JP3466017B2 - Toner supply device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner supply device for an image forming apparatus such as an electrophotographic copying machine and a printer, and more particularly, to a piezoelectric sensor for detecting the presence or absence of toner. The present invention relates to a toner supply device provided. 2. Description of the Related Art Conventionally, a toner replenishing device for replenishing consumed toner to a developing device includes a toner replenishing chamber for storing replenishing toner, a replenishing screw for replenishing the replenishing toner to the developing device, The sensor surface includes a piezoelectric sensor that detects the difference in vibration to detect the presence or absence of toner. As a toner replenishing method, a toner concentration sensor provided in the developing device detects that the toner concentration in the developer has decreased, and drives a replenishing screw provided in the toner replenishing chamber to supply the consumed toner to the developing device. Is replenished inside. The remaining amount of toner for replenishment in the toner replenishing chamber is detected by a piezoelectric sensor provided in the toner replenishing chamber, and when it is detected that there is no toner, the toner from the toner cartridge connected to the toner replenishing chamber is supplied to the toner replenishing chamber by a supply screw or the like. The toner is supplied until it is detected that toner is present. However, in the above-described toner replenishing apparatus, the toner for replenishment adheres to the sensor surface due to agglomeration of the toner for replenishment, and only the peripheral portion of the replenishing screw is hollowed out. Is present, the piezoelectric sensor does not work properly. For this reason, even if the signal indicates that the replenishing toner is present in the toner replenishing chamber, the replenishing toner is not actually present in the toner replenishing chamber, and an appropriate developer concentration can be maintained in the developing device. Disappears. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a toner replenishing apparatus capable of preventing erroneous detection of a piezoelectric sensor with a simple configuration. [0005] In order to solve the above-mentioned problems, the present invention provides a toner replenishing chamber provided adjacent to or continuous with a developing device and for storing toner therein, and a toner replenishing chamber. A supply screw which is disposed inside the toner supply unit and conveys the toner by the rotation thereof to supply the toner to the developing device; and a piezoelectric sensor which is provided on an inner wall of the toner supply chamber and detects the presence or absence of the toner in the toner supply device. In the toner replenishing device, a film member having a plurality of slit-shaped openings in the vertical direction or a plurality of cuts is provided so as to be in parallel with and close to the sensor surface of the piezoelectric sensor, The member has an upper end fixed to the inner wall of the toner supply chamber and a lower end provided in contact with the supply screw to receive rotation of the screw. It vibrates and acts to wipe off toner adhering to the sensor surface. In such a configuration, the toner concentration sensor of the developing device detects a decrease in the toner concentration in the developer and drives the supply screw in the toner supply chamber to develop the toner in the toner supply chamber. Refill the container. When the supply screw is driven, the film member in contact with the supply screw vibrates to wipe off toner supply toner attached to the sensor surface of the piezoelectric sensor. Further, the cavity formed around the replenishing screw is eliminated by being wiped off by the vibration of the film member. Thus, the cause of the erroneous detection of the piezoelectric sensor is eliminated, and the toner for replenishment is supplied from the toner cartridge into the replenishing chamber. The toner supplied from the toner cartridge contacts the sensor surface through the opening of the film member, detects the presence of toner in the toner supply chamber, and stops the supply of toner from the toner cartridge. A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of the toner supply device of the present invention. The toner replenishing device 1 is provided continuously with a developer agitating chamber 27 of a casing 10 of the developing device shown in FIG. 2 to be described later, and is disposed inside the toner replenishing chamber 2 for storing toner and described later. Screw 4 for replenishing toner to developing device 3 to be developed, piezoelectric sensor 5 provided on the inner wall of toner replenishing chamber 2 for detecting the presence or absence of toner, and toner agglomerated around sensor surface 6 of piezoelectric sensor 5 And a film member 7. FIG. 2 is a schematic sectional view of the developing device. An image is formed around the image carrier 8 by a known method. For example, a corona charger for uniformly charging the surface of the image carrier 8 around the image carrier 8, an optical device for projecting a document image to form an electrostatic latent image on the image carrier, and A developing device for developing an image, a transfer corona discharger, a separation corona discharger, a cleaning device for removing a developer remaining after transfer on the image carrier surface, and a uniform surface potential on the image carrier surface. And an eraser lamp for performing image formation. The developing device 3 includes a casing 10 having an opening 9 extending in a substantially horizontal direction at a position close to the image carrier 8,
A developing roller 13 including a magnet 11 and a rotatable sleeve 12 fixedly disposed inside the casing 10 so as to be partially exposed from an opening 9 of the casing 10; Stirring screw 14, 1
5 and a blade 16 for regulating the height of the developer layer formed on the surface of the developing roller 13. The stirring screws 14 and 15 are fixed to rotating shafts 26a and 26b, respectively, and are rotatable by a driving source (not shown). The image carrier 8 and the sleeve 12 are rotating downward in the forward direction at portions facing each other, and perform development by bringing the developer layer into or out of contact with the image carrier. FIG. 3 is a sectional view taken along line II of FIG. In the embodiment, the toner replenishing device 1 is provided with the casing 10 of the developing device 3 in common, and a toner cartridge 17 filled with replenishing toner to be supplied to the replenishing chamber is provided above the toner replenishing device 1. Have been. The toner cartridge 17 has an opening 18 provided in the toner supply device 1 and an opening 19 provided in the toner cartridge 17.
Are connected to each other through a sponge member 20. A supply screw 21 such as a coil spring is connected to a drive source (not shown) in the toner cartridge 17 so as to be drivable. The supply screw 21 operates based on a detection signal of the piezoelectric sensor 5 to supply toner for replenishment. The toner is supplied to the toner supply chamber 2. The toner supply chamber 2 of the toner supply device 1 and the developer stirring chamber 27 of the casing 10 of the developing device 3 communicate with each other. Since the stirring of the developer is performed by the stirring screws 14 and 15, the toner for replenishment is not supplied into the developer stirring chamber 27 unless the supply screw is operated. Reference numeral 22 denotes a toner density sensor that detects the toner density in the developer. The stirring screw 14 has a rotating shaft 26a.
The supply screw 4 is fixed to the rotating shaft 2
6a so as to be rotatable. For this reason, the stirring screw 14 and the replenishing screw 4 can be rotated by separate controls. A film member 7 is provided in the toner replenishing device 1 so as to be adjacent to and in parallel with the front surface of the sensor surface 6 of the piezoelectric sensor 5. One end 23 is fixed to the inner wall of the toner replenishing chamber 2 and the other end is fixed. 24 is in contact with the supply screw 4.
As an example of the film member 7, as shown in FIG.
A polyester film having a thickness of μm is preferably used. The slit may have any shape as long as the toner supplied from the toner cartridge 17 can come into contact with the sensor surface 6 without being hindered by the film member 7. In this example, slits having a width of 2.5 mm are provided at 1.5 mm intervals. ing. FIG. 5 shows another embodiment of a film member 7 in a state of being cut into a lotus shape. in this case,
As the film member 7, a polyester film of 30 μm to 70 μm is suitably used, and the film member 7 is cut at intervals of 2 mm. The film member 7 is provided close to the front surface of the sensor surface 6, and one end 23 of the film member 7 is fixed to the inner wall of the toner supply chamber 4, and the trimmed strip portion contacts the supply screw 4 as the other end 24. Let me. The operation of the toner replenishing device 1 having the above configuration will be described. Image formation is performed by a well-known method,
The toner in the developer in the developing device 3 is consumed. The consumed toner is stored in a toner concentration sensor 2 such as a magnetic sensor.
2, the replenishing screw 4 of the toner replenishing device 1 is driven by a drive source such as a motor (not shown) to replenish the replenishing toner in the developing device 3 with a predetermined developer concentration. The film member 7 in contact with the supply screw 4 vibrates with the driving of the supply screw 4. This vibration is transmitted to the entire film member 7 and efficiently removes toner adhered or aggregated on the sensor surface 6. Due to the replenishment from the toner replenishing device 1, the amount of toner in the replenishment supply chamber 2 decreases, the toner does not come into contact with the sensor surface 6 of the piezoelectric sensor 5, and the absence of toner is detected. The supply screw 21 of the toner cartridge 17 operates based on the detection signal indicating the absence of toner to supply toner to the toner supply chamber 2. By this supply, the toner reaches the sensor surface 6 from the opening portion 25 of the film member 7 or the cut-out portion of the goodwill and detects the presence of the toner.
Stop the operation of. In the embodiment, a slit-shaped or goodwill-shaped film member is used to form the opening 25, but the present invention is not limited to this shape. For example, a plurality of circular openings 25 are provided. Similar effects could be obtained by using a film member 7 in the form of a comb or a comb. The toner supply device of the present invention reliably detects the presence / absence of toner with a very simple structure in which a film member having an opening is provided so as to cover the sensor surface of the piezoelectric sensor in close proximity. be able to. In addition, since one end of the film member is provided in contact with the supply screw, the film member can be vibrated without providing a separate driving source to eliminate aggregation of the toner, and the toner attached to the sensor surface can be wiped off. Can be. [0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing a toner supply device according to the present invention. FIG. 2 is a schematic sectional view showing a developing device. FIG. 3 is a sectional view taken along line II in FIG. 1; FIG. 4 is a view showing the shape of a film member. FIG. 5 is a view showing the shape of another film member. [Description of Signs] 1 Toner replenishing device 2 Toner replenishing chamber 3 Developing device 4 Replenishing screw 5 Piezoelectric sensor 6 Sensor surface 7 Film member 8 Image carrier 9 Opening 10 Casing 11 Magnet 12 Sleeve 13 Developing rollers 14, 15 Stirring screw 16 Blade 17 toner cartridge 18 opening 19 opening 20 sponge member 21 supply screw 22 toner density sensor 23 one end 24 other end 25 opening 26a, b rotating shaft 27 developer stirring chamber

Continuation of front page (56) References JP-A-2-14872 (JP, A) JP-A-64-38779 (JP, A) JP-A-1-162367 (JP, U) (58) Fields studied (Int .Cl. ⁷ , DB name) G03G 15/08 112 G03G 15/08 114 G03G 15/08 507

Claims (1)

(57) and Patent Claims 1. A toner supply chamber for storing a and preparative toner provided adjacent the developing device or sequentially within, its rotation is arranged inside the preparative toner supply chamber And a piezoelectric sensor provided on an inner wall of the toner supply chamber for detecting the presence or absence of toner in the toner supply device. Parallel to the sensor surface of the sensor and
A plurality of slits are set up and down so as to be close to the sensor surface.
With openings or multiple cuts
A film member, and the upper end of the film member is the toner.
The supply screw is fixed to the inner wall of the supply chamber and has a lower end.
The screw is rotated by being provided in contact with the
And vibrates to remove toner adhering to the sensor surface.
A toner replenishing device that acts to remove toner.