JPS58214178A - Developing device - Google Patents

Abstract

PURPOSE:To always supply the uniform development to a development part, by providing a means to which stirs the developer and moves repetitively for approximation and separation to a supply means in a developer storing container. CONSTITUTION:The developer is stored in a developer container 1, and a developer supply roller 2 is set at the lower part and opposite to a photosensitive drum 5. The tip of a stirring member 7 which oscillates in the container 1 approximates to a sleeve 4 up to a gap D1. While the member 7 forms a gap D2 to the bottom surface of the container 1. For the member 7, the both ends of a round rod bent into substantially a U-shape are adhered at the places near edges of an oscillating shaft 7'. A single megnetic pole S2 of a magnet roller 3 is set at the side opposite to the toner carrier surface of a sleeve corresponding to the gap D1. The tip of the member 7 approximates most to the junction of the sleeve 4 and the bottom part of the container 1 at the avove-mentioned D1. The gap between the member 7 and the bottom surface of the container 1 is equivalent to said D2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dry developing device for an image forming device, and particularly to a dry developing device for an image forming device, and in particular, a dry developing device for uniformly carrying a developer (hereinafter simply referred to as toner) in a supply means for supplying the developer to a developing section. The invention relates to a developing device.

In a developing device used in an image forming apparatus such as a transfer-type electrophotographic copying machine, which develops an electrostatic latent image on a photoreceptor with a developer and then transfers the developed image to a transfer material to obtain a copy, a supply means is used. In order to appropriately supply developer powder to the developing section, the toner in the developer container is constantly in contact with the above-mentioned supply means. There are roller-like and belt-like means for developing and supplying agents. For example, for magnetic toner, the developing roller has a cylindrical non-magnetic sleeve in which a magnetic field generating means is arranged, and the relative rotational movement between the magnetic field and the sleeve causes the toner to be deposited on the sleeve. The processed toner is transported to the developing section. The developing roller is disposed substantially parallel to the surface of the photoreceptor carrying the electrostatic latent image, and most of the circumferential surface of the roller is housed in a hopper. Since the hopper gradually expands from the developer roller to the road force, the toner inside is focused by gravity toward the developer roller.

By the way, when using an actual copy machine, it is not always the case that full-size originals (the maximum size that can be copied) are used. When copying small-sized originals, the part where there is no original (on the original platen) is not always used. The document cover surface that covers the document is usually white).
Further, even if the document is a full-size document, the outer periphery of the document is often white. Therefore, if copying is continued in this state, less developer will be used up in the portion of the developing device corresponding to the white portion of the document, and the toner will become lumpy in this portion, resulting in uneven toner distribution.

Therefore, even though the toner degeneracy in the developing device is sufficient, there are areas on the photoreceptor where the toner supply is low, resulting in low development density, and areas with a lot of toner (both ends of the bottom of the hopper). (c) The toner becomes blocked due to its own weight, and toner is not sufficiently supplied to the sleeve opening, resulting in areas with low development density or areas that are not developed at all. As a means to solve this problem, it is known to drive and rotate a spiral screw in the developing device to agitate the developer, but the device becomes large and complicated, and the bearings are prone to clogging of the developer. There is a risk of causing Furthermore, even if a stirring means such as a blade, plate, wire rod, etc. is arranged in the upper part of the hopper in the longitudinal direction,
Although it has the effect of stirring and mixing the toner newly supplied to the hopper with the toner already stored, the area near the developer supplying means at the bottom of the hopper is not stirred, so it has the disadvantages as shown in F.

(1) Toner tends to accumulate at the bottom and both ends of the hopper, and the toner is not sufficiently supplied onto the developing roller provided at the bottom of the hopper, resulting in an oblique and low density image at the edges. This is because toner consumption is low in this area, so the toner accumulates, the toner's own weight increases the pressing force 17, and the toner becomes blocked and cannot be supplied to the opening. Furthermore, due to the increased pressing force of the toner 2, the developing roller is more likely to be contaminated by the toner.

This is particularly noticeable in pressure toner.

(2) Cross-linking and blocking tend to occur in the F side of the hopper, which causes uneven development and fogging when the aggregated toner is supplied to the developing roller.
There was a point. Furthermore, when the toner J- formed on the sleeve is regulated by a blade, the aggregated toner remains on the blade and scratches the subsequent toner layer, resulting in linear unevenness in addition to normal development unevenness and fog. Sometimes this occurred. In some cases, the agglomerated toner becomes more hardened and scratches the surface of the photosensitive drum, significantly shortening its lifespan.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a developing device that can always supply uniform developer to a developing section.

In a developing device, the present invention includes a storage container that stores a developer, a supply means that is provided below the storage container and supplies the developer to a developing section while holding the developer, and a supply means that is installed in the storage container. , and a stirring means for stirring the developer by repeatedly approaching and separating from the supply means.

An embodiment of the present invention will be specifically described below with reference to the drawings.

fJl, Figure 2.3 shows a first embodiment in which the present invention is applied to a copying machine that conveniently uses a drum-type photoreceptor. Figure 1 is a side view of the dry developing device, Figure 2 is a front view of the section viewed from the arrow XX, i@3
The figure is a plan view of the U push member 7. Although omitted from the figure,
Around the photosensitive drum 5, a charging machine + 1'11 image gil exposure mechanism, a transfer mechanism, a cleaning mechanism, and a static elimination mechanism, which are well-known electronic processes, are arranged.

In FIG. 1, a developing roller 2 is disposed substantially flat with a photosensitive drum 5 below a hopper 1 that has gradually expanded toward the road. The developing roller 2 has a non-magnetic sleeve 4 that rotates in a counterclockwise direction C7 and a magnetic roller 3 that is fixed inside the sleeve so as not to rotate. The photosensitive drum 5 is exposed from the photosensitive drum 5 and is disposed close to the photosensitive drum 5 in a substantially parallel state. A blade 6 is fixed to the hopper 1 above the developing roller 2 and close to the sleeve 4. Inside the hopper, a swinging stirring member 7 is provided so that its tip is close to the sleeve 4 up to a gap D1, while forming a close gap to the bottom wall of the hopper 1. It is being FIG. 3 is a plan view of the stirring member 7 used in the first embodiment. After inserting both ends of a round rod bent into a substantially U-shape into the vicinity of each end of the swing shaft 7', the short arm 7'' is bent into a substantially R-shape.
'iIt is just a stirring member.

Further, one magnetic pole S of the magnetic roller 3 is disposed on the opposite side of the toner carrying surface of the sleeve corresponding to the gap.

Incidentally, FIG. 4 is an explanatory diagram of the above-mentioned gap;
The junction of the sleeve 4 and the hopper bottom la is called point A. The gap when this point A and the tip of the stirring member 7 are closest to each other is as shown above, and the gap between the stirring rod 7 and the hopper bottom 1a is as shown above.

In Figure 2, the blade 6 maintains a constant gap between the blade and the developing roller by regulating spacers 9 provided at both ends of the developing roller 2, and The amount of toner supplied to the machine is regulated to be uniform and constant. (Currently, the rollers 10 and 11 disposed at both ends of the elephant rollers are in constant contact with the photosensitive drum 5 during operation to maintain a constant gap between the photosensitive drum and the sleeve.

The table shows the specifications of the dry developing device in the first embodiment and the second embodiment described later. As in the present invention, if the bottom of the hopper is moved toward the developing roller and is repeatedly stirred, even if the toner is temporarily shifted,
The surface pressing effect of the agitating member and the diffusion effect of the toner's own weight uniformize the toner up to the supply means and along the developing roller in an extremely short period of time, so that uneven distribution of the toner is eliminated. This effect is caused by the gap between point A and the stirring member shown in FIG.
depends on. According to experiments, >10Fl+I+
However, there is no sufficient effect on uneven toner distribution, and D+ <
1 yam, there is a possibility that the stirring member 7 and the developing sleeve 4 will come into contact with each other. In addition, even if the stirring member is the developing sleeve 4
Even if the magnetic pole 3 does not come into contact with the toner, it may come into contact with the toner currently captured on the sleeve 4 and pressurize it, causing blocking. However, in the first embodiment and the second embodiment described later, the gap is l haze≦D,
When ≦10, the developer was well uniformed along the developing roller, and more preferably fJ, 3≦D, and ≦7.

Incidentally, the toner in the hopper loses fluidity, especially in the toner layer area, due to the moisture content of the toner, the outside air condition, and the weight of the toner particles, but it remains in a fluidized state after being stirred by the stirring member 7. Since the developing roller side is pushed away, a magnetic field from the magnetic pole S provided on the back of the sleeve 4 and the magnetic poles N, N, adjacent to the magnetic pole S acts on the toner in the gap.Then, the sleeve that has passed the gap acts on the toner. upper toner e
Since the fluid flows through friction on the sleeve, there is no decrease in fluidity up to the blade 6. Furthermore, the amount of l/ner supplied to the blade 6 is determined by the specifications of the stirring member 7, so that an excessive amount of l/ner is not supplied.

That is, in this embodiment, the developer can be supplied to the developing roller without interrupting the flow of the developer.

Gap, cage, shape of stirring member, number of oscillations, magnetic field force.

This is determined by the sleeve rotation speed, etc.

The gap in the first embodiment is preferably 1 m or more in order to prevent blocking of toner on the inner wall surface of the hopper due to friction between the hopper 1 and the stirring part 7 (as will be described later).
In the second embodiment, the gap D2 is Ova due to its structure.
Even so, I can't help but ask. ) If necessary, the rotating shaft of the stirring member may be arranged so that, for example, the short yoke part f can be slid freely, or the swing shaft de can be moved, so that the gaps J), , and D can be adjusted. Q. Incidentally, as described above, D2 may be any value as long as it is within the range of 1 mm≦D and ≦lOm+a.

5.6 shows a second embodiment of the present invention, FIG. 5 is a side view, and FIG. 6 is a perspective view of the stirring member. In the figure, the first
The same symbols are attached to the same members as those in the embodiment described above, and the description thereof will be replaced. In Figure 5, hopper 1 has gradually expanded toward the road.
A developing roller 2 is disposed below. The developing roller is a non-magnetic IJ-pull that rotates in a counterclockwise direction C3.
and a magnetic roller 3 fixed inside so as not to rotate.
A portion of the longitudinal surface of the sleeve is exposed from the popper, and is disposed close to and substantially parallel to the sensitive drum 5. A blade 6 close to the sleeve 4 is fixed to the hopper l above the developing roller. A remaining toner amount detection wire 15 is arranged in the longitudinal direction of the center inside the popper. A rotatable toner replenishment cartridge is attached to an opening 13 at the top of the hopper l. A short arm portion 14 is provided at the upper part of the hopper l so as to be fixedly attached to a rotation shaft 14' and swingable. A stirring member 7 is attached to the free end of the short arm member 14, and while rubbing the hopper wall,
It is possible to get close to the developing roller until its tip is in a gap with the developing roller.

A stopper 16 is provided to prevent the lower stirring member 7 from contacting the sleeve 4 by 1ζb. FIG. 6 is a perspective view of the stirring member 14 used in the second embodiment. The short arm member 14'' is a round bar bent into a substantially U-shape, and the fJ end is connected to the rotation axis 1.
The stirring rod 7 is a round rod bent in a substantially U-shape, with both ends bent in a substantially U-shape attached to the short arm member 14. , can freely rotate relative to the short arm member. According to the agitation means 1 to 1 shown in the second embodiment, even if there is a remaining amount detection wire or other attached items in the hopper, the current level at the bottom of the hopper can be maintained without coming into contact with or being disturbed. The stirring action can be extended to the vicinity of the roller.

As explained above, according to the present invention, the following effects can be achieved by stirring the bottom of the hopper.

1゜Since the developer immediately before the developer supply means is constantly subjected to the stirring effect of the stirring member and the diffusion effect of the toner's own weight, the toner in the hopper is fluidized and homogenized, so any original can be used. However, the toner does not shift.

2. Since the toner is fluidized in a short time immediately before the supply means, there is no time for the pressing force due to the weight of the toner itself to increase. Therefore, the toner is not pushed against the supply means, and the toner does not adhere excessively, so that the developing sleeve is not contaminated.

3. Since the stirring member stirs the vicinity of the confluence of the developing sleeve and the bottom of the hopper and replaces the toner in that part υ), the toner on the developing sleeve is made to flow uniformly and a single layer of uniform toner can be formed.

4. Since the toner charges caused by friction with each other or with the sleeve are made uniform, a stable and good image quality can be obtained.

As described above, according to the present invention, extremely high quality and stable images can be obtained.

In the present invention, a rod-shaped stirring member will be described, and it goes without saying that it has one hole, but it does not need to be rod-shaped, and may be blade-shaped, plate-shaped, columnar, etc.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a dry type actual device showing a first embodiment of the present invention, FIG. 2 is a front view of the same, FIG. 3 is a plan view of the stirring member used in the above embodiment, and FIG. Figure 4 shows the gap, ,D!
FIG. 5 is a sectional side view of a dry developing device showing a second embodiment of the present invention, and FIG. 6 is a perspective view of a stirring member used in the second embodiment. 1... Hopper (container), 2... Developing roller (supply means), 7.14... Stirring member (stirring means),
8...Developing section, DI...Gap between sleeve and keyaki stirring member, D2...Gap between hopper and stirring member Applicant: Canon Co., Ltd. Agent Gi Marushima --Ma

Claims (2)

[Claims] (1) A storage container that stores a developer; a supply means that is provided below the storage container and supports the developer and supplies the developer to the developing section; and a supply means that is provided within the storage container. A developing device comprising: a stirring means that repeatedly moves close to and away from a developer to stir the developer. (2) The developing device according to claim 1, wherein a gap between the supply means and the stirring means in the close state is 1 m≦D and ≦10 m.