JPS5835564A - Detection for residual quantity of toner - Google Patents

Abstract

PURPOSE:To detect the residual quantity of a toner accurately, by detecting the residual quantity of the toner in a hopper after the elapse of a prescribed time from toner supply. CONSTITUTION:The density of the toner in a developer saucer 18 is detected, and a toner supply shaft 17 of a toner hopper 13 is rotated by a motor M in accordance with this detection value to supply the toner intermittently into the developer saucer. When the toner is supplied, the mechanical oscillation and the electric noise from the motor are generated. Therefore, the residual quantity is detected by a sensor 14 after the elapse of a prescribed time from the toner supply due to the toner supply shaft 17, and thus, the inside of the toner hopper becomes stable to detect the toner residual quantity easily and accurately without the influence of the noise upon the detection signal and restrictions due to the attaching position, the shape, or the circuit of a sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the remaining amount of developing toner in a high-speed electrophotographic printing device such as a laser printer, and the remaining amount of toner can be accurately detected. It is something.

FIG. 1 is a side view showing an outline of this type of printing device, in which a latent image forming device 2, a developing device 3, a transfer group w4, and a cleaning device w5 are arranged in this order around a drum-shaped latent image forming body l. has been done. A latent image 6 is formed on the surface of the latent image forming body 10 = photosensitive material 4 by a method such as irradiating the latent image forming body 1 with a laser beam as indicated by an arrow 112.

When the surface on which the latent image 6 is formed reaches the position of the next developing device I3, toner as a developer is electrostatically attached to the latent image surface to form a visible image 7. This visible image 7 is transferred to the next transfer device f
4, when the transferred visible image 9 is electrostatically transferred to the recording medium 8 such as plain paper and reaches the fixing unit 10, the toner constituting the visible image 9 is heated to the recording medium 8. The hard copy 11 is completed by welding. - The toner 12 in which the visible image 7 on the power tank image forming member 1 remains on the recording member L is moved to the position of the cleaning device 15 and removed, and then moved to the position of the original latent image forming group [2]. Then, the next latent image formation is performed.

By the way, in the developing device 3, since toner is supplied to the latent image surface of the latent image forming member 1, it is necessary to have a means to detect when the toner is consumed and the remaining amount is low and to let the operator etc. In particular, laser printers used as output devices for electronic computers print at high speed, so toner is consumed quickly and it is necessary to replenish toner frequently, so it is difficult to accurately measure the remaining toner amount. 2 is a side sectional view showing the inside of the developing device 3, in which a sensor '14 for detecting the remaining amount of toner is disposed in the toner hopper 13. The toner 15 in the hopper 13 is transferred to a toner supply shaft 170 having an axial groove 16.
The toner 19 in the toner tray 18 is magnetically attracted to the magnetic roller 20 to form a magnetic spike 21 , and the rotation of the magnetic roller 20 causes the magnetic spike 21 to be attached to the latent image forming body 10 . The latent image 64 is supplied to the surface and is attracted by electrostatic force, forming a visible image 7. Toner 15 in hopper 13
is supplied to the toner tray 18 and the remaining amount is low, and the sensor 1
When the toner level drops to position 4, it is detected by the sensor 14 and the operator is notified.

As the sensor 14 that detects the amount of toner remaining in the toner hopper 13, there are sensors that utilize the fact that an ultrasonic vibrator starts to vibrate when the amount of remaining toner becomes low, and sensors that utilize changes in capacitance. It is used. However, when detecting the level of toner, which is fine particles, the mechanical vibrations caused when the motor M rotates the toner replenishment shaft 17 to replenish toner into the toner tray 18, and the fact that the hopper 13 has a closed structure, cause toner replenishment. It is susceptible to the effects of air movement when the shaft 17 rotates, creating cavities in the toner near the sensor, or electrical noise from the motor M when replenishing toner, resulting in unstable operation and malfunctions. In order to eliminate these problems, conventional methods include installing the sensor in a position with less mechanical vibration, widening the detection surface of the sensor, and installing a filter to remove electrical noise. I've been dealing with it. However, with these methods, the mounting position and shape of the sensor are restricted, and the circuit configuration becomes complicated.

The present invention aims to solve these problems in the conventional toner remaining amount detection method, and to realize a toner remaining amount detection method in which the sensor mounting position and shape are not restricted and the circuit configuration is simple. To achieve this object, the present invention provides an apparatus for developing a latent image with toner, in which the operation of starting the amount of toner in the toner hopper is performed at a predetermined time after each replenishment operation of intermittently replenishing the toner tray with toner. The structure is such that 4 lines can be read after a certain period of time has elapsed.

Next, an embodiment of this toner remaining amount detection method will be described. FIG. 3 is a time chart showing an embodiment of the method of the present invention, in which a toner replenishment instruction signal is generated by inputting a toner replenishment instruction signal from a print density detecting section of a printed matter when the print density becomes thin. The motor M is operated by this toner replenishment instruction signal A, and the rotation of the toner replenishment shaft 17 causes a fixed amount of 1? Toner is supplied to toner tray 18 . By the way, when looking at the detection mark B of the sensor 14 in the toner hopper 13, it is found that a so-called chattering phenomenon occurs in the detection unit No. 4 B when the toner supply shaft 17 starts and finishes rotating due to the motor M. Therefore, the detection signal B at this time lacks credibility as a signal for detecting the amount of remaining toner in the toner hopper 13. This seems to be caused by mechanical vibrations caused by the intermittent rotation of the toner supply shaft 17 and disturbance noise received from the motor. Furthermore, even while the toner replenishment shaft 17 is being rotated by the motor, the detection signal B may indicate the presence of toner or the state of no toner, and is unstable. This seems to be because during 1'70 rotations, air in the toner hopper 13 moves and cavities are generated, causing the toner to become unstable.

After a certain period of time during which toner is replenished by the toner replenishment shaft 17, the inside of the toner hopper becomes stable, and the detection signal B also reaches a steady state. Therefore, the present invention attempts to detect the remaining amount of toner in this steady state, and for this purpose, the mis-sampling signal, C
The detection signal B is sampled and its status is monitored. Figure 4 shows a circuit for performing this operation.
The road structure is shown in a block diagram, and the printing density can be checked □
When the toner replenishment instruction signal A from the peak is input, the motor M is started by the motor drive circuit 22, and a certain amount of toner is supplied from the toner hopper 13 to the toner 118 by the toner replenishment shaft 17. The toner replenishment instruction signal A is also input to the delay circuit 23, and after a preset delay time T elapses, a sampling signal C is generated and input to the next AND circuit 24, which opens the gate. The detection signal from the sensor 14 in the toner hopper 13 is amplified and shaped by the toner detection circuit 25, and is output as a detection signal B to the AND circuit 24.
is input. Therefore, a signal based on the AND condition of the sampling signal C and the detection signal B by the delay circuit 23 is output. This detection signal is input to the next holding circuit 26 such as a flip-flop, and is output as a detection signal C. That is, if the detection signal from the AND circuit 24 indicates that toner is present, a signal indicating that toner is present is continuously generated from the holding circuit 26, and only after the AND circuit 24 generates a signal indicating that there is no toner, the holding circuit is activated. 26, a signal indicating that there is no 1st alarm is generated continuously and the operator etc. is notified.

As described above, according to the present invention, the toner replenishment axis
After a certain period of time has passed after the toner replenishment operation in step 7,
A method is used to obtain detection signals from sensors. Therefore, the detection section is in a steady state to detect the remaining amount of toner, and the reliability of the detection operation is ensured. Furthermore, the mounting position and shape of the sensor are not limited, and the circuit configuration is simplified.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an outline of an electrophotographic printing device, FIG. 2 is a side cross-sectional view showing the internal structure of a developing device used for same-sex characteristics, and FIG. 3 is an implementation of the toner remaining amount detection method according to the present invention. FIG. 4 is a block diagram showing a circuit configuration for carrying out the operation of the flowchart. In the figure, 3 is a developing device t, 13 is a toner hopper, 1
4 is a sensor, 17 is a toner supply shaft, M is a motor, 18 is a toner tray, and 23 is a delay circuit.

Claims (1)

[Claims] In a device that develops a latent image with toner, this method detects the amount of toner remaining in the toner hopper. A method for detecting the amount of remaining toner configured to be performed after a predetermined period of time has elapsed after each replenishment operation that replenishes a tray intermittently.