JP2613413B2 - Toner hopper blocking prevention mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a mechanism for preventing blocking of a toner hopper of a mixed two-component developing device used in an electrophotographic printing apparatus or the like. In a mixed two-component developing device comprising: a toner hopper; and a sponge roller provided below the toner hopper and driven by a driving source to rotate and supply the toner in the toner hopper to a developing tank. A coil-shaped agitator is provided, and at each end of the agitator, a support member including a pair of flanges provided with knurls on the outer periphery and a shaft protruding from the flange is fitted, and each of the support members is The outer periphery of the flange of the support member is pressed against the outer periphery of the sponge roller at a position near the outer wall in the toner hopper. A structure in which is supported by said shaft in opposing side walls of the toner hopper to.

[Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for preventing blocking (fixing and remaining of toner) of a toner hopper of a mixed two-component developing device used in an electrophotographic printing apparatus or the like.

2. Description of the Related Art In an electrophotographic printing apparatus, a latent image is formed on a toner image carrier such as a photosensitive drum by pre-charging and exposure, and the latent image is developed by a developing device to form a toner image. The toner image is transferred to paper and fixed. Printing. As a developing device, a mixed two-component developing device having a toner hopper is widely used. In this case, prevention of blocking of the toner hopper is an important issue.

[Conventional technology]

FIG. 4 is a side view schematically showing the structure of this type of mixed two-component developing device. In the drawing, 1 is a scraping roller, 2 is a developing roller, 3 is a doctor blade, 4 is a scraper, 5 is a developing tank, 6 Denotes a toner hopper and 7 denotes a sponge roller. The toner is supplied to the toner hopper 6 by dropping the toner from the toner cartridge 8 mounted on the toner hopper 6. A developer having an appropriate mixing ratio is previously charged into the developing tank 5, and the developer is agitated by the agitating roller 1, conveyed to the surface of the developing roller 2, and developed by the developing roller 2. While being conveyed to the position (a), Hotaka regulation by the doctor blade 3 is performed on the way. Then, the latent image on the photosensitive drum 9 is developed at the developing position (a). The residual toner remaining on the developing roller 2 after the development is scraped off by the scraper 4 and reused.
When the development is continued and the concentration of the developer decreases, the toner in the toner hopper 6 is replenished into the developing tank 5 by the rotation of the sponge roller 7, and the developer concentration in the tank is always kept constant. The driving of the sponge roller 7 is performed based on the detection result of a density sensor (not shown) that detects the developer density in the developing tank 5.

It is necessary to use up the toner in the toner hopper 6 which plays such a role until the toner is exhausted. However, since the toner is a powder having poor fluidity, the toner often remains in the hopper as shown in FIG. This is a phenomenon called blocking, and reference numeral 10 in FIG. 5 indicates the toner that has caused blocking. Therefore, measures to prevent this blocking are required. FIGS. 6 and 7 show a conventional toner hopper blocking prevention mechanism.
The operation will be described.

In the case of FIG. 6, the toner hopper blocking prevention mechanism is used.
Reference numeral 11 denotes an arm 12 rotatable outside the toner hopper 6 and a drive source (not shown) for driving the arm 12 to reciprocate between a solid line position and a dotted line position. 13 are provided. When the arm 12 comes to the position indicated by the solid line, the spherical portion 13 hits the outer wall of the toner hopper 6 and vibrates to cause the dotted toner adhered to the inner side of the outer wall.
10 is dropped as shown by the solid line to enable the sponge roller 7 to supply the developer into the developing tank 5.

In the case of FIG. 7, the toner hopper blocking prevention mechanism 12 is an agitator that can rotate inside the toner hopper 6.
22 and an external drive source (not shown) for driving the agitator 22 to reciprocate. Then, the rotation of the agitator 22 causes the toner attached to the inside of the outer wall of the toner hopper 6 to drop.

[Problems to be solved by the invention]

However, these conventional mechanisms have the following disadvantages.

(1) In the case of the mechanism shown in FIG. 6, the sound generated when the outer wall is hit by the spherical portion 13 is noisy. In addition, since a structure is provided outside the hopper, a space for this is required, and the cost increases. It is difficult to apply to desktop small and low-cost models.

(2) In the case of the mechanism shown in FIG. 7, sound does not matter, but the cost for driving is increased as in the case of FIG.

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner hopper blocking prevention mechanism capable of preventing occurrence of blocking in a toner hopper with a simple and inexpensive structure.

[Means for solving the problem]

FIG. 1 is a view for explaining the principle of the present invention. FIG. 1 (a) is a side view showing a state in which a toner hopper blocking prevention mechanism is mounted.
FIG. 1B is a perspective view showing the structure of the toner hopper blocking prevention mechanism. In the drawing, reference numeral 31 denotes a toner hopper blocking prevention mechanism, and reference numerals 6 and 7 denote the same toner hopper and sponge roller as in the related art.

The toner hopper blocking prevention mechanism 31 is a support member comprising a pair of flanges provided with knurls on the outer periphery at each end of the coiled agitator 32 and a shaft protruding from the flanges.
33, and each support member 33 is
The outer periphery of the flange 35 is supported by a shaft on the opposing side wall 6b of the toner hopper 6 so as to press against the outer periphery of the sponge roller 7 at a position near the outer wall 6a in the toner hopper 6.

(Operation)

When the sponge roller 7 is rotated at the time of toner replenishment, each support member 33 which comes into pressure contact with the sponge roller 7
Since it rotates at a position close to the outer wall 6a of the toner hopper 6 together with 32 and has an indentation on the outer periphery of the flange 35 constituting each support member 33, there is no drive failure. Therefore, even if the toner adheres to the outer wall 6a, the toner is effectively scraped off by the rotation of the coil-shaped agitator 32, and the occurrence of blocking is prevented.

It is more effective to provide this prevention mechanism close to both outer walls 6a as illustrated in FIG. 1 (a).

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 2 and FIG.

FIG. 2 is a structural explanatory view of a toner hopper blocking prevention mechanism according to the present invention, and FIG. 3 is an enlarged perspective view of a main part of FIG. 2, and 31 is a toner hopper blocking prevention similar to that described in FIG. A mechanism 34 is a drive motor for driving the sponge roller 7. Next, the configuration and operation of the toner hopper blocking prevention mechanism 31 will be described with additional information.

As described above, the toner hopper blocking prevention mechanism 31 is provided at each end of the coiled agitator 32 with a support member.
33, and the outer periphery of the support member 33 has an outer wall 6a.
The sponge roller 7 is supported by the side wall 6b at a position close to the position shown in FIG. This will be described in more detail as follows.

The support member 33 is formed by integrally protruding shafts 36 and 37 on both sides of a flange 35 which is a press contact portion with the sponge roller 7, and the agitator 32 is fitted to the shaft 37 by press fitting or the like. When supporting the support member 33 on the side wall 6b, the shaft 36 is
It is fitted into a hole 38 provided in the side wall 6b. As the agitator 32, for example, a thin wire wound in a coil shape over the substantially entire length of the sponge roller 7 with an inner diameter of about 5 mm is used.

When the drive motor 34 is operated at the time of toner supply with the toner hopper blocking prevention mechanism 31 mounted as described above, the sponge roller 7 is driven by the drive motor 34 via the gear drive system 39 and rotates. By the rotation of the sponge roller 7, the support member 33 which is in pressure contact with the sponge roller 7 rotates together with the agitator 32, and the agitator 32 scrapes off the adhered toner. In this case, since the agitator 32 is coil-shaped, the scraping force is
Acting in the circumferential and axial directions of the agitator 32, effective scraping is realized. As a result, it is possible to prevent the occurrence of blocking and use up all of the toner.

Note that the toner hopper blocking prevention mechanism 31 is
As shown in FIG. 7A, it is desirable to provide two sets of the outer walls 6a on both sides in close proximity to each other. In this case, it is more effective to reverse the coil winding directions of the agitators 32 of both prevention mechanisms.

In addition, since the outer periphery of the flange 35 of the support member 33 is notched as shown in FIG. 3, there is no drive failure.

〔The invention's effect〕

As described above, according to the present invention, the coil-shaped agitator has a simple structure in which the support members are fitted to both ends, and the driving force is received from the rotation of the sponge roller. Since a driving source is not required, cost can be reduced.

Further, the toner adhered to the outer wall is effectively scraped off by the rotation of the coiled agitator, and the blocking can be surely prevented.

[Brief description of the drawings]

1 (a) and 1 (b) are explanatory views of the principle of the present invention, FIG. 2 is a structural explanatory view of a toner hopper blocking prevention mechanism according to an embodiment of the present invention, and FIG. 3 is an enlarged view of a main part of FIG. FIG. 4 is a side view showing an outline of the structure of a mixed two-component developing device provided with a toner hopper, FIG. 5 is an explanatory view of occurrence of blocking of the toner hopper of the developing device of FIG. 4, and FIG. 6 is a conventional toner hopper. FIG. 7 is a side view showing another conventional toner hopper blocking prevention mechanism, in which 6 is a toner hopper, 6a and 6b are outer and side walls, 7 is a sponge roller, and 31 is a toner. A hopper blocking prevention mechanism, 32 is an agitator, and 33 is a support member.

Claims (1)

(57) [Claims] 1. A toner hopper (6), and a sponge roller (7) provided below the toner hopper (6) and driven by a driving source to rotate and supply the toner in the toner hopper (6) to a developing tank. And a coiled agitator (32) is provided in the mixed two-component developing device having the agitator (3).
2) At each end, a pair of flanges (35) provided with knurls on the outer periphery and shafts (36, 37) protruding from the flanges (35)
A support member (33) made of the same is fitted, and the outer periphery of a flange (35) of the support member (33) is attached to an outer wall (6a) inside the toner hopper (6).
Opposing side walls (6b) of the toner hopper (6) so as to press against the outer periphery of the sponge roller (7) at a position close to
A toner hopper blocking prevention mechanism supported by the shaft (36).