JPH01583A - developing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a developing device, and is particularly suitable for application to an electronic copying device.

[Prior Art] Conventionally, in a developing device using a two-component developer, the two-component developer stored at the bottom is supplied by a suction roller to a developing sleeve placed above, and the excess developer after development is removed. The toner is moved and conveyed in the longitudinal direction along with the replenishment toner by the action of a screw or a drift plate, and then dropped onto the suction roller, and is again stirred by the suction roller and magnetized and supplied onto the developing sleeve. Are known.

However, in this system, the lick developing device using a large suction roller is large in space and weight. Therefore, a developing device configured without using a suction roller has been proposed. However, with this miniaturization, the amount of developer to be handled is reduced, and a slight change in the amount of developer has a large effect on the circulating developer transport.
There have also been cases where the developer cannot be stably supplied, resulting in abnormal images.

[Object of the Invention] The present invention has been made in consideration of the above points, and an object thereof is to provide a developing device capable of stably and uniformly supplying developer and capable of obtaining good images.

[Structure of the invention] The present invention has been made to achieve the above object,
A developing sleeve having a group of magnets inside, a toner supply roller disposed near the developing sleeve and supplying toner to the developer magnetized and conveyed on the developing sleeve, and circulating the developer on the developing sleeve in the axial direction. The developing device is equipped with a circulating conveyance means for conveying the developer, and is characterized by being provided with a developer detection sensor that detects the amount of developer.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a toner replenishment roller 2 is disposed at the bottom of a toner tank 1, and a blade 4 whose one end is fixed to a frame 3 and is in pressure contact with the upper part of the toner replenishment roller 2 and the toner replenishment roller 2 are disposed at the bottom of a toner tank 1. Therefore, the toner tank 1 is blocked. The toner adhering to the upper part of the toner replenishing roller 2 passes between the blade 4 and the blade 4 as the toner replenishing roller 2 rotates, for example, in a counterclockwise direction. Developing three
given to Bu 5.

The developing sleeve 5 has a fixed magnet group 5a inside and is rotated counterclockwise as shown by the arrow, and the toner from the toner replenishing roller 2 is supplied to the developer magnetized and conveyed by the developing sleeve 5. be done. The developing sleeve 5 is surrounded by a frame 3 and a doctor blade 6 whose one end is fixed to the frame 3 so that a lower part thereof is exposed. A body 7 is provided. The height of the developer mixed with toner is regulated by the doctor blade 6, and the developer passes through the gap between the doctor blade 6 and the developing sleeve 5 and is supplied to the photoreceptor 7, forming an electrostatic latent image on the photoreceptor 7. Let it develop.

As shown in FIG. 2, a first screw 8 for conveying the developer in the axial direction of the developing sleeve 5 is provided in the developer pool formed by the developing sleeve 5 and the doctor blade 6. A second screw 9 is provided above the screw 8 for conveying the developer in the opposite direction. Second
The screw 9 is a screw guide 10 with a U-shaped cross section.
The first screw guide 10 is provided inside the screw guide 10.
A screw guide opening 11 having a notch configuration is provided in the end side wall of the screw 8 in the transport direction, and the surplus developer transported by the first screw 8 and regulated by a side plate (not shown) is passed through this opening 11. It is designed to be supplied to the conveyance path of the second screw 9 through the feeder. A through hole 12 is bored in the bottom surface of the end of the second screw 9 in the conveying direction of the screw guide 10, and the developer is supplied to the developing sleeve 5 again through the through hole 12.

In addition to the above configuration, this embodiment is provided with a configuration for monitoring developer shortage and replenishing the developer as necessary. In the screw guide opening 11, as shown in FIG. 3, there is an apron 13 that guides excess developer that is transported by the first screw 8 and accumulated at the end by a side plate (not shown) to the transport path of the second screw 9. A developer detection sensor 14 made of, for example, a piezoelectric sensor is provided on the apron 13. Therefore, when the amount of surplus developer supplied from the conveyance path of the first screw 8 to the conveyance path of the second screw 9 via the apron 1.3 is large, the level is high, and when the amount of surplus developer 1 is small, the level is high. The developer detection signal SE, which takes a low level, is detected by this sensor 14.
obtained from.

This detection signal SE is given to the signal processing circuit 15 shown in FIG. 4, and it is determined whether the developer is insufficient or sufficient.
The developer is supplied from a developer supply mechanism 16 shown in the figure. The developer replenishment mechanism 16 includes a developer tank 17 that stores developer and whose lower part narrows in one direction, a developer duct 1.9 that communicates the developer tank 17 with a developing device main body 18, and a developer duct 1.9. The developing device main body 18 passes through the inside of one developer duct from the inside lower part of the developer tank 17.
It is generally composed of a screw 20 extending to. The rotating shaft 20a of the screw 20 is connected to the developer tank 17.
side plate 17a on the side to which one developer duct is not connected.
The gear 21 protrudes outward through the protrusion.
is attached, and rotational force is applied from a drive motor via this gear 21 to convey the developer to the main body 18 of the developing device. Here, the side plate 2 of the developing device main body 18
The joint position of one developer duct with respect to 2 is fixed at 2 above the surplus developer retention area formed by the screw 8,
Replenishment developer is supplied to this retention section.

The drive control of the developer replenishing mechanism 16 having such a configuration is performed by the signal processing circuit 15 shown in FIG. 4, as described above. This signal processing circuit 15 receives the detection signal SE from the developer detection sensor 14 at the inverting input terminal of the comparator 23 .

Further, a reference signal REF obtained by dividing the power supply voltage by resistors R1 and R2 is applied to a non-inverting input terminal of the comparator 23. Thus, a comparison output 323 is obtained which takes logic r)(J when the sensing signal SE is less than the reference signal REF, and is provided to the controller 24.

The controller 24 controls the operation of the entire developing device, and controls the developing motor 25 for driving the developing device via a motor driver 26, and the developer replenishing mechanism 16.
The developer replenishment motor 27 for operating the toner replenishment roller 2 and the developing sleeve 5 are controlled via a motor driver 28, and two high voltage power supplies that supply high voltage power to the toner replenishment roller 2 and the developing sleeve 5 are controlled. Based on this, a toner replenishment clutch 30 that connects and connects the developing motor 25 and toner replenishment roller 2 is controlled via a driver 31. Further, the controller 24 is connected to the operation panel 3.
2 to receive operation input and provide display output to the operation panel 32 as necessary.

The controller 24 executes the monitoring operation based on the developer shortage monitoring program shown in FIG.
A developer replenishment operation is executed based on the developer replenishment program shown in the figure.

First, the developer shortage monitoring operation procedure will be explained. For example, after starting the developer shortage monitoring program at step SPI every predetermined period, the controller 24 proceeds to the next step SP2 and determines whether or not the developing motor 25 is in the on state. Next, the process proceeds to step SP3, and it is determined whether or not the comparison output S23 is the logic r) (J. As a result, if it is determined that the comparison output has risen to the logic rH), the process proceeds to step SP4, where the shortage detection flag is Determine the state of FLGI, and if the shortage detection flag FLGI has not risen, proceed to step SP.
After raising the shortage detection flag FLGI in Step 5, an internal timer for counting one second is set in Step SP6, and the process returns to the main routine in Step SP7.

On the other hand, if a positive result is obtained as a result of the determination in step SP4 because the shortage detection flag FLGI has already been set, the process proceeds to step SP8, and for one second after the shortage detection flag FLG1 is set based on the timer output. It is determined whether or not 1 second has elapsed, and if 1 second has not elapsed, the process immediately returns to the main routine in step SP7, and if 1 second has elapsed, the process proceeds to step SP9 to instruct developer replenishment. Developer replenishment flag FLG2
Set and return to the main routine.

Note that when the developing motor 25 is not in the on state, there is no need to monitor the amount of developer, so proceed to step 5PIO and step 5PII, reset both the shortage detection flag FLGI and the developer replenishment flag FLG2, and then return to the main routine. return. Further, if the comparison output 323 is determined to be logical "L" as a result of determination in step SP3, it means that the developer is sufficient, so similarly step 5PIO and step 5P
11, both flags FLGI and FLG2 are reset, and the process returns to the main routine.

Thus, the program detects the developer detection sensor 1.
When the detection signal SE from 4 continues to be at the insufficient level for one second or more, the developer replenishment flag FLG2 is set.

The controller 24 executes a replenishment operation program using this developer replenishment flag FLG2. The reason why the developer replenishment flag FLG2 is set is that the detection signal SE continues to be at the insufficient level for one second or more, in order to prevent erroneous replenishment due to noise or the like.

After the controller 24 starts the developer replenishment program at each predetermined period in step 5P15, for example,
In step 5P16, it is confirmed that the developing motor 25 is in an operating state, and the process proceeds to step 5P17.

In step 5P17, the controller 24
It is determined whether or not the second timer flag FLG3 is set, and if it is not set, the process proceeds to step 5P18, and this time it is determined whether or not the 20 second timer flag FLG4 is set, and this 20 second timer flag FLG
If 4 is not set, the process advances to step 5P19.

Immediately after the developer replenishment flag FLG2 is set, the 5 second timer flag FLG3 and the 20 second timer flag FLG4 are set.
Since both are not set and the developing motor 25 is in operation, the process advances to step 5P19.

In this step 5P19, the developer replenishment flag F
It is determined whether LG2 is set. As a result, if you get a negative result, the developer is sufficient, so
The process immediately proceeds to step 5P20 and returns to the main routine without any processing. In addition, the above step 5P
Even if a negative result is obtained in determining the operating state of the developing motor 25 in No. 16, since no developing operation is being performed, the process immediately proceeds to step 5P20 and returns to the main routine.

On the other hand, if a positive result is obtained in step 5P19 because the developer replenishment flag FLG2 is set, the process proceeds to step SP21, where the developer replenishment motor 27 is driven to execute a replenishment operation, and then, The 5-second timer flag FLG3 and the 20-second timer flag FLG4 are set through steps 5P22 to 5P25, the built-in 5-second timer and 20-second timer are activated, respectively, and the process returns to the main routine in step 5P20.

If the 5-second timer flag FLG3 and the 20-second timer flag FLG4 are set in this way, an affirmative result will be obtained in the above-mentioned step 5P17 or step 5P18 when the program is executed next time. If a positive result is obtained in step 5P17, the process proceeds to step 5P26 to determine whether 5 seconds have elapsed.If 5 seconds have not elapsed, the process immediately returns to the main routine; If so, step 5P2
At step 7, the developer replenishment motor 27 is stopped, and the process proceeds to steps 5P28 and 5P29, where the 5-second timer flag FLG3 and the 5-second timer are reset, respectively, to return to the full state, and the process returns to the main routine. In this way, when there is a shortage of developer, the developer is replenished for only 5 seconds.

If a positive result is obtained in step 5P18, which determines the set state of the 20 second timer flag FLG4, the process proceeds to step 5P30, where it is determined whether 20 seconds have elapsed, and if 20 seconds have not elapsed, the main routine is immediately executed. On the other hand, if 20 seconds have elapsed, the state of the developer replenishment flag FLG2 is determined in step 5P31. As a result, if the replenishment flag FLG2 is set, the process returns to step 5P21 described above and the replenishment operation is executed again from the beginning. On the other hand, if the replenishment flag FLG2 is reset, step SP32 and step 5
Proceeding to P33, the 20-second timer flag FLG4 and the 20-second timer are each reset to return to the state when they were satisfied, and the process returns to the main routine. Thus, 15 seconds after the replenishment operation ends, that is, 20 seconds after the start of replenishment, it is confirmed that the developer is sufficient, and the series of replenishment operations ends.

The reason for determining whether or not replenishment has been done properly after 20 seconds is to confirm that the developer has been sufficiently agitated by the transport operations of screws 8 and 9. This is because.

In the above configuration, when supplying developer, the toner supply roller 2 is rotated to supply the toner to the developing sleeve 5, the developer magnetized and conveyed by the developing sleeve 5 is mixed, and then developed by the screw 8. The agent and toner are mixed, smoothed in the axial direction, and supplied to the photoreceptor 7 by rotation of the developing sleeve 5. At this time, the excess developer is transported in one direction by the screw 8, is given to the transport path by the second screw 9 through the screw guide opening 11, is transported in the opposite direction, and falls through the through hole 12. Then, it is applied to the developing sleeve 5 again.

At this time, if there is a shortage of developer and the amount of developer supplied to the conveyance path of the second screw 9 via the apron 13 is small, the detection signal SE of the detection sensor 14 (FIG. 9(A)
) becomes smaller, and the comparator 23 outputs a ratio axis output 523 (FIG. 9(B)) of logic rH. The controller 24 monitors the time of this logic rH and output, and when this time continuously exceeds 1 second as shown in FIG. 9(B), the developer replenishment flag is set as shown in FIG. 9(C). FLG
Set 2.

With this set, the developer replenishment mechanism 16 executes the replenishment operation for 5 seconds, and after 20 seconds have elapsed from the start of replenishment when the replenished developer is sufficiently stirred, the developer replenishment state is checked again and the developer replenishment state is confirmed. If so, each flag that is set at the time of replenishment is reset to end the replenishment operation, and if the shortage level detection signal SE is detected even after 20 seconds, the replenishment operation is executed again.

Therefore, according to the above-described embodiment, the developer detection sensor 14 detects a shortage of developer, and when the shortage occurs, the developer is automatically replenished from the developer replenishment mechanism 16. The agent can be constantly circulated,
The developer can be stably supplied, and abnormal images can be prevented from occurring.

In the above-described embodiment, the developer is automatically replenished in response to the developer shortage abnormality. Alternatively, the problem may be dealt with by having the developer replenish the developer.

Further, in the above-described embodiment, the amount of developer applied from the conveyance path of the first screw 8 to the conveyance path of the second screw 9 was detected. A developer detection sensor may be provided to detect the amount of developer traveling from the second screw 9 conveyance path to the first screw 8 conveyance path.

[Effects of the Invention] As described above, according to the present invention, since a developer detection sensor is provided to detect the amount of developer being conveyed, it is possible to reliably detect when there is a shortage of developer. Therefore, it is possible to obtain a developing device that can perform, for example, a replenishment operation, an operation to display an abnormality in shortage, and can prevent the occurrence of an abnormal image.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of a developing device according to the present invention, FIG. 2 is a perspective view showing a developer circulation path, FIG. 3 is a perspective view showing main parts of the embodiment, and FIG. 5 and 6 are block diagrams showing the signal processing circuit for the developer amount detection signal.
The figure is a perspective view and a sectional view showing the developer replenishment mechanism 16.
The figure is a flowchart showing the procedure for monitoring developer shortage.
FIG. 8 is a flowchart showing the developer replenishment processing procedure;
FIG. 9 is a signal waveform diagram of each part. 2... Toner supply roller, 5... Developing sleeve, 7
...Photoreceptor, 8.9...Screw, 10...Screw guide, 11...Screw guide opening,
12... Through hole, 13... Apron, 14... Developer detection sensor, 15... Signal processing circuit, 16... Developer supply mechanism, 24... Controller. Applicant Rico Co., Ltd. - Figure 3! ¥y 4 Figure 6 Figure $ 9 Figure vine 7 Hard

Claims (3)

[Claims] (1) A developing sleeve having a group of magnets inside, a toner replenishing roller disposed near the developing sleeve and supplying toner to the developer magnetized and conveyed on the developing sleeve, and a developer on the developing sleeve. What is claimed is: 1. A developing device comprising: a circulating conveyance means for circulatingly conveying the developer in an axial direction, the developing device comprising: a developer detection sensor for detecting the amount of the developer. (2) The circulation conveyance means includes first and second screws whose conveyance directions are opposite to each other, a screw cover that isolates these first and second screws, and provided at both axial ends of the screw cover. an opening that communicates the conveyance path of the first screw with the conveyance path of the second screw, and is adapted to circulate and convey the developer in the axial direction through a path different from that of the developing sleeve;
2. The developing device according to claim 1, wherein the developer detection sensor is provided near one of the openings. (3) A developer replenishment mechanism for replenishing developer is provided on the developer transport path, and when the developer detection sensor detects a lack of developer, the developer replenishment mechanism replenishes the developer. A developing device according to claim 1.