JPH0648409B2 - Powder developing device - Google Patents

Description

The present invention relates to a powder developing device in an image forming apparatus such as an electronic copying machine or an electrostatic recording device.

More specifically, the developer accommodating chamber, the developing sleeve disposed in the developer accommodating chamber, and the developer in the developer accommodating chamber are moved in a sweeping direction toward the developing sleeve with respect to each longitudinal portion of the sleeve. While stirring, a rotary stirring member, a developer amount detecting means for detecting a change in developer amount in the developer accommodating chamber (including a change in developer concentration), and developer amount information detected by the developer amount detecting means. And a developer replenishing section for replenishing the developer into the developer accommodating chamber according to the above.

[Prior Art] FIG. 3 shows a schematic configuration of a specific example of the powder developing apparatus A having the above configuration.

In the figure, 1 is a developer accommodating chamber, 2 is a developing sleeve which is provided laterally with the substantially right half peripheral surface portion thereof entering the chamber 1, and the substantially left half peripheral surface portion thereof is exposed to the outside, and 3 is the accommodating developer in the chamber 1. Four
Is a rotary stirring member that stirs the stored developer in the direction of the developing sleeve while sweeping and moving the developer against each longitudinal portion of the sleeve.

Reference numerals 5 and 6 are first and second parallel antenna wires (conductors) stretched in the chamber 1 as a means for detecting the amount of developer stored in the chamber 1. The first antenna wire 5 is an antenna wire of the reference sensor, is stretched in the vicinity of the developing sleeve 2 along the length of the sleeve in parallel with the sleeve, and is in the reservoir of the stored developer 3. The second antenna wire 6 is an antenna wire of the comparison sensor, and is stretched in parallel with the first antenna wire 5 while keeping a predetermined distance from the first antenna wire 5, and the second antenna wire 6 is located outside the reservoir of the stored developer 3. It is in.

7 is controlled in accordance with the developer amount information detected by the developer amount detecting means 5.9, and the developer (3) is stored in the developer storage chamber 1.
Developer replenishment section (replenishment developer hopper section) for replenishing
Is an auxiliary rotary stirring member for sweeping and moving the developer (3) replenished into the chamber 1 from the replenishing section 7 to the side of the rotary stirring member 4, and 9 is a developing formed on the peripheral surface of the developing sleeve 1. It is a layer thickness control blade for the agent layer.

Reference numeral 10 designates a rotary drum (electrophotographic photosensitive drum, electrostatic recording dielectric drum, etc.) as a member to be developed, which is rotationally driven, and a web-like or sheet-like material which is wound or conveyed in one direction. A latent image is formed on the peripheral surface by an image forming process device (not shown), and the latent image surface faces the external exposed surface of the developing sleeve 1 of the developing device A and passes. The external exposed surface of the developing sleeve 1 is the drum 1
They are facing each other with a certain small gap to 0.

Developing sleeve 2, rotary stirring member 4, auxiliary rotary stirring member 8
Are rotationally driven in the direction of the arrow at a predetermined rotational speed.

Thus, the developer 3 which is stirred while being swept toward the sleeve by the rotary stirring member 4 is applied to and adheres to each longitudinal portion of the substantially right half peripheral surface portion inside the chamber 1 of the rotary developing sleeve 2 ( Magnetically or electrostatically), and the developer layer adhered thereto passes through the position of the blade 9 by the rotation of the developing sleeve, so that the developer layer is layered 3a to a predetermined layer thickness and faces the rotary drum 10. The latent image on the drum surface wraps around to a and is sequentially developed.

The accommodated developer 3 in the developer accommodating chamber 1 is used for developing the latent image and is consumed and reduced with time. The decrease with time is measured by the antenna wires 5 and 6 as a developer amount detecting means and a sensor circuit (not shown), and when it is detected that the developer amount reaches a predetermined lower limit, the developer is detected. The replenishment section 7 is controlled to start replenishment of the developer (3) into the developer accommodating chamber 1 from the replenishment section. The developer (3) replenished in the chamber 1 is sent toward the rotary stirring member 4 by the auxiliary rotary stirring member 8.

When the amount of the developer in the chamber 1 reaches a predetermined allowable upper limit value by the developer replenishment, when the antenna wires 5 and 6 and the sensor circuit measure and detect, the developer (3 ) Supply is stopped. In this way, the amount of the developer 3 in the chamber 1 is substantially maintained and controlled within a predetermined allowable range amount.

In this example, the amount of the developer 3 in the chamber 1 is detected by detecting the amount of the developer 3 in the chamber 1 when the alternating voltage is applied to the developing sleeve 2 and the voltage induced in the first antenna line 5 and the second antenna line 6 is detected. By utilizing the fact that it changes according to
The sensor output is compared and the arithmetic circuit measures and detects the current developer amount in the chamber 1. There are various other means for detecting a change in the amount of developer or a change in the toner concentration in the case of a two-component developer, such as a change in light transmittance, a change in magnetic permeability, a change in inductance and the like.

[Problems to be solved by the invention]

By the way, as the rotary stirring member 4 which swirls the developer 3 in the chamber 1 toward the developing sleeve 2 and stirs it, a round bar member corresponds to the substantially entire length L of the developing sleeve 2 as shown in FIG. It is generally bent in a horizontally long crank shape. According to the rotary stirring member 4, the developer 3 in the chamber 1 along with the rotation of the member 4 forms a horizontally long straight line corresponding to substantially the entire length L of the developing sleeve 2 with respect to each part along the length of the developing sleeve 2. The stirring rod portion 4a sweeps and moves in the same cycle.

Then, as the member 4 rotates, the stirring rod portion 4a rotates to the position x shown by the solid line in FIG. 3 which approaches the developing sleeve 2 and continues to rotate upward as the member 4 rotates. Then, the upper surface 3b of the pool portion of the developer 3 is raised as shown by a chain double-dashed line 3c. Raise of the upper surface of the developer reservoir 3
Since the stirring rod portion 4a corresponds to the substantially entire length L of the developing sleeve 2, c is generated in the same cycle with respect to the longitudinal entire length region L of the developing sleeve 2.

In the process in which the stirring rod portion 4a goes out of the developer accumulating portion and separates from the second antenna wire 6 as shown by the two-dotted line position y as the member 4 continues to rotate, the upper surface of the developer accumulating portion is the above-mentioned. The ridge 3c collapses and returns to the state of the upper surface 3b indicated by the solid line. The return of the upper surface level occurs with the same period with respect to the entire longitudinal area of the developing sleeve 2.

Therefore, with the rotation of the rotary stirring member 4, the upper surface level of the stored developer reservoir in the chamber 1 changes periodically in a considerably large manner as shown by 3a3b in the longitudinal entire length region L of the developing sleeve 2. This periodic fluctuation of the upper surface level of the developer reservoir is detected by the developer amount detecting means as a fluctuation of the apparent amount of the developer stored in the chamber 1, and the developer amount in the chamber 1 can be accurately controlled. Adversely affect

The case of the developer amount detecting means 5 and 6 as in this example will be described. In particular, a phenomenon in which the voltage induced in the second antenna line 6 largely fluctuates periodically due to the change in the apparent amount of the developer occurs. .

FIG. 5 shows an actual developing device having a structure as shown in FIG. 3, in which the voltage after smoothing the voltage induced in the first and second antenna lines 5 and 6 is the developer in the chamber 1. It is the graph which investigated how it changed as it was gradually introduced from 0 g and increased. 5A is the first antenna wire 5
6A is a graph of the induced voltage fluctuation of the second antenna wire 6. The voltage fluctuations in both graphs 5A and 6A correspond to the above fluctuations 3a3b of the upper surface level of the stored developer pool in the chamber 1, that is, the apparent fluctuations of the developer amount, which periodically occur each time the rotary stirring member 4 rotates once. The fluctuations in the induced voltage for the second antenna line 6 are particularly larger than those for the first antenna line 5.

Then, when the above-mentioned induced voltage fluctuation becomes large, the output of the sensor (comparison sensor) of the second antenna wire 6 becomes equal to that of the sensor (reference sensor) of the first antenna wire 5 every one rotation cycle of the rotary stirring member 4. When the output is crossed, the developer is erroneously supplied into the chamber 1 from the developer replenishing section 7 each time, and the chamber 1 is erroneously supplied.
The developer may be clogged in the chamber 1 due to the excessive supply of the developer to the inside.

The output fluctuation that occurs every one rotation of the rotary stirring member 4 can be electrically removed by using a condenser. In this case, however, the output fluctuation cycle is usually several seconds to several tens seconds, which is quite long. As a result, a large capacity is required and there is a cost problem.

The present invention solves the problem of deterioration of the developer amount management accuracy in the developer accommodating chamber based on the periodic fluctuation of the apparent amount of the developer in the developer accommodating chamber due to the rotation of the rotary stirring member as described above. The purpose is to solve it by a simple method.

B. Configuration of the Invention [Means for Solving Problems] The present invention relates to a developer accommodating chamber, a developing sleeve disposed in the developer accommodating chamber, to which an AC voltage is applied, and the developer. A rotary stirring member that stirs the developer in the accommodating chamber in the developing sleeve direction while periodically moving it with respect to each part in the longitudinal direction of the sleeve, and an antenna stretched in the developer accommodating chamber along the longitudinal direction of the sleeve. A powder developing device having a member, and a developer amount detecting means for detecting a change in the developer amount in the developer containing chamber by a voltage induced in the antenna when an AC voltage is applied to the sleeve. In this case, the developer is so moved by the rotary stirring member that the periodic movement of the developer in the direction of the developing sleeve is performed at different phases of the rotary stirring member rotation cycle for each of a plurality of sections along the longitudinal direction of the developing sleeve. Rotating stirring member Configuration was, it is a powder developing apparatus according to claim.

[Work]

According to the present invention, the periodic movement of the developer in the developing sleeve direction by the rotary stirring member is performed at different phases of the rotary stirring member rotation cycle for each of a plurality of sections along the developing sleeve longitudinal direction. As a result, the periodic fluctuation of the apparent amount of developer caused by the rotation of the rotary stirring member is caused to be out of phase with each other in each of the plurality of divided areas along the developing sleeve longitudinal direction, that is, the antenna member longitudinal direction. Become. Therefore, the variation degree of the apparent developer amount in the longitudinal direction of the developing sleeve, that is, the entire area in the longitudinal direction of the antenna member is an average of the variations in the apparent developer amount generated by the phase shift for each of the plurality of sections. The antenna member will generate an induced voltage corresponding to its averaged apparent developer amount.

Therefore, the developer amount information output from the antenna member has no relation to the rotation of the rotary stirring member and has little fluctuation during the repeated rotation process of the stirring member, or is substantially independent of the rotation of the stirring member. Since there is no periodic fluctuation, accurate developer detection is possible.

〔Example〕

This Example 1 (FIG. 1), for rotating the stirring member 4 in the length crank type corresponding to substantially the entire length L of the developing sleeve 2, the longitudinal direction of the front half region L _A and the rear of the developing sleeve 2 is obtained by constituting the stirring rod portion 4A · 4B respectively corresponding to the side halves region L _B in a substantially 180 ° phase shift allowed form each other.

With the rotary stirring rod member 4 in this form, the apparent developer amount variation caused by the rotation of the member 4 causes the developing sleeve 2
Of a developer reservoir portion of the longitudinal front half region L _A, per revolution of the member 4 between each other between the developer reservoir section at the inner side half region L _B
Shift by 1/2 cycle.

That is, when the apparent developer amount in the one area L _A changes in a direction in which the apparent developer amount increases, the other area L _B changes in a direction in which the apparent developer amount decreases in the opposite direction. As a result the sensor output of the second antenna line 6 is assumed that the developer amount fluctuation in the apparent one region L _A and the other region L _B above is averaged over substantially the entire length range L of the developing sleeve 2. Therefore, the degree of fluctuation of the sensor output due to the rotation of the member 4 is reduced to half in principle as compared with the case of the conventional rotary stirring member of FIG.

Embodiment 2 (FIGS. 2 (a) and 2 (b)) Apparent developer amount fluctuations caused by rotation of the developer rotation stirring member, that is, fluctuations in the sensor output of the developer amount detecting means are caused by the stirring member. The sweeping movement of the developer toward the developing sleeve in one rotation process is performed at different phases of the rotation stirring member rotation cycle for a plurality of sections along the length of the developing sleeve so as to be as small as possible. Can be

In this example, the developing sleeve 2 is virtually divided into seven parts L _{A to} L _G along the length, and the developer rotary stirring member 4 is rotated at the rotation center line 4H.
With respect to the seven virtual segmented areas L _A
The ~L _G is obtained by the respectively corresponding seven substantially 50 to each other with a stir bar portion 4A~4G of DEG single phase shift allowed by were provided forms.

According to the developer rotary stirring member 4 of this embodiment,
In this case, the fluctuation of the sensor output from the developer amount detecting means becomes smaller.

In addition, since the small output fluctuations that are still generated have a short fluctuation cycle, it is easy to perform smoothing treatment by electrically passing a filter or the like, and the output fluctuations can be further reduced.

C. Effect of the Invention As described above, according to the present invention, the developer amount control accuracy in the developer accommodating chamber based on the periodic apparent fluctuation of the developer in the developer accommodating chamber due to the rotation of the developer rotation stirring member can be improved. The degradation problem is solved in a simple way and the intended purpose is often achieved.

[Brief description of drawings]

FIG. 1 is a perspective view showing the form of the developer rotary stirring member of the first embodiment, FIG. 2 (a) is a perspective view showing the form of the same member of the second embodiment, and FIG. FIG. 3 is a side view of the member, FIG. 3 is a cross-sectional view showing a schematic configuration of an example of a developing device, FIG. 4 is a plan view of a developer rotation stirring member of the device, and FIG. 5 is a first part of a developer amount detecting means. Sensor output fluctuation of the antenna wire of the
Graph of sensor output fluctuation of the antenna line. 1 is a developer storage chamber, 2 is a developing sleeve, 3 is a developer, 4
Is a rotary developer stirring member, 5 and 6 are first and second antenna wires as a developer amount detecting means, and 7 is a developer replenishing section.

Claims (1)

[Claims] 1. A developer accommodating chamber, a developing sleeve disposed in the developer accommodating chamber, to which an AC voltage is applied, and a developer in the developer accommodating chamber extending in the direction of the developing sleeve. A rotary stirring member that stirs while periodically moving with respect to each direction portion, and an antenna member stretched along the longitudinal direction of the sleeve in the developer accommodating chamber, and an AC voltage is applied to the sleeve. In the powder developing device, a developer amount detecting means for detecting a change in the amount of the developer in the developer containing chamber by a voltage induced in the antenna at the time of developing the developer by the rotary stirring member. The developer rotary stirring member is configured so that the periodical movement in the sleeve direction is performed at different phases of the rotary stirring member rotation cycle for each of a plurality of sections along the developing sleeve longitudinal direction. Development device