JPH0255724B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a powder developer detection device suitable for detecting the presence or absence of powder developer in a powder developer storage container in an electrophotographic apparatus.

In electrophotographic apparatuses, a two-component development method using a developer consisting of toner and a carrier, and a one-component development method using a developer consisting only of toner are known and widely used. In any of these methods, toner is consumed during development, and it is necessary to replenish the toner. Normally, toner is automatically replenished from a storage container, and toner must be added to the replenishment container as needed. Therefore, means are used to detect whether or not enough toner remains in the supply container and to notify the operator when there is not enough toner.

Conventional means for detecting the presence or absence of toner include a device that irradiates light into developer powder, detects it with a photodetector such as CdS, and detects the presence or absence of powder developer that blocks the optical path, a piezoelectric element, etc. There are known devices that detect the presence or absence of powder developer in contact with a detector using magnetic means, and devices that use magnetic means to detect the presence or absence of powder developer. In all of these devices, the powder developer in a limited area around the detector in the storage container is generally prone to crosslinking, and even if the amount of powder in the entire container is extremely small, the detector There are cases where crosslinking occurs only around the area, resulting in malfunction. Conversely, a cavity may be created around the detector. Therefore, it is necessary to provide a mechanical stirring means in the container to prevent crosslinking.

The present invention aims to solve the above-mentioned problems in conventional powder developer detection devices and provide a device that reliably detects the presence or absence of developer in a storage container. The device includes a container for containing a powder developer, a detector for detecting the presence or absence of the powder developer in the container, and agitating the powder developer near the detector in the container. In the powder developer detection device having a stirrer, based on the plurality of detection results detected by the detector, there are a plurality of detection results corresponding to the absence of the powder developer among the detection results. In addition to having a means for determining that there is no powder developer when the above is the case,
The determining means is characterized in that it inputs the detection results of the detector at a detection cycle different from the operation cycle of the stirrer.

In one embodiment of the present invention, the determining means may be configured such that among the plurality of detection results, the detection result corresponding to the absence of powder developer is higher than the detection result corresponding to the presence of powder developer. It is characterized in that it determines that there is no powder developer when there is too much powder developer.

In another embodiment of the present invention,
The discriminating means has a counter that obtains the plurality of detection results within a predetermined period of time, and the discriminating means has a counter that obtains the plurality of detection results within a predetermined time, and when the counter has counted the detection result corresponding to the absence of the powder developer a preset plurality of times or more, The present invention is characterized in that it determines that there is no powder developer.

That is, the device of the present invention uses the detection means to detect
The presence or absence of the powder developer is detected multiple times and the results are subjected to logical operations to determine the presence or absence of the powder developer. Therefore, the detection period of the detector is set to be different from the operation period of the stirring means.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a powder developing device in an electrophotographic apparatus embodying the present invention. In the figure, 1 is a photoreceptor of an electrophotographic device, 2 is a developing device, and the developing device 2 is a developer container 3 that stores a powder developer.
, a developing sleeve 4, and a blade 5. The one-component developer in the developer container 3 is regulated by a blade 5 made of a magnetic material and applied onto the sleeve 4, facing the photoreceptor 1, and develops the latent image on the photoreceptor 1. A magnet is arranged within the sleeve 4.

In order to detect the presence or absence of powder developer stored in the developer container 3, a detector 6 detects the presence or absence of powder in a predetermined area within the developer container 3; A stirrer 7 is provided which operates periodically in the vicinity of the area. This stirrer 7 rotates in the direction shown by the arrow in conjunction with the operation of the developing device. In practice, its rotational speed is about 2r.pm. This stirrer 7 is provided with a brush 8, which removes powder developer adhering to the surface of the detector. The detector is a detector using a piezoelectric element. The circuit configuration is shown in FIG.

The circuit shown in FIG. 2 constitutes an oscillation circuit using the piezoelectric element 10. When the developer is not in contact with the piezoelectric element, the piezoelectric element 10 freely vibrates, causing oscillation. The oscillation signal is detected and integrated to become an output signal. When the developer powder comes into contact with the piezoelectric element, the vibration of the piezoelectric element is hindered and the oscillation is stopped.

In this embodiment, a logical operation circuit performs logical calculations on the detection results detected by the detector 6 multiple times at a cycle different from the operating cycle of the agitator 7 to determine the presence or absence of powder developer. will be provided. FIG. 3 shows an example of a logic operation circuit. FIG. 3a shows an example in which a bidirectional shift register 20 is used. The clock is generated at a different frequency from the agitator depending on the operation of the apparatus, and in this example, approximately 6 times per minute is appropriate. The clock spacing does not have to be exact.

In the circuit shown in Figure 3a, the output signal of the detector is applied to the input. When the signal from the detector is at a high level (when there is no developer powder), 1 is input to the shift register 20 from the left, and the data is shifted to the right. When the level is low, it is shifted to the left and 0 is input from the right side.

Therefore, when the number of high level cases is greater than the number of low level cases, one of the shift registers 20
The signal gradually shifts to the right, and a 1 is output from the output terminal, indicating that the flip-flop is set and there is no developer. When developer is added, for example, it detects that the lid of the container is opened, sets the reset terminal to low level, resets the flip-flop, and at the same time sets each bit of the shift register to 0. In the device shown in FIG. 3a, the desired effect could be obtained by using a TTI.SN74198 (Texas Instruments Inc.) 8-bit shift register as the shift register. FIG. 3b shows an example using two counters. In the figure, 30 and 31 are counters. Counter 30 is a hexadecimal counter and clears counter 31 every 16 clocks. The counter 31 is a decimal counter, which counts clocks when the input is at a high level, and generates a carry signal when the count is 9. That is, in this circuit, the flip-flop is set if the detection signal is at a high level nine times or more out of 15 detections. In the device shown in FIG. 3b, the counter 3
By using SN74161 (Texas Instruments Inc.) as the counter 31 and SN74160 (Texas Instruments Inc.) as the counter 31, the desired effect could be obtained.

Although many other variations are possible in the content of the logical operation, the important point in the present invention is that the result of the operation does not depend on a single detection, but rather that the results of multiple detections are combined. It is to be determined. Further, in the present invention, it is important that the operation cycle of the stirrer and the detection cycle are different.

If a brush or the like is provided to remove the developer from the detection part as in the example shown in Figure 2, the effect of removing toner adhering to the detection part is extremely large, but the brush may come into contact with the detection part even when there is no developer. Therefore, the detection circuit may determine that there is developer.

However, according to the present invention, since the detection period and the movement period of the stirring means are different, the detection operation is not performed only when the brush comes into contact with the detector. Furthermore, since the detection period does not need to be accurate, there is no need to provide a dedicated detection signal generating means, and there is an advantage that an appropriate signal generated along with the operation of the device can be used. Further, there is no need to detect the operation of the stirring means.

In the above example, a dedicated hard logic circuit was used to perform logical operations, but if a microprocessor is used to control the sequence of the entire device, software It would be more reasonable to perform the calculation manually.

As described above, the present invention provides an apparatus for reliably detecting the presence or absence of powder developer in a powder developer storage container.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a developing device of an electrophotographic apparatus embodying the present invention, FIG. 2 is a diagram showing a circuit configuration of a detector, and FIGS. 3 a and b are diagrams showing an example of a logic operation circuit. . DESCRIPTION OF SYMBOLS 1...Photoreceptor, 2...Developing device, 3...Developer container, 4...Developing sleeve, 5...Blade, 6
...Detector, 7...Stirrer, 8...Brush, 10
... Piezoelectric element, 20 ... Shift register, 30,
31...Counter.

Claims (1)

[Claims] 1. A container for containing a powder developer, a detector for detecting the presence or absence of the powder developer in the container, and a powder developer near the detector in the container. In a powder developer detection device having a stirrer for stirring the developer, based on the multiple detection results detected by the detector, one of the detection results corresponding to the absence of the powder developer It has means for determining that there is no powder developer when there is a plurality of detection results, and the determining means inputs the detection results of the detector at a detection cycle different from the operation cycle of the agitator. A powder developer detection device characterized in that: 2. The determining means determines that there is no powder developer when the number of detection results corresponding to the absence of powder developer is greater than the number of detection results corresponding to the presence of powder developer among the plurality of detection results. 2. The powder developer detection device according to claim 1, wherein the powder developer detection device determines whether 3. The determining means has a counter that obtains the plurality of detection results within a predetermined period of time, and when the counter has counted the detection results corresponding to the absence of the powder developer a preset plurality of times or more, 2. The powder developer detection device according to claim 1, wherein the powder developer detection device determines whether there is any powder developer in response to the detection result.