JPS5997166A - Agitator for developer - Google Patents

Abstract

PURPOSE:To agitate a developer in the rotating direction with respect to a shaft and to enable the axial movement thereof by providing the 1st and 2nd agitating vanes and isolating the two vanes from each other by means of a shielding body. CONSTITUTION:The driving shaft 18 of an agitator 17 is rotated during developing, and the 1st and 2nd spiral vanes 19, 23 are respectively rotated. A developer 24 is conveyed while it is agitated by the rotation of the vane 23. The conveyed developer 24 is fed through an aperture 22 into a cylindrical body 20 and as the vane 19 rotates, the developer is agitated in the direction opposite from the direction where it is fed by the vane 23, and is thus conveyed. More specifically, the developer 24 is agitated and conveyed while it circulates between the outside and inside of the body 20 around the shaft 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a developer stirring device provided in a developing device of a dry type electrophotographic apparatus, for example.

For example, a stirring blade 1 as shown in FIG. 1 is used as a developer stirring device in a dry electrophotographic developing device using a type of developer. An example of a developing device equipped with this stirring blade I is as shown in FIG. Since there is no movement of the developer 3 in the axial direction, it is necessary to drop the toner 4 uniformly in the axial direction when replenishing the toner 4. Basically, the toner hopper 5 is structurally located above the developer 6. Become. Although it depends on the capacity of the toner 4, the height of the developing device 6 as a whole can be reduced to a certain extent, and the size of the entire copying machine can only be reduced to a certain extent. Furthermore, the means for replenishing the hopper 5 with the toner 4 is also relatively troublesome. Also, developer 3
Since the toner does not move in the axial direction, when a transfer sheet other than the effective development width is continuously copied, the toner 4 is consumed only in the width of the transfer sheet, resulting in a shortage. Therefore, when a transfer sheet having an effective width for development is subsequently copied, the resulting copy image is non-uniform, that is, the left and right images have different densities. Furthermore, the location where the toner concentration detection device is installed is also a problem, as the functionality is halved and may cause malfunctions. Furthermore, it is necessary for a copying machine having a developing device 2 having such a structure to be installed and used in a horizontal position, and if
When a copying machine is installed with a slight inclination, the developer 3 in the developing device 6 may be shifted to one side, and the developer 3 may be tilted to the other side.
This overflows and contaminates the inside of the copying machine, and at the same time causes defects in the copied images.

The only way to solve the above-mentioned problem is to completely collect the developer 3 that has been used for development, replenish the collected developer 3 with toner 4, and stir it thoroughly before using it. In order to stir and transport the developer 3 in both the left and right directions, the structure becomes complicated and the developing device 6 itself becomes large.

In fact, all the developing devices in copying machines on the market that perform the functions of horizontal stirring and conveyance have complicated structures and are large in size. Several eye 7" 4a types have been proposed for coaxially configured double swivel stirrers, but all of them only have excellent stirring performance in the circumferential direction relative to the shaft. There is no complete lateral movement of the developer, but there is only movement with a pitch difference between the double spiral and the double spiral.Therefore, the above-mentioned disadvantages cannot be solved.

In addition, in order to confirm the performance of the coaxial double spiral system, we dropped toner from a certain point and measured the time it took for the toner to spread in the left and right directions.We found that the toner specific concentration only increased significantly only near the toner falling point. Even after stirring for several minutes, there was no tendency for the relative concentration of the left and right toners to increase. That is, there is no movement of the developer in the axial direction, and no toner diffusion occurs. Further, depending on the rotating direction of the developing magnet roller 7, a function for scraping up the developer 3 must be added, resulting in a structurally complicated button.

Note that 8 in the figure is a photoreceptor.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to have a relatively simple structure, but also to be able to stir the developer in the rotational direction with respect to the shaft. It is an object of the present invention to provide a developer stirring device that can also move the developer.

[Summary of the invention]

The present invention has first and second agitating blades coaxially, the first and second agitating blades are separated by a 5-shield, and the rotation of the first and second agitating blades allows development. This conveys the agent in the rotational and axial directions.

[Embodiments of the invention]

The present invention will be described below with reference to an embodiment shown in FIGS. 3 to 5. In the figure, reference numeral 11 denotes a developing device provided close to the photoreceptor 12. This developing device 11 has a container 13, and within this container 13, a developing magnet and a troller 14 are provided facing the photoreceptor 12. A blade 15 is opposed to the surface of the developing magnet roller 14 with a predetermined interval therebetween, and one end of the blade 15 is brought into contact with the circumferential surface of the developing magnet roller 14 at the lower part thereof. A scraping plate 16 is provided. Further, a stirring device 17 is provided inside the container 13 in parallel with the developing magnet roller 14 . This stirring device 11 has a drive shaft 18 as shown in FIG. 4, and a first spiral blade 196- as a first stirring blade is attached to the outer peripheral surface of the drive shaft 18. The drive shaft 18 is rotatably driven by a drive mechanism (not shown). Further, the first S/4' spiral blade 19 is surrounded by a cylindrical body 20 as a shield, and both ends of this cylindrical body 200 are fixed to the drive shaft 18 via seven flange 21 (one end side (only shown). Further, openings 22 are formed at both ends of the cylindrical body 20 (only one end is shown), and a second spiral blade 23 as a second stirring blade is attached to the outer peripheral surface. There is. The second spiral blade 23 has a different torsional direction and pitch from the first spiral blade 19.

Therefore, during development, the drive shaft 18 of the stirring device 17
is rotated by a drive source (not shown). This rotation causes the first and second spiral blades 19 and 23 to rotate, respectively, and the rotation of the second spiral blade 23 transports the developer 24 in the direction of the arrow while being stirred. The transported developer 24 is then transferred to the opening 2 of the cylindrical body 20.
2 into the cylindrical body 20, and is then conveyed while being agitated by the rotation of the first spiral blade 19 and the rotation of the second spiral blade 23 in the opposite direction to the direction in which it was sent. . That is, the developer 24 is circulated around the drive shaft 18 between the outside and inside of the cylindrical body 2o and is agitated.
transported.

Incidentally, FIG. 5 shows the results of an experiment in which the performance of the stirring device 17 was confirmed. In other words, it is a method of dropping toner from a certain point and seeing how long it takes for it to spread.
450 Il! In the range of l+I st4, it takes only 4 seconds for the toner specific density to become uniform regardless of the amount of toner falling.

The diffusion time of the developer can be adjusted by combining the rotational speed of the stirring device 17 and the pitch width and span width of the spiral blades 19.degree. 23.

In addition, since the stirring effect is sufficient, it is possible to prevent the interior of the copying machine from becoming dirty due to scattering of uncharged toner.

〔Effect of the invention〕

As explained above, the present invention is provided with first and second stirring blades, the first and second stirring blades are separated by a shield, and the rotation of the first and second stirring blades is performed. Because the developer is conveyed in the rotational and axial directions, it is not restricted by the rotational direction of the developing magnet roller, and there is no difference in density in the copied image. .

Furthermore, even if copying machines are somewhat similar, no defects will occur in the copied images, and furthermore, the structure can be simplified and a compact and inexpensive developing device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a side view showing a conventional stirring device, FIG. 2 is a side sectional view showing a developing device equipped with the stirring device, and FIGS. 3 to 5 show an embodiment of the present invention. FIG. 3 is a side sectional view showing the developing device, FIG. 4 is a side view showing the stirring device, and FIG. 5 is a graph showing the diffusion speed of the developer. 9-19...First stirring blade (first snowboard blade)
, 23... second stirring blade (second spiral blade)
, 20... Shielding body (cylindrical body). Applicant's agent Patent attorney Takehiko Suzue 10-ku ff1t ”IJ41U) Saddle

Claims (5)

[Claims] (1) A first stirring blade rotatably provided on the rotating shaft, a second stirring blade provided on the rotating shaft without interfering with the first stirring blade, and these first and second stirring blades. A developer agitator characterized by separating the agitating blades and transporting the developer in the axial direction. Pushing device. (2) The developer agitating device 0 according to claim 1, wherein the shielding body is configured in a cylindrical shape. (3) The developer stirring device according to claim 1 or 2, wherein the first and second stirring blades are spiral blades having different torsional directions. (4) Claim 1@J3 characterized in that each spiral blade has a different twist pitch.
Item: Shell sparrow image agent bag stirring device. (5) The developer stirring device according to claim 2, wherein openings are formed at both ends of the cylindrical shield.