JPH0480780A - Developer monitoring device - Google Patents

Abstract

PURPOSE:To reduce the number of parts in a developing part by providing a light shielding member for moving upward and downward with interlocking with a floating member moving upward and downward in accordance with the surface of the developer and which is arranged between a light emitting means and a light receiving means so that it can shield the light and judging the appropriate concentration of the developer and the appropriate quantity of the developer by the output signal of the light receiving means. CONSTITUTION:In the case that the developer fully remains, the light shielding member 5b which is arranged between the light emitting means 4a and the light receiving means 4b so that it can shield the light is moved upward while interlocking with the floating member 5a, so that the light beam emitted from the light emitting means 4a cannot be shielded. Then, the light beam emitted from the light emitting means 4a is made to decay in comparison with the concentration of the developer and then reaches the light receiving means 4b. Then, it is judged by judging parts 9 and 13 based on the output signal of the light receiving means 4b that the quantity of the developer is the full one, and then, it is judged whether or not the concentration of the developer is appropriate. And in the case that the developer is reduced and the liquid level descends, the floating member 5a descends in accordance with the liquid level, and then, the light shielding member 5b interlocking with the floating member 5a shields the light emitted from the light emitting means 4a, so that the light beam cannot be detected by the light receiving means 4b. Then, the lowering of the quantity of the developer can be judged by the judging parts 9 and 13 based on the output signal of the light receiving means 4b. Thus, the number of parts can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developer monitoring device for monitoring the concentration and amount of developer in a wet electrophotographic apparatus or the like.

[Prior Art] As shown in FIG. 5, a developing section in a wet electrophotographic apparatus or the like includes a developing tank 51, a developing electrode 53, and a developing pump 54.
Consisting of

The developer tank 51 stores liquid developer toner 52 therein, and its liquid level is below the top surface A of the development electrode 53 and above the back surface B of the development electrode 53.

The developing electrode 53 is arranged at the center of the developing tank 51.

The developer pump 54 is disposed within the developer tank 51 and pumps the developer toner 52 onto the upper surface A of the developer electrode 53. The developing toner 52 develops the object to be developed that passes over the developing electrode 53 .

The developer monitoring device includes a concentration detection section 59 and a liquid level detection section 60.

A density detection section 59 that detects the density of the developing toner 52 is arranged at the bottom of the developing tank 51.

Its structure consists of a light-emitting diode 57 and a photodiode 58 placed opposite to the light-emitting diode 57 at a predetermined distance, and a developing toner 5 is placed in the gap.
2 exists. The light emitted from the light emitting diode 57 is attenuated in proportion to the density of the developing toner 52 and reaches the photodiode 58 . That is, when the output signal of the photodiode 58 rises above the specified threshold level, the density of the developing toner 52 is determined to be below the specified density.

A liquid level detection section 60 that detects the amount of the developing toner 52 is composed of a microswitch 56 and a float 55, and is disposed above the developing tank 51. The float 55 connected to the microswitch 56 moves up and down according to the liquid level of the developing toner 52, and when the liquid level reaches the vicinity of the back surface B of the developing electrode 53, the microswitch 56 is turned on.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional device, the concentration detection section 59 that monitors the concentration of the developing toner 52 and the liquid level detection section 60 that monitors the liquid amount are required separately, and the number of parts is reduced. There is a problem in that this increases the cost of the developing section and also complicates the control system such as monitoring each sensor.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a developer monitoring device that can monitor developer concentration and developer amount and has a reduced number of component parts than before. shall be.

[Means for Solving the Problems] In order to achieve this object, the developer monitoring device of the present invention has the following features:
a light-emitting means installed in the developer; a light-receiving means placed opposite the light-emitting means; a floating member that moves up and down according to the level of the developer; a light shielding member arranged to be able to shield light between the means;
and a determination section that determines the appropriateness of the developer concentration and the amount of the developer from the output signal of the light receiving means.

[Function] In the developer monitoring device of the present invention configured as described above,
When there is enough developer, the floating member rises according to the liquid level, so the light shielding member also rises in conjunction with the floating member,
The light emitted from the light emitting means is not blocked. Therefore, the light emitted from the light emitting means is attenuated in proportion to the concentration of the developer before reaching the light receiving means. The determination section determines from the output signal of the light receiving means that there is a sufficient amount of developer, and then determines whether the concentration of the developer is appropriate. Further, when the amount of developer decreases and the level of the developer drops, the floating member descends according to the level of the developer. Since the light shielding member interlocked with the floating member blocks the light beam emitted from the light emitting means, the light receiving means cannot detect the light beam. Therefore, the determining section determines whether the amount of the developer has decreased from the output signal of the light receiving means.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing the structure of a developing section of a wet type electrophotographic apparatus using the present invention, and FIG. 2 is a block diagram showing its electrical structure.

The main structure of the developing section is arranged below the photosensitive drum 30 of the wet electrophotographic apparatus. Its structure includes a developing tank 1, a developing electrode 2, a developing pump 3, a concentration detecting section 4, a liquid level detecting section 5, an agitation pump 6, and a liquid replenishing section 7.

The developer tank 1 stores liquid developer toner 8 therein, and its liquid level is below the top surface A of the development electrode 2 and above the back surface B of the development electrode 2.

The developing electrode 2 is installed in the middle of the developing tank 1 so that its upper surface A, which is curved along the photosensitive drum 30, has a slight gap from the photosensitive drum 30.

The developer pump 3 is disposed in the developer tank, and supplies the developer toner 8.
The charged developing toner 8 fills the small gap between the developing electrode 2 and the photosensitive drum 30 described above. The developing toner 8 on the developing electrode 2 develops the electrostatic latent image formed on the photosensitive drum 30 into a visible image.

The concentration detection section 4 is arranged at the bottom of the developing tank 1 and is composed of a light emitting diode 4a and a photodiode 4b. Both are arranged opposite to each other, and developing toner 8 exists in the gap between them. The light emitting diode 4a constitutes a light emitting means, and the photodiode 4b constitutes a light receiving means.

The liquid level detection section 5 is arranged above the concentration detection section 4. Its structure consists of a float 5a, a shutter 5b attached to the lower surface of the float 5a, and a guide 5c supporting the shutter 5b attached to the inner wall surface of the developing tank 1. The float 5a moves up and down according to the liquid level of the developing toner 8, and when the liquid level reaches near the back surface B of the developing electrode 2, the float 5a and the shutter 5 supported by the guide 5c
b is lowered so that its lower part is located within the gap between the light emitting diode 4a and the photodiode 4b. This shutter 5b constitutes a light shielding member.

The stirring pump 6 is connected to the developing tank 1 adjacent to the concentration detecting section 4.
It is installed at the bottom of the tank 1 and stirs the developer toner 8 in the tank 1 to make its concentration uniform.

The liquid replenishing section 7 is located at the upper part of the developing tank 1, and is a first liquid replenishing section for replenishing concentrated toner stored in a replenishing tank (not shown).
It consists of a nozzle 7a and a second nozzle 7b for replenishing the thinning liquid. The first nozzle 11a of the first nozzle 7a and the second nozzle llb of the second nozzle 7b are controlled by the control section 9.

As shown in FIG. 2, on the output side of the I10 port 10, which is a data input/output unit connected to the bus of the control unit 9, there are actuators, namely a developer pump 3 and an agitation pump 6.
, the first sensor lla and the second sensor llb, and the photodiode 4b of the concentration detection section 4 is connected to the input side via the A/D converter 12. The bus of the control unit 9 includes a first bus for determining the output of the photodiode 4b.
A storage device 13 that stores the specified value and the second specified value is connected. The first specified value is the highest limit value of the appropriate density of the developing toner 8, and the second specified value is the lowest limit value. This storage device 1
3 and the control section 9 constitute a judgment section.

The operation of the developing section of the wet type electrophotographic apparatus configured as described above will be explained with reference to the flowchart of developer management processing shown in FIG. In addition, the symbol Si (i=1.2,
...) indicates each step.

The control section 9 normally controls the wet type electrophotographic apparatus. When an interrupt signal is input at regular intervals by a timer means (not shown), the control section 9 executes developer management processing. In this process, the control unit 9 first determines whether there is an output from the photodiode 4b from the I10 port 10 via the A/D converter 12 (Sl). If there is no output from the photodiode 4b (Sl: No), it is determined that the liquid amount of the developing toner 8 has fallen below the specified value. That is, the shutter 5b of the liquid level detection section 5 is
) has reached the inside of the concentration detection section 4. Therefore, the light beam emitted from the light emitting diode 4a is completely blocked, the photodiode 4b is turned off, and there is no output signal. Therefore, the control unit 9 performs a replenishment operation and operates the stirring pump 6 to perform stirring (S2). That is, the control unit 9 opens the first nozzle 7a of the first nozzle 7a and the second nozzle 7b of the second nozzle 7b, and replenishes the concentrated toner and the thinning liquid in a predetermined ratio. The control unit 9 again determines whether or not there is an output from the photodiode 4b.
l) If there is no output, repeat the above operation (S2).

As a result, the liquid level of the developing toner 8 rises, and the shutter 5b moves away from the density detection section 4 as shown in FIG. 3(b).

If there is an output from photodiode 4b (Sl: YES
), it is determined that the liquid amount of the developing toner 8 is the specified amount. That is, the shutter 5b of the liquid level detection section 5 does not block the light beam emitted from the light emitting diode 4a of the concentration detection section 4, as shown in FIG. 3(b). Therefore, the light emitted from the light emitting diode 4a is attenuated in proportion to the density of the developing toner 8, and reaches the photodiode 4b.

The control unit 9 controls the output value of the photodiode 4b to be
It is determined whether the value is below the specified value (S3). Photodiode 4
If the output value of b is not less than the first specified value (S3: No)
, it is determined that the density of the developing toner 8 is equal to or higher than the normal density. The control unit 9 opens the second tank Ilb to supply a certain amount of the thinning liquid into the developing tank 1, and operates the stirring pump 6 to make the concentration in the tank 1 uniform (S4). The control unit 9 again determines whether the output value of the photodiode 4b is below the first specified value (S3), and if it is not below the specified value, repeats the above-mentioned operation (S4).

If the output value of the photodiode 4b is less than or equal to the first specified value (S3: YES), the control unit 9 determines whether it is greater than or equal to the second specified value (S5). If the output value of the photodiode 4b is not higher than the second specified value (S5: NO), the developing toner 8
It is determined that the concentration of is below the normal concentration. Control unit 9
The first tank 11a is opened to supply a certain amount of concentrated toner into the developing tank 1, and the stirring pump 6 is operated to make the concentration in the tank 1 uniform (S6). The control unit 9 again determines whether the output value of the photodiode 4b is equal to or greater than the second specified value (S5), and if it is not equal to or greater than the specified value, repeats the above-mentioned operation (S6).

In this way, the concentration of the developing toner 8 and the liquid amount can be detected simultaneously by simply monitoring the output of the photodiode 4b of the concentration detection section.

Therefore, liquid concentration detection and liquid volume detection can be realized with the same sensor, and the number of parts in the developing section can be reduced.

[Effects of the Invention] As is clear from the detailed description above, the developer monitoring device of the present invention includes a light emitting means installed in the developer, a light receiving means disposed opposite to the light emitting means, and a developer monitoring device. a floating member that moves up and down according to the liquid level; and a floating member that moves up and down in conjunction with the floating member;
It is comprised of a light shielding member disposed between the light emitting means and the light receiving means so as to be able to shield light, and a determining section that determines the appropriateness of the developer concentration and liquid amount from the output signal of the light receiving means.

Therefore, liquid concentration detection and liquid amount detection can be realized with the same sensor, and the number of parts in the developing section can be reduced.

[Brief explanation of the drawing]

1 to 4 show an embodiment embodying the present invention, FIG. 1 is a sectional view showing the configuration of a developing section of a wet type electrophotographic apparatus, FIG. 2 is a block diagram showing the electrical configuration, Figure 3 (a
) and (b) are explanatory diagrams showing the operation of this embodiment, and FIG. 4 is a flowchart of the developer management process. FIG. 5 is a sectional view showing the structure of a developing section of a conventional wet type electrophotographic apparatus. In the figure, 4a is a light emitting diode (light emitting means), 4b is a photodiode (light receiving means), 5a is a float (floating member),
5b is a shutter (light shielding member), 9 is a control section, and 13 is a storage device (the control section and the storage device constitute the determination section).

Claims (1)

[Scope of Claims] 1. A developer monitoring device for monitoring the concentration and amount of a developer, comprising: a light emitting means installed in the developer; a light receiving means disposed opposite to the light emitting means; a floating member that moves up and down according to the liquid level; a light-shielding member that moves up and down in conjunction with the floating member and is arranged to block light between the light-emitting means and the light-receiving means; and determining the concentration of the developer and the liquid from the output signal of the light-receiving means. A developer monitoring device characterized by comprising a judgment section that judges whether the amount is appropriate.