JPH02197880A - Developer detection device - Google Patents

Abstract

PURPOSE:To detect a developer quantity as an analog quantity by detecting electrostatic capacity between two parallel electrodes extending with the component of top and bottom directions. CONSTITUTION:A conductor member 21 which is used as the first electrode and a conductor member 22 which is used as the second electrode are provided mutually in parallel and vertically to the surface of developer. The voltage of a power source 43 for a developing sleeve 1 is impressed on the conductor member 22 and the other conductor member 21 is connected to a rectification circuit 41. The rectification circuit 41 is connected to a CPU 42 so that the output of the rectification circuit is A/D-converted and indicated. In such a way, the quantity of the developer is detected by two parallel electrodes 21 and 22 which are disposed almost in a vertical direction to a developing roller 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer remaining amount detection device for an image forming apparatus that visualizes an electrostatic latent image using a developer.

[Prior Art] Conventionally, as a means for detecting the amount of developer remaining in a developing device, an ultrasonic vibration element such as a piezo element, an inductance change detection element using a coil, etc. are used, and it is possible to detect the amount of developer remaining depending on the presence or absence of developer. There was one that took advantage of the fact that those signals changed. Furthermore, in recent years, a method of detecting the amount of developer by detecting the capacitance between electrodes has been put into practical use because of its high detection accuracy and low cost. The method using this electrode will be outlined below.

FIG. 10 is a schematic diagram showing a developer amount detection means using the above electrode. Power supply 63 applied to developing roller 61
A conductive wire member 62 as a toner amount detection means stretched parallel to the developing roller 61 by an AC bias from
A current flows in accordance with the impedance between the developing roller 61 and the conductive wire member 62, the current is rectified by a rectifier circuit 64, converted to a DC voltage 65, and the output is compared with a reference voltage l1i7 by a comparator 66. Occur.

Between the developing roller 61 and the conducting wire member 62, since there is a difference in dielectric constant and a difference in resistance between the toner (developer) and air, the impedance changes depending on the amount of toner in the developing device, and this change is utilized. This method detects toner acid. In the case of the above example, the developing roller 61 and the conducting wire member 62 serve as the electrodes.

Conventional developer amount means using a Vieso element etc. could only detect at one point in the developing device, or the method using the electrodes uses a conducting wire member stretched parallel to the developing roller. Detection can be performed in the entire axial direction, which improves accuracy.In recent years, process units around the latent image carrier, such as developing devices and cleaners, have been Disposable process cartridge type image forming apparatuses are widely used.

In this type of image forming apparatus, especially in the above-mentioned developer detection method, only the electrodes are provided in the developing unit and the detection circuit is provided in the main body, so the cost of the cartridge does not increase. Therefore, running costs can be greatly reduced.

[Problem to be solved by the invention] However, in any case, the conventional developer amount detection means described above can only detect the remaining amount at a certain fixed position, that is, the fixed position where the detection means is arranged. Can not.

Therefore, the above-mentioned detection means must be placed at a position where the developing agent is about to run out, and therefore, it is necessary to display an indication that there is no developer at such a time and prompt the operator to replenish the developer or replace the cartridge. Ta.

As a result, in the above-mentioned method, the operator is only able to tell when the amount of developer remaining is about to run out, resulting in the following inconvenience.

(2) Even if you suddenly realize that you have run out of developer, you will not be able to make copies or print outs because you will not have any spare developer to replenish or process cartridges to replace.

(Of course, when the printer is used as an output for a computer such as a laser beam printer, or when used for facsimile, there is often no one near the printer to replenish the developer or replace the cartridge, The agent has run out, and even if a white spot occurs, it will not be known, and the information will be lost.

The present invention solves the above-mentioned problems and, despite its simple configuration, constantly emits a signal corresponding to the remaining amount of developer, thereby predicting when to replenish the developer or replace the cartridge. The purpose of this invention is to provide a drug detection device.

[Means for Solving the Problems] According to the present invention, the above object is to form a latent image on a latent image carrier by an electrostatic latent image forming process means disposed around the latent image carrier.

In a developer detection device for an image forming apparatus in which a developer is attached to this latent image by a developing means to make it visible, a first detector located in a plane intersecting a horizontal plane and at an angle with the developing roller is used. An electrode and a second electrode arranged in parallel with the first electrode are arranged in the developing device, and the value of the electric signal is set based on the capacitance between the first and second electrodes. This is achieved by having a circuit that compares it with a reference value, and detecting the remaining amount of developer by that comparison.

[Function] According to the present invention as described in 1, since the two electrodes extend with a component in the vertical direction, it is possible to detect the level of the developer at any position. The amount of developer is detected as an analog amount, from when the amount is large to when it is about to run out, and the information is transmitted to the display or external device.

[Example] Hereinafter, the present invention will be described in detail based on FIGS. 1 to 9) of the accompanying drawings.

FIG. 1 is a simple diagram showing a first embodiment of the present invention, and FIG. 2 is a sectional view thereof.

In FIG. 1, l is a developing roller, 21 is a conductive wire member as a first electrode, and 22 is a conductive wire member as a second electrode, and the conductive wire members 21 and 22 are approximately parallel in a plane that intersects with a horizontal plane. and at an angle that is not parallel to the axis of the developing roller l. The two conductive wire members 21.
The interval between 22 and 22 is approximately 5 to 201 cm, which is appropriate, especially lO
The am position is good.

The conductive wire member 22 includes a power source 4 for the developing sleeve l.
3 voltage is applied, and the other conductor member 21 is connected to the rectifier circuit 41. The rectifier circuit 41 is (:
Connected to PU 42, output of rectifier circuit or A/D
It has been transformed and directed.

In this embodiment of the apparatus having such a configuration, first, when one image forming operation is started, the developing sleeve l and stirring rod 2 rotate in the direction of the arrow (see FIG. 2).Next, the developing roller l is connected to the AC power source 43 At the same time that the bias is applied, the same bias is also applied to the second electrode 22. Then, a current flows through the first electrode 21 stretched parallel to the second electrode 22 in accordance with the impedance between the first electrode 21 and the second electrode 22, and the current flows through the rectifier circuit 41. It is rectified by DC voltage and taken into the PU 42. c
In pu, the voltage is A/D converted and monitored.

The voltage detected at this time is different between the first electrode 21 and the second electrode 22 when there is toner or not, based on the difference in dielectric constant and the difference in resistance between the air and the developer. arise. Furthermore, since the inner electrodes 21 and 22 extend with vertical components, the detection voltage becomes an integral value of each portion when the developer is halfway through, as shown in FIG. Therefore, there is a difference in output voltage between when the developer is at position A above and when it is at position B below. In other words, as shown in FIG. 3, the output voltage varies depending on the amount of developer. By monitoring this voltage, the remaining amount is detected as an analog quantity.

As shown in Fig. 2, the amount of developer is controlled by two parallel electrodes 21 and 22 (spaced apart in the direction perpendicular to the plane of the paper) arranged substantially perpendicular to the developing roller l, that is, in the vertical direction. By detecting the amount of developer, it is possible to constantly detect the amount of developer from a state where there is a large amount of developer to a state where there is little remaining, and there is no need to use piezo elements etc. even in the case of cartridge type copiers and printers. Since the cost of cartridges hardly increases, running costs can also be reduced.

FIGS. 4 and 5 are diagrams showing a second embodiment of the present invention.

In the first embodiment described above, the two parallel electrodes were arranged almost vertically, but in this embodiment, as shown in FIGS. It is laid out at an angle. That is, in FIG. 4 when viewed from above, the developing roller 1 is substantially perpendicular to the developing roller l, or in FIG. 5 as a longitudinal section, it is disposed at an angle. By arranging the two parallel electrodes 23, 24 at an angle with respect to the vertical direction in this manner, the detection area is increased, and therefore the detection accuracy is improved.

In the third embodiment shown in FIG. 6, the two parallel electrodes 25, 26 are arranged at an angle to the horizontal plane and also to the vertical plane. Note that, as in the case of the second embodiment, the detection accuracy is improved by making an angle with respect to the vertical direction.

FIG. 7 shows a fourth embodiment of the invention.

4 in the figure is a stirring rod that rotates around point O, and the stirring rod 4
A wiping plate 41 made of a thin plate with high resistance, such as urethane rubber or PET, is attached to the tip of the wiping plate 41 .

Further, inside the container 40, there are curved electrodes 27 extending vertically,
28 are arranged at intervals perpendicular to the paper surface,
The amount of developer is detected by rotating the electrodes 27 and 28 as in the first embodiment.

In such a configuration, when the image forming operation is started, the driving means (
When the developing roller 1 (not shown) rotates in the direction of the arrow, the stirring rod 4 also rotates in the direction of the arrow to prevent the developer from shifting or agglomerating, and at the same time convey the developer to the developing roller.

Next, when the stirring bar 4 comes within the range of A to B, the wiping plate 41 wipes the electrodes 27, 28 to prevent the developer from agglomerating on the electrodes, and thus the detection accuracy decreases with use time. prevent

FIG. 8 shows a fifth embodiment of the present invention.

In the figure, 5 is a stirring rod, and both ends have bearing parts so and s.

It consists of a crank-shaped conductive member 5:l, 54 supported by a crank. As shown in FIG. 8, the conductive members 53 and 54 are mechanically connected by an insulating material 55 and electrically separated. Furthermore, the wiping plates 51 and 52 are also separated and attached to the conductive members 53 and 54, respectively. Here, at least one of the wiping plates 51 is a conductive member, and only the conductive member 53 to which the wiping plate 51 is attached is grounded.

With this configuration, the image forming operation and the developer amount detection operation are performed.Then, the stirring function of the stirring rod is the same as in the previous embodiment, but when it comes to the positions A to B, the bias side electrode 24 is Wiped by the wiping plate 54, the detection side electrode 23
is wiped by a grounded wiping plate 51. Then, as shown in FIG. 9, when the stirring bar is in the range A-8, the detected voltage becomes Ov. At this time, the CPU stops determining the amount of developer.

This prevents the developer from agglomerating on the electrode due to the wiping operation, and at the same time, even if the developer is temporarily disturbed while wiping the electrode, the amount of developer is not detected during that time. , the amount of developer can be detected with higher accuracy.

[Effects of the Invention] According to the present invention as described above, by detecting the electrostatic capacitance between two parallel electrodes extending with vertical components, it is possible to eliminate a large amount of developer at a low cost. It can be detected as an analog ψ until the moment the developer runs out, and the operator can always know the process until the developer runs out, and can take measures in advance. Therefore, the developer suddenly runs out, and there is no spare developer, making it impossible to print.

This has the effect that problems such as data sent during the night disappearing even with facsimile etc. do not occur.

Moreover, even in the case of a cartridge system, the cost of the cartridge is almost 1 or less, that is, the running cost does not increase.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the general configuration of the device according to the first embodiment of the present invention, FIG. 2 is a vertical sectional view of the device shown in FIG. 1, FIG. 3 is a diagram showing the output of the device shown in FIG. 1, and FIG. 5 is a vertical sectional view of the device of FIG. 4, FIG. 6 is a plan view of the device of the third embodiment, and FIG. 7 is a plan view of the device of the fourth embodiment. FIG. 8 is a plan view showing the general configuration of the device of the fifth embodiment; FIG. 9 is a diagram showing the output of the device shown in FIG. 8; FIG. 1O shows the general configuration of the conventional device. FIG. 21.22;2:1,24:25,26;27,28・
Old...Electrode 3...Developer 43...Power output voltage

Claims (1)

[Scope of Claims] A latent image is formed on a latent image carrier by an electrostatic latent image forming process means disposed around the latent image carrier, and a developer is applied to this latent image by a developing means to make it visible. In a developer detection device for an image forming apparatus, a first electrode is disposed in a plane intersecting a horizontal plane and at an angle to a developing roller, and a developer detection device is disposed parallel to the first electrode. and a second electrode arranged in the developing device, and a circuit that compares the value of the electric signal based on the capacitance between the first and second electrodes with a set reference value. A developer detection device that detects the remaining amount of developer.