameter of several to several tens of micrometers, it is a problem that it scatters and floats during the movement of the developing machine and contaminates the inside of the device. Furthermore, contamination inside the apparatus due to this toner scattering has a negative effect on printing quality. For this reason, it is necessary to periodically clean toner that has scattered or accumulated inside the device. On the other hand, one of the important issues for printers and copying machines is to reduce the printing cost per page, and in order to reduce maintenance costs, there is a need to make the devices maintenance-free and to extend the maintenance inspection period. In particular, there is a need to prevent toner scattering around developing machines, which have short maintenance and inspection cycles.

3 and 4 show a conventional example of a developing machine for an electrophotographic apparatus. As shown in the figure, a developing magnet roll 3 is provided inside the developing container 1 so as to face the photosensitive drum 2 .

Further, facing the developing magnet roll 3, a conveying magnet roll 4 and a doctor plate 6 for regulating the developer 5 conveyed to the developing magnet roll 3 to a constant thickness are attached. Also, toner 8 is contained inside the toner container 7.
is housed therein, and a toner supply roll 9 for supplying toner 8 is provided. A stirring roll 10 having an impeller is provided below the toner supply roll 9 and at the part where the developer 5 falls. Further, at the lower part of the toner container 7 outside the developer container 1, a toner shielding plate 11 is provided, which faces the photosensitive drum 2 via a microsensor G.

Next, toner scattering during development in the developing machine configured as described above will be described. The developer 5 transported by the rotation of the transport magnet roll 4 and the developing magnet roll 3 is
The doctor plate 6 regulates the thickness to an optimum value and sends it to the photosensitive drum 2 side. At this time, the toner 8 in the developer 5 is scattered by the centrifugal force caused by the rotation of the developing magnet roll 3. Further, the toner 8 that has fallen onto the stirring roll 10 due to the rotation of the toner supply roll 9 is stirred together with the developer 5 by the rotation of the stirring roll 10, but at this time, the toner 8 is also scattered. In order to prevent the scattered toner 8a thus scattered from coming out of the developing machine, a toner shielding plate 11 is provided facing the photosensitive drum 2.

[Problem to be solved by the invention]

In order to effectively prevent the scattered toner from leaking out of the developing machine using the above conventional technology, the distance between the toner shielding plate and the photosensitive drum must be approximately 0.5+m+ or less, and the first assembly of the device is There is a drawback that it cannot be done easily. Furthermore, since the spacing is as narrow as 0.5 nn or less, scattered toner adheres and accumulates on the toner shielding plate, contacts the photosensitive drum, and causes problems such as printing stains. Therefore, the toner shielding plate must be cleaned periodically. In this way, unless the distance between the toner shielding plate and the photosensitive drum is narrowed, it will not be useful to prevent toner from scattering outside the developing machine, and the scattered toner that has accumulated on the toner shielding plate must be left alone. was the problem.

The present invention has been made in view of the above points.

A developing machine for electrophotographic equipment that allows for easy adjustment of the interval between toner shielding plates, no accumulation of scattered toner on the toner shielding plates, less scattering of toner outside the machine, and long maintenance and inspection cycles. The purpose is to provide the following.

[Means to solve the problem]

The above purpose is to provide an insulating plate between the toner shielding plate and the developer container, as well as a power supply connected between the toner shielding plate and the ground, and to apply a voltage to the toner shielding plate of the same polarity as the charge polarity of the scattered toner. This is achieved by applying .

[Effect]

Since the above means is provided, a repulsive force is generated between the toner shielding plate and the scattered toner, making it difficult for toner to adhere to the toner shielding plate.

〔Example〕

The present invention will be explained below based on the illustrated embodiments. An embodiment of the present invention is shown in FIGS. 1 and 2. It should be noted that the same parts as in the prior art have been given the same reference numerals, so their explanation will be omitted. In this embodiment, a toner shielding plate 11 and a developing container l are used.
An insulating plate 12 is provided between the toner shielding plate 11 and the toner shielding plate 11.
A power source E connected between the toner and the ground was provided, and a voltage having the same polarity as the charging polarity of the scattered toner 8a was applied to the toner shielding plate 11. By doing this, a repulsive force is generated between the toner shielding plate 11 and the scattered toner 8a,
This prevents the scattered toner 8a from adhering to the toner shielding plate 11, making it easy to adjust the interval between the toner shielding plates 11, preventing the scattered toner 8a from accumulating on the toner shielding plate 11, and preventing the scattered toner 8a from scattering outside the machine. In other words, between the developer container 1 and the toner shielding plate 11 and between the lower part of the toner container 7 and the toner shielding W & plate 11, it is possible to obtain a developing machine for an electrophotographic apparatus that can have a long maintenance and inspection cycle. In each case, an insulating plate 12 is provided as a holding member for the toner shielding plate 11. A voltage having the same polarity as the charged polarity of the scattered toner 8a is applied to the toner shielding plate 11 by a suitable power source E. By doing this, the scattered toner 8 during development.
However, since a voltage having the same polarity as the charging polarity of the scattered toner 8a is applied to the toner shielding plate 11, a repulsive force acts between the toner shielding plate 11 and the scattered toner 8a. Therefore, it becomes difficult for the scattered toner 8a to adhere to the toner shielding plate 11, and printing stains caused by the accumulated scattered toner 8a can be prevented, and the cleaning cycle of the toner shielding plate 11 can be lengthened. Also, due to the effect of this repulsive force, the distance G between the toner shielding plate 1 and the photosensitive drum 2 is wider than before (about lam).
However, the effect of preventing the scattered toner 8a from scattering outside the machine is improved compared to the conventional method. Therefore, the distance G between the toner shielding plate 11 and the photosensitive drum 2 can be eliminated without adjustment. Note that the toner shielding plate 11
Appropriately, the voltage to be applied is about several hundred to 1,000 V (more than the bias voltage and less than 1 surface potential).

According to this embodiment, since a voltage with the same polarity as the charged polarity of the scattered toner is applied to the toner shielding plate, the interval between the toner shielding plates can be easily adjusted, and maintenance can be performed with less scattering of toner outside the machine. It is possible to provide a developing machine with a long inspection cycle and good maintainability.

〔Effect of the invention〕

As described above, according to the present invention, it is easy to adjust the interval between the toner shielding plates, there is no accumulation of scattered toner on the toner shielding plates, there is little scattering of toner outside the machine, and the maintenance inspection cycle can be extended. This makes it easy to adjust the spacing between the toner shielding plates, there is no accumulation of scattered toner on the toner shielding plates, less toner is scattered outside the machine, and the electronic photography allows for longer maintenance and inspection intervals. You can get a developing device.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of an embodiment of a developing machine of an electrophotographic apparatus according to the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a vertical sectional side view of a conventional developing machine of an electrophotographic apparatus. , FIG. 4 is a partially enlarged view of FIG. 3. 1 is a developer container, 2 is a photosensitive drum, 8a is a scattered toner, 1
1 is a toner shielding plate, and 12 is an insulating plate.

Claims (1)

[Claims] 1. In a developing machine of an electrophotographic apparatus, a toner shielding plate is provided at a predetermined position on the outer edge of the developing container facing the photosensitive drum to prevent scattered toner from scattering outside the machine. An insulating plate is provided between the shielding plate and the developer container, and a power source connected between the toner shielding plate and the ground is provided, and a voltage having the same polarity as the charging polarity of the scattered toner is applied to the toner shielding plate. A developing machine for an electrophotographic device characterized by applying an electric voltage.