JPH05323788A - Residual toner detector for developing device - Google Patents

Abstract

PURPOSE:To provide a residual toner detector for a developing device, capable of preventing the unexpected stop of a machine, etc., by accurately detecting ever-changing residual toner and informing an operator of it, without having a failure in the complication of a mechanism and signal processing, etc. CONSTITUTION:The residual toner detector for the developing device, is provided with first and second encoder impellers 16 and 18 disposed to coaxially and relatively rotate and face each other, and having the same shape, a coil spring 17 located between both encoder impellers and holding each blade of both encoder impellers, in a matching positional relation, an optical sensor 21 detecting relative rotation when a detecting arm 6d passes in toner and both encoder impellers are relatively rotated because of a load imparted to one of the encoder impellers, and a control part judging that the detecting arm is located in the toner only while a signal finished to detect the relative rotation is outputted from the optical sensor, and deciding a toner quantity based on the result of the judgement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a toner remaining amount detecting device of a developing device used in an image forming apparatus utilizing an electrophotographic process, and particularly to a low cost without complicated mechanism and complicated signal processing. The present invention relates to a remaining amount detecting device capable of accurately detecting the remaining amount of toner every moment.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic process such as a copying machine, a printer, a facsimile machine, it is possible to attach toner from a developing device to an electrostatic latent image on a photosensitive drum. An image is formed by visualizing the image and transferring and fixing the visible image on the recording paper. By the way, it is necessary for the operator to know the presence / absence of toner and the remaining amount of toner in the copying operation, and thus various remaining amount detecting methods have been developed. For example, a device for detecting the remaining amount has been put into practical use by providing a detection arm in the hopper and a detector for detecting the remaining amount of toner using the torque difference in the detection arm. The number of points to detect the remaining amount was limited to one point, and it was not possible to accurately detect how much remaining amount.

In Japanese Utility Model Laid-Open No. 61-132858, the characteristics of a DC electric motor are utilized, and the driving force generated on the drive shaft when the stirring member in the toner of the developing device is rotated is used to rotate the electric motor. The remaining amount of toner is detected by measuring and detecting changes in the number, current value, angular velocity and the like. This conventional example is special in that it is premised on the presence of a DC electric motor, and detection is impossible without the electric motor. Moreover, since changes in the number of revolutions, current value, angular velocity, etc. of the electric motor are measured, the signal processing becomes complicated, resulting in increased cost and increased failure.

Further, in Japanese Patent Laid-Open No. 60-79374, a load proportional to the amount of toner is applied to a drive system of a stirring member for stirring toner in a toner bottle. The detection mechanism is activated when the value exceeds a certain value, but this method cannot accurately detect the remaining toner amount that changes from moment to moment.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to accurately detect a toner remaining amount which changes moment by moment without causing problems such as a complicated mechanism and a complicated signal processing. It is an object of the present invention to provide a toner remaining amount detecting device of a developing device capable of preventing an unexpected stop of a machine or the like by notifying an operator.

[0006]

To achieve the above object, the present invention provides a developing device for an image forming apparatus utilizing an electrophotographic process, the developing device having a base end supported by a shaft projecting into a toner storage hopper. And a drive mechanism for transmitting a drive force from a drive means outside the developing device to the shaft, and a toner remaining amount detection mechanism arranged in the drive force transmission path of the drive mechanism. And a control unit, and the toner remaining amount detection mechanism is located between the encoder impellers and first and second encoder impellers of the same shape, which are coaxially opposed to each other so as to be relatively rotatable. A coil spring that holds the blades of the vehicle in alignment with each other and both encoder impellers due to the load applied to one encoder impeller when the detection arm passes through the toner. An optical sensor that detects the relative rotation when the optical sensor rotates, and the control unit is configured such that the detection arm is positioned in the toner only during a period in which a signal indicating the relative rotation is output from the optical sensor. It is determined that the amount of toner is present, and the toner amount is determined based on the determination result.

The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a structural explanatory view showing an example of an image forming apparatus to which the present invention is applied. This image forming apparatus includes a sheet feeding cassette 1 on which recording sheets are stacked, a sheet feeding roller 2, and a manual sheet feeding port for recording sheets. 3, a manual paper feeding unit 3a, a numeric keypad,
An operation unit 5 including a copy start button and the like, a developing device 6, a photoconductor drum 7, a fixing unit 8, a laser beam writing unit 9, and a control board 10 that controls electric control of the entire image forming apparatus. Have. As shown in FIG. 2, the developing device 6 includes a developing roller 6a, a toner stirring and supply roller 6
b, a toner storage hopper 6c, a toner remaining amount detecting arm 6d, and the like. The arm 6d is configured to rotate by its base end being supported by a shaft 11 connected to a drive mechanism outside the developing device. It is to detect the quantity.

FIG. 3 is a schematic diagram showing the construction of the drive mechanism and the detecting means connected to the toner remaining amount detecting arm, and FIG. 4 is a diagram showing the structure of the detecting means. Toner level detection arm 6
The first gear 12 is attached to one end of the shaft 11 that supports the base end portion of d.
Is integrally fixed, and second, third, and fourth gears 13, 14, and 15 are sequentially meshed with the first gear 12, and the driving force from a motor (not shown) is The signals are sequentially transmitted from the fourth gear 15 to the first gear 12.

A first pulse plate (first encoder impeller) 16 having a plurality of blades 16a as shown in the drawing has a shaft center integrated with the rotating shaft of the fourth gear 15. The pulse plate 16 is coaxially connected to a second pulse plate (second encoder impeller) 18 via a coil spring 17. Further, the second pulse plate 18 is integrated with the shaft center of a sixth gear 19, and a drive gear 20 connected to a motor (not shown) meshes with the sixth gear 19.
The blade 16a of the first pulse plate 16 and the second pulse plate 1
The number, shape, interval, and size of the blades 18a of 8 are the same, and when the load from the toner is not applied to the detection arm 6d, the blades 16 of the pulse plates 16 and 18 are provided.
The positions and angles of a and 18 are set by the spring 17 so that they are completely overlapped. It should be noted that the spring 17 has its both end portions 17a at the respective pulse plates 1
By being fixed to Nos. 6 and 18, the positional relationship between both pulse plates when no load is applied is defined.

Reference numeral 21 is a reflection type optical sensor,
Is arranged on the back side of the pulse plate 16 and detects whether or not the positions of the blades of the pulse plates 16 and 18 or the notches between the blades match. That is, when the rotating detection arm 6d is located in the toner, the coil spring 17
Is deflected by the load from the toner, the rotation of the first pulse plate is delayed, and both pulse plates 16, 1
Relative rotation occurs between eight. As a result, the positions of the notches of both pulse plates are displaced, so that the light emitted from the light emitting portion of the sensor is reflected by the blades 18a of the second pulse plate 18 and returns to the light receiving portion of the sensor 21. The detection signal from the sensor 21 is output only while the detection arm 6d is located in the toner. A control unit (not shown) that receives the detection signal from the sensor 21 calculates the toner remaining amount based on the time (pulse number) during which the detection signal is output, and displays the toner remaining amount on the display unit on the operation unit. To do.

When there is no toner, the detection arm 6d rotates without receiving any resistance, so that relative rotation does not occur between the two pulse plates, and the detection arm 6d emits the first pulse plate 16 from the sensor 21. The light passing through the notch passes through the notch of the first pulse plate 18 as it is. Therefore, the control unit determines that there is no toner, and causes the machine to stop, display no toner, and display toner replenishment. In order to enable the above detection operation, the blade of the pulse plate 16 on the side closer to the sensor is made black which does not reflect light, and the blade of the other pulse plate 18 is made white which reflects light.

5 (a), (b) and (c) are views showing the rotation angle of the second pulse plate 18 with respect to the first pulse plate 16, and FIG.
2nd with respect to the 1st pulse board 16 in the rotation angle of (a)
When the pulse plate 18 of is in the state of (b), the blade 16a
Since the positions of and are completely coincident with each other, the waveform detected by the sensor is as shown in the lower diagram of (b), which corresponds to the case without toner. Further, the second pulse plate 18 is in the state of (c) with respect to the first pulse plate 16 at the rotation angle of FIG. 5 (a) (the notches of the pulse plate 16 are completely shielded by the blades of the pulse plate 18). The state detected by the sensor is different because the positional relationship between the two blades is misaligned.
It becomes like (c). In other words, while the optical path of the detection light is constant (immovable), the two pulse plates rotate with a deviation, so that the presence or absence of light reflection can be detected as the presence or absence of a pulse. .. The number of the pulses (the length of all the pulses) fluctuates according to the load (time spent in the toner) that the detection arm 6d receives from the toner, and is proportional to the remaining amount of the toner. It becomes possible to accurately calculate the remaining amount of toner based on the pulse width.

In the above embodiment, an example using a reflection type optical sensor is shown, but a transmission type optical sensor may be used.
In this case, the light emitting element and the light receiving element are arranged so as to face each other with the both pulse plates sandwiched therebetween, and the interval between the blades at which the light emitted from the light emitting element can be received by the light receiving element can be detected as the pulse width.

[0014]

As described above, according to the present invention, problems such as complicated mechanism and complicated signal processing do not occur,
Accurate detection of the remaining toner amount that changes from moment to moment and notification to the operator can prevent an unexpected stop of the machine. In addition, depending on the model, it is necessary to change the operation of other units related to image formation according to the change in the remaining amount of toner. It is possible to realize it appropriately according to the amount.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory diagram of an image forming apparatus to which the present invention is applied.

FIG. 2 is a diagram illustrating the overall configuration of a developing device according to the present invention.

FIG. 3 is a schematic configuration explanatory view of a developing device and a remaining toner amount detection mechanism of the present invention.

FIG. 4 is an enlarged view of a toner remaining amount detection mechanism.

5 (a), (b) and (c) are the second pulse for the first pulse plate.
It is a figure which shows the rotation angle of a pulse board.

[Explanation of symbols]

1 paper feed cassette, 2 paper feed rollers, 5 operation unit, 6
Developing device, 6a developing roller, 6b toner stirring and supplying roller, 6c toner accommodating hopper, 6d toner remaining amount detecting arm, 7 photosensitive drum, 8 fixing unit,
9 laser light writing unit, 10 control board, 11 jig, 12 to 15, 19 gear, 16, 18 pulse plate,
16a, 18a pulse plate, 17 coil spring, 20
Drive gear, 21 sensors

Claims (1)

[Claims] 1. A developing device for an image forming apparatus utilizing an electrophotographic process, the developing device comprising a detection arm having a base end supported by a shaft projecting into a toner storage hopper and moving in the toner. A drive mechanism for transmitting a drive force from a drive means outside the developing device to the shaft, a toner remaining amount detection mechanism arranged in the drive force transmission path of the drive mechanism, and a control unit. The detection mechanism is located between the first and second encoder impellers of the same shape, which are coaxially opposed to each other so as to be rotatable relative to each other, and is located between both encoder impellers, and holds the respective blades of both encoder impellers in an alignment positional relationship. A coil spring and a light that detects the relative rotation of both encoder impellers due to the load applied to one of the encoder impellers when the detection arm passes through the toner. A sensor, and the control unit determines that the detection arm is located in the toner only during a period in which a signal that detects the relative rotation is output from the optical sensor, and based on the determination result. A remaining toner amount detecting device for a developing device, characterized in that the amount of toner is determined according to the toner amount.