JP3504909B2 - Toner supply device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner replenishing device for replenishing toner to a developing device provided in an electrophotographic apparatus such as a laser printer, a copying machine and a facsimile.

[0002]

2. Description of the Related Art Generally, an electrophotographic printer is
A toner supply tank called a toner hopper is provided together with a developing device that forms a toner image. The toner hopper stores a reserve toner and supplies new toner to the developing device according to the amount of toner consumed by the development.

Further, the toner hopper is equipped with a toner stirring member for stirring the toner inside and conveying the toner to the developing device. This toner stirring member is
It is called an agitator or a stirring shaft and has a function of stirring the toner to ensure the toner transportability and at the same time preventing deterioration of the toner due to aggregation or the like.

The toner conveying member is usually made of a relatively hard material such as metal or resin and is firmly formed in a ladder shape. Therefore, since the elastic bending is extremely small, the toner that can be stirred and conveyed is only the toner located within the effective range of the rotation radius. Therefore, when the amount of toner in the toner hopper decreases to some extent, the amount of toner in the effective range of the toner conveying member decreases, and it becomes impossible to sufficiently convey the toner to the developing device. Insufficient amount of toner in the developing device causes blurring of printing and lowering of toner concentration, which hinders high-quality image formation.

Therefore, in the conventional printer, in order to always keep the amount of toner in the toner hopper above a certain amount,
It was necessary to frequently replenish the toner in the toner hopper, and it was impossible to avoid deterioration of operating efficiency and increase of operating cost.

In order to solve such a problem, in the toner hopper described in Japanese Patent Laid-Open No. 6-236110, a rectangular toner carrying sheet having a strong elastic force is provided at the tip of the toner carrying member. Since the transport sheet is set so as to slide on the inner wall of the toner hopper, a sufficient amount of toner can be transported to the developing device even when the amount of toner in the toner hopper becomes small. As a result, the toner in the hopper can be effectively used in this toner hopper, so that the operating efficiency and the operating cost can be improved.

[0007]

However, in the toner hopper described in the above publication, since the conveying sheet slides on the inner wall of the hopper, sliding noise is generated between the conveying sheet and the inner wall. , Has a new problem of increasing driving noise.

Such a sliding noise is not noticeable when the amount of toner held is relatively large because it is absorbed by the toner. However, when the toner holding amount decreases, the sliding sound leaks to the outside without being absorbed by the toner and reaches the user as an unpleasant noise. In recent years, when it is important to reduce the noise of the printer in order to meet various needs, it is strongly required to take sufficient measures against such sliding noise.

The present invention has been made in order to solve the above-mentioned conventional problems. The purpose of the present invention is to effectively use the toner and to improve the operating efficiency and the operating cost. Another object of the present invention is to provide a toner replenishing device capable of suppressing the generation of unpleasant noise.

[0010]

In order to achieve the above-mentioned object, the present invention is characterized in that a slidable member having a small frictional resistance is provided at the leading end of the conveying sheet.
That is, the toner replenishing device according to the present invention includes a stirring member for stirring the toner in the toner replenishing tank, and a conveying sheet that is provided at an end of the stirring member and rotates together with the stirring member to convey the toner to the developing tank. In the toner replenishing device including the above, the length from the base end to the leading end of the conveying sheet is larger than the radius of rotation of the stirring member, and the leading end of the conveying sheet slides on the inner wall of the toner replenishing tank by the rotation of the stirring member. It is characterized in that it is set to a relatively long length and that a slidable member is provided at the leading end of the conveying sheet.

Since the conveying sheet is set to be long enough to slide on the inner wall of the toner replenishing tank, the utilization efficiency of the toner can be improved and a slidable member having a small frictional resistance is provided at the leading end of the conveying sheet. The frictional force that acts when sliding on the inner wall of the toner supply tank can be reduced. As a result, even when the toner replenishing tank is relatively filled with toner, the toner can be smoothly transported by the transport sheet, and the stress applied to the toner can be suppressed. Further, even if the amount of toner in the toner replenishing tank decreases and sliding noise is likely to occur, the high-frequency noise generated by sliding can be reduced, and unpleasant noise can be reduced. As a result, it is possible to improve the quality of the toner replenishing device and the entire electrophotographic apparatus including the toner replenishing device.

As a slidable member having a small frictional resistance provided at the leading end of the conveying sheet, a dynamic friction coefficient is 0.40 or less, preferably about 0.20 (ASTM D-1894), and a static friction coefficient is 0.28 ( ASTM D-189
4) is preferable.

Further, if the slidable member is made of a soft elastic material, for example, a material having a repulsion elastic modulus of 80% or less, it deforms along the shape of the inner wall of the toner replenishing tank when it comes into contact with the inner wall. It becomes possible to keep the frictional resistance at the time of sliding smaller.

As the material of the slidable member satisfying these conditions, a fluororesin tape, an ultra-high polymer polyamide resin film ("Polyslider" manufactured by Asahi Polyslider Co., Ltd.),
Examples thereof include soft elastic materials (soft and restorative materials) having a small frictional resistance such as an ultra high molecular weight polyethylene resin film mixed with carbon filaments (“Penron C954” manufactured by NTN Co., Ltd.). In particular, a polyolefin resin-based film having a dynamic friction coefficient of about 0.20 (ASTM D-1894) and a static friction coefficient of about 0.28 (ASTM D-1894) is preferable.

Further, in this case, if the thickness of the slidable member is made thinner than the thickness of the conveying sheet, deformation along the shape of the inner wall can be easily performed, and in addition to friction resistance,
It is advantageous that the thickness is thin, and since the absolute value of the dynamic friction coefficient and the increase with time are small, the load on the drive system of the stirring member and the toner stress can be reduced. For example,
The thickness is preferably about 30 to 80 μm, or 50 μm soil 10 μm.

Since the toner is carried by the carrying sheet, it is not necessary to enhance the strength and rigidity of the slidable member, and there is no problem in durability even if a thin soft elastic material is used.

If a notch is provided at the tip of the slidable member, the contact area with the inner wall surface of the toner supply tank can be reduced. As a result, the contact resistance can be reduced, the operations of the stirring member and the conveying sheet can be smoothed, and the toner can be efficiently conveyed. As the cutout portion, various shapes such as a rectangular shape, a wavy shape, a sawtooth shape or a triangular shape that can reduce the contact resistance can be adopted.

Furthermore, if a plurality of openings are provided at the tip of the slidable member, the toner will escape at the opening at the tip of the slidable member, so the amount of toner captured by the slidable member Therefore, the resistance (toner pressure) applied to the conveying sheet can be reduced, and the operations of the conveying sheet and the stirring member can be smoothed. The openings are preferably arranged at equal intervals on the slidable member in terms of pressure balance, and are preferably formed in a rectangular shape or a circular shape from the viewpoint of ease of toner removal.

If the slidable member is bent into a substantially U-shape and the curved portion is projected from the leading end of the conveying sheet and fixed at both ends so as to wrap the leading end of the conveying sheet, the slidable member is formed. Since the curved surface of (1) can be brought into contact with the inner wall of the toner replenishing tank, the contact state can be stabilized, and the operation of the conveying sheet and the stirring member can be smoothed. Further, since the slidable member can be firmly fixed to the conveying sheet at both ends,
Loss and peeling of the slidable member can be suppressed, and reliability can be improved.

Further, if the leading end of the conveying sheet is bent in the rotational direction to form a bent portion and a slidable member protruding from the bent portion is provided on the bent portion, the rigidity of the conveying sheet and the The toner conveying power can be improved. Further, in this case, when the slidable member is provided on the back side of the bent portion (opposite to the rotating direction), the bent portion comes into contact with the inner wall surface of the toner supply tank earlier than the slidable member. Since the frictional force at the time of sliding cannot be reduced, it is desirable to provide the slidable member on the front side of the bent portion, that is, on the surface in the direction of rotation, so that the slidable member is placed on the inner wall first. Since they are brought into contact with each other, the frictional force during sliding can be reduced.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

The developing device equipped with the toner replenishing device according to the present embodiment (hereinafter referred to as the main developing device) is provided in an electrophotographic device incorporated in a laser printer, a copying machine, a facsimile, etc., and is formed on a photoreceptor. It has a function of developing the formed latent image.

First, the structure of the developing device will be described.

FIGS. 1A to 1C are explanatory views showing the structure and operation of the developing device. As shown in FIG. 1A, the present developing device includes a developing unit 1 and a toner replenishing unit 2. The developing section 1 is provided with a stirring roller 4, a developing roller 5, a toner sensor 6 and a blade 7 in a developing tank 3.

The stirring roller 4 is a roller for stirring the toner T in the developing tank 3. The developing roller 5 is a roller for supplying the toner T to the photosensitive drum 8. The blade 7 is a member that adjusts the thickness of the toner T on the surface of the developing roller 5. The toner sensor 6 is a magnetic permeability sensor that detects the toner concentration by a coil.

The toner replenishing section 2 includes a toner replenishing roller 1 in a toner replenishing tank 9 for accommodating the toner T.
0, the stirring member 11, and the conveying sheet 12 are provided. The stirring member 11 stirs the toner T by rotating around the stirring shaft 11a. The conveying sheet 12 draws up the toner T in the toner replenishing tank 9 and conveys it to the toner replenishing roller 10.
It is provided at one end of No. 1 and is made of a PET sheet. In addition, the stirring member 11 and the conveying sheet 12
The configuration will be described in detail later.

The toner replenishing roller 10 is used as the conveying sheet 12.
The toner T conveyed by is supplied to the developing tank 3 through the toner supply port 31. The canopy 14 is the developing tank 3 from the outside.
The lid is opened and closed to replenish the toner T.

Next, the operation of the developing device will be briefly described. As shown in FIGS. 1A and 1B, in the present developing device, the stirring member 11 rotates in the direction of the arrow to stir the toner T, and the conveying sheet 12 scoops up the toner T.

At this time, as shown in FIGS. 1 (b) and 1 (c), due to its flexibility, the conveying sheet 12 slides on the inner wall of the toner replenishing tank 9 and the canopy 14 and is deformed while being rotated. Proceed to. Then, when the toner T is separated from the canopy 14, it is restored to its original shape by its own elastic force, and at the same time, the held toner T is supplied to the toner replenishing roller 10.

As described above, in the present developing device, since the leading end of the conveying sheet 12 is set to slide on the inner wall of the toner replenishing tank 9, all the toner T in the toner replenishing tank 9 is agitated. -It can be transported. This makes it possible to improve the utilization efficiency of the toner T.

Next, the stirring member 11 and the conveying sheet 12
The configuration will be described in detail.

As shown in FIG. 2, the stirring member 11 has a ladder shape with the stirring shaft 11a as a central axis.
It is set to rotate around the stirring shaft 11a. The stirring member 11 is formed of a relatively hard material such as metal or resin, and is set so that its elastic bending is extremely small.

The transport sheet 12 is a PET sheet having a thickness of about 0.125 to 0.188 mm provided at the end of the stirring member 11, and is bent in the rotational direction at the front end with a predetermined angle. It has a bent portion 12a.

The conveying sheet 12 rotates while contacting the inner wall of the toner replenishing tank 9 as the stirring member 11 rotates, so that the toner T is drawn up and supplied to the toner replenishing roller 10. Further, the transport sheet 12 is
By providing the bent portion 12a, the carrying amount of the toner T is increased and the strength of the carrying sheet 12 itself is enhanced.

As shown in FIGS. 2 and 3, the slidable member 1 is formed on the surface (rotation direction side) of the bent portion 12a.
5 are provided. The slidable member 15 is a strip-shaped thin plate and is formed so as to project outward from the tip of the bent portion 12a.

That is, the slidable member 15 is the stirring member 1
It is set to slide on the inner wall of the toner replenishing tank 9 in place of the bent portion 12a when rotating 1.

The slidable member 15 is made of a fluororesin tape, an ultra-high polymer polyamide resin film (such as "Polyslider" manufactured by Asahi Polyslide Co., Ltd.), an ultra-high polymer polyethylene resin film (NT) mixed with a carbon filament.
Conveyor sheet 1 such as "Penron C954" manufactured by N company)
It is made of a soft elastic material (soft material having resilience) having a frictional resistance smaller than 2. Dynamic friction coefficient is 0.40 or less, preferably 0.20 (ASTM D-1
894) is desirable, and the coefficient of static friction is 0.28 (AS
TM D-1894) is preferable. Especially, the dynamic friction coefficient is 0.20 (ASTM D-1894), and the static friction coefficient is 0.2.
A film of a polyolefin resin base material of about 28 (ASTM D-1894) is suitable. Usually, it has excellent slidability among resins and has good friction and wear characteristics.
An OM resin (polyacetal resin) can be used, and its dynamic friction coefficient is about 0.4 to 0.5. Therefore, it is possible to understand how the frictional wear of the slidable member used in the present invention is excellent. it can. It is obvious that the coefficient of kinetic friction further increases in a PET sheet that is frequently used as a transport sheet for this type of apparatus, and a structure in which the transport sheet 12 slides directly on the inner wall surface of the toner replenishing tank 9 is provided. It will be easily understood that it is better to avoid it as much as possible.

When attaching the slidable member 15 to the conveying sheet 12, an adhesive such as an epoxy adhesive can be used, but in the case of a material such as "Penron C954" which cannot use the adhesive, Use double-sided adhesive tape.

As shown in FIG. 3, when sliding on the inner wall of the toner replenishing tank 9, the slidable member 15 moves the toner replenishing tank 9
A large amount of warp is caused along the inner wall of the sheet, and it is deformed so as to be wound around the bent portion 12a. Therefore, the slidable member 15 can slide on the inner wall of the toner replenishing tank 9 with a large surface having a small resistance and can prevent the tip of the bent portion 12a from coming into contact with the inner wall.

As a result, in the present developing device, the stirring member 1
1. The frictional force acting on the inner wall of the toner replenishing tank 9 when the transport sheet 12 is rotated is set to be small. Therefore, it is possible to smoothly carry the toner T by the carrying sheet 12 accompanying the rotation of the stirring member 11. Further, since the toner replenishing tank 9 is slid with a soft material having a small frictional force, the high-frequency sliding noise caused by sliding on the inner wall of the toner replenishing tank 9 can be made extremely small. As a result, unpleasant noise can be reduced, so that it is possible to improve the quality of the main developing device and the entire electrophotographic apparatus including the same.

The slidable member 15 is preferably composed of a sound absorbing member that is hard to transmit vibration. By doing so, the sliding noise can be reliably reduced. In addition, the thickness of the slidable member 15 is preferably set thinner than that of the transport sheet 12 from the viewpoint of flexibility and reduction of the dynamic friction coefficient,
For example, 30 ~ 80μm, or 50μm soil 10μ
A thickness of about m is preferable.

If the slidable member 15 is composed of a thin soft elastic member, when the slidable member 15 comes into contact with the inner wall of the toner supply tank 9, the slidable member 15 can be easily deformed along the shape of the inner wall. Therefore, the frictional resistance during sliding can be kept smaller. Since the toner T is transported by the transport sheet 12 and the bent portion 12a, it is not necessary to enhance the strength and rigidity of the slidable member 15.

Further, as shown in FIG. 4, it is not preferable to provide the slidable member 15 on the back side (the side opposite to the rotating direction) of the bent portion 12a. That is, in this configuration, the bent portion 12
This is because a is in contact with the inner wall surface of the toner replenishing tank 9 earlier than the slidable member 15, and the frictional force during sliding cannot be reduced.

Further, as shown in FIG. 5, the slidable member 15
Is bent into a substantially U shape, and the curved portion 15a is attached to the transport sheet 1.
It may be fixed to the conveying sheet at both ends so as to project from the leading end of the sheet 2 and wrap around the leading end of the conveying sheet 12. In this configuration, the curved surface of the slidable member 15 slides on the inner wall of the toner supply tank 9, so that the sliding state can be stabilized. This makes it possible to keep the frictional force small,
The smoothness of the operation of the transport sheet 12 and the stirring member 11 can be improved. Further, since the slidable member 15 can be firmly fixed to the bent portion 12a, the slidable member 15 can be prevented from being lost or peeled off, and the reliability can be improved.

Further, as shown in FIG. 6, the slidable member 15
At the tip (contact area with the inner wall of the toner supply tank 9)
Alternatively, a rectangular cutout portion 15b may be provided. By doing so, the contact area with the inner wall surface of the toner replenishing tank 9 can be reduced, and thus the contact resistance can be reduced. further,
The amount of toner T captured by the slidable member 15 can be reduced. As a result, the resistance (toner pressure) applied to the conveying sheet 12 can be reduced, and thus the operations of the stirring member 11 and the conveying sheet 12 can be made smoother. Further, the shape of the cutout portion 15b is not limited to the rectangular shape.
For example, it may be formed in a waveform as shown in FIG. 7A, a trapezoidal shape (sawtooth shape), a mountain shape (triangular shape) as shown in FIG. 7B.

Further, as shown in FIG. 8, the slidable member 15
You may make it provide the several opening part 15c which has a rectangular shape in the front-end | tip part. By doing this, the transport sheet 1
Since a part of the toner T can be leaked from the opening 15c during the rotation of 2, the amount of the toner T captured by the slidable member 15 can be reduced. As a result, the transport sheet 12
The resistance (toner pressure) applied to the sheet can be reduced, and the operations of the transport sheet 12 and the stirring member 11 can be made smoother.
It is preferable that the openings 15c are arranged at equal intervals on the slidable member 15 in terms of pressure balance. Further, the shape of the opening 15c is not limited to the rectangular shape, and may be any shape as long as the toner T can be leaked. For example, as shown in FIG. 9, a circular opening 15c may be provided.

[0047]

As described above in detail, in the toner replenishing device according to the present invention, a slidable member having a small frictional resistance is provided at the leading end of the conveying sheet which is set long enough to slide on the inner wall of the toner replenishing tank. Since the toner can be conveyed smoothly, the toner utilization efficiency can be improved, and even if the amount of toner in the toner replenishment tank decreases and sliding noise easily occurs, Since the generated high-frequency sound can be reduced, unpleasant noise can be reduced, and quietness can be achieved.

As such a slidable material, as shown in claims 2 and 3, a soft elastic material, for example, a repulsion elastic modulus of 8 is used.
It is preferable to use a material of 0% or less, and it becomes possible to keep the frictional resistance during sliding smaller.

Further, as described in claim 4, a slidable member having a dynamic friction coefficient of 0.40 or less and a small frictional resistance is preferable, and the generation of sliding noise can be effectively prevented.

If the thickness of the slidable member is made thinner than the thickness of the conveying sheet as described in claim 5, deformation along the shape of the inner wall can be easily performed and friction resistance can be improved. Is advantageous in that the thickness is thin, and the absolute value of the dynamic friction coefficient and the increase with time are small, so that the load on the drive system of the stirring member and the toner stress can be reduced.

As described in claims 6 and 7, when the slidable member is provided with the notch at the tip, the contact area with the inner wall surface of the toner replenishing tank can be reduced and the contact resistance can be reduced. Therefore, the operation of the stirring member and the conveying sheet can be smoothed, and the toner can be efficiently conveyed.

When a slidable member having a plurality of openings at the leading end thereof is used as described in claim 8, the amount of toner captured by the slidable member can be reduced, so that the resistance (toner) applied to the conveying sheet can be reduced. Pressure) and the operation of the conveying sheet and the stirring member can be smoothed.

According to a ninth aspect of the present invention, the slidable member is bent into a substantially U-shape, and the curved portion is projected from the leading end of the conveying sheet and fixed at both ends so as to wrap the leading end of the conveying sheet. In this case, the contact state with the inner wall of the toner replenishing tank is stabilized, the operation of the conveying sheet and the stirring member can be smoothed, and the slidable member can be firmly fixed to the conveying sheet at both ends, so that the sliding It is possible to suppress the loss and peeling of the elastic member and improve the reliability.

Further, as described in claims 10 and 11, the front end of the conveying sheet is bent in the rotational direction to form a bent portion, and a slidable member protruding from the bent portion is provided on the bent portion. If so, the rigidity of the conveying sheet and the toner conveying force can be improved.

[Brief description of drawings]

FIG. 1 illustrates an embodiment of a developing device that implements a toner replenishing device according to the present invention, and includes FIGS. 1 (a) to 1 (c).
Shows the operating state.

FIG. 2 is a perspective view showing an embodiment of configurations of a stirring member and a conveying sheet which are essential parts of the toner replenishing device according to the present invention.

FIG. 3 is a side view of the stirring member and a conveying sheet.

FIG. 4 is an explanatory diagram of how a slidable member is attached to a conveyance sheet.

5A and 5B show another embodiment of the configuration of a stirring member and a conveying sheet, FIG. 5A is a side view, and FIG. 5B is a partially enlarged view.

FIG. 6 is a perspective view showing another embodiment of the slidable member attached to the conveying sheet.

7A and 7B show still another embodiment of the slidable member, wherein FIG. 7A shows a state in which the slidable member is attached to a conveying sheet, and FIG. 7B shows only a tip portion of the slidable member.

FIG. 8 is a perspective view showing still another embodiment of the slidable member.

FIG. 9 is a perspective view showing still another embodiment of the slidable member.

[Explanation of symbols]

1 ... Developer 2 ... Toner supply section 3 ... Development tank 4 ... stirring roller 5 ... Developing roller 6 ... Toner sensor 7 ... Blade 8 ... Photosensitive drum 9 ... Toner supply tank 10 ... Toner supply roller 11 ... Stirring member 11a ... stirring shaft 12 ... Transport sheet 12a ... bent part 13 ... Toner supply port 14 ... Canopy 15 ... Sliding member 15a ... curved portion 15b ... Notch 15c ... opening

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Tanizawa 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture Sharp Corporation (72) Haruko Yoneda 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Sharp Corporation (56) Reference JP-A-8-123180 (JP, A) JP-A-8-62966 (JP, A) JP-A-6-236110 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/08 110 G03G 15/08 112

Claims (10)

(57) [Claims] 1. A method for stirring toner in a toner supply tank
A rotatable stirring member and provided at the end of this stirring member to contact the inner wall of the toner replenishing tank as the stirring member rotates.
And pumping the toner by rotating while, and a transfer sheet for conveying the toner to the toner supply roller, the sliding member provided at the tip of the <br/> conveying sheet, the slide
The thickness of the elastic member is thinner than the thickness of the carrier sheet
A toner replenishing device characterized in that 2. A method for stirring toner in a toner supply tank
A rotatable stirring member and provided at the end of this stirring member to contact the inner wall of the toner replenishing tank as the stirring member rotates.
Pumping a toner by rotating while, and a transfer sheet for conveying the toner to the toner supply roller, the sliding member provided at the tip of the <br/> conveying sheet, sliding resistance
The member is bent into a substantially U shape, and the curved portion is conveyed sheet.
Wrap the leading edge of the transport sheet by projecting from the leading edge of the
Is fixed to the transport sheet at both ends.
That the toner supply device. 3. The bent portion is formed by bending the leading end of the conveying sheet in the rotational direction.
The toner replenishing device described in. 4. A method for stirring toner in a toner supply tank
A rotatable stirring member and provided at the end of this stirring member to contact the inner wall of the toner replenishing tank as the stirring member rotates.
Pumping a toner by rotating while, and a transfer sheet for conveying the toner to the toner supply roller, before
Bend the leading edge of the transport sheet in the direction of rotation to form the bent portion.
And project from the bent part on the surface of the bent part in the direction of rotation.
The toner replenishing device is characterized in that a slidable member is provided . 5. The toner supply device according to claim 1-4 in which the sliding member is characterized in that it consists of a soft elastic material. 6. The toner replenishing device according to claim 5 , wherein the slidable member is made of a material having a repulsion elastic modulus of 80% or less. 7. The toner replenishing device according to claim 1, wherein the slidable member is made of a material having a dynamic friction coefficient of 0.40 or less. 8. The toner replenishing device according to claim 1, wherein the slidable member is provided with a notch at the tip thereof. 9. The toner replenishing device according to claim 8 , wherein the notch has a rectangular shape, a wavy shape, a sawtooth shape, or a triangular shape. 10. The method of claim 1-9 noise, wherein a plurality of openings in the distal end portion of the sliding member is provided
Toner supply device of Rekani described.