JPH0568698B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a toner replenishing device used in an electrostatic copying apparatus that performs dry development.

Structure of conventional example and its problems In an electrostatic copying apparatus using two-component toner, a developing means is required to attach charged toner to a photoreceptor drum to form a visible image, but in this case, Toner is sequentially consumed from the developing section, which contains toner and carrier mixed at a constant ratio. For this reason, a toner replenishing device is used in which a toner storage section is separately provided and toner is sequentially replenished from this storage section into the developer container as the amount of toner in the developer container decreases.

However, in conventional toner replenishment devices, an opening of an appropriate size is provided at the bottom of the hopper with a deep bottom, and a sponge roller or a roller with multiple grooves on the circumference is placed in the opening. By rotating the hopper a certain amount, a certain amount of toner in the hopper is replenished into the developer container, but since the toner itself tends to harden and adhere easily, the toner clumps inside the hopper. Or, a toner cavity is created in the hopper, and the toner in the hopper does not fall into the developing section. Further, there is a drawback that the hardened toner falls and causes an adverse effect on the image, such as the appearance of spots on the image.

OBJECTS OF THE INVENTION The present invention aims to eliminate the drawbacks of the above-mentioned conventional examples, and provides a toner replenishing device that prevents toner from solidifying and allows smooth replenishment to a developing device.

Structure of the Invention In order to achieve the above object, the present invention includes a hopper having a toner replenishment opening formed at the bottom, a toner replenishment roller rotatably disposed in the opening, and a toner replenishment roller rotatably disposed in the opening. A first transporting means for transporting toner in one direction, and a second transporting means for transporting toner in a direction opposite to the first transporting means, the first transporting means and the second transporting means are connected to the replenishing roller. The first and second transfer means are arranged in parallel with each other and are coaxially provided with a screw coil, have a smaller diameter than the inner diameter of the screw coil, and rotate integrally with the screw coil. Then, the configuration includes a rotating shaft.

DESCRIPTION OF EMBODIMENTS The present invention will be described below based on illustrated embodiments.

FIG. 1 is an overall perspective view of a toner replenishing device according to the present invention, FIG. 2 is a cross-sectional plan view taken along line A-A, FIG. 3 is a cross-sectional plan view taken along line B-B, and FIG. 4 is a cross-sectional plan view taken along line C-C. A line cross-sectional view is shown.

In those figures, reference numeral 1 denotes a hopper in which magnetic toner 2 is stored, which has a toner filling opening, and has a vertical first storage section 1a and a horizontal second storage section 1a.
It is composed of b. 3 is a rotary lid for opening and closing the toner filling opening on the first storage portion 1a of the hopper; 4;
is an upper lid that seals the second storage section 1b of the hopper 1. Reference numeral 5 denotes a right-handed helical screw coil, one end of which is press-fitted into a boss 6, and the other end fitted into an impeller-shaped sleeve 7 having four protrusions on its outer periphery, as shown in FIG. There is. The boss 6 and the sleeve 7 are fixed to a rotating shaft 8 whose both ends are rotatably supported on the side wall of the second storage portion 1b, so that the boss 6 and the sleeve 7 rotate together with the screw coil 5. . 9 indicates an oil seal. Reference numeral 10 denotes a rectangular plate-shaped rotating blade made of an elastic material such as rubber or plastic, whose one end is fixed to one side of the rotating shaft 8 with a screw or the like, and when the other end rotates, the second storage section 1
It has a length that reaches the bottom wall of b, and is configured to scoop up the magnetic toner 2 at the bottom. The rotating shaft 8 is rotated counterclockwise by a drive system to be described later, and the screw coil 5 transports the magnetic toner in the direction of arrow D. Here, the outer diameter of the rotating shaft 8 is smaller than the inner diameter of the screw coil 5, and a gap is formed between the rotary shaft 8 and the screw coil.

Similarly, 11 is a left-handed helical screw coil, 12 is a boss, 13 is a sleeve, 14 is a rotating shaft, 15 is a rotating blade, and the above-mentioned screw coil 5, boss 6, sleeve 7, rotating shaft 8, It has exactly the same configuration as the rotating blade 10, and is arranged in the opposite direction. The rotating shaft 14 is rotated counterclockwise by a drive system, which will be described later, so that the screw coil 11 transports the magnetic toner in the direction of arrow E. Therefore, when the rotating shafts 8 and 14 rotate counterclockwise, the magnetic toner is transported in the directions of arrows D and E by the screw coils 5 and 11, respectively. At the same time, since the rotating blades 10 and 15 disposed at the opposite end are also rotating, D
The magnetic toner sent in the direction shown in FIG. handed over to.

As described above, since the magnetic toner is transferred while being stirred by the screw coil and the rotary blade in the second storage section 1b, it is possible to prevent the magnetic toner from solidifying in the hopper.

Providing a gap between the screw coil and the rotating shaft to give fluidity to the magnetic toner even between one pitch of screw coils has a more effective effect.

Reference numeral 16 denotes a replenishment roller, which is rotatably disposed parallel to the screw coil and approximately at the bottom of the second storage section 1b. In this embodiment, a recess corresponding to the length of the replenishment roller 16 is formed at the bottom between the screw coils, and a slight gap is provided between the screw coil and the replenishment roller. A slit-like opening or a plurality of elongated openings H for supplying magnetic toner to a developing device (not shown) is formed in this recess.

As shown in FIG. 5, magnets 17 such as rubber magnets are provided along the entire length of both shoulders of this recess. The magnet 17 is an anisotropic type permanent magnet, magnetized N-S in the thickness direction, and is arranged so that the concentration of magnetic lines of force is located on the replenishment roller 16 side, as shown in FIG. be. Therefore, the supply roller 16
A magnetic curtain is formed between the magnet 17 and the magnet 17 due to the concentration of magnetic lines of force, and the magnetic toner is attracted to the magnet 17 and forms a seal between the magnetic toner and the replenishment roller 16, preventing leakage to the developer side. do not have.

The replenishment roller 16 has a flat portion 16a formed by cutting out a part of its outer circumference in the axial direction, and when the replenishment roller 16 rotates once, a magnet 17 is attached to the flat portion.
The magnetic toner adhering to the toner is scraped off and dropped through the opening H at the bottom of the recess, and is replenished to the developing device.

By disposing anisotropic type magnets in which magnetic lines of force are concentrated at the tip on both shoulders of the bottom concave portion of the second storage section 1b facing the replenishment roller, the magnetic force is released from the gap between the replenishment roller and the replenishment roller by the action of the magnetic force lines. Natural falling of the toner can be prevented, and furthermore, by increasing the magnetic force, the gap between the replenishment roller and the inner wall of the recess can be designed to be large, so that it is possible to prevent the inability to replenish magnetic toner due to an increase in the rotational load of the replenishment roller 16.

18 is a gear pivotally supported by the rotating shaft 8, 19 is a gear pivotally supported by the rotating shaft 14, and power from a drive source (not shown) is driven via a driving gear 20 and a transmission gear 21. There is. 22 is an intermediate gear that transmits the rotation of gear 19 to gear 18;
It is rotatably supported on the shaft of the supply roller 16. 23 is pivotally supported by the shaft of the replenishment roller 16, and power from a drive source (not shown) is transmitted through a drive gear 24. The supply roller 16 is normally controlled by a control system to rotate clockwise and to stop after each rotation. Note that the rotation may be stopped every several rotations depending on the amount of replenishment, and this can be selected freely.

25 is a sensor for detecting the remaining amount of magnetic toner, and in this embodiment, an electrostrictive vibrator is used; It is arranged on the inner wall of section 1b.

26 is a diaphragm made of elastic material such as plastic such as polyester film, rubber, metal plate, etc.
It is arranged close to the sensor 25.

As shown in FIG. 7, the diaphragm 26 has a bent piece 26
A is formed, one side is attached to the sensor 25 via a sponge seal 27, and a bent piece 26a is slidably engaged with the screw coil 5. Note that the diaphragm 26 may be directly attached without using the sponge seal 27.

When the screw coil 5 rotates, the bending piece 26
a is bent in the direction of arrow D. However, when the screw coil 5 rotates further, the engagement is disengaged and returns in the direction of arrow E by elastic force, and this operation is repeated while the screw coil 5 rotates. Therefore, the diaphragm 26 vibrates periodically, and this vibration is transmitted to the sensor 2.
5, and the magnetic toner adhering to the sensor surface is repelled. This action removes the magnetic toner adhering to the sensor surface, eliminating the problem of the sensor detecting the presence of magnetic toner even though there is almost no magnetic toner in the hopper due to adhesion of magnetic toner. Ru. Therefore, the sensor stably performs the remaining amount detection operation, and the problem of a decrease in image density due to insufficient supply of magnetic toner can be prevented.

Reference numeral 28 denotes a regulating sheet such as a plastic film made of polyester or the like or a thin plate, which is disposed on the inner wall of the first storage portion 1a of the hopper 1. The lower opening of the first storage section 1a that communicates with the second storage section 1b is connected to the rotation shaft 1.
The screw coil 5 has a width corresponding to one end of the screw coil 5 and the rotating blade 15 fixed to the magnetic toner inlet side end of the magnetic toner 4. The regulation sheet 28 is the second
As shown in the figure, the length is such that it covers almost all of the screw coil 5 in the diametrical direction from the right end of the opening of the first storage section 1a, and has a width slightly narrower than the width of the first storage section.

This regulation sheet 28 prevents the magnetic toner in the first storage section 1a from being directly transferred by the screw coil 5.

Here, the function of the regulation sheet 28 will be further explained using FIG. 8. FIG. 8 is a diagram showing the relationship between the amount of magnetic toner and the drive load torque of the rotating shafts 8 and 14. The curve A shows the case without the regulation sheet 28, and the curve B shows the case with the regulation sheet 28. It shows. As is clear from the figure, in the case of curve A, the amount of magnetic toner in hopper 1 is 200g.
When the amount increases, the load torque increases rapidly, and 500
When it comes to g, it exceeds 9Kg-cm. This is because the magnetic toner, which has been agitated and transferred by the rotary blade 15 even though there is a sufficient amount of magnetic toner in the second storage section 1b, is transferred to the right and left screw coils 5 in the right angle direction. This is because the screw coil 5 attempts to directly feed the magnetic toner in the first storage portion 1a to the back side, which compresses the magnetic toner and requires a large force to feed it. On the other hand, when the regulation sheet 28 is disposed above the screw coil 5, the screw coil 5 only needs to feed the magnetic toner that is transferred by the rotary blade 15, so the load torque is not large as shown by the curve B. Does not increase.

Next, the operation of the above embodiment of the present invention will be explained.

When the rotating lid of the hopper 1 is opened and the magnetic toner 2 is stored in the first storage portion 1a, and a drive source (not shown) is driven, the rotating shafts 8 and 14 are rotated counterclockwise.

The magnetic toner 2 is sent into the screw coil 5 by the rotating blade 15. The magnetic toner is moved in the direction of arrow D by the screw coil 5, and when it reaches the rotating blade 10, it is sent in the direction of arrow F. The magnetic toner that has reached the boss 12 is sent in the direction of arrow E by the rotation of the screw coil 11.

Through the above-described operations, the magnetic toner is stored in the second storage section 1b and is constantly circulated within the second storage section 1b. The magnetic toner placed in the first storage section 1a moves to the second storage section 1b, but when a predetermined amount is reached, the magnetic toner moves in the direction of arrow G and moves to the toner regulating sheet 28 and the second storage section 1b. The size surrounded by the bottom of the portion 1b is the size of the inflow port, and magnetic toner exceeding a predetermined amount does not enter the screw coil 5. When replenishing the magnetic toner 2, move a drive source (not shown) to connect the connecting gears 23,
24 to rotate the supply roller 16 once clockwise, a predetermined amount of magnetic toner 2 falls from the opening at the bottom of the second storage section 1b into a developing section (not shown).

Although the above embodiments of the present invention have been described using magnetic toner as an example, the toner is not limited to this, and the same effect can be obtained even if an insulating toner is used.

Effects of the Invention As detailed above, the toner replenishment device of the present invention is provided with screw coils on both sides of the replenishment roller for stirring and transporting the toner, and there is a risk that the toner will harden even if left in the hopper. will disappear. Further, since the space between the screw coil and the rotating shaft is hollow, even when the screw coil rotates, no excessive force is applied to the toner, and the toner does not harden in the screw coil. Furthermore, since the toner does not harden, the toner replenishment roller rotates smoothly at all times, which eliminates the negative effects of hardened toner on images, and prevents toner from clumping at the ends of the screw coil, increasing the rotational drive load. Many of the effects mentioned above can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of a toner replenishing device according to the present invention, FIG. 2 is a cross-sectional plan view taken along line A-A, FIG. 3 is a cross-sectional plan view taken along line B-B, and FIG. 4 is a cross-sectional plan view taken along line C-C. 5 is an enlarged perspective view of the essential parts of the bottom of the hopper in the embodiment of the present invention, FIG. 6 is the sectional view, FIG. 7 is an enlarged perspective view of the diaphragm, and FIG. 8 is an enlarged perspective view of the toner amount FIG. 3 is a characteristic diagram showing the relationship between drive load torque of a rotating shaft. 1... hopper, 1a... first storage section, 1b...
...Second storage section, 5, 11...Screw coil,
8, 14... Rotating shaft, 10, 15... Rotating blade,
16... Supply roller, 17... Magnet, 25... Sensor, 26... Vibration plate, 28... Regulation sheet,
H...opening.

Claims (1)

[Scope of Claims] 1. A hopper having an opening for toner replenishment formed at the bottom, a replenishment roller for toner replenishment rotatably disposed in the opening, and a first hopper for transporting toner in one direction. The toner is provided with a transfer means and a second transfer means for transferring the toner in a direction opposite to the first transfer means, and the first transfer means and the second transfer means are arranged parallel to each other with the replenishment roller in between. In addition, the first and second transfer means are provided with a screw coil coaxially, and include a rotating shaft having a smaller diameter than the inner diameter of the screw coil and rotating integrally with the screw coil. A toner replenishing device characterized in that the toner replenishing opening is a slit-shaped opening or a plurality of elongated openings having approximately the same length as the replenishing roller, and the opening is located at an upper part of the developer. 2. The toner replenishing device according to claim 1, wherein one of the screw coils is a right-handed screw coil, and the other is a left-handed screw coil.