JPH04121765A - Toner replenishment device - Google Patents

Abstract

PURPOSE:To prevent toner from being aggregated and to stably and surely replenish it for a long time by arranging two toner replenishment members whose surface layer parts are rugged and which are formed of a soft material by bringing them into contact with each other by prescribed nip width and driving and rotating at least one of them. CONSTITUTION:A pair of toner replenishment members 13 and 14 on the upper end of a toner hopper 11 is roll-shaped. Besides, they are obtained by winding the soft foamed material of synthetic resin around the central shafts 131 and 141 and provided with many ruggednesses for holding toner on the surface. Then, they are brought into contact with each other in parallel by the prescribed nip width and arranged so as to bury the toner discharging port 12 of the hopper. When the concentration of the toner from a toner concentration detection sensor 18 is equal to or above a reference value, a toner supply motor M and a pawl driving device 145 are turned off and the replenishment member 13 and 14 are stopped by a control part 17. Then, the toner is not replenished. When the concentration of the toner is smaller than the reference value, only the motor M is turned on and the replenishment member 13 is rotated. Then, the toner is replenished. When the concentration of the toner is further smaller, the driving device 145 is turned on and a pawl 144 is separated from a gear 143. Then, more toner is replenished by rotating the replenishment member 14 in accordance with the replenishment member 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a toner replenishing device for replenishing developing toner to a developing device in an image forming apparatus such as a copying machine or a printer.

[Conventional technology]

As this type of toner replenishment device, U.S. Reissue Patent No. 2
7876, JP 56-121067, JP 58-25672, JP 1-314269
2. Description of the Related Art Devices of the type disclosed in, for example, Japanese Patent Application No.

This type of toner replenishing device is made of a flexible material, such as a flexible foam material, with at least an uneven surface layer.
It consists of a toner replenishment roller that is arranged at the toner discharge port of the toner hopper and is driven and rotated, and a protrusion member that abuts the roller so as to bite into it slightly.

According to this toner replenishing device, the toner in the toner hopper is dropped and supplied to the toner replenishing roller from a position above the toner replenishing roller, and as the roller rotates, the toner is squeezed or scraped off by the protruding member to the toner outlet. and falls into the developing device.

(Problems to be Solved by the Invention) However, with this type of toner replenishment device, the toner on the toner replenishment roller is constantly subjected to toner pressure from above, and is also pressed against the roller by the protruding member due to the rotation of the roller. As a result, toner agglomeration, toner supply roller clogging, toner sticking to the protruding member, etc. are likely to occur. If such toner aggregation or sticking or roller clogging occurs, stable and reliable supply of toner will be hindered.

In addition, when aggregated toner is supplied into the developing device, the fluidity of the toner in the developing device deteriorates, and in the case of a two-component developer, frictional charging failure with the carrier occurs, resulting in Even in this case, frictional charging failure occurs with the toner regulating member provided for the developer carrying and supplying roller of the developing device. When toner charging failure occurs in this manner, problems such as image fogging and toner scattering occur.

Furthermore, since the protruding member in contact with the toner supply roller is made of a hard material such as metal, the roller tends to wear out or deteriorate after a short period of use, resulting in a short lifespan.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a toner replenishing device that is less likely to cause toner aggregation and that can reliably replenish toner in a stable manner over a long period of time.

[Means to solve the problem]

The toner replenishing device of the present invention which achieves the above object is configured to bring two toner replenishing members made of a flexible material having at least an uneven surface into contact with each other with a predetermined nip width, and to supply the toner to the toner outlet of the toner hopper. The replenishment member is arranged so as to fill the replenishment members, and at least one of the two replenishment members is configured to be driven and rotated.

When one of the two toner replenishing members is fixed and the other rotates in contact with it, both can be rotatable, and if necessary, only one or both of them can be rotated. If two members have the same surface roughness, they may differ.

[For production]

According to the toner replenishing device of the present invention, the toner enters and is held in the uneven surface of each toner replenishing member, and when one of the members is rotationally driven, the toner falls from the nip between the two members and is supplied to the developing device. be done.

〔Example〕

The embodiment described below is for replenishing toner to a developing device that uses a two-component developer containing toner and carrier.

FIG. 1 shows an embodiment and a cross section of a two-component developing device attached thereto.

This toner replenishing device 1 includes a toner hopper 11 that stores toner, a pair of toner replenishing members 13 and 14 provided at a toner discharge port 12 at the lower end of the hopper, and a stirring member 1 provided within the hopper.
5 and a toner aggregation prevention member 16 provided on the inner wall of the hopper.

The toner supply member 13 has a roll shape, and the central axis 1
31 wrapped with a flexible synthetic resin foam material, and has a large number of toner holding unevenness on its surface.

The toner supply member 14 also has a roll shape, and the central axis 1
The toner replenishing member 13 is made of a flexible synthetic resin foamed material wrapped around the toner replenishing member 13, and its surface has many irregularities for holding toner, and the surface roughness is larger than that of the toner replenishing member 13.

A specific example of the flexible synthetic resin foam material is what is called Maltbrain.

Both toner supply members 13, 14 are parallel to each other and are in contact with each other with a constant nip width. Both of these members are arranged so as to fill the toner discharge port 12 of the hopper which extends in the same direction as their central axes, and are rotatably supported by the hopper at the central axes 131 and 141.

The stirring member 15 in the hopper is rotationally driven in the counterclockwise direction in the drawing by a driving means (not shown).

The toner aggregation prevention member 16 is formed from a flexible plate,
The stirring member 15 is arranged so that it can be flipped up at its tip by rotation.

As shown in FIG. 2, the toner supply member 13 is rotated clockwise in the figure by a toner supply motor M via a gear transmission 133. As shown in FIG.

On the other hand, the toner supply member 14 has a gear 14 at the end of its shaft 141.
3, and a pawl 144 is engaged with this gear. The pawl 144 is supported by a pawl driving device 145 consisting of a solenoid, and when the solenoid is off, it engages with the gear 143 to prevent the toner replenishing member 14 from rotating, and when the solenoid is on, it rises and separates from the gear 143. The toner supply member 14 is in a state where it can freely rotate.

Therefore, when the toner replenishing member 13 is rotationally driven in the clockwise direction in the figure and the pawl driving device 145 is lifting the pawl 144, the toner replenishing member 14 is driven to rotate in the counterclockwise direction in the diagram. When the pawl 144 is engaged with the gear 143, only the toner replenishing member 13 is driven and rotated, and the toner replenishing member 14 is stopped.

The toner supply motor M and the pawl driving device 145 are configured to be turned on and off based on instructions from the control section 17, and a toner concentration signal is inputted to the control section 17 from the toner concentration detection sensor 18. It looks like this.

In this example, the toner concentration detection sensor 18 is provided at the bottom of the developing device 2, and detects the toner concentration in the developer from the carrier magnetic permeability, and outputs the toner concentration as a voltage value.

As the toner density detection means, an image density detection means or the like may be used.

When the toner concentration input from the toner concentration detection sensor 18 is equal to or higher than a predetermined toner concentration reference value (D≧D), the control unit 17 controls the toner supply motor M and the pawl drive device 145. is turned off, the toner replenishing members 13 and 14 are stopped, toner is not replenished, and the detected toner concentration value is smaller than the reference value, and another predetermined toner reference value D is set. 2 (however, D>D2) or above (D,>D≧D2), only the toner replenishment motor M is turned on to rotate the toner replenishment member 13, thereby replenishing toner, and the detected toner concentration is If the value is smaller than the reference value D2 (Dg > D
), further, the pawl driving device 145 is turned on to move the pawl 144.
is moved away from the gear 143, thereby causing the toner replenishing member 14 to rotate following the toner replenishing member 13, thereby replenishing more toner.

According to the toner supply device described above, the toner hopper 1
The toner T stored in the toner T is removed by the rotation of the stirring member 15 which is driven simultaneously when the toner replenishing member 13 is rotated, and by the toner aggregation prevention member which is driven to bounce up as the stirring member 15 rotates. 16, the mixture is stirred in the hopper 11 to prevent agglomeration.

On the other hand, the sensor 18 detects the toner concentration in the developer A in the developing device 2, and the detected toner concentration value is input to the control section 17.

The control unit 17 turns off the toner replenishment motor M and the pawl drive device 145 while the detected toner concentration value D≧D, and turns only the toner replenishment motor M off when the state D,>D≧D. When turned on, the toner replenishing member 13 is rotated clockwise in the figure as shown in FIG. At this time, the pawl 144 is still engaged with the gear 143, so the toner replenishing member 14 does not rotate following the toner replenishing member 13 and remains stopped.

Thus, the toner replenishing member 13 rotates while in contact with the toner replenishing member 14, and the toner held on the surface of the member 13 and sent from the nip portion X between the two members 13 and 14 falls into the developing device 2.

When this toner replenishment results in a state of D≧D1, the control unit 17 stops the toner replenishment motor M and stops toner replenishment.

However, despite such toner replenishment, the detected toner concentration value continues to decrease and when a state of D>D is reached, the control unit 17 turns on the claw drive device 145 while keeping the toner supply motor M on. Then, the claw 144 is separated from the gear 143. Thus, as shown in FIG. 4, the toner replenishing member 14 becomes rotatable and begins to rotate counterclockwise in the figure following the rotation of the toner replenishing member 13.

The toner thus held in the toner replenishing members 13 and 14 falls into the developing device 2 from the nip X between the two members.

Due to this toner replenishment, the toner concentration in the developer A gradually increases, and when it returns to the state >D≧D2, the control unit 1
Step 7 turns off the pawl drive device 145 and stops the toner replenishing member 14. Thereafter, the toner concentration further increases due to the rotation of only the toner replenishing member 13, and when the state of D≧D1 is reached, the toner supply motor M is also turned off and the toner replenishing member 13
toner replenishment.

Toner replenishment is performed as described above.

The toner supplied from the toner replenishing device 1 is turned into developer A in the developer tank 21 of the developing device 2 by an agitation roller 22 that is rotated counterclockwise in the figure by a driving means (not shown).
The developer A is mixed and agitated and supplied to the packet roller 23, which is rotated clockwise in the figure by a driving means (not shown) to supply the developer A to the developing sleeve 24.

The developing sleeve 24 is rotationally driven in the clockwise direction in the figure by a driving means (not shown), and a fixed magnet body 25 is disposed inside the sleeve.The developer is thus held on the developing sleeve 24 in the form of a magnetic brush, and the sleeve 24 is rotated, it is transported to the developing area Y, and the height regulating plate 2
6 regulates the amount of developer to be transported.

The developer conveyed to the development area Y is supplied to the electrostatic latent image on the photoconductor drum PC, which is an electrostatic latent image carrier facing the sleeve 24, to visualize the latent image, and the remaining developer is transferred again. It is returned to the packet roller.

The visible image on the irradiating drum PC-hi is transferred onto a transfer material by a transfer device (not shown), fixed on the transfer material by a fixing device (not shown), and discharged outside the machine. The developer whose progress is prevented by the height regulating plate 26 is returned toward the stirring roller 22 along the inclined plate 27.

When only the toner replenishing member 13 rotates, the amount of toner replenished by the toner replenishing device is determined mainly by the surface roughness (fineness) of the toner replenishing member 13.
When both of the toner replenishing member I4 rotate, it is determined mainly by the surface roughness (roughness) of the toner replenishing member I4.

Note that the toner replenishing member 14 is not configured to rotate following the toner replenishing member 13, but is configured to be able to be driven separately. Alternatively, the amount of toner replenishment may be increased by stopping the toner replenishing member 13 and rotating only the toner replenishing member 14.

The toner concentration reference value is set to a value lower than the detected toner concentration value D0 when the toner concentration in the developer A is a proper toner concentration, so that the toner supply does not become excessive. , the toner density does not increase more than necessary, and a good image can be obtained.

Further, according to the embodiment, the amount of toner replenishment can be adjusted in two stages, ie, small and large, while keeping the rotation of the toner replenishing member 13 constant. Since there is no need to raise it and it can be set at a lower value, there is an advantage that clogging and toner aggregation that occur when the toner replenishing member is rotated quickly do not occur. In this regard, in conventional toner replenishment devices, when attempting to increase the amount of toner replenishment, the toner replenishment roller was rotated quickly, which caused problems such as clogging of the toner replenishment roller and toner aggregation. Ta. Such problems are solved in this embodiment.

FIG. 5 shows another embodiment of the invention.

According to this embodiment, the toner discharge port 12° of the toner hopper 11 is filled with two toner supply members 130 and 140, and one member 130 is filled with the toner discharge port 12°.
The other member 140 is formed in the form of a roller which rotates in contact with the other member 140.

The member 130 is made of a flexible synthetic resin foam material such as Moltoprene, and the toner replenishing member 140 is also made of a flexible foamed synthetic resin material in the area around its central rotating shaft 140a. It contacts the member 130 with a constant nip width.

According to this embodiment, the member 140 is rotationally driven in the counterclockwise direction in the figure by a driving means (not shown), so that the toner T held in the member 140 falls from the nip portion and is supplied to the developing device 2. .

Also in this embodiment, the timing for driving the toner replenishing member 140 is determined in response to a toner replenishment instruction signal from the toner concentration detection means.

In any of the above embodiments, the two toner replenishing members that contact each other are made of the same flexible material, so compared to the conventional case where a hard protruding member contacts the toner replenishing roller, these two toner replenishing members are in contact with each other. There is little wear or deterioration of the components, and toner can be supplied stably and reliably over a long period of time.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a toner replenishing device that is less likely to cause toner aggregation and can reliably replenish toner in a stable manner over a long period of time.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment of the present invention together with a developing device, Fig. 2 is an explanatory diagram showing the driving section and control section of the embodiment shown in Fig. 1, and Fig. 3 is an explanation of a small amount of toner replenishment state. FIG. 4 is an explanatory diagram of a state in which a large amount of toner is supplied. FIG. 5 is a sectional view of a main part of another embodiment of the present invention. 1... Toner replenishing device 11... Toner hopper 12... Toner discharge port 13.14... Toner replenishing member 131.141... Central shaft 132.142... Flexible portion M having unevenness on the surface・
... Toner supply motor 133 ... Gear transmission device 143 ... Gear 144 ... Pawl 145 ... Pawl drive device 17 ... Control section 18 ... Toner concentration detection sensor 130, 140 ... Toner Replenishment member 140a... Central shaft 140b... Flexible portion with unevenness 12''... Toner outlet T... Toner... Toner replenishing device 11... Toner hopper 12... Toner outlet 13. 14... Toner replenishing member 161. 141... Central axis + 32. 142... Lower flexible part with uneven surface.
...Toner chart Fig. 12'... Toner discharge port

Claims (1)

[Claims] (1) Two toner replenishing members made of a flexible material having at least an uneven surface layer are placed in contact with each other with a predetermined nip width in the toner outlet of the toner hopper so as to fill the toner outlet; A toner replenishing device characterized in that at least one of the two replenishing members is configured to be driven and rotated.