JP2891373B2 - Developing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device incorporated in an electrophotographic apparatus such as a facsimile, a printer, a copying machine, etc., and more particularly, to a developing device capable of preventing toner scattering or toner drop after development. Related to the device.

2. Description of the Related Art Conventionally, as shown in FIG. 3, for example, a developing roller is formed by opposing a photosensitive drum 2 carrying an electrostatic latent image at an opening of a toner container 1 containing a one-component or two-component toner. After the developer is charged with the toner by charging the toner with the carrier or by rubbing the carrier with the carrier, the developing roller 3 is rotated.
While the layer thickness is regulated at 20, the layer is guided to a developing position, and toner spikes formed by using a fixed magnet assembly or the like included in the developing position are rubbed against the peripheral surface of the photosensitive drum 2, or the bias electric field is applied. A developing device incorporated in so-called electrophotographic equipment is known in which the toner is selectively transferred to the photosensitive drum 2 while the toner is in an electromagnetically floating state by utilizing the above.

In this type of developing device, as described above, the toner is transferred to the photosensitive drum 2 and then collected and reused while being collected in the toner container 1 side. Alternatively, all of the toner in the electromagnetically floating state may be collected again in the toner container 1 while being held again on the developing roller 3 side by using a fixed magnet assembly or other magnetic attraction or charged power. Are difficult, and some of them are scattered or fall off, causing internal contamination.

In order to solve such a drawback, a metal part 51 is provided on the side of the lower end of the container downstream of the developing position facing the photosensitive drum 2,
By applying a voltage having a polarity opposite to the charged potential of the toner to the metal part 51 by the bias power supply 52, the toner to be scattered or dropped is positively adsorbed to the metal part 51 so as to prevent contamination in the apparatus. Technology exists.

"Technical problem to be solved by the invention" However, in such a conventional technique, the metal part
Since the rotational force of the developing roller 3 is used as a means for merely adsorbing the toner to the toner 51 and recovering the adsorbed toner to the toner container 1 side, for example, when the photosensitive member 51 The toner adhering to the side facing the body drum 2 is left as it is, and the toner is deposited on the metal part 51 by using the developing device for a long time, and the toner is re-scattered due to the replacement of the device and other impacts. Cannot be prevented.

Further, in the related art, since the above-described action is generated by applying a voltage having a polarity opposite to that of the toner to the metal part 51, the suction action disappears unless a voltage is applied even when the power is turned off, Again, secondary contamination occurs.

SUMMARY OF THE INVENTION In view of the drawbacks of the related art, it is an object of the present invention to provide a developing device configured to adsorb the scattered or dropped toner and to be able to positively collect the adsorbed toner in a toner container.

According to the invention described in claim 1), a developing roller is disposed in an opening of a toner container so as to face a photosensitive drum, and the toner in the opening is rotated by rotation of the developing roller. From the supply side, the toner guided to a developing position formed by the photosensitive drum and the developing roller can be selectively transferred to the photosensitive drum side, and the toner is positioned below the developing position. A developing device configured to collect toner from a toner collecting side of an opening, wherein the toner collecting side of the opening is on a bottom surface of the toner container, and a rotation center of the developing roller is on a side of the photosensitive drum. A magnetic member having a rotation center and capable of adsorbing toner provided in a non-contact state with the developing roller and the photosensitive drum, and rubbing the surface of the rotating member inside the developing roller; The magnetic pole to be formed is fixedly arranged, and connected to a bias power source in which the rotating member is provided with a charge (potential) having a polarity opposite to that of the charge injected into the toner. The toner adsorbed on the surface of the toner container can be collected in the toner container while rotating the toner container in the toner container collecting direction.

According to the present invention, a rotating member 4 capable of adsorbing scattered or dropped toner is provided on the surface, magnetic chains are formed on the residual toner carried on the developing roller, and the magnetic chains can be brought into contact with the surface of the rotating member.

The toner scattered or dropped at the developing position between the photosensitive drum and the developing roller is adsorbed and captured on the surface of the rotating member, and the adsorbed toner guided on the magnetic chain by the rotation thereof is rubbed with the magnetic chain. The toner is scraped off and collected by the toner container.

In this case, the material of the rotating member 4 is not particularly limited as long as a charge (potential) having a polarity opposite to that of the charge injected into the toner can be applied by a bias power supply. It is preferable to use a metal material whose surface is covered with an insulating layer.

According to this configuration, since the bias voltage is applied to the rotating member by the DC bias power supply having the opposite polarity to the toner charge, in the case of the rotating member extended in the axial direction, the rotating member is non-uniformly charged, such as frictional charging. And there is no restriction on the mounting position of the rotating member, so that the rotating member can be brought closer to the photosensitive drum side, and can be disposed immediately below the developing position of the photosensitive drum, so that the toner is captured. Becomes easier.

On the other hand, according to the invention described in claim 2, after the scattered or dropped toner is adsorbed on the surface of the rotating member 4, the rotation is performed by using the scraping means (5, 6) and the rotating force of the developing roller 3. The toner can be collected in the toner container 1 while scraping off the toner adsorbed on the member surface.

In this case, the rotating member 4 is preferably formed of a member capable of adsorbing toner, but is not limited thereto.

The scraping means (5, 6) are also provided with a magnetic brush capable of rubbing the surface of the rotating member and a base end side fixed to the inner wall surface of the toner container 1 as shown in an embodiment described later, and a free end side thereof. Various configurations are possible, such as a scraper in which the abutment is in contact with the surface of the rotating member 4.

According to this configuration, the residual toner on the rotating member that has not been scraped off due to the rubbing with the magnetic chain is guided to the pressure contact position of the scraping plate according to the rotation of the rotation member, and the adsorbed toner is scraped at the pressure contact position. By scraping with a plate and guiding it to the upper surface side of the scraping plate, the toner collecting effect can be improved. This is particularly favorable in an apparatus for forming a toner layer in a thin film, such as a flight development method.

"Example" Hereinafter, an example of the present invention will be illustratively described in detail with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples. Not just.

FIGS. 1 and 2 show a developing device according to an embodiment of the present invention. The difference from the prior art will be mainly described. FIG. 1 shows the first embodiment. The developing roller 3 opposed to 2 includes a fixed magnet assembly 10 and constitutes a developing device for high-resistance magnetic toner.

A roller-shaped rotating member 4 is disposed on the bottom free end 1a side of the toner container 1 located below the developing position facing the photosensitive drum 2. The rotation center of the rotating member 4 is disposed closer to the photosensitive drum 2 than the rotation center of the developing roller 3.

The rotating member 4 is extended with substantially the same length as the developing roller 3, the surface of the rotating member 4 is covered with an insulating layer 4 a, and a bias voltage is applied by a DC bias power supply 7 having a polarity opposite to that of the toner charge. It is configured to rotate in a direction opposite to the rotation direction.

The bias power supply connected to the rotating member is configured to save power so that the power is cut off in conjunction with the stop of development.

A magnetic pole 9 is arranged on a fixed magnet assembly 10 located slightly closer to the toner container 1 than a line connecting the developing roller 3 and the axis of the rotating member 4, and the magnetic pole 9 is used on the developing roller 3. Magnetic spikes 6 are formed on the residual toner to be carried, and the magnetic spikes 6 are configured to be able to contact the surface of the rotating member 4.

According to this embodiment, since the rotation center of the rotating member 4 is disposed closer to the photosensitive drum 2 than the rotation center of the developing roller 3, the toner falling from the developing position can be captured well.

The toner scattered or dropped at the developing position between the photosensitive drum 2 and the developing roller 3 is adsorbed and captured on the surface of the rotating member 4, and the adsorbed toner guided on the magnetic spikes 6 according to the rotation of the toner The toner can be scraped off by the rubbing with the ear 6 and collected in the toner container 1 side.

In the case where the developing roller 3 is formed thick as in the magnetic brush developing method, the scraping effect by the magnetic chain 6 is high, but the apparatus for forming the toner layer into a thin film as in the flying developing method is used. Cannot always achieve the expected effect.

In this case, as shown in FIG.
The two scraping means 5, 6 may be used in combination.

Next, the second embodiment shown in FIG. 2 will be described focusing on differences from FIG.

The free end of a scraping plate 5 made of a thin resin plate is pressed against the upper surface of the rotating member 4. The scraper plate 5 has its base end fixed to the bottom side of the toner container 1, its free end extending from the base end to the upper surface of the rotating member 4, and its peripheral surface being press-contactable. ing.

In this case, it is preferable that the scraping plate 5 is slightly inclined downward so as to be lowered.

According to this embodiment, the toner scattered or dropped at the developing position between the photosensitive drum 2 and the developing roller 3 is adsorbed and captured on the surface of the rotating member 4 and guided on the magnetic chain 6 according to the rotation. The adsorbed toner is scraped off by rubbing with the magnetic spikes 6, and residual toner on the rotating member 4 that is not scraped off by rubbing with the magnetic spikes 6 is scraped by the rotation of the rotating member 4. The adhering toner is scraped off by the scraping plate 5 at the pressure contact position of the plate 5, and is guided to the upper surface side of the scraping plate 5.

Since the adsorbing force between the scraping plate 5 and the rotating member 4 is released, the residual toner layer carried on the surface of the developing roller 3 is not dragged by the toner layer together with the residual toner layer. Will be collected.

In this embodiment, the action is further promoted because the scraping plate 5 is inclined obliquely downward.

The scraping plate 5 also has a role as a cover member for preventing toner from entering between the rotating member 4 and the bottom surface of the toner container 1.

As described above in detail, in the first and second embodiments, since the bias voltage is applied to the rotating member by the DC bias power supply having a polarity opposite to that of the toner charge, the rotating member is extended in the axial direction. In this case, there is no possibility of non-uniform charging as in the case of frictional charging, and since there is no particular restriction on the mounting position of the rotating member, it is possible to bring the rotating member closer to the photosensitive drum side and directly below the developing position of the photosensitive drum. The toner can be easily captured.

[Effect] According to the present invention as described above, the scattered or dropped toner generated during development is positively captured by the rotating member below the toner, and the absorbed toner is removed by the rotating force of the rotating member and the scraping means. Since the toner can be collected on the toner container side by using the rotational force of the developing roller, in other words, it is possible to simultaneously capture the scattered or dropped toner generated during development and collect the toner in the container simultaneously during development. In addition, the toner does not accumulate in the trapped portion, and therefore, the toner drops from the trapped portion even in various operations performed after the development is stopped, for example, when the upper body is divided and opened or when the developing device is replaced. Etc. can be prevented.

Even when a bias power supply or the like is used for the rotating member, even if the bias power supply is cut off in conjunction with the stop of development, no problem occurs and power is saved.

 And so on.

[Brief description of the drawings]

FIG. 1 is a schematic front sectional view of a developing device according to a first embodiment of the present invention, FIG. 2 is a schematic front sectional view of a developing device according to a second embodiment of the present invention, and FIG. FIG. 2 is a schematic front view of the developing device according to FIG.

Continuation of the front page (56) References JP-A-55-118060 (JP, A) JP-A-59-232370 (JP, A) JP-A-61-240261 (JP, A) JP-A-63-106768 (JP) , A) Japanese Utility Model 1-57763 (JP, U) Japanese Utility Model 3-29956 (JP, U) Japanese Utility Model 2-36844 (JP, U) Japanese Utility Model 2-138759 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 15/08 G03G 15/09

Claims (3)

(57) [Claims] A developing roller is disposed at an opening of a toner container so as to face a photosensitive drum, and is formed by the photosensitive drum and the developing roller from the toner supply side of the opening by rotation of the developing roller. The toner guided to the developing position to be transferred can be selectively transferred to the photosensitive drum side, and the toner is collected from the toner collecting side of the opening located below the developing position. In the developing device, on the toner recovery side of the opening, on the bottom surface of the toner container, a rotation member capable of adsorbing toner, having a rotation center closer to the photoconductor drum than a rotation center of the developing roller, A magnetic pole that forms a magnetic brush that rubs the surface of the rotating member is fixedly disposed inside the developing roller, and is provided in a non-contact state with the photosensitive drum. Connected to a bias power source that applies a charge (potential) of the opposite polarity to the charge injected into the toner to the material, and rotates the peripheral surface of the rotating member on the developing roller side in a direction to collect toner into the toner container. A developing device characterized in that the toner adsorbed on the surface can be collected in the toner container side. 2. A developing roller is disposed at an opening of a toner container so as to face a photosensitive drum, and the developing roller is formed by the photosensitive drum and the developing roller from the toner supply side of the opening by the rotation of the developing roller. The toner guided to the developing position to be transferred can be selectively transferred to the photosensitive drum side, and the toner is collected from the toner collecting side of the opening located below the developing position. In the developing device, on the toner recovery side of the opening, on the bottom surface of the toner container, a rotation member capable of adsorbing toner, having a rotation center closer to the photoconductor drum than a rotation center of the developing roller, The developing roller of the rotating member is provided so as to face the photosensitive drum in a non-contact state and to scrape off the toner adsorbed on the surface of the rotating member. While the peripheral surface is rotated in the direction of collecting the toner in the toner container, the toner adsorbed on the surface of the rotating member is collected by the scraping means and the developing roller using the rotational force of the developing roller. A developing device characterized in that it can be configured. 3. A magnetic brush capable of rubbing the surface of the rotating member by the scraping means, and a base end fixed to an inner wall surface of the toner container, and a free end of the magnetic brush contacting the surface of the rotating member. 3. The developing device according to claim 2, wherein the developing device is a scraping plate.