JPS60102667A - Toner remaining quantity detecting device - Google Patents

Abstract

PURPOSE:To prevent a toner run-out by placing a coil in a laminated area of a toner having a magnetism, detecting an inductance variation of a coil, and obtaining a remaining quantity detecting output of a toner by plural stages of three stages or more, or continuously. CONSTITUTION:A follow-core coil 10 is installed to the outside surface of a toner box 2 formed by an insulating material so that a hand direction becomes a vertical direction. An inductance of the coil 10 is varied by a relative position to the coil 10 of an upper face 1a of a toner 1. The smaller a quantity of the toner 1 is, the better a line of magnetic force of the coil 10 passes through in the air, therefore, by a difference of a magnetic permeability of the air and the toner, the inductance is varied so as to become small. A voltage output of an F/V converter 12 is inputted to a window comparator 16 having a comparison reference of several stages and compared, and by its comparison output, several indicators 17 are driven, by which a toner remaining quantity can be known comparatively in detail, and a toner run-out can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a remaining toner amount detection device in a copying machine.

(Prior Art) An electrophotographic copying apparatus guides an image of a document onto a photosensitive drum by scanning an exposure light source relative to the document.
An electrostatic latent image corresponding to the image of the document is formed on the photosensitive drum surface, and toner is electrostatically attracted to the electrostatic latent image portion of the photosensitive drum from a developing device to form a toner image (development). This toner image is transferred to recording paper and fixed to form an image on the recording paper that corresponds to the original image.

By the way, in the above-mentioned development, as shown in FIG. 1, a magnetic toner 1 is supplied from a toner box 2 to a developing device 4 by opening a control valve 3, and is applied magnetically to the surface of a developing sleeve 5 in the form of a brush. It is made to attract and transfer to the photosensitive drum 6 by electrostatic force 7 . That is, the developing sleeve 5
The photosensitive tram 6 rotates in the direction of the arrow a, and a magnet 7 fixedly disposed inside attracts magnetic toner to its circumferential surface to form a so-called magnetic brush, thereby efficiently applying the magnetic toner to the photosensitive tram 6 rotating in the direction of the arrow. It is designed to absorb toner. 8 is an agitator, and 9 is a separator for scraping off toner remaining on the surface of the developing sleeve 5.

On the other hand, the amount of toner in the toner box 2 has conventionally been determined by providing a piezoelectric element that vibrates at a predetermined frequency, applying pressure by the weight of the toner 20 to the piezoelectric element, and reducing the pressure to a predetermined value or less. For example, by detecting a change in the vibration state due to the toner no longer coming into contact with the detection surface of a piezoelectric element, it is possible to detect that the remaining amount of toner is below a predetermined amount, or by using a transmission type light amount detector. was used to detect whether the amount of toner was below a predetermined amount based on the amount of received light. In other words, the conventional method for detecting the remaining amount of toner is based on whether the remaining amount is less than or equal to a predetermined amount.
It was value detection.

For this reason, there is a drawback that if the remaining amount of toner falls below a predetermined amount when the spare toner is used up, the copying device may become unusable until new toner is delivered. Ta.

(Object of the Invention) An object of the present invention is to provide a toner remaining amount detection device that allows the remaining amount of toner to be known in comparative detail and prevents the problems described above from occurring. It is to be.

(Structure of the Invention) To this end, the toner remaining amount detection device of the present invention arranges a coil so that magnetic lines of force penetrate into the laminated region of magnetic toner, and responds to changes in the laminated remaining amount of niJ toner. detecting a change in the inductance of the coil that changes by
With this, the toner remaining amount detection output is set to three or more stages #1.
I try to get it in stages or continuously.

(Example) Examples of the present invention will be described below. FIG. 2 shows an air-core coil 10 as an embodiment of the sensor, and its shape is an oval shape made by winding an insulated wire multiple times, and as shown in FIG. 3, it is made of an insulating material. The toner box 2 is attached to an outer surface (or an inner wall surface) of the toner box 2 so that its longitudinal direction is the vertical direction. That is, coil 10
The coil 10 is arranged so that the lines of magnetic force of the toner l pass through the laminated region of the toner l.

Therefore, part or all of the magnetic path (route of magnetic lines of force) of the coil IO on the toner box 2 side is formed by the magnetic toner 1 stacked inside the toner box 2 . Therefore, the inductance of the coil 10 changes depending on where the upper surface 1a of the toner 1 (indicated by the dashed line) is positioned relative to the coil 10.

If this change occurs, the higher the upper surface 1a of the toner l is, the more
In other words, the larger the amount of toner 1, the larger the inductance, and conversely, the more the upper surface ia becomes], that is, the smaller the amount of toner 1, the more the magnetic field lines of the coil 10 pass through the air, so the permeability between the air and the toner increases. The difference in magnetic flux causes a change in which the inductance decreases.

FIG. 4 shows a toner remaining amount detection circuit, and 11 is an oscillation circuit including the above-mentioned coil 10 as one resonant element, for example, a Colpitts type oscillation circuit is used. 12 is an F/V converter that generates a DC voltage proportional to the frequency oscillated by the oscillation circuit 11; 13 is the F/V converter 12;
An A/D converter that converts the DC voltage from the
14 is an arithmetic circuit that calculates the digital signal from the A/D converter and outputs a toner remaining amount signal, and 5 is an arithmetic circuit that continuously calculates the toner remaining amount based on the output from the arithmetic circuit 14, for example, by a bar graph or the like. This is an indicator for displaying information.

As described above, the inductance of the coil 10 increases as the amount of toner 1 remaining in the toner box 2 increases, and decreases as the amount of toner 1 remaining in the toner box 2 decreases. The frequency oscillated by the oscillation circuit 1 is inversely proportional to the root value of the inductance. Therefore, the frequency output from the oscillation circuit 11 will be lower if there is more toner in the toner box 2, and higher if there is less. This frequency signal is then converted into a voltage signal by the F/V converter 12, converted into a digital value by the A/D converter 13, and then sent to the arithmetic circuit 14. In this arithmetic circuit 14, the relative magnetic permeability per unit amount of toner l, the toner box 2
The toner box 2 The remaining toner amount signal in can be displayed.

Fig. 5 shows another toner remaining amount detection circuit.
The voltage output of the converter 12 is inputted to a window comparator 16 having, for example, a four-stage comparison standard, and compared, and the comparison output is used to display the display 1 consisting of four LEDs 17 to 174.
7.

According to this example, the amount of toner remaining in the toner box 2 is actually changed from zero to 10,000 cups, for example, by an even amount, in four steps, without considering the shape of the l.carbosox 2, etc.
Since the value of the comparison base Yi of the window comparator can be determined by actual measurement, the design becomes easy. In this case, when the remaining amount of toner is between zero and the first stage, the LED
17+ lit, LE when between 1st stage and 2nd stage
D172 lights up, L when it is between the 2nd crotch and the 3rd stage
When the ED173 is lit and the remaining toner level is between the third stage and the remaining toner level, 4 stages can be displayed as a 74-point illusion of the LED1. Note that this is the window comparator 16
Of course, it is possible to use any number of stages as long as the reference value for comparison is set to other than four stages and the LEDs are adapted to the number of stages.

Figure 6 fat~(C) shows an example of another coil,
First, the coil 20 has an air-core perfect circular shape, fbl
A coil 30 wound around a U-shaped core 31 as shown in FIG.
The coil 40 shown in tel is wound around a rod-shaped core 41. As shown in Fig. 3, the coil 20 is connected to the toner box 2.
Riushi ζ is attached to the outer surface or inner wall surface of (bl
, (The coil 30.40 not shown in C1 is shown in FIG. 7 (al, fb
As shown in FIG. 1, it is installed so that the lines of magnetic force are effectively transmitted in one direction of the toner stack inside the toner box 2.

In the above embodiments, the amount of toner remaining in the toner box is detected. It goes without saying that the present invention can also be applied to a structure in which the toner box 2 and the developing device 4 are integrated.

(Effects of the Invention) As described above, according to the present invention, the detection output of the remaining amount of toner is increased in three stages by changing the inductance of the coil arranged so that the magnetic lines of force pass through the laminated region of magnetic toner. Since the above-mentioned detection can be performed in multiple stages or continuously, the current amount of toner remaining can be known relatively precisely, and it is possible to prevent the toner from running out.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a developing device of a conventional copying machine, FIG. 2 is a diagram showing an example of a coil used in a remaining toner amount detection device according to an embodiment of the present invention, and FIG. A schematic diagram of the toner box, FIG. 4 is a circuit diagram of a remaining toner amount detection circuit, FIG. 5 is a circuit diagram of another example of a remaining toner amount detection circuit, and FIG. 6 is a coil of another modified example. Figure 7+al is a schematic diagram of the toner box with the coil shown in Figure 6 (bl) attached, and fbl is a schematic diagram of the toner box with the coil installed in Figure 6 (tel). - Magnetic toner, 2... Toner box, 3... Control valve, 4... Developing device, 5... Developing sleeve, 6... Photosensitive drum, 7... Magnet, 8...・
- Stirrer, 9... Separator, 10... Oval coil, 11... Oscillation circuit, 12... F/V converter,
I3...A/D converter, 14... Arithmetic circuit, 15.
...Indicator, 16...Window comparator, 17.
...LED, 20.30.40...Coil, 31.4
1...Core. Patent applicant: Konishiroku Photo Industry Co., Ltd. Representative Patent Attorney Ikiaki Nagao

Claims (2)

[Claims] (1) A coil is arranged so that magnetic lines of force pass through a laminated region of magnetic toner, and a change in inductance of the coil that changes in response to a change in the remaining amount of laminated toner is detected. A toner remaining amount detection device characterized in that the remaining amount detection output is obtained in three or more stages or continuously. (2) The remaining toner amount detecting device according to claim 1, wherein the coil is arranged in an oval shape having a longitudinal direction in a direction in which the remaining amount of laminated toner changes.