JPH05173423A - Developing device - Google Patents

Abstract

PURPOSE:To prevent display indicating no toner regardless of the existence of the toner due to detection error of a toner residue quantity sensor in the developing device where the toner inside a toner container is replenished to developer when the toner concentration is lowered in a two component developer and the residual toner quantity in the toner container is detected by the residual toner quantity sensor. CONSTITUTION:When the toner T is refilled to the toner container 8 and the existence of the toner is detected by the first residual toner quantity detection sensor 12, this information is retained until the fact that the toner quantity inside the toner container is below a specified quantity is detected by a second residual toner quantity sensor 112, and during this time, even when a detection error is made by the first residual toner quantity sensor 12, the display indicating no toner is inhibited from being carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention visualizes an electrostatic latent image formed on a latent image carrier as a toner image by using a two-component type developer formed by mixing toner and carrier. The present invention relates to a developing device.

[0002]

2. Description of the Related Art It is well known that an image forming apparatus such as an electronic copying machine, a facsimile machine, a printer or a printing machine uses a dry type developing device of the above type.

In this type of developing device, a latent image carrier is visualized by using a two-component type developer contained in a developer container, but toner is generated as the developing operation progresses. Since the toner is sequentially consumed, the toner concentration of the developer decreases.

Therefore, the toner concentration of the developer is detected by the toner concentration sensor, and when the decrease in the concentration is detected, the toner contained in the toner container is replenished into the developer, and the toner concentration can be reduced. This prevents the image density of the visual image from decreasing.

On the other hand, since the amount of toner in the toner container also decreases in sequence, the remaining amount of toner in this container is detected by the toner remaining amount sensor, and based on the detection results of this toner remaining amount sensor and the above-mentioned toner concentration sensor. When the state of the amount of toner in the toner container is determined, the amount of toner in the toner container is displayed on the display unit based on the result of the determination, and when an instruction to replenish the toner is displayed, the operator follows the toner amount in the toner container. I am trying to replenish.

By the way, the above-described toner remaining amount sensor does not always correctly detect the remaining amount of toner, and it detects that there is no toner even though a sufficient amount of toner still remains in the toner container. It may end up. When such an erroneous detection occurs, a large amount of toner remains in the toner container, but there is little or no toner remaining in the display means, and thus "toner" should be replenished immediately. "Toner near end" indicating that "End" is displayed or is about to be "toner end"
Is displayed, which may force the operator to perform unnecessary work.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device capable of correctly displaying the toner amount state even if the above-mentioned erroneous detection occurs.

[0008]

In order to achieve the above object, the present invention provides a developer container containing a two-component developer obtained by mixing a toner and a carrier, and a two-component developer in the container. A toner container containing toner to be replenished to the developer, a toner concentration sensor for detecting the toner concentration of the developer, a toner remaining amount sensor for detecting the remaining amount of toner in the toner container, the toner concentration sensor and the toner remaining amount sensor. A control unit for determining the state of the toner amount in the toner container based on the detection result of the amount sensor; and a display unit for displaying the state of the toner amount in the toner container based on the determination result. In a developing device that visualizes an electrostatic latent image formed on a latent image carrier as a toner image by using a component type developer, the control unit detects the presence of toner detected by the toner remaining amount sensor. Emotion The amount of toner in the toner container is to propose a developing apparatus comprising information holding means for holding until detection that has become less than a predetermined amount.

At this time, the toner remaining amount sensor attached to the toner container detects that the amount of toner in the toner container has fallen below a predetermined amount, and releases the holding of toner information. You can also

A second toner remaining amount sensor, which is different from the toner remaining amount sensor attached to the toner container, detects that the amount of toner in the toner container has dropped below a predetermined amount, and toner is present. It can also be configured to release the retention of information.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a drum-shaped photoconductor which is an example of the constitution of a latent image carrier, and a developing device 2 is arranged so as to face the photoconductor 1.

The developing device 2 has a developer container 3 containing a two-component developer D formed by mixing toner and carrier, and the developer D is agitated by a paddle wheel 4 rotating clockwise. , To the developing roller 5 which is driven in the clockwise direction. The supplied developer is carried on the surface of the developing roller by the action of a magnet (not shown) arranged inside the developing roller 5, and is conveyed in the rotation direction by the rotation of the roller 5. The developer thus conveyed has its layer thickness regulated by the doctor blade 6, and the regulated developer rotates in the direction of arrow A and the photoconductor 1 and the developing roller 5.
The toner in the developer is electrostatically transferred to the electrostatic latent image formed on the photoconductor 1 and is visualized as a toner image. It

The developer that has passed through the developing area is scraped off from the surface of the developing roller 5 by the scraper 7 and returned to the bottom of the developer container 3.

A toner container 8 containing replenishment toner T is provided adjacent to the developer container 3, and a toner replenishing roller 9 is arranged between the container 8 and the developer container 3. On the other hand, a toner concentration sensor 1 for detecting the toner concentration of the developer is provided in the flow path of the developer falling from the scraper 7.
0 is provided, and when the sensor 10 detects that the toner concentration of the developer D has dropped to a predetermined value or less, the agitator 11 in the toner container 8 rotates and the toner replenishing roller 9 described above rotates. As a result, the toner T in the toner container 8 is replenished in the developer D in the developer container 3. In this way, the toner density of the developer D is maintained within the predetermined range, and the deterioration of the image quality of the toner image formed on the photoconductor 1 is prevented.

A toner remaining amount sensor 12 for detecting the remaining amount of the toner T in the toner container is provided at the bottom of the toner container 8. As such a sensor, for example, a piezoelectric sensor,
Alternatively, a photo interrupter reed switch or the like can be used.

As the developing operation progresses, the amount of toner T in the toner container 8 also decreases. The state of the toner amount is based on the detection results of the toner remaining amount sensor 12 and the toner concentration sensor 10, as will be described later, and the control unit 13 shown in FIG.
The state of the toner amount in the toner container 8 is displayed on the display unit 14 based on the determination result. The display unit 14 has a display unit arranged outside the image forming apparatus, and predetermined information is displayed here. Such display means 1
When a toner end or toner near end indication for replenishing toner is displayed on the display unit 4, the operator replenishes the toner container 8 with toner according to this indication.

In this example, as shown in FIG. 1, the toner cartridge 15 is detachably mounted on the upper portion of the toner container 8 and is housed inside the cartridge 15 by peeling off the flexible seal 16 for sealing the bottom surface thereof. The toner is dropped into the toner container 8 and the toner is replenished there.

When the toner container 8 is replenished with toner as described above, there is no indication on the display means 14 that the toner should be replenished. However, as described above, due to the erroneous detection of the toner remaining amount sensor 12, in the conventional developing device, although the toner container 8 is replenished with toner, it is indicated that the toner should be replenished. was there. The present invention prevents the occurrence of such inconvenience, and the specific examples thereof and modes of erroneous detection will be specifically described below.

In FIG. 2, the toner concentration sensor 10 is
It is connected to the toner concentration sensor logic 17 of the control means (CPU & memory) 13, the output of which is input to the first AND gate 19 via the inverting circuit 18 and the second
Is directly input to the AND gate 20 of.

On the other hand, the output of the toner remaining amount sensor 12 is first input to the third AND gate 21, and at the same time, the output of the sensor 12 is input to the fourth AND gate 23 via the inverting circuit 22. The clock signal of the clock oscillator 24 is also input to the AND gate 23, and the output of the AND gate 23 synchronized with this clock signal is input to the toner remaining amount counter 25. Further, its output is input to the toner full counter 27 via the first comparator 26, and its output is input to the flip-flop 29 via the second comparator 28. The output of the flip-flop 29 is input to the aforementioned third AND gate 21.

When a sufficient amount of toner remains in the toner container 8, the output of the toner remaining amount sensor 12 becomes L (low) level, and conversely, the toner in the toner container 8 runs out,
Alternatively, when the remaining amount becomes less than or equal to a predetermined amount, the output of the toner remaining amount sensor 12 becomes H (high) level.

On the other hand, when the toner density of the developer D is high, the H level signal is output from the logic 17 by the output of the toner density sensor 10 which detects this. On the contrary, when the toner density falls below a predetermined value, the output from the logic 17 becomes L level. However, in the following description, the output of the toner density sensor 10 becomes H level according to the toner density of the developer.
Described as a level or L level.

Now, let us consider a case where the amount of toner in the toner container 8 decreases and the toner remaining amount sensor 12 outputs no toner, that is, an H level detection signal. At this time, the H level detection signal output from the toner remaining amount sensor 12 is input to the third AND gate 21,
At this time, if the other input of the AND gate 21 (input from the flip-flop 29) is H level, the output of the third AND gate 21 becomes H level,
This is input to the first and second AND gates 19 and 20, respectively.

At this time, the toner density of the developer D is high,
Therefore, if an H-level detection signal is output from the toner concentration sensor 10, the output is inverted by the inversion circuit 18 and input to the first AND gate 19 as an L level signal, and the second AND gate 20 outputs the H level signal. The detection signal with the same level is input. As a result, the first AND gate 1
The output of 9 becomes L level and the output of the second AND gate 20 becomes H level. Based on such a detection result, the control unit 30 determines that the toner is near the end state. Based on the determination result, "toner near end" is displayed on the display unit 14. That is, it is about to be displayed that the toner in the developing device will be used up soon. The above relationship and the display contents of the display means at this time are shown in (3) of Table 1 below.

[0026]

[Table 1]

Next, consider a case where the toner remaining amount sensor 12 detects the absence of toner, outputs a detection signal of H level, and the toner density of the developer D is low. At this time, the H level detection signal from the toner remaining amount sensor 12 is input to the third AND gate 21. If the other input of the AND gate 21 is also H level here, the AND gate 21 outputs Outputs an H level signal, which is input to the first AND gate 19 and the second AND gate 20, respectively. Further, since the output of the toner density sensor 10 becomes L level, the first
The input of the AND gate 19 is at H level, and the input of the second AND gate 20 is at L level. Therefore, the outputs of the first AND gate 19 and the second AND gate 20 become H level and L level, respectively. Based on the detection result, the control unit 30 determines the toner end state,
“Toner end” is displayed on the display means 14. That is, it is displayed that the toner container 8 should be immediately replenished with toner. The state at this time is shown in (4) of Table 1.

When the operator replenishes the toner container 8 with toner as described above in accordance with the display of the toner near end or the toner end, the output of the toner remaining amount sensor 12 is as follows.
The L level indicates the presence of toner. Therefore, one input of the third AND gate 21 becomes L level, and therefore the output of this AND gate 21 becomes L level. As a result, as shown in (1) and (2) of Table 1, regardless of whether the output of the toner concentration sensor 10 is at the H level or the L level, the first and second AND gates 19 and 20 have Both outputs are at L level. Based on the detection result, the control unit 30 determines that "toner is present", and accordingly, the display means 14 displays "Ready to copy". There is a sufficient amount of toner in the toner container 8, and therefore, it is indicated that copying can be performed without any trouble.

Normally, after the toner is replenished in the toner container 8, the toner T in the toner container 8 is exhausted or the remaining amount of the toner T becomes small, until the absence of toner is detected.
Although the above-mentioned "ready to copy" display is continuously output to the display means 14, even though there is a sufficient amount of toner in the toner container 8 due to an erroneous detection of the toner remaining amount sensor 12, the toner is not detected. When the H-level signal is output from the sensor 12, in the conventional developing device, the toner end or the toner near end is displayed on the display means 14 as in the case of (3) or (4) in Table 1, which is confusing to the operator. There was a problem.

Therefore, in the present invention, the control means is provided with an information holding means for holding the toner present information detected by the toner remaining amount sensor until it is detected that the toner amount in the toner container is equal to or less than a predetermined amount. Has been.

In the example shown in FIG. 2, the above-mentioned flip-flop 29 serves as an information holding means. When the toner container 8 is replenished with toner and it is confirmed that the toner is contained in the toner container, the output of the flip-flop 29 is maintained at the L level, and henceforth, even if the toner remaining amount sensor 12 Sensor 1 due to the false detection of
Even if 2 outputs an H level signal and this is input to the third AND gate 21, the output of this AND gate 21 is always at the L level. As a result, the outputs of the first and second AND gates 19 and 20 are both at the L level, and the display means "copyable" continues to be displayed.

More specifically, the toner container 8 is replenished with toner, whereby the toner remaining amount sensor 12
When the output from is at the L level, it is inverted by the inverting circuit 22 and becomes the H level signal by the fourth AND gate 23.
Is input to the gate 23 and an H level signal synchronized with the clock signal is output from the gate 23.
It is input to 5 and the number is counted. When the count number reaches a predetermined reference value t, the output of the first comparator 26 is input to the toner full counter 27, and when the count number reaches the reference value k, the second comparator 28 outputs the count value. Is output to the flip-flop 29. This sets the flip-flop 29. After that, the output of the flip-flop 29 is maintained at the L level, so that the output of the third AND gate 21 is always at the L level as described above. Toner container 8
When the second toner remaining amount sensor 112 (FIG. 1) attached to the sensor detects that the remaining amount of toner in the toner container 8 has become equal to or less than a predetermined amount, the flip-flop 29 is reset.

In this way, the output of the third AND gate 21 is at the L level until the presence of toner is held by the setting of the flip-flop 29 and then the remaining amount of toner is detected to be low. During this time, even if the output of the remaining toner sensor 12 becomes H level due to the erroneous detection of the toner remaining amount sensor 12, the outputs of the first and second AND gates 19 and 20 always become L level, and the display unit 1
No. 4 keeps displaying "Ready to copy".

Further, by providing the toner remaining amount counter 25 and the toner full counter 27, the flip-flop 29 is set after the presence of toner is detected for a predetermined time, so that the toner is reliably stored in the toner container 8. The flip-flop 29 is set only when it is in the off state, and its malfunction is prevented. Either one of the counter 25 and the comparator 26 and the counter 27 and the comparator 28 can be omitted.

After the flip-flop 29 is reset, its output becomes H level, so that the toner remaining amount sensor 12 detects the decrease of the toner amount in the toner container 8 and
When the output becomes H level, the third and-cade 21
Output becomes H level, and the toner end and toner near end states can be reliably detected as described above ((3) and (4) in Table 1).

FIG. 3 is a flow chart of the above operation. First, in step (1), it is determined whether or not the toner full flag = 1, that is, whether or not the flip-flop 29 is set.

If No here, it is checked in step (2) whether the toner is out. The toner end is the first and second AND gates 19, as described above.
This is when the output of 20 is at the H level and the L level ((4) in Table 1).

If No in step (2), it is determined in step (3) whether toner is near end.
Toner near end is the first and second AND gates 19 and 2.
0 output is at L level and H level respectively (Table 1
(3)).

If No in step (3), the toner remaining amount counter 25 is incremented by 1 in step (4), and then it is judged in step (5) whether the count number of the toner remaining amount counter 25 is t or more, If Yes, the toner full counter 27 is incremented by 1 in step (6), and the toner remaining amount counter 25 is cleared in step (7).

Next, in step (8), it is checked whether the count number of the toner full counter 27 is k or more. If Yes, the toner full flag is set, that is, the flip-flop 29 is set in step (9). It

In step (10), it is checked whether or not the second toner remaining amount sensor 112 detects the absence of toner, and if No, the process goes directly to EXIT. If Yes, the toner full flag is reset in step (11), that is, the flip-flop 29 is reset, and the toner full counter 27 is reset in step (12).
To reset.

When the toner full flag = 1 is checked in step (1), the toner remaining amount counter 25 is cleared in step (13), and the step (14) is executed.
Display "Ready to copy" on the display means 14,
After that, go to the bottom of step (9).

If Yes in step (2),
The toner remaining amount counter 25 is cleared in step (15), and then the toner end is displayed in step (16). Similarly, if Yes in step (3), the toner remaining amount counter 25 is cleared and the toner near end is displayed (steps (17) and (18)).

As can be seen from the above description, before the flip-flop 29 is set, that is, before the toner full flag = 1, the output of the flip-flop 29 is at the H level, which is the third AND gate. 21 is input to the toner container 8, so that when the toner level sensor 12 outputs an H level signal due to an erroneous detection of the toner level sensor 12 despite the large amount of toner in the toner container 8, the toner end is displayed on the display unit 14. Alternatively, the toner near end is controlled to be displayed, but the time until the flip-flop 29 is set is extremely short, so there is no practical problem. After the flip-flop 29 is set, the message "Ready to copy" is displayed as described above.

In the above-described embodiment, the amount of toner in the toner container 8 becomes less than the predetermined amount by the second toner amount sensor 112, which is different from the toner amount sensor 12 attached to the toner container 8. Is detected, the flip-flop 29 is reset, and the holding of the information with toner is released. Therefore, the configuration of the control unit 13 can be simplified.

On the other hand, the toner remaining amount sensor 12 detects that the amount of toner in the toner container 8 has become less than or equal to a predetermined amount, resets the flip-flop 29, and releases the holding of toner information. The second toner remaining amount sensor 112 can be omitted, and the structure can be simplified accordingly.

FIG. 4 shows an embodiment of the latter configuration. In this example, the output of the toner remaining amount sensor 12 is also input to the other fifth AND gate 23a. The clock signal of the clock oscillator 24a is also input to the AND gate 23a, and the AND gate 23a synchronized with this clock signal
Is output to the counter 25a. Further, its output is input to another counter 27a via the comparator 26a, and its output is input to another comparator 28a. The comparator 28a is a flip-flop 29
It is connected to the. The second toner remaining amount sensor 112 shown in FIGS. 1 and 2 is not provided. Other configurations in FIG. 4 are the same as those in FIGS. 1 and 2. Also in this case,
The counter 25a and the comparator 26a, and the counter 2
Either one of 7a and the comparator 28a may be omitted.

Here, as described above, the flip-flop 2
It is assumed that 9 is set. At this time, when the toner level sensor 12 outputs an H level signal due to an erroneous detection of the toner remaining amount sensor 12 while the toner is sufficiently contained in the toner container 8, the output of the third AND gate 21 is L.
As described above, the level has been reached and the display means "copy available" is displayed.

When this state continues and the remaining amount of toner in the toner container 8 becomes low, the remaining toner amount sensor 12 outputs an H level signal. This is not a false positive. This H level output is input to the AND gate 23a, and an H level signal synchronized with the clock signal is output from the gate 23a, and this is input to the counter 25a and the number thereof is counted. When this count reaches the reference value T, the output of the comparator 26a is input to the other counter 27a. When the count number reaches K, the output from the comparator 28a is input to the flip-flop 29, which resets the flip-flop 29. The rest of the operation is the same as the above-mentioned embodiment.

In the embodiment shown in FIG. 4, the amount of toner remaining in the toner container 8 is actually low, and as a result, the toner remaining amount sensor 12 is correctly outputting an H level signal.
After confirming with the counters 25a and 27a, the flip-flop 29 is reset.

When the toner amount in the toner container is large,
Even if the H-level signal is output from the remaining toner amount sensor 12 by erroneous detection, the count number of the counters 25a and 27a does not normally reach T or K, and therefore the flip-flop 29 is not reset by erroneous detection. Absent.

It is obvious that the present invention can be applied to various developing devices other than the type shown in FIG.

[0053]

According to the first aspect of the present invention, when the toner container is replenished with toner, it is detected by the toner remaining amount sensor that the toner amount is sufficient, and the toner present information indicates the toner amount. Since the toner is held until it is detected that the amount becomes equal to or less than the predetermined amount, during that time, even if the remaining toner amount sensor is erroneously detected, it is possible to always display on the display means that there is toner.

According to the second aspect of the invention, the number of sensors can be reduced and the structure can be simplified.

According to the third aspect of the invention, the structure of the control means can be simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a developing device.

FIG. 2 is a block diagram of an embodiment of the present invention.

FIG. 3 is a flowchart thereof.

FIG. 4 is a block diagram showing another embodiment.

[Explanation of symbols]

 2 developing device 3 developer container 8 toner container 10 toner concentration sensor 12 toner remaining amount sensor 13 control means 14 display means 112 toner remaining amount sensor D developer T toner

Claims (3)

[Claims] 1. A developer container containing a two-component developer formed by mixing toner and a carrier, a toner container containing toner to be replenished to the two-component developer in the container, and the developer. Toner concentration sensor that detects the toner concentration of
A toner remaining amount sensor for detecting the remaining amount of toner in the toner container, a control unit for determining the state of the toner amount in the toner container based on the detection results of the toner concentration sensor and the toner remaining amount sensor, and the determination Display means for displaying the state of the amount of toner in the toner container based on the result, and the electrostatic latent image formed on the latent image carrier can be converted into a toner image by using the two-component developer. In a developing device that visualizes an image, the control unit retains the information with toner detected by the toner remaining amount sensor until the amount of toner in the toner container is detected to be equal to or less than a predetermined amount. A developing device comprising means. 2. The holding of the toner present information is released by detecting that the amount of toner in the toner container has fallen below a predetermined amount by the toner remaining amount sensor attached to the toner container. Developing device. 3. A toner remaining amount sensor attached to the toner container, which is different from the toner remaining amount sensor, detects that the amount of toner in the toner container is below a predetermined amount, and the toner is present. The developing device according to claim 1, wherein holding of information is released.