JPH0542441Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a toner supply device used in an electrophotographic copying machine.

(Prior art) Conventionally, in electronic copying machines, so-called two-component toner, which is a mixture of powder toner and iron powder or magnetic powder called carrier, has been used as a developer to develop the electrostatic latent image formed on the photoreceptor. Alternatively, a one-component toner in which the toner itself has magnetism is used. These toners are triboelectrically charged by stirring and magnetically conveyed to a development position, where they are attracted to the electrostatic latent image and developed.

Therefore, each time development is performed, for example, in the case of two-component toner, the proportion of powder toner in the developer decreases, and the developer concentration decreases, and in the case of one-component toner, the developing device The magnetic toner itself decreases. Therefore, in order to always obtain clear copies, it is necessary to appropriately replenish toner in an amount equivalent to the consumed toner.

By the way, when toner is supplied into the developing device, if the toner is not evenly distributed and replenished within the developing device case, uneven supply will occur in the axial direction of the developing device, which will adversely affect development. Therefore, as shown in Japanese Patent Application Laid-Open No. 54-30840,
By providing a screw and a screw cover for transporting toner from a toner introduction section into a toner box that replenishes toner to the developing device case, the wall surface of this screw cover is sloped sequentially from the toner introduction section side and is lowered. A toner replenishing device has been proposed which is capable of simultaneously carrying and uniformly distributing toner into a toner box.

However, in the above-mentioned conventional device, in order to prevent toner from clogging, a relatively large opening is provided at the end of the opening, and the toner that has not completely fallen from the opening at the top of the sloped surface of the screw cover is allowed to fall through this opening. ing. For this reason, there is a risk that toner will be excessive at the lower position of the open end, causing toner scattering, and that the toner will not be sufficiently stirred, which may adversely affect the copied image.

(Purpose of the invention) The present invention was devised in view of the above-mentioned conventional problems, and includes an agitation roller having double agitation blades with different toner conveyance directions below the screw cover having the toner replenishment port. The purpose of the present invention is to provide a toner replenishing device that enables uniform toner replenishment, prevents toner scattering as described above, improves agitation performance, and enables uniform image quality development. do.

(Structure of the invention) The present invention has a cylindrical shape that is open at both ends in the axial direction, has agitation blades on the inner and outer circumferential surfaces that transport the toner in opposite directions, and is installed in a developing device case that contains an agitation roller that agitates the toner. The toner replenishing device replenishes toner, and is provided with a toner introduction section at one end, and a screw cover, which is equipped with a screw for conveying the toner supplied from the introduction section toward the other end, is placed above the agitation roller. The screw cover is provided over almost the entire length of the stirring roller in the axial direction, and is opened at a lower position sequentially in the axial direction from the toner introduction section side, and is located near the other end of the screw cover. A toner replenishment port is formed with a large opening at one opening position.

With this configuration, when the toner supplied from the toner supply port is replenished at the end of the supply port, it is sent to the other end by one stirring blade of the stirring roller located below the toner, and then the other stirring blade The developer is sent to one side while being stirred by the developer, and the developer is uniformly supplied to the developing section.

(Example) An example of the present invention will be described with reference to FIGS. 1 and 2.

A developing device 2 is disposed on the circumferential surface of the photoreceptor drum 1, and this developing device 2 includes a non-magnetic sleeve 5a which is rotatably driven within a developing device case 4 containing a developer 3, and this non-magnetic sleeve. a developing roller 5 consisting of a cylindrical magnet 5b arranged concentrically inside the developing roller 5a; and an agitating roller 6 that supplies the developer 3 to the developing roller 5 while stirring the developer 3.
A doctor blade 7 regulates the layer thickness of the developer 3 adsorbed onto the non-magnetic sleeve 5a, that is, the height of the so-called magnetic brush, and the toner blocked by the doctor blade 7 is transferred to the stirring roller 6 side. It is composed of a guide plate 8 and the like for refluxing the water to the water. A toner introduction section 9 as a hopper into which the toner 3a to be replenished is introduced is provided at one upper end of the developing device 2, and the toner introduction section 9 is connected to the toner introduction section 9 to receive the toner supplied from the introduction section. A screw cover 11 containing a screw 10 for conveying the toner toward the other end is provided above the stirring roller 6 over substantially the entire length of the stirring roller 6 in the axial direction.

A toner replenishing port 12 is formed on the wall surface of the screw cover 11. The toner replenishing port 12 is sequentially inclined in the axial direction from the toner introducing portion 9 side, opens at a lower position, and opens wide at an open end 12a near the other end. Also,
The screw 10 is rotatably driven by a motor (not shown) or the like via a drive shaft 10a.

On the other hand, the agitation roller 6 has a cylindrical shape with both ends opened in the axial direction, and has agitation blades 6a and 6b on the inner and outer circumferential surfaces for conveying toner in opposite directions.
Further, stirring plates 13 are provided opposite to the openings at both ends of the stirring roller 6, and the stirring roller 6 and the stirring plate 13 are fixed to a stirring roller shaft 14 which is rotatably supported by the developing device case 4. The roller shaft 14 is rotatably driven by a drive source of the main body of the device via a drive gear 15.

The opening end 12a of the toner supply port 12 of the screw cover 11 is located above the opening at the end (left side in FIG. 2) of the stirring roller 6, and The stirring blade 6a on the inner peripheral surface has a spiral shape and is configured to be able to transport toner from the left end to the right end in FIG. 2, and the stirring blade 6b on the outer peripheral surface moves from the right end to the left end. It is configured to be able to transport toner.

Next, the operation of the above configuration will be explained. The developer 3 in the developing device case 4 is agitated by the stirring roller 6 and is attracted to the surface of the non-magnetic sleeve 5a by the magnetic attraction force of the cylindrical magnet 5b of the developing roller 5, and as the sleeve 5a rotates in the direction of the arrow. The film is transported to a developing section facing the photosensitive drum 1 while its thickness is regulated by a doctor blade 7.
Here, a so-called magnetic brush is formed and the photosensitive drum 1 is
The electrostatic latent image is developed by contacting the electrostatic latent image formed on the surface of the electrostatic latent image.

After completing the development, the toner components of the magnetic brush are attracted to the electrostatic latent image, so that the magnetic brush is composed mostly of carrier iron powder and falls into the developing device 4 again. Then, new toner is supplied onto the agitation roller 6 from the toner replenishing device having the above-mentioned structure by the amount of toner that has decreased. That is, the toner 3a introduced into the toner introduction section 9 is transferred to the screw cover 1 by the action of the screw 10 which is rotationally driven.
1 receives a force in the thrust direction and is transported from one end of the introduction section side to the other end, and also receives centrifugal force due to the rotation of the screw 10 and is also blown away in the circumferential direction. At this time, a toner supply port 1 is formed on the wall surface of the screw cover 11, which is gradually inclined and lowered.
2, the toner 3a falling from the toner supply port 12 onto the stirring roller 6 is uniformly scattered in the axial direction of the stirring roller 6.

Further, the toner that has not completely fallen from the toner supply port 12 is removed from the open end 12 to prevent toner clogging.
It falls from a to the vicinity of the opening at the end of the stirring roller 6 and is replenished, but at this point, with the help of the rotation of the stirring plate 13, it is carried into the inside of the stirring roller 6 from the opening at the end as shown by the arrow. The developer 3 is conveyed from the left to the right in FIG. 2 by the spiral of the stirring blades 6a formed on the circumferential surface while being stirred with the carrier of the developer 3.
At the right end opening of this stirring roller 6, the other stirring plate 1
The developing material is conveyed to the outer peripheral surface of the stirring roller 6 with the help of the rotation of the stirring roller 6, and further stirred and transported from the right to the left by the action of the stirring blades 6b formed on the outer peripheral surface of the stirring roller 6. It is attracted to the surface of the cylindrical sleeve 5b of the roller 5.

The toner 3a replenished at the end of the toner replenishment port 12 falls near the end opening of the agitation roller 6, and is conveyed while being agitated with the carrier by the agitation blades 6a on the inner peripheral surface. The toner 3a no longer remains near the bottom of the toner 12a, and therefore,
Toner scattering in that area does not occur, and the toner is prevented from being adsorbed to the developing roller 5 with insufficient stirring, improving the stirring performance and increasing the triboelectric charging effect of the developer 3. Development with stable and uniform image quality is possible at all times.

Note that in an embodiment in which the photosensitive drum 1 and the developing roller 5 of the developing device 2 are rotationally driven in the forward direction as in the above embodiment, the agitation roller 6 also functions as a pumping roller for pumping up the developer to the developing roller 5. However, in the case of a configuration other than the forward direction type, a developer pumping roller may be separately provided between the stirring roller 6 and the developing roller 5.

Further, the toner 3a introduced into the toner introduction section 9
The present invention can also be applied to a type in which the toner scraped from the surface of the photoreceptor drum 1 is reused in a cleaning device in the post-transfer process of a copying machine; in this case, a hopper part is not necessary. It disappears.

Further, in the above description, the description has been made mainly of two-component toner, but the present invention is not necessarily limited to this, and can be similarly applied to a case where a one-component toner is used as necessary.

(Effects of the invention) As described above, according to the invention, the stirring roller has a cylindrical shape that is open at both ends in the axial direction and has stirring blades on the inner and outer peripheral surfaces that transport toner in opposite directions. A screw cover, which is equipped with a screw for conveying the toner supplied from the introduction part toward the other end, is provided above the agitation roller over almost the entire length in the axial direction. Since the toner replenishment port is formed on the wall surface in a sequentially inclined manner in the axial direction from the toner introduction section side and opens at a low position, near the other end, and has a large opening at one opening position of the stirring roller, The replenished toner is uniformly replenished over the entire length of the stirring roller in the axial direction, and the toner that falls from the opening end of the toner replenishing port to prevent toner clogging is immediately removed by one stirring blade of the stirring roller. Since the toner is conveyed to the other end while being stirred, the toner does not stay in the vicinity of the lower part of the opening. Therefore, it is possible to effectively prevent the toner from scattering in that area, and the toner is evenly distributed. , it is possible to supply a homogeneous developer and to make the image quality uniform.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a developing device equipped with a toner replenishing device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line of FIG. 1. 2...Developing device, 3...Developer, 3a...Toner, 4...Developing device case, 5...Developing roller,
6... Stirring roller, 6a, 6b... Stirring blade, 9...
...Toner introduction part, 10... Screw, 11...
Screw cover, 12...Toner supply port, 12
a...Open end.

Claims (1)

[Scope of utility model registration request] The toner replenishing device has a cylindrical shape that is open at both ends in the axial direction, has agitation blades on the inner and outer circumferential surfaces that transport the toner in opposite directions, and replenishes toner into a developing device case that includes an agitation roller that agitates the toner. The screw cover is equipped with a toner introduction section at one end and a screw that transports the toner supplied from the introduction section toward the other end.
The screw cover is provided above the stirring roller over almost the entire length of the stirring roller in the axial direction, and is opened at a lower position sequentially inclined in the axial direction from the toner introduction section side on the wall surface of the screw cover and near the other end. . A toner replenishing device, characterized in that a toner replenishing port having a large opening is formed at one opening position of the stirring roller.