JPS6232300Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for an electrostatic copying apparatus, and more particularly to a developing device for applying a developer to an electrostatic latent image to form a developed image in an electrostatic copying device.

A developing device in an electrostatic copying apparatus has conventionally included a developer holding member that holds a developer on its surface and applies the developer to an electrostatic latent image to be developed, and a developer that is supplied to the surface of the developer holding member. 2. Description of the Related Art A type of developing device equipped with a developer container containing a developer has been proposed and put into practical use.

However, as is well known to those skilled in the art, in the above-mentioned developing device, especially when the developer contained in the developer container is a so-called one-component developer consisting only of toner particles, The stored developer becomes lumpy and causes a so-called blocking phenomenon, which obstructs the smooth flow of the developer from the inside of the developer container to the surface of the developer holding member, resulting in uneven development, insufficient development, etc. There is an important problem that needs to be solved in that developing defects often occur.

Therefore, as disclosed in Japanese Patent Application Laid-open No. 52-148133, for example, a stirring member is provided in the developer container so as to be able to move back and forth, and the stirring member is moved back and forth during the copying process. Stir the developer inside.
Thus, it has been proposed to prevent the blocking phenomenon of the developer.

However, as a result of repeated experiments and ideas by the present inventors regarding the developing device configured according to the above proposal, it has been found that in the developing device configured according to the above proposal, the above-mentioned The agitation member is generally configured to be driven by a main motor for driving the various movable components of the electrostatographic apparatus, and when the electrostatographic apparatus is switched on, the reciprocating movement of the agitation member is It has been found that the following problems occur due to the fact that the reciprocating movement is continuously maintained during the copying process. That is, if the reciprocating movement of the agitating member disposed in the developer container is performed continuously during the copying process, the agitation work for the developer contained in the developer container becomes excessive, and the It has been found that agglomeration of the developer is promoted at the peripheral edge of the reciprocating range of the agitating member, promoting the blocking phenomenon, and therefore it is not possible to sufficiently prevent the occurrence of development defects.

The present invention has been developed in view of the above facts, and its main purpose is to effectively prevent the occurrence of developer blocking within the developer container, and to sufficiently prevent the occurrence of development defects. An object of the present invention is to provide an improved developing device in an electrostatographic reproduction apparatus.

Another object of the present invention is to effectively prevent the occurrence of developer blocking within a developer container with a relatively simple and inexpensive structure without requiring a complicated and expensive structure. Therefore, it is an object of the present invention to provide an improved developing device for an electrostatic copying apparatus, which can sufficiently prevent the occurrence of developing defects.

As a result of intensive research and experiments, the inventors of the present invention have developed a stirring member that is reciprocably disposed inside the developer container.
Instead of continuously reciprocating during the copying process, if the reciprocating movement is made for a limited period of time during the copying process, excessive agitation will cause a blocking phenomenon of the developer. It has been found that it is possible to effectively prevent the occurrence of the blocking phenomenon of the developer within the developer container, and therefore to sufficiently prevent the occurrence of poor development.

That is, according to the present invention, a developer holding member that holds a developer on its surface and applies the developer to an electrostatic latent image to be developed, and a developer that is supplied to the surface of the developer holding member are accommodated. In a developing device for an electrostatic copying apparatus, which includes a developer container and a stirring member for preventing developer blocking that is movably disposed in the developer container; the stirring member feeds copy paper. It is characterized in that it is drive-coupled to a paper feed roller which is rotationally driven for a certain period in each copying process in order to do so, and is moved only for a limited period of time in the copying process in accordance with the rotation of the paper feed roller. A developing device is provided.

In a preferred embodiment of the developing device of the present invention,
The developer container is configured to supply the developer contained therein to the surface of the developer holding member through a developer outlet opening, and the stirring member is arranged opposite to the developer outlet opening. It has an elongated rod-shaped portion extending across substantially the entire width of the developer outlet opening, and is reciprocally pivotable about an axis extending parallel to the width direction of the developer outlet opening.

Hereinafter, preferred embodiments of the developing device of the present invention will be described in more detail with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the developing device, generally designated by the number 2, includes a developer holding member 4 and a developer container 6. As shown in FIG.

The developer holding member 4 may be of any form as long as it can hold the developer 8 on its surface and apply the developer 8 to the electrostatic latent image to be developed to make it visible. In the illustrated example, the developing sleeve 12 is comprised of a cylindrical developing sleeve 12 that is rotatably mounted and rotationally driven in the direction shown by the arrow 10, and a stationary permanent magnet 14 disposed within the developing sleeve 12. The stationary permanent magnet 14 has a roll shape, and a plurality of magnetic poles (four in the illustrated case) are formed on the peripheral edge thereof at intervals in the circumferential direction.

The developer container 6 may be of any type as long as it can supply the developer contained therein to the surface of the developer holding member 4, but in the illustrated example, the developer container 6 It consists of a box-shaped body with an open top surface, which is disposed adjacent to and behind the holding member 4 (on the right side of the developer holding member 4 in FIG. 1). At the lower end of the front wall of the developer container 6, that is, the wall located close to the surface of the developer holding member 4, there is provided a wall extending approximately across the entire width of the developer holding member 4 in the direction perpendicular to the plane of the paper in FIG. A developer outlet opening 16 is formed that extends therethrough. Further, a spike length adjusting member 18 having a free end projecting beyond the lower edge of the developer outlet opening 16 toward the surface of the developer holding member 4 is attached to the lower side of the developer outlet opening 16. ing.

In the developing device 2 as described above, an appropriate developer 8, preferably a so-called one-component developer consisting only of magnetic toner particles, is introduced into the developer container 6 from the upper surface of the developer container 6, and the developer is developed. It is housed in the agent container 6. The developer 8 in the developer container 6 then flows out through the developer outlet opening 16 and is supplied to the developer holding member 4 . Developer holding member 4
magnetically holds the developer 8 on the surface of the developing sleeve 12 by the action of the magnetic field generated by the stationary permanent magnet 14. The developer 8 held on the surface of the developing sleeve 12 is moved as the developing sleeve 12 is rotated in the direction shown by the arrow 10, and in the illustrated example, is rotated in the direction of the arrow 20. Photosensitive drum 22
is applied to the electrostatic latent image to be developed, which has been formed on the surface of the electrostatic latent image, thus making the electrostatic latent image visible. The amount of developer 8 supplied from the developer container 6 and held on the surface of the developing sleeve 12 can be controlled by appropriately setting the distance between the free end of the spike length adjusting member 18 and the surface of the developing sleeve 12. and adjusted as required.

Although the above-described structure and operation of the developing device 2 are already well-known, in the developing device having only the above-described structure, as already mentioned, the developer 8 contained in the developer container 6 is The developer becomes agglomerated and causes a so-called blocking phenomenon, which obstructs the smooth flow of the developer 8 from inside the developer container 6 through the developer outlet opening 16 to the surface of the developing sleeve 12, thus preventing the development. Development defects such as spots and insufficient development often occur.

In order to solve this problem, in the developing device 2 constructed according to the present invention, a stirring member 24 for preventing developer blocking is provided in the developer container 6 so as to be able to move back and forth. 24 is configured to be reciprocated during a limited portion of the copying process performed in the electrostatographic reproduction apparatus.

The stirring member 24 may have any form as long as it can appropriately stir the developer 8 contained in the developer container 6 by reciprocating. The stirring member 24 in the illustrated example includes a portion 26 that faces the developer outlet opening 16 of the developer container 6 and extends within the developer container 6 in the width direction of the developer outlet opening 16 over substantially the entire width thereof; This part 26
portions 28 and 30 that curve upwardly from both ends of the developer container 6 and extend upwardly along the respective inner surfaces of both side walls of the developer container 6; It is composed of an elongated rod-like body having portions 32 and 34 extending in the lateral direction, and by rotatably supporting each of the portions 32 and 34 on each side wall of the developer container 6, the first It is mounted so that it can swing back and forth as shown by arrow 36 between the position shown by the solid line and the position shown by the two-dot chain line in the figure.

It is important that the stirring member 24 be allowed to reciprocate only during a limited portion of the copying process performed by the electrostatographic reproduction device.

During the copying process, the stirring member 2
If the agitating member 4 continues to reciprocate, as mentioned above, the agitation effect on the developer 8 contained in the developer container 6 will become excessive, and the developer 8 will become more concentrated at the periphery of the area where the agitating member 24 reciprocates. Clumping is promoted, and blocking development of the developer 8 is promoted.

As a method for causing the stirring member 24 to reciprocate only for a limited period of time during the copying process, as in the specific example shown in the drawings, a sheet copy paper 40 ( At the beginning of each copying process, the developing device 2 normally develops the electrostatic latent image in order to feed the copy paper (or copy paper unwound from a roll of copy paper) to a required copy paper transport path (not shown). If the electrostatic copying apparatus is equipped with a feeding roller 44 that is rotationally driven in the direction shown by the arrow 42 for a short period of time immediately before printing, the stirring member 24 is rotated by the feeding roller 44.
If the agitating member 24 is driven and connected to the feed roller 44 so that the agitating member 24 is reciprocated in accordance with the rotation of the paper feed roller 44, the agitating member 24 can be moved as required without requiring a relatively complicated and expensive configuration. It can be made to move back and forth.

Referring to FIG. 3 as well as FIGS. 1 and 2, in the illustrated example, the pair of paper feed rollers 44 are fixed to a rotating shaft 46. The rotary shaft 46 is operated as described above by means of a drive input transmitted to one end located on the left in FIG. As such, it is rotated only for a limited period of time during each copying process. The agitating member 24 of the developing device 2 constructed according to the present invention is connected to the rotating shaft 4.
6, that is, the end located on the right side in FIG.

An example of a drive connection mechanism between the stirring member 24 and the rotating shaft 46 will be described. A gear 48 is fixed to the other end of the rotating shaft 46, and this gear 48 is connected to the third end of the developer container 6. The gear 5 is rotatably mounted on the side wall located on the right side in Figure 2.
0 and 52 of the second developer container 6.
It is drivingly connected to a gear 54 rotatably mounted on the side wall located on the right side in the figure. gear 54
A pin 56 is implanted on the outer surface of the pin 56 at a position eccentric from the central axis by a predetermined amount. On the other hand, the second portion of the developer container 6 in the above-mentioned portion 34 of the stirring member 24
A lever 58 is fixed to the tip portion that protrudes through the side wall located on the right side in the figure. An elongated slot 60 is formed in the lever 58, and the pin 56 is inserted into the slot 60.

In the drive coupling mechanism as described above, when shaft 46 rotates in the direction shown by arrow 42 in FIGS.
4 and the pin 56 to the lever 58 and the stirring member 24 to which it is fixed, and the lever 58
The stirring members 24 and 24 are reciprocated as shown by arrows 36 between the positions shown by solid lines and the positions shown by two-dot chain lines in FIGS. 3 and 1, respectively.

Therefore, when the rotating shaft 46 to which the pair of paper feed rollers 44 is fixed is rotated for a limited period of time during each copying process as described above,
Correspondingly, the stirring member 24 of the developing device 2 is also caused to reciprocate only for a limited period of time during each copying process.

Thus, according to the developing device 2 constructed according to the present invention, blocking of the developer in the developer container can be achieved with a relatively simple and inexpensive construction without requiring a complicated and expensive construction. The occurrence of this phenomenon can be effectively prevented, and therefore the occurrence of development defects can be sufficiently prevented.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view showing a specific example of a developing device constructed according to the present invention. FIG. 2 is a sectional view taken along the line - in FIG. 1. FIG. 3 is a simplified diagram showing an example of a drive connection mechanism between the paper feed roller and the stirring member. 2...Developing device, 4...Developer holding member, 6...
... Developer container, 8 ... Developer, 24 ... Stirring member, 44 ... Paper feed roller.

Claims (1)

[Claims for Utility Model Registration] 1. A developer holding member that holds a developer on its surface and applies the developer to an electrostatic latent image to be developed, and a developer that accommodates the developer that is supplied to the surface of the developer holding member. In a developing device for an electrostatic copying apparatus, the developing device includes a developer container for transporting copy paper, and a stirring member for preventing developer blocking, which is movably disposed in the developer container; The paper feed roller is driven to rotate for a certain period of time during each copying process in order to feed the paper, and is moved only for a limited period of time during the copying process in accordance with the rotation of the paper feed roller. Characteristic developing device. 2. The developer container is configured to supply the developer contained therein to the surface of the developer holding member through a developer outlet opening, and the stirring member is opposite to the developer outlet opening. The utility model has an elongated bar-shaped portion extending in the width direction of the developer outlet opening over almost the entire width thereof, and is capable of reciprocating rotation about an axis extending parallel to the width direction of the developer outlet opening. Developing device according to scope 1.